[MIPI,CABC,2/2] drm/i915: CABC support for backlight control

Submitted by Deepak M on March 22, 2016, 5:41 a.m.

Details

Message ID 1458625270-29433-3-git-send-email-m.deepak@intel.com
State New
Headers show
Series "CABC patch list" ( rev: 4 ) in Intel GFX

Not browsing as part of any series.

Commit Message

Deepak M March 22, 2016, 5:41 a.m.
In CABC (Content Adaptive Brightness Control) content grey level
scale can be increased while simultaneously decreasing
brightness of the backlight to achieve same perceived brightness.

The CABC is not standardized and panel vendors are free to follow
their implementation. The CABC implementaion here assumes that the
panels use standard SW register for control.

In this design there will be no PWM signal from the SoC and DCS
commands are sent to enable and control the backlight brightness.

v2: Moving the CABC bkl functions to new file.(Jani)

v3: Rebase

v4: Rebase

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Yetunde Adebisi <yetundex.adebisi@intel.com>
Signed-off-by: Deepak M <m.deepak@intel.com>
---
 drivers/gpu/drm/i915/Makefile         |   1 +
 drivers/gpu/drm/i915/i915_drv.h       |   2 +-
 drivers/gpu/drm/i915/intel_dsi.c      |  19 +++-
 drivers/gpu/drm/i915/intel_dsi.h      |   4 +
 drivers/gpu/drm/i915/intel_dsi_cabc.c | 179 ++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_panel.c    |   4 +
 6 files changed, 206 insertions(+), 3 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/intel_dsi_cabc.c

Patch hide | download patch | download mbox

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 7ffb51b..065c410 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -83,6 +83,7 @@  i915-y += dvo_ch7017.o \
 	  intel_dp_mst.o \
 	  intel_dp.o \
 	  intel_dsi.o \
+	  intel_dsi_cabc.o \
 	  intel_dsi_panel_vbt.o \
 	  intel_dsi_pll.o \
 	  intel_dvo.o \
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 050d860..d196404 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3489,7 +3489,7 @@  void intel_sbi_write(struct drm_i915_private *dev_priv, u16 reg, u32 value,
 		     enum intel_sbi_destination destination);
 u32 vlv_flisdsi_read(struct drm_i915_private *dev_priv, u32 reg);
 void vlv_flisdsi_write(struct drm_i915_private *dev_priv, u32 reg, u32 val);
-
+int intel_dsi_cabc_init_backlight_funcs(struct intel_connector *intel_connector);
 int intel_gpu_freq(struct drm_i915_private *dev_priv, int val);
 int intel_freq_opcode(struct drm_i915_private *dev_priv, int val);
 
diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index 456676c..7aa707f 100644
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -1209,10 +1209,25 @@  void intel_dsi_init(struct drm_device *dev)
 	else
 		intel_encoder->crtc_mask = BIT(PIPE_B);
 
-	if (dev_priv->vbt.dsi.config->dual_link)
+	if (dev_priv->vbt.dsi.config->dual_link) {
 		intel_dsi->ports = BIT(PORT_A) | BIT(PORT_C);
-	else
+		switch (dev_priv->vbt.dsi.config->dl_cabc_port) {
+		case CABC_PORT_A:
+			intel_dsi->bkl_dcs_ports = BIT(PORT_A);
+			break;
+		case CABC_PORT_C:
+			intel_dsi->bkl_dcs_ports = BIT(PORT_C);
+			break;
+		case CABC_PORT_A_AND_C:
+			intel_dsi->bkl_dcs_ports = BIT(PORT_A) | BIT(PORT_C);
+			break;
+		default:
+			DRM_ERROR("Unknown MIPI ports for sending DCS\n");
+		}
+	} else {
 		intel_dsi->ports = BIT(port);
+		intel_dsi->bkl_dcs_ports = BIT(port);
+	}
 
 	/* Create a DSI host (and a device) for each port. */
 	for_each_dsi_port(port, intel_dsi->ports) {
diff --git a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
index 0e758f1..5c07d59 100644
--- a/drivers/gpu/drm/i915/intel_dsi.h
+++ b/drivers/gpu/drm/i915/intel_dsi.h
@@ -34,6 +34,10 @@ 
 #define DSI_DUAL_LINK_FRONT_BACK	1
 #define DSI_DUAL_LINK_PIXEL_ALT		2
 
+#define CABC_PORT_A                     0x00
+#define CABC_PORT_C                     0x01
+#define CABC_PORT_A_AND_C               0x02
+
 struct intel_dsi_host;
 
 struct intel_dsi {
diff --git a/drivers/gpu/drm/i915/intel_dsi_cabc.c b/drivers/gpu/drm/i915/intel_dsi_cabc.c
new file mode 100644
index 0000000..d14a669
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_dsi_cabc.c
@@ -0,0 +1,179 @@ 
+/*
+ * Copyright © 2006-2010 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Author: Deepak M <m.deepak at intel.com>
+ */
+
+#include "intel_drv.h"
+#include "intel_dsi.h"
+#include "i915_drv.h"
+#include <drm/drm_mipi_dsi.h>
+
+#define CABC_OFF                        (0 << 0)
+#define CABC_USER_INTERFACE_IMAGE       (1 << 0)
+#define CABC_STILL_PICTURE              (2 << 0)
+#define CABC_VIDEO_MODE                 (3 << 0)
+
+#define CABC_BACKLIGHT                  (1 << 2)
+#define CABC_DIMMING_DISPLAY            (1 << 3)
+#define CABC_BCTRL                      (1 << 5)
+
+#define CABC_MAX_VALUE                  0xFF
+
+#define MIPI_DCS_CABC_LEVEL_RD          0x52
+#define MIPI_DCS_CABC_MIN_BRIGHTNESS_RD 0x5F
+#define MIPI_DCS_CABC_CONTROL_RD        0x56
+#define MIPI_DCS_CABC_CONTROL_BRIGHT_RD 0x54
+#define MIPI_DCS_CABC_LEVEL_WR          0x51
+#define MIPI_DCS_CABC_MIN_BRIGHTNESS_WR 0x5E
+#define MIPI_DCS_CABC_CONTROL_WR        0x55
+#define MIPI_DCS_CABC_CONTROL_BRIGHT_WR 0x53
+
+static u32 cabc_get_backlight(struct intel_connector *connector)
+{
+	struct intel_dsi *intel_dsi = NULL;
+	struct intel_encoder *encoder = NULL;
+	struct mipi_dsi_device *dsi_device;
+	u8 data[2] = {0};
+	enum port port;
+
+	encoder = connector->encoder;
+	intel_dsi = enc_to_intel_dsi(&encoder->base);
+
+	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
+		dsi_device = intel_dsi->dsi_hosts[port]->device;
+		mipi_dsi_dcs_read(dsi_device, MIPI_DCS_CABC_LEVEL_RD, data, 2);
+	}
+
+	return data[1];
+}
+
+static void cabc_set_backlight(struct intel_connector *connector, u32 level)
+{
+	struct intel_dsi *intel_dsi = NULL;
+	struct intel_encoder *encoder = NULL;
+	struct mipi_dsi_device *dsi_device;
+	u8 data[2] = {0};
+	enum port port;
+
+	encoder = connector->encoder;
+	intel_dsi = enc_to_intel_dsi(&encoder->base);
+
+	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
+		dsi_device = intel_dsi->dsi_hosts[port]->device;
+		data[1] = level;
+		data[0] = MIPI_DCS_CABC_LEVEL_WR;
+		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
+	}
+}
+
+static void cabc_disable_backlight(struct intel_connector *connector)
+{
+	struct intel_dsi *intel_dsi = NULL;
+	struct intel_encoder *encoder = NULL;
+	struct mipi_dsi_device *dsi_device;
+	enum port port;
+	u8 data[2] = {0};
+
+	encoder = connector->encoder;
+	intel_dsi = enc_to_intel_dsi(&encoder->base);
+
+	cabc_set_backlight(connector, 0);
+
+	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
+		dsi_device = intel_dsi->dsi_hosts[port]->device;
+		data[1] = CABC_OFF;
+		data[0] = MIPI_DCS_CABC_CONTROL_WR;
+		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
+		data[0] = MIPI_DCS_CABC_CONTROL_BRIGHT_WR;
+		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
+	}
+}
+
+static void cabc_enable_backlight(struct intel_connector *connector)
+{
+	struct intel_dsi *intel_dsi = NULL;
+	struct intel_encoder *encoder = NULL;
+	struct intel_panel *panel = &connector->panel;
+	struct mipi_dsi_device *dsi_device;
+	enum port port;
+	u8 data[2] = {0};
+
+	encoder = connector->encoder;
+	intel_dsi = enc_to_intel_dsi(&encoder->base);
+
+	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
+		dsi_device = intel_dsi->dsi_hosts[port]->device;
+		data[0] = MIPI_DCS_CABC_CONTROL_BRIGHT_WR;
+		data[1] = CABC_BACKLIGHT | CABC_DIMMING_DISPLAY | CABC_BCTRL;
+		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
+		data[0] = MIPI_DCS_CABC_CONTROL_WR;
+		data[1] = CABC_STILL_PICTURE;
+		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
+	}
+
+	cabc_set_backlight(connector, panel->backlight.level);
+}
+
+static int cabc_setup_backlight(struct intel_connector *connector,
+		enum pipe unused)
+{
+	struct drm_device *dev = connector->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_panel *panel = &connector->panel;
+
+	if (dev_priv->vbt.backlight.present)
+		panel->backlight.present = true;
+	else {
+		DRM_ERROR("no backlight present per VBT\n");
+		return 0;
+	}
+
+	panel->backlight.max = CABC_MAX_VALUE;
+	panel->backlight.level = CABC_MAX_VALUE;
+
+	return 0;
+}
+
+int intel_dsi_cabc_init_backlight_funcs(struct intel_connector *intel_connector)
+{
+	struct drm_device *dev = intel_connector->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_encoder *encoder = intel_connector->encoder;
+	struct intel_panel *panel = &intel_connector->panel;
+
+	if (!dev_priv->vbt.dsi.config->cabc_supported)
+		return -EINVAL;
+
+	if (encoder->type != INTEL_OUTPUT_DSI) {
+		DRM_ERROR("Use DSI encoder for CABC\n");
+		return -EINVAL;
+	}
+
+	panel->backlight.setup = cabc_setup_backlight;
+	panel->backlight.enable = cabc_enable_backlight;
+	panel->backlight.disable = cabc_disable_backlight;
+	panel->backlight.set = cabc_set_backlight;
+	panel->backlight.get = cabc_get_backlight;
+
+	return 0;
+}
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 8c8996f..0f9bf80 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -1718,6 +1718,10 @@  intel_panel_init_backlight_funcs(struct intel_panel *panel)
 		container_of(panel, struct intel_connector, panel);
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
 
