[v5 0/5] drm: Support basic DPCD backlight in panel-simple and add a new panel ATNA33XC20

[v5 0/5] drm: Support basic DPCD backlight in panel-simple and add a new panel ATNA33XC20

[Rajeev Nandan]

This series adds the support for the eDP panel that needs the backlight
controlling over the DP AUX channel using DPCD registers of the panel
as per the VESA's standard.

This series also adds support for the Samsung eDP AMOLED panel that
needs DP AUX to control the backlight, and introduces new delays in the
@panel_desc.delay to support this panel.

This patch series depends on the following two series:
- Doug's series [1], exposed the DP AUX channel to the panel-simple.
- Lyude's series [2], introduced new drm helper functions for DPCD
  backlight.

This series is the logical successor to the series [3].

Changes in v1:
- Created dpcd backlight helper with very basic functionality, added
  backlight registration in the ti-sn65dsi86 bridge driver.

Changes in v2:
- Created a new DisplayPort aux backlight driver and moved the code from
  drm_dp_aux_backlight.c (v1) to the new driver.

Changes in v3:
- Fixed module compilation (kernel test bot).

Changes in v4:
- Added basic DPCD backlight support in panel-simple.
- Added support for a new Samsung panel ATNA33XC20 that needs DPCD
  backlight controlling and has a requirement of delays between enable
  GPIO and regulator.

Changes in v5:
Addressed review suggestions from Douglas:
- Created a new API drm_panel_dp_aux_backlight() in drm_panel.c
- Moved DP AUX backlight functions from panel-simple.c to drm_panel.c
- panel-simple probe() calls drm_panel_dp_aux_backlight() to create
  backlight when the backlight phandle is not specified in panel DT
  and DP AUX channel is present.
- Added check for drm_edp_backlight_supported() before registering.
- Removed the @uses_dpcd_backlight flag from panel_desc as this
  should be auto-detected.
- Updated comments/descriptions.  

[1] https://lore.kernel.org/dri-devel/20210525000159.3384921-1-dianders@chromium.org/
[2] https://lore.kernel.org/dri-devel/20210514181504.565252-1-lyude@redhat.com/
[3] https://lore.kernel.org/dri-devel/1619416756-3533-1-git-send-email-rajeevny@codeaurora.org/

Rajeev Nandan (5):
  drm/panel: add basic DP AUX backlight support
  drm/panel-simple: Support DP AUX backlight
  drm/panel-simple: Support for delays between GPIO & regulator
  dt-bindings: display: simple: Add Samsung ATNA33XC20
  drm/panel-simple: Add Samsung ATNA33XC20

 .../bindings/display/panel/panel-simple.yaml       |   2 +
 drivers/gpu/drm/drm_panel.c                        | 108 +++++++++++++++++++++
 drivers/gpu/drm/panel/panel-simple.c               |  67 +++++++++++++
 include/drm/drm_panel.h                            |  15 ++-
 4 files changed, 188 insertions(+), 4 deletions(-)

-- 
2.7.4

[v5 1/5] drm/panel: add basic DP AUX backlight support

[Rajeev Nandan]

Some panels support backlight control over DP AUX channel using
VESA's standard backlight control interface.
Using new DRM eDP backlight helpers, add support to create and
register a backlight for those panels in drm_panel to simplify
the panel drivers.

The panel driver with access to "struct drm_dp_aux" can create and
register a backlight device using following code snippet in its
probe() function:

	err = drm_panel_dp_aux_backlight(panel, aux);
	if (err)
		return err;

Then drm_panel will handle backlight_(enable|disable) calls
similar to the case when drm_panel_of_backlight() is used.

Currently, we are not supporting one feature where the source
device can combine the backlight brightness levels set through
DP AUX and the BL_PWM_DIM eDP connector pin. Since it's not
required for the basic backlight controls, it can be added later.

Signed-off-by: Rajeev Nandan <rajeevny@codeaurora.org>
---

Changes in v5:
- New (Douglas) [1] 

[1] https://lore.kernel.org/dri-devel/CAD=FV=UuWuKibpT15McweuZ24qxsSAsSvJ3Q2MbZqgw5oggBVQ@mail.gmail.com/

 drivers/gpu/drm/drm_panel.c | 108 ++++++++++++++++++++++++++++++++++++++++++++
 include/drm/drm_panel.h     |  15 ++++--
 2 files changed, 119 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index f634371..f290315 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -26,12 +26,20 @@
 #include <linux/module.h>
 
