Re: [RFC CABC v3 PATCH 2/2] drm/i915: CABC support for backlight control

Daniel Vetter
2015-09-14T09:38:52Z

On Fri, Sep 11, 2015 at 10:17:48AM +0530, Deepak M 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:
> - Created a new backlight driver for cabc, which will be registered
> only when it cabc is supported by panel. (Daniel Vetter)
> v3:
> - Use for_each_dsi_port macro for handling port C also (Gaurav)
> - Rebase
>
> Signed-off-by: Deepak M <m.deepak@intel.com>
> ---
> drivers/gpu/drm/i915/Makefile | 1 +
> drivers/gpu/drm/i915/intel_dsi.c | 18 +++++++++++++++---
> drivers/gpu/drm/i915/intel_panel.c | 23 +++++++++++++++++++----
> include/video/mipi_display.h | 8 ++++++++
> 4 files changed, 43 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 44d290a..d87c690 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -82,6 +82,7 @@ i915-y += dvo_ch7017.o \
> intel_dsi.o \
> intel_dsi_panel_vbt.o \
> intel_dsi_pll.o \
> + intel_dsi_cabc.o \

You've forgotten to git add intel_dsi_cabc.c. Makes reviewing things a bit
hard ;-)
-Daniel

> intel_dvo.o \
> intel_hdmi.o \
> intel_i2c.o \
> diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
> index 781c267..1d98ed8 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.c
> +++ b/drivers/gpu/drm/i915/intel_dsi.c
> @@ -35,6 +35,7 @@
> #include "i915_drv.h"
> #include "intel_drv.h"
> #include "intel_dsi.h"
> +#include "intel_dsi_cabc.h"
>
> static const struct {
> u16 panel_id;
> @@ -398,7 +399,10 @@ static void intel_dsi_enable(struct intel_encoder *encoder)
> intel_dsi_port_enable(encoder);
> }
>
> - intel_panel_enable_backlight(intel_dsi->attached_connector);
> + if (dev_priv->vbt.dsi.config->cabc_supported)
> + cabc_enable_backlight(intel_dsi->attached_connector);
> + else
> + intel_panel_enable_backlight(intel_dsi->attached_connector);
> }
>
> static void intel_dsi_pre_enable(struct intel_encoder *encoder)
> @@ -458,12 +462,17 @@ static void intel_dsi_enable_nop(struct intel_encoder *encoder)
>
> static void intel_dsi_pre_disable(struct intel_encoder *encoder)
> {
> + struct drm_device *dev = encoder->base.dev;
> + struct drm_i915_private *dev_priv = dev->dev_private;
> struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
> enum port port;
>
> DRM_DEBUG_KMS("\n");
>
> - intel_panel_disable_backlight(intel_dsi->attached_connector);
> + if (dev_priv->vbt.dsi.config->cabc_supported)
> + cabc_disable_backlight(intel_dsi->attached_connector);
> + else
> + intel_panel_disable_backlight(intel_dsi->attached_connector);
>
> if (is_vid_mode(intel_dsi)) {
> /* Send Shutdown command to the panel in LP mode */
> @@ -1133,7 +1142,10 @@ void intel_dsi_init(struct drm_device *dev)
> }
>
> intel_panel_init(&intel_connector->panel, fixed_mode, NULL);
> - intel_panel_setup_backlight(connector, INVALID_PIPE);
> + if (dev_priv->vbt.dsi.config->cabc_supported)
> + cabc_setup_backlight(connector, INVALID_PIPE);
> + else
> + intel_panel_setup_backlight(connector, INVALID_PIPE);
>
> return;
>
> diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
> index e2ab3f6..ff2e586 100644
> --- a/drivers/gpu/drm/i915/intel_panel.c
> +++ b/drivers/gpu/drm/i915/intel_panel.c
> @@ -34,6 +34,7 @@
> #include <linux/moduleparam.h>
> #include <linux/pwm.h>
> #include "intel_drv.h"
> +#include "intel_dsi_cabc.h"
>
> #define CRC_PMIC_PWM_PERIOD_NS 21333
>
> @@ -1586,15 +1587,29 @@ void intel_panel_fini(struct intel_panel *panel)
> void intel_backlight_register(struct drm_device *dev)
> {
> struct intel_connector *connector;
> + struct drm_i915_private *dev_priv = dev->dev_private;
>
> - list_for_each_entry(connector, &dev->mode_config.connector_list, base.head)
> - intel_backlight_device_register(connector);
> + list_for_each_entry(connector, &dev->mode_config.connector_list,
> + base.head) {
> + if (connector->encoder->type == INTEL_OUTPUT_DSI &&
> + dev_priv->vbt.dsi.config->cabc_supported)
> + cabc_backlight_device_register(connector);
> + else
> + intel_backlight_device_register(connector);
> + }
> }
>
> void intel_backlight_unregister(struct drm_device *dev)
> {
> struct intel_connector *connector;
> + struct drm_i915_private *dev_priv = dev->dev_private;
>
> - list_for_each_entry(connector, &dev->mode_config.connector_list, base.head)
> - intel_backlight_device_unregister(connector);
> + list_for_each_entry(connector, &dev->mode_config.connector_list,
> + base.head) {
> + if (connector->encoder->type == INTEL_OUTPUT_DSI &&
> + dev_priv->vbt.dsi.config->cabc_supported)
> + cabc_backlight_device_unregister(connector);
> + else
> + intel_backlight_device_unregister(connector);
> + }
> }
> diff --git a/include/video/mipi_display.h b/include/video/mipi_display.h
> index ddcc8ca..5b8eeec 100644
> --- a/include/video/mipi_display.h
> +++ b/include/video/mipi_display.h
> @@ -117,6 +117,14 @@ enum {
> MIPI_DCS_GET_SCANLINE = 0x45,
> MIPI_DCS_READ_DDB_START = 0xA1,
> MIPI_DCS_READ_DDB_CONTINUE = 0xA8,
> + MIPI_DCS_CABC_LEVEL_RD = 0x52,
> + MIPI_DCS_CABC_MIN_BRIGHTNESS_RD = 0x5F,
> + MIPI_DCS_CABC_CONTROL_RD = 0x56,
> + MIPI_DCS_CABC_CONTROL_BRIGHT_RD = 0x54,
> + MIPI_DCS_CABC_LEVEL_WR = 0x51,
> + MIPI_DCS_CABC_MIN_BRIGHTNESS_WR = 0x5E,
> + MIPI_DCS_CABC_CONTROL_WR = 0x55,
> + MIPI_DCS_CABC_CONTROL_BRIGHT_WR = 0x53,
> };
>
> /* MIPI DCS pixel formats */
> --
> 1.7.9.5
>
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--
Daniel Vetter
Software Engineer, Intel Corporation