+	if (connector->base.connector_type == DRM_MODE_CONNECTOR_DSI &&
+			intel_dsi_cabc_init_backlight_funcs(connector) == 0)
+		return;
+
 	if (IS_BROXTON(dev_priv)) {
 		panel->backlight.setup = bxt_setup_backlight;
 		panel->backlight.enable = bxt_enable_backlight;

Comments

On Tue, 22 Mar 2016, Deepak M <m.deepak@intel.com> wrote:
> In CABC (Content Adaptive Brightness Control) content grey level
> scale can be increased while simultaneously decreasing
> brightness of the backlight to achieve same perceived brightness.
>
> The CABC is not standardized and panel vendors are free to follow
> their implementation. The CABC implementaion here assumes that the
> panels use standard SW register for control.
>
> In this design there will be no PWM signal from the SoC and DCS
> commands are sent to enable and control the backlight brightness.
>
> v2: Moving the CABC bkl functions to new file.(Jani)
>
> v3: Rebase
>
> v4: Rebase
>
> Cc: Jani Nikula <jani.nikula@intel.com>
> Cc: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Yetunde Adebisi <yetundex.adebisi@intel.com>
> Signed-off-by: Deepak M <m.deepak@intel.com>
> ---
>  drivers/gpu/drm/i915/Makefile         |   1 +
>  drivers/gpu/drm/i915/i915_drv.h       |   2 +-
>  drivers/gpu/drm/i915/intel_dsi.c      |  19 +++-
>  drivers/gpu/drm/i915/intel_dsi.h      |   4 +
>  drivers/gpu/drm/i915/intel_dsi_cabc.c | 179 ++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_panel.c    |   4 +
>  6 files changed, 206 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/gpu/drm/i915/intel_dsi_cabc.c
>
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 7ffb51b..065c410 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -83,6 +83,7 @@ i915-y += dvo_ch7017.o \
>  	  intel_dp_mst.o \
>  	  intel_dp.o \
>  	  intel_dsi.o \
> +	  intel_dsi_cabc.o \
>  	  intel_dsi_panel_vbt.o \
>  	  intel_dsi_pll.o \
>  	  intel_dvo.o \
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 050d860..d196404 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -3489,7 +3489,7 @@ void intel_sbi_write(struct drm_i915_private *dev_priv, u16 reg, u32 value,
>  		     enum intel_sbi_destination destination);
>  u32 vlv_flisdsi_read(struct drm_i915_private *dev_priv, u32 reg);
>  void vlv_flisdsi_write(struct drm_i915_private *dev_priv, u32 reg, u32 val);
> -
> +int intel_dsi_cabc_init_backlight_funcs(struct intel_connector *intel_connector);

This probably fits better in intel_drv.h under a /* intel_dsi_cabc.c */
comment, see the file for examples.

>  int intel_gpu_freq(struct drm_i915_private *dev_priv, int val);
>  int intel_freq_opcode(struct drm_i915_private *dev_priv, int val);
>  
> diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
> index 456676c..7aa707f 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.c
> +++ b/drivers/gpu/drm/i915/intel_dsi.c
> @@ -1209,10 +1209,25 @@ void intel_dsi_init(struct drm_device *dev)
>  	else
>  		intel_encoder->crtc_mask = BIT(PIPE_B);
>  
> -	if (dev_priv->vbt.dsi.config->dual_link)
> +	if (dev_priv->vbt.dsi.config->dual_link) {
>  		intel_dsi->ports = BIT(PORT_A) | BIT(PORT_C);
> -	else
> +		switch (dev_priv->vbt.dsi.config->dl_cabc_port) {
> +		case CABC_PORT_A:
> +			intel_dsi->bkl_dcs_ports = BIT(PORT_A);
> +			break;
> +		case CABC_PORT_C:
> +			intel_dsi->bkl_dcs_ports = BIT(PORT_C);
> +			break;
> +		case CABC_PORT_A_AND_C:
> +			intel_dsi->bkl_dcs_ports = BIT(PORT_A) | BIT(PORT_C);
> +			break;
> +		default:
> +			DRM_ERROR("Unknown MIPI ports for sending DCS\n");
> +		}
> +	} else {
>  		intel_dsi->ports = BIT(port);
> +		intel_dsi->bkl_dcs_ports = BIT(port);
> +	}
>  
>  	/* Create a DSI host (and a device) for each port. */
>  	for_each_dsi_port(port, intel_dsi->ports) {
> diff --git a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
> index 0e758f1..5c07d59 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.h
> +++ b/drivers/gpu/drm/i915/intel_dsi.h
> @@ -34,6 +34,10 @@
>  #define DSI_DUAL_LINK_FRONT_BACK	1
>  #define DSI_DUAL_LINK_PIXEL_ALT		2
>  
> +#define CABC_PORT_A                     0x00
> +#define CABC_PORT_C                     0x01
> +#define CABC_PORT_A_AND_C               0x02
> +
>  struct intel_dsi_host;
>  
>  struct intel_dsi {
> diff --git a/drivers/gpu/drm/i915/intel_dsi_cabc.c b/drivers/gpu/drm/i915/intel_dsi_cabc.c
> new file mode 100644
> index 0000000..d14a669
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/intel_dsi_cabc.c
> @@ -0,0 +1,179 @@
> +/*
> + * Copyright © 2006-2010 Intel Corporation

2016

> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> + * DEALINGS IN THE SOFTWARE.
> + *
> + * Author: Deepak M <m.deepak at intel.com>
> + */
> +
> +#include "intel_drv.h"
> +#include "intel_dsi.h"
> +#include "i915_drv.h"
> +#include <drm/drm_mipi_dsi.h>
> +
> +#define CABC_OFF                        (0 << 0)
> +#define CABC_USER_INTERFACE_IMAGE       (1 << 0)
> +#define CABC_STILL_PICTURE              (2 << 0)
> +#define CABC_VIDEO_MODE                 (3 << 0)
> +
> +#define CABC_BACKLIGHT                  (1 << 2)
> +#define CABC_DIMMING_DISPLAY            (1 << 3)
> +#define CABC_BCTRL                      (1 << 5)
> +
> +#define CABC_MAX_VALUE                  0xFF
> +

The defines below should be added to the relevant enum in
include/video/mipi_display.h using the MIPI DCS specification
names. I'll copy them below. Please create a separate prep patch and
send it to dri-devel.

> +#define MIPI_DCS_CABC_LEVEL_RD          0x52

MIPI_DCS_GET_DISPLAY_BRIGHTNESS

> +#define MIPI_DCS_CABC_MIN_BRIGHTNESS_RD 0x5F

MIPI_DCS_GET_CABC_MIN_BRIGHTNESS

> +#define MIPI_DCS_CABC_CONTROL_RD        0x56

MIPI_DCS_GET_POWER_SAVE

> +#define MIPI_DCS_CABC_CONTROL_BRIGHT_RD 0x54

MIPI_DCS_GET_CONTROL_DISPLAY

> +#define MIPI_DCS_CABC_LEVEL_WR          0x51

MIPI_DCS_SET_DISPLAY_BRIGHTNESS

> +#define MIPI_DCS_CABC_MIN_BRIGHTNESS_WR 0x5E

MIPI_DCS_SET_CABC_MIN_BRIGHTNESS

> +#define MIPI_DCS_CABC_CONTROL_WR        0x55

MIPI_DCS_WRITE_POWER_SAVE

> +#define MIPI_DCS_CABC_CONTROL_BRIGHT_WR 0x53

MIPI_DCS_WRITE_CONTROL_DISPLAY

> +
> +static u32 cabc_get_backlight(struct intel_connector *connector)
> +{
	struct intel_encoder *encoder = connector->encoder;
	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);

Same for all functions below.

> +	struct intel_dsi *intel_dsi = NULL;
> +	struct intel_encoder *encoder = NULL;
> +	struct mipi_dsi_device *dsi_device;
> +	u8 data[2] = {0};
> +	enum port port;
> +
> +	encoder = connector->encoder;
> +	intel_dsi = enc_to_intel_dsi(&encoder->base);
> +
> +	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
> +		dsi_device = intel_dsi->dsi_hosts[port]->device;
> +		mipi_dsi_dcs_read(dsi_device, MIPI_DCS_CABC_LEVEL_RD, data, 2);
> +	}
> +
> +	return data[1];

Hmm, it's up to the manufacturer whether the this is 8 or 16 bits. I
guess you're just assuming 8 bits? I wonder if this should be more
generic wrt 8 vs. 16 bits.

> +}
> +
> +static void cabc_set_backlight(struct intel_connector *connector, u32 level)
> +{
> +	struct intel_dsi *intel_dsi = NULL;
> +	struct intel_encoder *encoder = NULL;
> +	struct mipi_dsi_device *dsi_device;
> +	u8 data[2] = {0};
> +	enum port port;
> +
> +	encoder = connector->encoder;
> +	intel_dsi = enc_to_intel_dsi(&encoder->base);
> +
> +	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
> +		dsi_device = intel_dsi->dsi_hosts[port]->device;
> +		data[1] = level;
> +		data[0] = MIPI_DCS_CABC_LEVEL_WR;
> +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);

Please use mipi_dsi_dcs_write(). Same for all functions below.