 #include <drm/drm_crtc.h>
+#include <drm/drm_dp_helper.h>
 #include <drm/drm_panel.h>
 #include <drm/drm_print.h>
 
 static DEFINE_MUTEX(panel_lock);
 static LIST_HEAD(panel_list);
 
+struct dp_aux_backlight {
+	struct backlight_device *base;
+	struct drm_dp_aux *aux;
+	struct drm_edp_backlight_info info;
+	bool enabled;
+};
+
 /**
  * DOC: drm panel
  *
@@ -342,6 +350,106 @@ int drm_panel_of_backlight(struct drm_panel *panel)
 	return 0;
 }
 EXPORT_SYMBOL(drm_panel_of_backlight);
+
+static int dp_aux_backlight_update_status(struct backlight_device *bd)
+{
+	struct dp_aux_backlight *bl = bl_get_data(bd);
+	u16 brightness = backlight_get_brightness(bd);
+	int ret = 0;
+
+	if (brightness > 0) {
+		if (!bl->enabled) {
+			drm_edp_backlight_enable(bl->aux, &bl->info, brightness);
+			bl->enabled = true;
+			return 0;
+		}
+		ret = drm_edp_backlight_set_level(bl->aux, &bl->info, brightness);
+	} else {
+		if (bl->enabled) {
+			drm_edp_backlight_disable(bl->aux, &bl->info);
+			bl->enabled = false;
+		}
+	}
+
+	return ret;
+}
+
+static const struct backlight_ops dp_aux_bl_ops = {
+	.update_status = dp_aux_backlight_update_status,
+};
+
+/**
+ * drm_panel_dp_aux_backlight - create and use DP AUX backlight
+ * @panel: DRM panel
+ * @aux: The DP AUX channel to use
+ *
+ * Use this function to create and handle backlight if your panel
+ * supports backlight control over DP AUX channel using DPCD
+ * registers as per VESA's standard backlight control interface.
+ *
+ * When the panel is enabled backlight will be enabled after a
+ * successful call to &drm_panel_funcs.enable()
+ *
+ * When the panel is disabled backlight will be disabled before the
+ * call to &drm_panel_funcs.disable().
+ *
+ * A typical implementation for a panel driver supporting backlight
+ * control over DP AUX will call this function at probe time.
+ * Backlight will then be handled transparently without requiring
+ * any intervention from the driver.
+ *
+ * drm_panel_dp_aux_backlight() must be called after the call to drm_panel_init().
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux)
+{
+	struct dp_aux_backlight *bl;
+	struct backlight_properties props = { 0 };
+	u16 current_level;
+	u8 current_mode;
+	u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE];
+	int ret;
+
+	if (!panel || !panel->dev || !aux)
+		return -EINVAL;
+
+	bl = devm_kzalloc(panel->dev, sizeof(*bl), GFP_KERNEL);
+	if (!bl)
+		return -ENOMEM;
+
+	bl->aux = aux;
+
+	ret = drm_dp_dpcd_read(aux, DP_EDP_DPCD_REV, edp_dpcd,
+			       EDP_DISPLAY_CTL_CAP_SIZE);
+	if (ret < 0)
+		return ret;
+
+	if (!drm_edp_backlight_supported(edp_dpcd)) {
+		DRM_DEV_INFO(panel->dev, "DP AUX backlight is not supported\n");
+		return 0;
+	}
+
+	ret = drm_edp_backlight_init(aux, &bl->info, 0, edp_dpcd,
+				     &current_level, &current_mode);
+	if (ret < 0)
+		return ret;
+
+	props.type = BACKLIGHT_RAW;
+	props.brightness = current_level;
+	props.max_brightness = bl->info.max;
+
+	bl->base = devm_backlight_device_register(panel->dev, "dp_aux_backlight",
+						  panel->dev, bl,
+						  &dp_aux_bl_ops, &props);
+	if (IS_ERR(bl->base))
+		return PTR_ERR(bl->base);
+
+	panel->backlight = bl->base;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_panel_dp_aux_backlight);
 #endif
 
 MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
index 33605c3..b1ba4de 100644
--- a/include/drm/drm_panel.h
+++ b/include/drm/drm_panel.h
@@ -32,6 +32,7 @@ struct backlight_device;
 struct device_node;
 struct drm_connector;
 struct drm_device;
+struct drm_dp_aux;
 struct drm_panel;
 struct display_timing;
 