> +	}
> +}
> +
> +static void cabc_disable_backlight(struct intel_connector *connector)
> +{
> +	struct intel_dsi *intel_dsi = NULL;
> +	struct intel_encoder *encoder = NULL;
> +	struct mipi_dsi_device *dsi_device;
> +	enum port port;
> +	u8 data[2] = {0};
> +
> +	encoder = connector->encoder;
> +	intel_dsi = enc_to_intel_dsi(&encoder->base);
> +
> +	cabc_set_backlight(connector, 0);
> +
> +	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
> +		dsi_device = intel_dsi->dsi_hosts[port]->device;
> +		data[1] = CABC_OFF;
> +		data[0] = MIPI_DCS_CABC_CONTROL_WR;
> +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
> +		data[0] = MIPI_DCS_CABC_CONTROL_BRIGHT_WR;
> +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
> +	}
> +}
> +
> +static void cabc_enable_backlight(struct intel_connector *connector)
> +{
> +	struct intel_dsi *intel_dsi = NULL;
> +	struct intel_encoder *encoder = NULL;
> +	struct intel_panel *panel = &connector->panel;
> +	struct mipi_dsi_device *dsi_device;
> +	enum port port;
> +	u8 data[2] = {0};
> +
> +	encoder = connector->encoder;
> +	intel_dsi = enc_to_intel_dsi(&encoder->base);
> +
> +	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
> +		dsi_device = intel_dsi->dsi_hosts[port]->device;
> +		data[0] = MIPI_DCS_CABC_CONTROL_BRIGHT_WR;
> +		data[1] = CABC_BACKLIGHT | CABC_DIMMING_DISPLAY | CABC_BCTRL;
> +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
> +		data[0] = MIPI_DCS_CABC_CONTROL_WR;
> +		data[1] = CABC_STILL_PICTURE;
> +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
> +	}
> +
> +	cabc_set_backlight(connector, panel->backlight.level);
> +}
> +
> +static int cabc_setup_backlight(struct intel_connector *connector,
> +		enum pipe unused)
> +{
> +	struct drm_device *dev = connector->base.dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct intel_panel *panel = &connector->panel;
> +
> +	if (dev_priv->vbt.backlight.present)
> +		panel->backlight.present = true;
> +	else {
> +		DRM_ERROR("no backlight present per VBT\n");
> +		return 0;
> +	}

None of the above is needed.

dev_priv->vbt.backlight.present is checked higher level in
intel_panel_setup_backlight(), and panel->backlight.present = true is
set there as well if this hook returns 0.

> +
> +	panel->backlight.max = CABC_MAX_VALUE;
> +	panel->backlight.level = CABC_MAX_VALUE;
> +
> +	return 0;
> +}
> +
> +int intel_dsi_cabc_init_backlight_funcs(struct intel_connector *intel_connector)
> +{
> +	struct drm_device *dev = intel_connector->base.dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct intel_encoder *encoder = intel_connector->encoder;
> +	struct intel_panel *panel = &intel_connector->panel;
> +
> +	if (!dev_priv->vbt.dsi.config->cabc_supported)
> +		return -EINVAL;

-ENODEV seems more appropriate.

> +
> +	if (encoder->type != INTEL_OUTPUT_DSI) {
> +		DRM_ERROR("Use DSI encoder for CABC\n");
> +		return -EINVAL;
> +	}

	if (WARN_ON(encoder->type != INTEL_OUTPUT_DSI))
		return -EINVAL;

> +
> +	panel->backlight.setup = cabc_setup_backlight;
> +	panel->backlight.enable = cabc_enable_backlight;
> +	panel->backlight.disable = cabc_disable_backlight;
> +	panel->backlight.set = cabc_set_backlight;
> +	panel->backlight.get = cabc_get_backlight;
> +
> +	return 0;
> +}
> diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
> index 8c8996f..0f9bf80 100644
> --- a/drivers/gpu/drm/i915/intel_panel.c
> +++ b/drivers/gpu/drm/i915/intel_panel.c
> @@ -1718,6 +1718,10 @@ intel_panel_init_backlight_funcs(struct intel_panel *panel)
>  		container_of(panel, struct intel_connector, panel);
>  	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>  
> +	if (connector->base.connector_type == DRM_MODE_CONNECTOR_DSI &&
> +			intel_dsi_cabc_init_backlight_funcs(connector) == 0)

Indentation is not quite right.

> +		return;
> +
>  	if (IS_BROXTON(dev_priv)) {
>  		panel->backlight.setup = bxt_setup_backlight;
>  		panel->backlight.enable = bxt_enable_backlight;
> -----Original Message-----

> From: Nikula, Jani

> Sent: Tuesday, March 22, 2016 7:19 PM

> To: Deepak, M <m.deepak@intel.com>; intel-gfx@lists.freedesktop.org

> Cc: Deepak, M <m.deepak@intel.com>; Vetter, Daniel

> <daniel.vetter@intel.com>; Adebisi, YetundeX

> <yetundex.adebisi@intel.com>

> Subject: Re: [MIPI CABC 2/2] drm/i915: CABC support for backlight control

> 

> On Tue, 22 Mar 2016, Deepak M <m.deepak@intel.com> wrote:

> > In CABC (Content Adaptive Brightness Control) content grey level scale

> > can be increased while simultaneously decreasing brightness of the

> > backlight to achieve same perceived brightness.

> >

> > The CABC is not standardized and panel vendors are free to follow

> > their implementation. The CABC implementaion here assumes that the

> > panels use standard SW register for control.

> >

> > In this design there will be no PWM signal from the SoC and DCS

> > commands are sent to enable and control the backlight brightness.

> >

> > v2: Moving the CABC bkl functions to new file.(Jani)

> >

> > v3: Rebase

> >

> > v4: Rebase

> >

> > Cc: Jani Nikula <jani.nikula@intel.com>

> > Cc: Daniel Vetter <daniel.vetter@intel.com>

> > Cc: Yetunde Adebisi <yetundex.adebisi@intel.com>

> > Signed-off-by: Deepak M <m.deepak@intel.com>

> > ---

> >  drivers/gpu/drm/i915/Makefile         |   1 +

> >  drivers/gpu/drm/i915/i915_drv.h       |   2 +-

> >  drivers/gpu/drm/i915/intel_dsi.c      |  19 +++-

> >  drivers/gpu/drm/i915/intel_dsi.h      |   4 +

> >  drivers/gpu/drm/i915/intel_dsi_cabc.c | 179

> ++++++++++++++++++++++++++++++++++

> >  drivers/gpu/drm/i915/intel_panel.c    |   4 +

> >  6 files changed, 206 insertions(+), 3 deletions(-)  create mode

> > 100644 drivers/gpu/drm/i915/intel_dsi_cabc.c

> >

> > diff --git a/drivers/gpu/drm/i915/Makefile

> > b/drivers/gpu/drm/i915/Makefile index 7ffb51b..065c410 100644

> > --- a/drivers/gpu/drm/i915/Makefile

> > +++ b/drivers/gpu/drm/i915/Makefile

> > @@ -83,6 +83,7 @@ i915-y += dvo_ch7017.o \

> >  	  intel_dp_mst.o \

> >  	  intel_dp.o \

> >  	  intel_dsi.o \

> > +	  intel_dsi_cabc.o \

> >  	  intel_dsi_panel_vbt.o \

> >  	  intel_dsi_pll.o \

> >  	  intel_dvo.o \

> > diff --git a/drivers/gpu/drm/i915/i915_drv.h

> > b/drivers/gpu/drm/i915/i915_drv.h index 050d860..d196404 100644

> > --- a/drivers/gpu/drm/i915/i915_drv.h

> > +++ b/drivers/gpu/drm/i915/i915_drv.h

> > @@ -3489,7 +3489,7 @@ void intel_sbi_write(struct drm_i915_private

> *dev_priv, u16 reg, u32 value,

> >  		     enum intel_sbi_destination destination);

> >  u32 vlv_flisdsi_read(struct drm_i915_private *dev_priv, u32 reg);

> > void vlv_flisdsi_write(struct drm_i915_private *dev_priv, u32 reg, u32

> > val);

> > -

> > +int intel_dsi_cabc_init_backlight_funcs(struct intel_connector

> > +*intel_connector);

> 

> This probably fits better in intel_drv.h under a /* intel_dsi_cabc.c */

> comment, see the file for examples.

> 

> >  int intel_gpu_freq(struct drm_i915_private *dev_priv, int val);  int

> > intel_freq_opcode(struct drm_i915_private *dev_priv, int val);

> >

> > diff --git a/drivers/gpu/drm/i915/intel_dsi.c

> > b/drivers/gpu/drm/i915/intel_dsi.c

> > index 456676c..7aa707f 100644

> > --- a/drivers/gpu/drm/i915/intel_dsi.c

> > +++ b/drivers/gpu/drm/i915/intel_dsi.c

> > @@ -1209,10 +1209,25 @@ void intel_dsi_init(struct drm_device *dev)

> >  	else

> >  		intel_encoder->crtc_mask = BIT(PIPE_B);

> >

> > -	if (dev_priv->vbt.dsi.config->dual_link)

> > +	if (dev_priv->vbt.dsi.config->dual_link) {

> >  		intel_dsi->ports = BIT(PORT_A) | BIT(PORT_C);

> > -	else

> > +		switch (dev_priv->vbt.dsi.config->dl_cabc_port) {

> > +		case CABC_PORT_A:

> > +			intel_dsi->bkl_dcs_ports = BIT(PORT_A);

> > +			break;

> > +		case CABC_PORT_C:

> > +			intel_dsi->bkl_dcs_ports = BIT(PORT_C);

> > +			break;

> > +		case CABC_PORT_A_AND_C:

> > +			intel_dsi->bkl_dcs_ports = BIT(PORT_A) |

> BIT(PORT_C);

> > +			break;

> > +		default:

> > +			DRM_ERROR("Unknown MIPI ports for sending

> DCS\n");

> > +		}

> > +	} else {

> >  		intel_dsi->ports = BIT(port);

> > +		intel_dsi->bkl_dcs_ports = BIT(port);

> > +	}

> >

> >  	/* Create a DSI host (and a device) for each port. */

> >  	for_each_dsi_port(port, intel_dsi->ports) { diff --git

> > a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h

> > index 0e758f1..5c07d59 100644

> > --- a/drivers/gpu/drm/i915/intel_dsi.h

> > +++ b/drivers/gpu/drm/i915/intel_dsi.h

> > @@ -34,6 +34,10 @@

> >  #define DSI_DUAL_LINK_FRONT_BACK	1

> >  #define DSI_DUAL_LINK_PIXEL_ALT		2

> >

> > +#define CABC_PORT_A                     0x00

> > +#define CABC_PORT_C                     0x01

> > +#define CABC_PORT_A_AND_C               0x02

> > +

> >  struct intel_dsi_host;

> >

> >  struct intel_dsi {

> > diff --git a/drivers/gpu/drm/i915/intel_dsi_cabc.c

> > b/drivers/gpu/drm/i915/intel_dsi_cabc.c

> > new file mode 100644

> > index 0000000..d14a669

> > --- /dev/null

> > +++ b/drivers/gpu/drm/i915/intel_dsi_cabc.c

> > @@ -0,0 +1,179 @@

> > +/*

> > + * Copyright © 2006-2010 Intel Corporation

> 

> 2016

> 

> > + *

> > + * Permission is hereby granted, free of charge, to any person

> > + obtaining a

> > + * copy of this software and associated documentation files (the

> > + "Software"),

> > + * to deal in the Software without restriction, including without

> > + limitation

> > + * the rights to use, copy, modify, merge, publish, distribute,

> > + sublicense,

> > + * and/or sell copies of the Software, and to permit persons to whom

> > + the

> > + * Software is furnished to do so, subject to the following conditions:

> > + *

> > + * The above copyright notice and this permission notice (including

> > + the next

> > + * paragraph) shall be included in all copies or substantial portions

> > + of the

> > + * Software.

> > + *

> > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY

> KIND,

> > + EXPRESS OR

> > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

> > + MERCHANTABILITY,

> > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN

> NO EVENT

> > + SHALL

> > + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,

> DAMAGES

> > + OR OTHER

> > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR

> OTHERWISE,

> > + ARISING

> > + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE

> OR

> > + OTHER

> > + * DEALINGS IN THE SOFTWARE.

> > + *

> > + * Author: Deepak M <m.deepak at intel.com> */

> > +

> > +#include "intel_drv.h"

> > +#include "intel_dsi.h"

> > +#include "i915_drv.h"

> > +#include <drm/drm_mipi_dsi.h>

> > +

> > +#define CABC_OFF                        (0 << 0)

> > +#define CABC_USER_INTERFACE_IMAGE       (1 << 0)

> > +#define CABC_STILL_PICTURE              (2 << 0)

> > +#define CABC_VIDEO_MODE                 (3 << 0)

> > +

> > +#define CABC_BACKLIGHT                  (1 << 2)

> > +#define CABC_DIMMING_DISPLAY            (1 << 3)

> > +#define CABC_BCTRL                      (1 << 5)

> > +

> > +#define CABC_MAX_VALUE                  0xFF

> > +

> 

> The defines below should be added to the relevant enum in

> include/video/mipi_display.h using the MIPI DCS specification names. I'll

> copy them below. Please create a separate prep patch and send it to dri-

> devel.

> 

> > +#define MIPI_DCS_CABC_LEVEL_RD          0x52

> 

> MIPI_DCS_GET_DISPLAY_BRIGHTNESS

> 

> > +#define MIPI_DCS_CABC_MIN_BRIGHTNESS_RD 0x5F

> 

> MIPI_DCS_GET_CABC_MIN_BRIGHTNESS

> 

> > +#define MIPI_DCS_CABC_CONTROL_RD        0x56

> 

> MIPI_DCS_GET_POWER_SAVE

> 

> > +#define MIPI_DCS_CABC_CONTROL_BRIGHT_RD 0x54

> 

> MIPI_DCS_GET_CONTROL_DISPLAY

> 

> > +#define MIPI_DCS_CABC_LEVEL_WR          0x51

> 

> MIPI_DCS_SET_DISPLAY_BRIGHTNESS

> 

> > +#define MIPI_DCS_CABC_MIN_BRIGHTNESS_WR 0x5E

> 

> MIPI_DCS_SET_CABC_MIN_BRIGHTNESS

> 

> > +#define MIPI_DCS_CABC_CONTROL_WR        0x55

> 

> MIPI_DCS_WRITE_POWER_SAVE

> 

> > +#define MIPI_DCS_CABC_CONTROL_BRIGHT_WR 0x53

> 

> MIPI_DCS_WRITE_CONTROL_DISPLAY

> 

> > +

> > +static u32 cabc_get_backlight(struct intel_connector *connector) {

> 	struct intel_encoder *encoder = connector->encoder;

> 	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);

> 

> Same for all functions below.

> 

> > +	struct intel_dsi *intel_dsi = NULL;

> > +	struct intel_encoder *encoder = NULL;

> > +	struct mipi_dsi_device *dsi_device;

> > +	u8 data[2] = {0};

> > +	enum port port;

> > +

> > +	encoder = connector->encoder;

> > +	intel_dsi = enc_to_intel_dsi(&encoder->base);

> > +

> > +	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {

> > +		dsi_device = intel_dsi->dsi_hosts[port]->device;

> > +		mipi_dsi_dcs_read(dsi_device, MIPI_DCS_CABC_LEVEL_RD,

> data, 2);

> > +	}

> > +

> > +	return data[1];

> 

> Hmm, it's up to the manufacturer whether the this is 8 or 16 bits. I guess

> you're just assuming 8 bits? I wonder if this should be more generic wrt 8 vs.

> 16 bits.

> 

[Deepak, M] Need to think on how to make it generic wrt 8 vs 16 bits, problem here is to somehow we have to identify the no of parameters or we have to pass this info in VBT...
> > +}

> > +

> > +static void cabc_set_backlight(struct intel_connector *connector, u32

> > +level) {

> > +	struct intel_dsi *intel_dsi = NULL;

> > +	struct intel_encoder *encoder = NULL;

> > +	struct mipi_dsi_device *dsi_device;

> > +	u8 data[2] = {0};

> > +	enum port port;

> > +

> > +	encoder = connector->encoder;

> > +	intel_dsi = enc_to_intel_dsi(&encoder->base);

> > +

> > +	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {

> > +		dsi_device = intel_dsi->dsi_hosts[port]->device;

> > +		data[1] = level;

> > +		data[0] = MIPI_DCS_CABC_LEVEL_WR;

> > +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);

> 

> Please use mipi_dsi_dcs_write(). Same for all functions below.

> 

> > +	}

> > +}

> > +

> > +static void cabc_disable_backlight(struct intel_connector *connector)

> > +{

> > +	struct intel_dsi *intel_dsi = NULL;

> > +	struct intel_encoder *encoder = NULL;

> > +	struct mipi_dsi_device *dsi_device;

> > +	enum port port;

> > +	u8 data[2] = {0};

> > +

> > +	encoder = connector->encoder;

> > +	intel_dsi = enc_to_intel_dsi(&encoder->base);

> > +

> > +	cabc_set_backlight(connector, 0);

> > +

> > +	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {

> > +		dsi_device = intel_dsi->dsi_hosts[port]->device;

> > +		data[1] = CABC_OFF;

> > +		data[0] = MIPI_DCS_CABC_CONTROL_WR;

> > +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);

> > +		data[0] = MIPI_DCS_CABC_CONTROL_BRIGHT_WR;

> > +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);

> > +	}

> > +}

> > +

> > +static void cabc_enable_backlight(struct intel_connector *connector)

> > +{

> > +	struct intel_dsi *intel_dsi = NULL;

> > +	struct intel_encoder *encoder = NULL;

> > +	struct intel_panel *panel = &connector->panel;

> > +	struct mipi_dsi_device *dsi_device;

> > +	enum port port;

> > +	u8 data[2] = {0};

> > +

> > +	encoder = connector->encoder;

> > +	intel_dsi = enc_to_intel_dsi(&encoder->base);

> > +

> > +	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {

> > +		dsi_device = intel_dsi->dsi_hosts[port]->device;

> > +		data[0] = MIPI_DCS_CABC_CONTROL_BRIGHT_WR;

> > +		data[1] = CABC_BACKLIGHT | CABC_DIMMING_DISPLAY |

> CABC_BCTRL;

> > +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);

> > +		data[0] = MIPI_DCS_CABC_CONTROL_WR;

> > +		data[1] = CABC_STILL_PICTURE;

> > +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);

> > +	}

> > +

> > +	cabc_set_backlight(connector, panel->backlight.level); }

> > +

> > +static int cabc_setup_backlight(struct intel_connector *connector,

> > +		enum pipe unused)

> > +{

> > +	struct drm_device *dev = connector->base.dev;

> > +	struct drm_i915_private *dev_priv = dev->dev_private;

> > +	struct intel_panel *panel = &connector->panel;

> > +

> > +	if (dev_priv->vbt.backlight.present)

> > +		panel->backlight.present = true;

> > +	else {

> > +		DRM_ERROR("no backlight present per VBT\n");

> > +		return 0;

> > +	}

> 

> None of the above is needed.

> 

> dev_priv->vbt.backlight.present is checked higher level in

> intel_panel_setup_backlight(), and panel->backlight.present = true is set

> there as well if this hook returns 0.

> 

> > +

> > +	panel->backlight.max = CABC_MAX_VALUE;

> > +	panel->backlight.level = CABC_MAX_VALUE;

> > +

> > +	return 0;

> > +}

> > +

> > +int intel_dsi_cabc_init_backlight_funcs(struct intel_connector

> > +*intel_connector) {

> > +	struct drm_device *dev = intel_connector->base.dev;

> > +	struct drm_i915_private *dev_priv = dev->dev_private;

> > +	struct intel_encoder *encoder = intel_connector->encoder;

> > +	struct intel_panel *panel = &intel_connector->panel;

> > +

> > +	if (!dev_priv->vbt.dsi.config->cabc_supported)

> > +		return -EINVAL;

> 

> -ENODEV seems more appropriate.

> 

> > +

> > +	if (encoder->type != INTEL_OUTPUT_DSI) {

> > +		DRM_ERROR("Use DSI encoder for CABC\n");

> > +		return -EINVAL;

> > +	}

> 

> 	if (WARN_ON(encoder->type != INTEL_OUTPUT_DSI))

> 		return -EINVAL;

> 

> > +

> > +	panel->backlight.setup = cabc_setup_backlight;

> > +	panel->backlight.enable = cabc_enable_backlight;

> > +	panel->backlight.disable = cabc_disable_backlight;

> > +	panel->backlight.set = cabc_set_backlight;

> > +	panel->backlight.get = cabc_get_backlight;

> > +

> > +	return 0;

> > +}

> > diff --git a/drivers/gpu/drm/i915/intel_panel.c

> > b/drivers/gpu/drm/i915/intel_panel.c

> > index 8c8996f..0f9bf80 100644

> > --- a/drivers/gpu/drm/i915/intel_panel.c

> > +++ b/drivers/gpu/drm/i915/intel_panel.c

> > @@ -1718,6 +1718,10 @@ intel_panel_init_backlight_funcs(struct

> intel_panel *panel)

> >  		container_of(panel, struct intel_connector, panel);

> >  	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);

> >

> > +	if (connector->base.connector_type ==

> DRM_MODE_CONNECTOR_DSI &&

> > +			intel_dsi_cabc_init_backlight_funcs(connector) == 0)

> 

> Indentation is not quite right.

> 

> > +		return;

> > +

> >  	if (IS_BROXTON(dev_priv)) {

> >  		panel->backlight.setup = bxt_setup_backlight;

> >  		panel->backlight.enable = bxt_enable_backlight;

> 

> --

> Jani Nikula, Intel Open Source Technology Center
On Wed, 23 Mar 2016, "Deepak, M" <m.deepak@intel.com> wrote:
>> -----Original Message-----
>> From: Nikula, Jani
>> Sent: Tuesday, March 22, 2016 7:19 PM
>> To: Deepak, M <m.deepak@intel.com>; intel-gfx@lists.freedesktop.org
>> Cc: Deepak, M <m.deepak@intel.com>; Vetter, Daniel
>> <daniel.vetter@intel.com>; Adebisi, YetundeX
>> <yetundex.adebisi@intel.com>
>> Subject: Re: [MIPI CABC 2/2] drm/i915: CABC support for backlight control
>> 
>> On Tue, 22 Mar 2016, Deepak M <m.deepak@intel.com> wrote:
>> > In CABC (Content Adaptive Brightness Control) content grey level scale
>> > can be increased while simultaneously decreasing brightness of the
>> > backlight to achieve same perceived brightness.
>> >
>> > The CABC is not standardized and panel vendors are free to follow
>> > their implementation. The CABC implementaion here assumes that the
>> > panels use standard SW register for control.
>> >
>> > In this design there will be no PWM signal from the SoC and DCS
>> > commands are sent to enable and control the backlight brightness.
>> >
>> > v2: Moving the CABC bkl functions to new file.(Jani)
>> >
>> > v3: Rebase
>> >
>> > v4: Rebase
>> >
>> > Cc: Jani Nikula <jani.nikula@intel.com>
>> > Cc: Daniel Vetter <daniel.vetter@intel.com>
>> > Cc: Yetunde Adebisi <yetundex.adebisi@intel.com>
>> > Signed-off-by: Deepak M <m.deepak@intel.com>
>> > ---
>> >  drivers/gpu/drm/i915/Makefile         |   1 +
>> >  drivers/gpu/drm/i915/i915_drv.h       |   2 +-
>> >  drivers/gpu/drm/i915/intel_dsi.c      |  19 +++-
>> >  drivers/gpu/drm/i915/intel_dsi.h      |   4 +
>> >  drivers/gpu/drm/i915/intel_dsi_cabc.c | 179
>> ++++++++++++++++++++++++++++++++++
>> >  drivers/gpu/drm/i915/intel_panel.c    |   4 +
>> >  6 files changed, 206 insertions(+), 3 deletions(-)  create mode
>> > 100644 drivers/gpu/drm/i915/intel_dsi_cabc.c
>> >
>> > diff --git a/drivers/gpu/drm/i915/Makefile
>> > b/drivers/gpu/drm/i915/Makefile index 7ffb51b..065c410 100644
>> > --- a/drivers/gpu/drm/i915/Makefile
>> > +++ b/drivers/gpu/drm/i915/Makefile
>> > @@ -83,6 +83,7 @@ i915-y += dvo_ch7017.o \
>> >  	  intel_dp_mst.o \
>> >  	  intel_dp.o \
>> >  	  intel_dsi.o \
>> > +	  intel_dsi_cabc.o \
>> >  	  intel_dsi_panel_vbt.o \
>> >  	  intel_dsi_pll.o \
>> >  	  intel_dvo.o \
>> > diff --git a/drivers/gpu/drm/i915/i915_drv.h
>> > b/drivers/gpu/drm/i915/i915_drv.h index 050d860..d196404 100644
>> > --- a/drivers/gpu/drm/i915/i915_drv.h
>> > +++ b/drivers/gpu/drm/i915/i915_drv.h
>> > @@ -3489,7 +3489,7 @@ void intel_sbi_write(struct drm_i915_private
>> *dev_priv, u16 reg, u32 value,
>> >  		     enum intel_sbi_destination destination);
>> >  u32 vlv_flisdsi_read(struct drm_i915_private *dev_priv, u32 reg);
>> > void vlv_flisdsi_write(struct drm_i915_private *dev_priv, u32 reg, u32
>> > val);
>> > -
>> > +int intel_dsi_cabc_init_backlight_funcs(struct intel_connector
>> > +*intel_connector);
>> 
>> This probably fits better in intel_drv.h under a /* intel_dsi_cabc.c */
>> comment, see the file for examples.
>> 
>> >  int intel_gpu_freq(struct drm_i915_private *dev_priv, int val);  int
>> > intel_freq_opcode(struct drm_i915_private *dev_priv, int val);
>> >
>> > diff --git a/drivers/gpu/drm/i915/intel_dsi.c
>> > b/drivers/gpu/drm/i915/intel_dsi.c
>> > index 456676c..7aa707f 100644
>> > --- a/drivers/gpu/drm/i915/intel_dsi.c
>> > +++ b/drivers/gpu/drm/i915/intel_dsi.c
>> > @@ -1209,10 +1209,25 @@ void intel_dsi_init(struct drm_device *dev)
>> >  	else
>> >  		intel_encoder->crtc_mask = BIT(PIPE_B);
>> >
>> > -	if (dev_priv->vbt.dsi.config->dual_link)
>> > +	if (dev_priv->vbt.dsi.config->dual_link) {
>> >  		intel_dsi->ports = BIT(PORT_A) | BIT(PORT_C);
>> > -	else
>> > +		switch (dev_priv->vbt.dsi.config->dl_cabc_port) {
>> > +		case CABC_PORT_A:
>> > +			intel_dsi->bkl_dcs_ports = BIT(PORT_A);
>> > +			break;
>> > +		case CABC_PORT_C:
>> > +			intel_dsi->bkl_dcs_ports = BIT(PORT_C);
>> > +			break;
>> > +		case CABC_PORT_A_AND_C:
>> > +			intel_dsi->bkl_dcs_ports = BIT(PORT_A) |
>> BIT(PORT_C);
>> > +			break;
>> > +		default:
>> > +			DRM_ERROR("Unknown MIPI ports for sending
>> DCS\n");
>> > +		}
>> > +	} else {
>> >  		intel_dsi->ports = BIT(port);
>> > +		intel_dsi->bkl_dcs_ports = BIT(port);
>> > +	}
>> >
>> >  	/* Create a DSI host (and a device) for each port. */
>> >  	for_each_dsi_port(port, intel_dsi->ports) { diff --git
>> > a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
>> > index 0e758f1..5c07d59 100644
>> > --- a/drivers/gpu/drm/i915/intel_dsi.h
>> > +++ b/drivers/gpu/drm/i915/intel_dsi.h
>> > @@ -34,6 +34,10 @@
>> >  #define DSI_DUAL_LINK_FRONT_BACK	1
>> >  #define DSI_DUAL_LINK_PIXEL_ALT		2
>> >
>> > +#define CABC_PORT_A                     0x00
>> > +#define CABC_PORT_C                     0x01
>> > +#define CABC_PORT_A_AND_C               0x02
>> > +
>> >  struct intel_dsi_host;
>> >
>> >  struct intel_dsi {
>> > diff --git a/drivers/gpu/drm/i915/intel_dsi_cabc.c
>> > b/drivers/gpu/drm/i915/intel_dsi_cabc.c
>> > new file mode 100644
>> > index 0000000..d14a669
>> > --- /dev/null
>> > +++ b/drivers/gpu/drm/i915/intel_dsi_cabc.c
>> > @@ -0,0 +1,179 @@
>> > +/*
>> > + * Copyright © 2006-2010 Intel Corporation
>> 
>> 2016
>> 
>> > + *
>> > + * Permission is hereby granted, free of charge, to any person
>> > + obtaining a
>> > + * copy of this software and associated documentation files (the
>> > + "Software"),
>> > + * to deal in the Software without restriction, including without
>> > + limitation
>> > + * the rights to use, copy, modify, merge, publish, distribute,
>> > + sublicense,
>> > + * and/or sell copies of the Software, and to permit persons to whom
>> > + the
>> > + * Software is furnished to do so, subject to the following conditions:
>> > + *
>> > + * The above copyright notice and this permission notice (including
>> > + the next
>> > + * paragraph) shall be included in all copies or substantial portions
>> > + of the
>> > + * Software.
>> > + *
>> > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
>> KIND,
>> > + EXPRESS OR
>> > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
>> > + MERCHANTABILITY,
>> > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN
>> NO EVENT
>> > + SHALL
>> > + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
>> DAMAGES
>> > + OR OTHER
>> > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
>> OTHERWISE,
>> > + ARISING
>> > + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
>> OR
>> > + OTHER
>> > + * DEALINGS IN THE SOFTWARE.
>> > + *
>> > + * Author: Deepak M <m.deepak at intel.com> */
>> > +
>> > +#include "intel_drv.h"
>> > +#include "intel_dsi.h"
>> > +#include "i915_drv.h"
>> > +#include <drm/drm_mipi_dsi.h>
>> > +
>> > +#define CABC_OFF                        (0 << 0)
>> > +#define CABC_USER_INTERFACE_IMAGE       (1 << 0)
>> > +#define CABC_STILL_PICTURE              (2 << 0)
>> > +#define CABC_VIDEO_MODE                 (3 << 0)
>> > +
>> > +#define CABC_BACKLIGHT                  (1 << 2)
>> > +#define CABC_DIMMING_DISPLAY            (1 << 3)
>> > +#define CABC_BCTRL                      (1 << 5)
>> > +
>> > +#define CABC_MAX_VALUE                  0xFF
>> > +
>> 
>> The defines below should be added to the relevant enum in
>> include/video/mipi_display.h using the MIPI DCS specification names. I'll
>> copy them below. Please create a separate prep patch and send it to dri-
>> devel.
>> 
>> > +#define MIPI_DCS_CABC_LEVEL_RD          0x52
>> 
>> MIPI_DCS_GET_DISPLAY_BRIGHTNESS
>> 
>> > +#define MIPI_DCS_CABC_MIN_BRIGHTNESS_RD 0x5F
>> 
>> MIPI_DCS_GET_CABC_MIN_BRIGHTNESS
>> 
>> > +#define MIPI_DCS_CABC_CONTROL_RD        0x56
>> 
>> MIPI_DCS_GET_POWER_SAVE
>> 
>> > +#define MIPI_DCS_CABC_CONTROL_BRIGHT_RD 0x54
>> 
>> MIPI_DCS_GET_CONTROL_DISPLAY
>> 
>> > +#define MIPI_DCS_CABC_LEVEL_WR          0x51
>> 
>> MIPI_DCS_SET_DISPLAY_BRIGHTNESS
>> 
>> > +#define MIPI_DCS_CABC_MIN_BRIGHTNESS_WR 0x5E
>> 
>> MIPI_DCS_SET_CABC_MIN_BRIGHTNESS
>> 
>> > +#define MIPI_DCS_CABC_CONTROL_WR        0x55
>> 
>> MIPI_DCS_WRITE_POWER_SAVE
>> 
>> > +#define MIPI_DCS_CABC_CONTROL_BRIGHT_WR 0x53
>> 
>> MIPI_DCS_WRITE_CONTROL_DISPLAY
>> 
>> > +
>> > +static u32 cabc_get_backlight(struct intel_connector *connector) {
>> 	struct intel_encoder *encoder = connector->encoder;
>> 	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
>> 
>> Same for all functions below.
>> 
>> > +	struct intel_dsi *intel_dsi = NULL;
>> > +	struct intel_encoder *encoder = NULL;
>> > +	struct mipi_dsi_device *dsi_device;
>> > +	u8 data[2] = {0};
>> > +	enum port port;
>> > +
>> > +	encoder = connector->encoder;
>> > +	intel_dsi = enc_to_intel_dsi(&encoder->base);
>> > +
>> > +	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
>> > +		dsi_device = intel_dsi->dsi_hosts[port]->device;
>> > +		mipi_dsi_dcs_read(dsi_device, MIPI_DCS_CABC_LEVEL_RD,
>> data, 2);
>> > +	}
>> > +
>> > +	return data[1];
>> 
>> Hmm, it's up to the manufacturer whether the this is 8 or 16 bits. I guess
>> you're just assuming 8 bits? I wonder if this should be more generic wrt 8 vs.
>> 16 bits.
>> 
> [Deepak, M] Need to think on how to make it generic wrt 8 vs 16 bits,
> problem here is to somehow we have to identify the no of parameters or
> we have to pass this info in VBT...

Look at the maximum value to decide? That's what needs to be set in
setup if the size changes, so no need to add another variable.

BR,
Jani.

>> > +}
>> > +
>> > +static void cabc_set_backlight(struct intel_connector *connector, u32
>> > +level) {
>> > +	struct intel_dsi *intel_dsi = NULL;
>> > +	struct intel_encoder *encoder = NULL;
>> > +	struct mipi_dsi_device *dsi_device;
>> > +	u8 data[2] = {0};
>> > +	enum port port;
>> > +
>> > +	encoder = connector->encoder;
>> > +	intel_dsi = enc_to_intel_dsi(&encoder->base);
>> > +
>> > +	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
>> > +		dsi_device = intel_dsi->dsi_hosts[port]->device;
>> > +		data[1] = level;
>> > +		data[0] = MIPI_DCS_CABC_LEVEL_WR;
>> > +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
>> 
>> Please use mipi_dsi_dcs_write(). Same for all functions below.
>> 
>> > +	}
>> > +}
>> > +
>> > +static void cabc_disable_backlight(struct intel_connector *connector)
>> > +{
>> > +	struct intel_dsi *intel_dsi = NULL;
>> > +	struct intel_encoder *encoder = NULL;
>> > +	struct mipi_dsi_device *dsi_device;
>> > +	enum port port;
>> > +	u8 data[2] = {0};
>> > +
>> > +	encoder = connector->encoder;
>> > +	intel_dsi = enc_to_intel_dsi(&encoder->base);
>> > +
>> > +	cabc_set_backlight(connector, 0);
>> > +
>> > +	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
>> > +		dsi_device = intel_dsi->dsi_hosts[port]->device;
>> > +		data[1] = CABC_OFF;
>> > +		data[0] = MIPI_DCS_CABC_CONTROL_WR;
>> > +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
>> > +		data[0] = MIPI_DCS_CABC_CONTROL_BRIGHT_WR;
>> > +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
>> > +	}
>> > +}
>> > +
>> > +static void cabc_enable_backlight(struct intel_connector *connector)
>> > +{
>> > +	struct intel_dsi *intel_dsi = NULL;
>> > +	struct intel_encoder *encoder = NULL;
>> > +	struct intel_panel *panel = &connector->panel;
>> > +	struct mipi_dsi_device *dsi_device;
>> > +	enum port port;
>> > +	u8 data[2] = {0};
>> > +
>> > +	encoder = connector->encoder;
>> > +	intel_dsi = enc_to_intel_dsi(&encoder->base);
>> > +
>> > +	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
>> > +		dsi_device = intel_dsi->dsi_hosts[port]->device;
>> > +		data[0] = MIPI_DCS_CABC_CONTROL_BRIGHT_WR;
>> > +		data[1] = CABC_BACKLIGHT | CABC_DIMMING_DISPLAY |
>> CABC_BCTRL;
>> > +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
>> > +		data[0] = MIPI_DCS_CABC_CONTROL_WR;
>> > +		data[1] = CABC_STILL_PICTURE;
>> > +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
>> > +	}
>> > +
>> > +	cabc_set_backlight(connector, panel->backlight.level); }
>> > +
>> > +static int cabc_setup_backlight(struct intel_connector *connector,
>> > +		enum pipe unused)
>> > +{
>> > +	struct drm_device *dev = connector->base.dev;
>> > +	struct drm_i915_private *dev_priv = dev->dev_private;
>> > +	struct intel_panel *panel = &connector->panel;
>> > +
>> > +	if (dev_priv->vbt.backlight.present)
>> > +		panel->backlight.present = true;
>> > +	else {
>> > +		DRM_ERROR("no backlight present per VBT\n");
>> > +		return 0;
>> > +	}
>> 
>> None of the above is needed.
>> 
>> dev_priv->vbt.backlight.present is checked higher level in
>> intel_panel_setup_backlight(), and panel->backlight.present = true is set
>> there as well if this hook returns 0.
>> 
>> > +
>> > +	panel->backlight.max = CABC_MAX_VALUE;
>> > +	panel->backlight.level = CABC_MAX_VALUE;
>> > +
>> > +	return 0;
>> > +}
>> > +
>> > +int intel_dsi_cabc_init_backlight_funcs(struct intel_connector
>> > +*intel_connector) {
>> > +	struct drm_device *dev = intel_connector->base.dev;
>> > +	struct drm_i915_private *dev_priv = dev->dev_private;
>> > +	struct intel_encoder *encoder = intel_connector->encoder;
>> > +	struct intel_panel *panel = &intel_connector->panel;
>> > +
>> > +	if (!dev_priv->vbt.dsi.config->cabc_supported)
>> > +		return -EINVAL;
>> 
>> -ENODEV seems more appropriate.
>> 
>> > +
>> > +	if (encoder->type != INTEL_OUTPUT_DSI) {
>> > +		DRM_ERROR("Use DSI encoder for CABC\n");
>> > +		return -EINVAL;
>> > +	}
>> 
>> 	if (WARN_ON(encoder->type != INTEL_OUTPUT_DSI))
>> 		return -EINVAL;
>> 
>> > +
>> > +	panel->backlight.setup = cabc_setup_backlight;
>> > +	panel->backlight.enable = cabc_enable_backlight;
>> > +	panel->backlight.disable = cabc_disable_backlight;
>> > +	panel->backlight.set = cabc_set_backlight;
>> > +	panel->backlight.get = cabc_get_backlight;
>> > +
>> > +	return 0;
>> > +}
>> > diff --git a/drivers/gpu/drm/i915/intel_panel.c
>> > b/drivers/gpu/drm/i915/intel_panel.c
>> > index 8c8996f..0f9bf80 100644
>> > --- a/drivers/gpu/drm/i915/intel_panel.c
>> > +++ b/drivers/gpu/drm/i915/intel_panel.c
>> > @@ -1718,6 +1718,10 @@ intel_panel_init_backlight_funcs(struct
>> intel_panel *panel)
>> >  		container_of(panel, struct intel_connector, panel);
>> >  	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>> >
>> > +	if (connector->base.connector_type ==
>> DRM_MODE_CONNECTOR_DSI &&
>> > +			intel_dsi_cabc_init_backlight_funcs(connector) == 0)
>> 
>> Indentation is not quite right.
>> 
>> > +		return;
>> > +
>> >  	if (IS_BROXTON(dev_priv)) {
>> >  		panel->backlight.setup = bxt_setup_backlight;
>> >  		panel->backlight.enable = bxt_enable_backlight;
>> 
>> --
>> Jani Nikula, Intel Open Source Technology Center
On Wed, 23 Mar 2016, Jani Nikula <jani.nikula@intel.com> wrote:
> [ text/plain ]
> On Wed, 23 Mar 2016, "Deepak, M" <m.deepak@intel.com> wrote:
>>> -----Original Message-----
>>> From: Nikula, Jani
>>> Sent: Tuesday, March 22, 2016 7:19 PM
>>> To: Deepak, M <m.deepak@intel.com>; intel-gfx@lists.freedesktop.org
>>> Cc: Deepak, M <m.deepak@intel.com>; Vetter, Daniel
>>> <daniel.vetter@intel.com>; Adebisi, YetundeX
>>> <yetundex.adebisi@intel.com>
>>> Subject: Re: [MIPI CABC 2/2] drm/i915: CABC support for backlight control
>>> 
>>> On Tue, 22 Mar 2016, Deepak M <m.deepak@intel.com> wrote:
>>> > In CABC (Content Adaptive Brightness Control) content grey level scale
>>> > can be increased while simultaneously decreasing brightness of the
>>> > backlight to achieve same perceived brightness.
>>> >
>>> > The CABC is not standardized and panel vendors are free to follow
>>> > their implementation. The CABC implementaion here assumes that the
>>> > panels use standard SW register for control.
>>> >
>>> > In this design there will be no PWM signal from the SoC and DCS
>>> > commands are sent to enable and control the backlight brightness.
>>> >
>>> > v2: Moving the CABC bkl functions to new file.(Jani)
>>> >
>>> > v3: Rebase
>>> >
>>> > v4: Rebase
>>> >
>>> > Cc: Jani Nikula <jani.nikula@intel.com>
>>> > Cc: Daniel Vetter <daniel.vetter@intel.com>
>>> > Cc: Yetunde Adebisi <yetundex.adebisi@intel.com>
>>> > Signed-off-by: Deepak M <m.deepak@intel.com>
>>> > ---
>>> >  drivers/gpu/drm/i915/Makefile         |   1 +
>>> >  drivers/gpu/drm/i915/i915_drv.h       |   2 +-
>>> >  drivers/gpu/drm/i915/intel_dsi.c      |  19 +++-
>>> >  drivers/gpu/drm/i915/intel_dsi.h      |   4 +
>>> >  drivers/gpu/drm/i915/intel_dsi_cabc.c | 179
>>> ++++++++++++++++++++++++++++++++++
>>> >  drivers/gpu/drm/i915/intel_panel.c    |   4 +
>>> >  6 files changed, 206 insertions(+), 3 deletions(-)  create mode
>>> > 100644 drivers/gpu/drm/i915/intel_dsi_cabc.c
>>> >
>>> > diff --git a/drivers/gpu/drm/i915/Makefile
>>> > b/drivers/gpu/drm/i915/Makefile index 7ffb51b..065c410 100644
>>> > --- a/drivers/gpu/drm/i915/Makefile
>>> > +++ b/drivers/gpu/drm/i915/Makefile
>>> > @@ -83,6 +83,7 @@ i915-y += dvo_ch7017.o \
>>> >  	  intel_dp_mst.o \
>>> >  	  intel_dp.o \
>>> >  	  intel_dsi.o \
>>> > +	  intel_dsi_cabc.o \
>>> >  	  intel_dsi_panel_vbt.o \
>>> >  	  intel_dsi_pll.o \
>>> >  	  intel_dvo.o \
>>> > diff --git a/drivers/gpu/drm/i915/i915_drv.h
>>> > b/drivers/gpu/drm/i915/i915_drv.h index 050d860..d196404 100644
>>> > --- a/drivers/gpu/drm/i915/i915_drv.h
>>> > +++ b/drivers/gpu/drm/i915/i915_drv.h
>>> > @@ -3489,7 +3489,7 @@ void intel_sbi_write(struct drm_i915_private
>>> *dev_priv, u16 reg, u32 value,
>>> >  		     enum intel_sbi_destination destination);
>>> >  u32 vlv_flisdsi_read(struct drm_i915_private *dev_priv, u32 reg);
>>> > void vlv_flisdsi_write(struct drm_i915_private *dev_priv, u32 reg, u32
>>> > val);
>>> > -
>>> > +int intel_dsi_cabc_init_backlight_funcs(struct intel_connector
>>> > +*intel_connector);
>>> 
>>> This probably fits better in intel_drv.h under a /* intel_dsi_cabc.c */
>>> comment, see the file for examples.
>>> 
>>> >  int intel_gpu_freq(struct drm_i915_private *dev_priv, int val);  int
>>> > intel_freq_opcode(struct drm_i915_private *dev_priv, int val);
>>> >
>>> > diff --git a/drivers/gpu/drm/i915/intel_dsi.c
>>> > b/drivers/gpu/drm/i915/intel_dsi.c
>>> > index 456676c..7aa707f 100644
>>> > --- a/drivers/gpu/drm/i915/intel_dsi.c
>>> > +++ b/drivers/gpu/drm/i915/intel_dsi.c
>>> > @@ -1209,10 +1209,25 @@ void intel_dsi_init(struct drm_device *dev)
>>> >  	else
>>> >  		intel_encoder->crtc_mask = BIT(PIPE_B);
>>> >
>>> > -	if (dev_priv->vbt.dsi.config->dual_link)
>>> > +	if (dev_priv->vbt.dsi.config->dual_link) {
>>> >  		intel_dsi->ports = BIT(PORT_A) | BIT(PORT_C);
>>> > -	else
>>> > +		switch (dev_priv->vbt.dsi.config->dl_cabc_port) {
>>> > +		case CABC_PORT_A:
>>> > +			intel_dsi->bkl_dcs_ports = BIT(PORT_A);
>>> > +			break;
>>> > +		case CABC_PORT_C:
>>> > +			intel_dsi->bkl_dcs_ports = BIT(PORT_C);
>>> > +			break;
>>> > +		case CABC_PORT_A_AND_C:
>>> > +			intel_dsi->bkl_dcs_ports = BIT(PORT_A) |
>>> BIT(PORT_C);
>>> > +			break;
>>> > +		default:
>>> > +			DRM_ERROR("Unknown MIPI ports for sending
>>> DCS\n");
>>> > +		}
>>> > +	} else {
>>> >  		intel_dsi->ports = BIT(port);
>>> > +		intel_dsi->bkl_dcs_ports = BIT(port);
>>> > +	}
>>> >
>>> >  	/* Create a DSI host (and a device) for each port. */
>>> >  	for_each_dsi_port(port, intel_dsi->ports) { diff --git
>>> > a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
>>> > index 0e758f1..5c07d59 100644
>>> > --- a/drivers/gpu/drm/i915/intel_dsi.h
>>> > +++ b/drivers/gpu/drm/i915/intel_dsi.h
>>> > @@ -34,6 +34,10 @@
>>> >  #define DSI_DUAL_LINK_FRONT_BACK	1
>>> >  #define DSI_DUAL_LINK_PIXEL_ALT		2
>>> >
>>> > +#define CABC_PORT_A                     0x00
>>> > +#define CABC_PORT_C                     0x01
>>> > +#define CABC_PORT_A_AND_C               0x02
>>> > +
>>> >  struct intel_dsi_host;
>>> >
>>> >  struct intel_dsi {
>>> > diff --git a/drivers/gpu/drm/i915/intel_dsi_cabc.c
>>> > b/drivers/gpu/drm/i915/intel_dsi_cabc.c
>>> > new file mode 100644
>>> > index 0000000..d14a669
>>> > --- /dev/null
>>> > +++ b/drivers/gpu/drm/i915/intel_dsi_cabc.c
>>> > @@ -0,0 +1,179 @@
>>> > +/*
>>> > + * Copyright © 2006-2010 Intel Corporation
>>> 
>>> 2016
>>> 
>>> > + *
>>> > + * Permission is hereby granted, free of charge, to any person
>>> > + obtaining a
>>> > + * copy of this software and associated documentation files (the
>>> > + "Software"),
>>> > + * to deal in the Software without restriction, including without
>>> > + limitation
>>> > + * the rights to use, copy, modify, merge, publish, distribute,
>>> > + sublicense,
>>> > + * and/or sell copies of the Software, and to permit persons to whom
>>> > + the
>>> > + * Software is furnished to do so, subject to the following conditions:
>>> > + *
>>> > + * The above copyright notice and this permission notice (including
>>> > + the next
>>> > + * paragraph) shall be included in all copies or substantial portions
>>> > + of the
>>> > + * Software.
>>> > + *
>>> > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
>>> KIND,
>>> > + EXPRESS OR
>>> > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
>>> > + MERCHANTABILITY,
>>> > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN
>>> NO EVENT
>>> > + SHALL
>>> > + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
>>> DAMAGES
>>> > + OR OTHER
>>> > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
>>> OTHERWISE,
>>> > + ARISING
>>> > + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
>>> OR
>>> > + OTHER
>>> > + * DEALINGS IN THE SOFTWARE.
>>> > + *
>>> > + * Author: Deepak M <m.deepak at intel.com> */
>>> > +
>>> > +#include "intel_drv.h"
>>> > +#include "intel_dsi.h"
>>> > +#include "i915_drv.h"
>>> > +#include <drm/drm_mipi_dsi.h>
>>> > +
>>> > +#define CABC_OFF                        (0 << 0)
>>> > +#define CABC_USER_INTERFACE_IMAGE       (1 << 0)
>>> > +#define CABC_STILL_PICTURE              (2 << 0)
>>> > +#define CABC_VIDEO_MODE                 (3 << 0)
>>> > +
>>> > +#define CABC_BACKLIGHT                  (1 << 2)
>>> > +#define CABC_DIMMING_DISPLAY            (1 << 3)
>>> > +#define CABC_BCTRL                      (1 << 5)
>>> > +
>>> > +#define CABC_MAX_VALUE                  0xFF
>>> > +
>>> 
>>> The defines below should be added to the relevant enum in
>>> include/video/mipi_display.h using the MIPI DCS specification names. I'll
>>> copy them below. Please create a separate prep patch and send it to dri-
>>> devel.
>>> 
>>> > +#define MIPI_DCS_CABC_LEVEL_RD          0x52
>>> 
>>> MIPI_DCS_GET_DISPLAY_BRIGHTNESS
>>> 
>>> > +#define MIPI_DCS_CABC_MIN_BRIGHTNESS_RD 0x5F
>>> 
>>> MIPI_DCS_GET_CABC_MIN_BRIGHTNESS
>>> 
>>> > +#define MIPI_DCS_CABC_CONTROL_RD        0x56
>>> 
>>> MIPI_DCS_GET_POWER_SAVE
>>> 
>>> > +#define MIPI_DCS_CABC_CONTROL_BRIGHT_RD 0x54
>>> 
>>> MIPI_DCS_GET_CONTROL_DISPLAY
>>> 
>>> > +#define MIPI_DCS_CABC_LEVEL_WR          0x51
>>> 
>>> MIPI_DCS_SET_DISPLAY_BRIGHTNESS
>>> 
>>> > +#define MIPI_DCS_CABC_MIN_BRIGHTNESS_WR 0x5E
>>> 
>>> MIPI_DCS_SET_CABC_MIN_BRIGHTNESS
>>> 
>>> > +#define MIPI_DCS_CABC_CONTROL_WR        0x55
>>> 
>>> MIPI_DCS_WRITE_POWER_SAVE
>>> 
>>> > +#define MIPI_DCS_CABC_CONTROL_BRIGHT_WR 0x53
>>> 
>>> MIPI_DCS_WRITE_CONTROL_DISPLAY
>>> 
>>> > +
>>> > +static u32 cabc_get_backlight(struct intel_connector *connector) {
>>> 	struct intel_encoder *encoder = connector->encoder;
>>> 	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
>>> 
>>> Same for all functions below.
>>> 
>>> > +	struct intel_dsi *intel_dsi = NULL;
>>> > +	struct intel_encoder *encoder = NULL;
>>> > +	struct mipi_dsi_device *dsi_device;
>>> > +	u8 data[2] = {0};
>>> > +	enum port port;
>>> > +
>>> > +	encoder = connector->encoder;
>>> > +	intel_dsi = enc_to_intel_dsi(&encoder->base);
>>> > +
>>> > +	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
>>> > +		dsi_device = intel_dsi->dsi_hosts[port]->device;
>>> > +		mipi_dsi_dcs_read(dsi_device, MIPI_DCS_CABC_LEVEL_RD,
>>> data, 2);
>>> > +	}
>>> > +
>>> > +	return data[1];
>>> 
>>> Hmm, it's up to the manufacturer whether the this is 8 or 16 bits. I guess
>>> you're just assuming 8 bits? I wonder if this should be more generic wrt 8 vs.
>>> 16 bits.
>>> 
>> [Deepak, M] Need to think on how to make it generic wrt 8 vs 16 bits,
>> problem here is to somehow we have to identify the no of parameters or
>> we have to pass this info in VBT...
>
> Look at the maximum value to decide? That's what needs to be set in
> setup if the size changes, so no need to add another variable.

Or just ignore this part for now, and go for either 8 or 16 bits, not
this sometimes this sometimes that.




>
> BR,
> Jani.
>
>>> > +}
>>> > +
>>> > +static void cabc_set_backlight(struct intel_connector *connector, u32
>>> > +level) {
>>> > +	struct intel_dsi *intel_dsi = NULL;
>>> > +	struct intel_encoder *encoder = NULL;
>>> > +	struct mipi_dsi_device *dsi_device;
>>> > +	u8 data[2] = {0};
>>> > +	enum port port;
>>> > +
>>> > +	encoder = connector->encoder;
>>> > +	intel_dsi = enc_to_intel_dsi(&encoder->base);
>>> > +
>>> > +	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
>>> > +		dsi_device = intel_dsi->dsi_hosts[port]->device;
>>> > +		data[1] = level;
>>> > +		data[0] = MIPI_DCS_CABC_LEVEL_WR;
>>> > +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
>>> 
>>> Please use mipi_dsi_dcs_write(). Same for all functions below.
>>> 
>>> > +	}
>>> > +}
>>> > +
>>> > +static void cabc_disable_backlight(struct intel_connector *connector)
>>> > +{
>>> > +	struct intel_dsi *intel_dsi = NULL;
>>> > +	struct intel_encoder *encoder = NULL;
>>> > +	struct mipi_dsi_device *dsi_device;
>>> > +	enum port port;
>>> > +	u8 data[2] = {0};
>>> > +
>>> > +	encoder = connector->encoder;
>>> > +	intel_dsi = enc_to_intel_dsi(&encoder->base);
>>> > +
>>> > +	cabc_set_backlight(connector, 0);
>>> > +
>>> > +	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
>>> > +		dsi_device = intel_dsi->dsi_hosts[port]->device;
>>> > +		data[1] = CABC_OFF;
>>> > +		data[0] = MIPI_DCS_CABC_CONTROL_WR;
>>> > +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
>>> > +		data[0] = MIPI_DCS_CABC_CONTROL_BRIGHT_WR;
>>> > +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
>>> > +	}
>>> > +}
>>> > +
>>> > +static void cabc_enable_backlight(struct intel_connector *connector)
>>> > +{
>>> > +	struct intel_dsi *intel_dsi = NULL;
>>> > +	struct intel_encoder *encoder = NULL;
>>> > +	struct intel_panel *panel = &connector->panel;
>>> > +	struct mipi_dsi_device *dsi_device;
>>> > +	enum port port;
>>> > +	u8 data[2] = {0};
>>> > +
>>> > +	encoder = connector->encoder;
>>> > +	intel_dsi = enc_to_intel_dsi(&encoder->base);
>>> > +
>>> > +	for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
>>> > +		dsi_device = intel_dsi->dsi_hosts[port]->device;
>>> > +		data[0] = MIPI_DCS_CABC_CONTROL_BRIGHT_WR;
>>> > +		data[1] = CABC_BACKLIGHT | CABC_DIMMING_DISPLAY |
>>> CABC_BCTRL;
>>> > +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
>>> > +		data[0] = MIPI_DCS_CABC_CONTROL_WR;
>>> > +		data[1] = CABC_STILL_PICTURE;
>>> > +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
>>> > +	}
>>> > +
>>> > +	cabc_set_backlight(connector, panel->backlight.level); }
>>> > +
>>> > +static int cabc_setup_backlight(struct intel_connector *connector,
>>> > +		enum pipe unused)
>>> > +{
>>> > +	struct drm_device *dev = connector->base.dev;
>>> > +	struct drm_i915_private *dev_priv = dev->dev_private;
>>> > +	struct intel_panel *panel = &connector->panel;
>>> > +
>>> > +	if (dev_priv->vbt.backlight.present)
>>> > +		panel->backlight.present = true;
>>> > +	else {
>>> > +		DRM_ERROR("no backlight present per VBT\n");
>>> > +		return 0;
>>> > +	}
>>> 
>>> None of the above is needed.
>>> 
>>> dev_priv->vbt.backlight.present is checked higher level in
>>> intel_panel_setup_backlight(), and panel->backlight.present = true is set
>>> there as well if this hook returns 0.
>>> 
>>> > +
>>> > +	panel->backlight.max = CABC_MAX_VALUE;
>>> > +	panel->backlight.level = CABC_MAX_VALUE;
>>> > +
>>> > +	return 0;
>>> > +}
>>> > +
>>> > +int intel_dsi_cabc_init_backlight_funcs(struct intel_connector
>>> > +*intel_connector) {
>>> > +	struct drm_device *dev = intel_connector->base.dev;
>>> > +	struct drm_i915_private *dev_priv = dev->dev_private;
>>> > +	struct intel_encoder *encoder = intel_connector->encoder;
>>> > +	struct intel_panel *panel = &intel_connector->panel;
>>> > +
>>> > +	if (!dev_priv->vbt.dsi.config->cabc_supported)
>>> > +		return -EINVAL;
>>> 
>>> -ENODEV seems more appropriate.
>>> 
>>> > +
>>> > +	if (encoder->type != INTEL_OUTPUT_DSI) {
>>> > +		DRM_ERROR("Use DSI encoder for CABC\n");
>>> > +		return -EINVAL;
>>> > +	}
>>> 
>>> 	if (WARN_ON(encoder->type != INTEL_OUTPUT_DSI))
>>> 		return -EINVAL;
>>> 
>>> > +
>>> > +	panel->backlight.setup = cabc_setup_backlight;
>>> > +	panel->backlight.enable = cabc_enable_backlight;
>>> > +	panel->backlight.disable = cabc_disable_backlight;
>>> > +	panel->backlight.set = cabc_set_backlight;
>>> > +	panel->backlight.get = cabc_get_backlight;
>>> > +
>>> > +	return 0;
>>> > +}
>>> > diff --git a/drivers/gpu/drm/i915/intel_panel.c
>>> > b/drivers/gpu/drm/i915/intel_panel.c
>>> > index 8c8996f..0f9bf80 100644
>>> > --- a/drivers/gpu/drm/i915/intel_panel.c
>>> > +++ b/drivers/gpu/drm/i915/intel_panel.c
>>> > @@ -1718,6 +1718,10 @@ intel_panel_init_backlight_funcs(struct
>>> intel_panel *panel)
>>> >  		container_of(panel, struct intel_connector, panel);
>>> >  	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>>> >
>>> > +	if (connector->base.connector_type ==
>>> DRM_MODE_CONNECTOR_DSI &&
>>> > +			intel_dsi_cabc_init_backlight_funcs(connector) == 0)
>>> 
>>> Indentation is not quite right.
>>> 
>>> > +		return;
>>> > +
>>> >  	if (IS_BROXTON(dev_priv)) {
>>> >  		panel->backlight.setup = bxt_setup_backlight;
>>> >  		panel->backlight.enable = bxt_enable_backlight;
>>> 
>>> --
>>> Jani Nikula, Intel Open Source Technology Center