@@ -64,8 +65,8 @@ enum drm_panel_orientation;
  * the panel. This is the job of the .unprepare() function.
  *
  * Backlight can be handled automatically if configured using
- * drm_panel_of_backlight(). Then the driver does not need to implement the
- * functionality to enable/disable backlight.
+ * drm_panel_of_backlight() or drm_panel_dp_aux_backlight(). Then the driver
+ * does not need to implement the functionality to enable/disable backlight.
  */
 struct drm_panel_funcs {
 	/**
@@ -144,8 +145,8 @@ struct drm_panel {
 	 * Backlight device, used to turn on backlight after the call
 	 * to enable(), and to turn off backlight before the call to
 	 * disable().
-	 * backlight is set by drm_panel_of_backlight() and drivers
-	 * shall not assign it.
+	 * backlight is set by drm_panel_of_backlight()/drm_panel_dp_aux_backlight()
+	 * and drivers shall not assign it.
 	 */
 	struct backlight_device *backlight;
 
@@ -208,11 +209,17 @@ static inline int of_drm_get_panel_orientation(const struct device_node *np,
 #if IS_ENABLED(CONFIG_DRM_PANEL) && (IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \
 	(IS_MODULE(CONFIG_DRM) && IS_MODULE(CONFIG_BACKLIGHT_CLASS_DEVICE)))
 int drm_panel_of_backlight(struct drm_panel *panel);
+int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux);
 #else
 static inline int drm_panel_of_backlight(struct drm_panel *panel)
 {
 	return 0;
 }
+static inline int drm_panel_dp_aux_backlight(struct drm_panel *panel,
+					     struct drm_dp_aux *aux)
+{
+	return 0;
+}
 #endif
 
 #endif
-- 
2.7.4

Re: [v5 1/5] drm/panel: add basic DP AUX backlight support

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 4142 bytes --]

Hi Rajeev,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on drm-intel/for-linux-next]
[also build test ERROR on drm-tip/drm-tip drm-exynos/exynos-drm-next tegra-drm/drm/tegra/for-next linus/master v5.13-rc3 next-20210528]
[cannot apply to drm/drm-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Rajeev-Nandan/drm-Support-basic-DPCD-backlight-in-panel-simple-and-add-a-new-panel-ATNA33XC20/20210530-235810
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
config: openrisc-randconfig-r002-20210530 (attached as .config)
compiler: or1k-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/1cf1b3f6b1f766d4e932422d1cdec19354acdcc3
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Rajeev-Nandan/drm-Support-basic-DPCD-backlight-in-panel-simple-and-add-a-new-panel-ATNA33XC20/20210530-235810
        git checkout 1cf1b3f6b1f766d4e932422d1cdec19354acdcc3
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=openrisc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> drivers/gpu/drm/drm_panel.c:39:32: error: field 'info' has incomplete type
      39 |  struct drm_edp_backlight_info info;
         |                                ^~~~
   drivers/gpu/drm/drm_panel.c: In function 'dp_aux_backlight_update_status':
>> drivers/gpu/drm/drm_panel.c:362:4: error: implicit declaration of function 'drm_edp_backlight_enable'; did you mean 'backlight_enable'? [-Werror=implicit-function-declaration]
     362 |    drm_edp_backlight_enable(bl->aux, &bl->info, brightness);
         |    ^~~~~~~~~~~~~~~~~~~~~~~~
         |    backlight_enable
>> drivers/gpu/drm/drm_panel.c:366:9: error: implicit declaration of function 'drm_edp_backlight_set_level' [-Werror=implicit-function-declaration]
     366 |   ret = drm_edp_backlight_set_level(bl->aux, &bl->info, brightness);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/gpu/drm/drm_panel.c:369:4: error: implicit declaration of function 'drm_edp_backlight_disable'; did you mean 'backlight_disable'? [-Werror=implicit-function-declaration]
     369 |    drm_edp_backlight_disable(bl->aux, &bl->info);
         |    ^~~~~~~~~~~~~~~~~~~~~~~~~
         |    backlight_disable
   drivers/gpu/drm/drm_panel.c: In function 'drm_panel_dp_aux_backlight':
>> drivers/gpu/drm/drm_panel.c:428:7: error: implicit declaration of function 'drm_edp_backlight_supported' [-Werror=implicit-function-declaration]
     428 |  if (!drm_edp_backlight_supported(edp_dpcd)) {
         |       ^~~~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/gpu/drm/drm_panel.c:433:8: error: implicit declaration of function 'drm_edp_backlight_init' [-Werror=implicit-function-declaration]
     433 |  ret = drm_edp_backlight_init(aux, &bl->info, 0, edp_dpcd,
         |        ^~~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for LOCKDEP
   Depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT && (FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86)
   Selected by
   - PROVE_LOCKING && DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
   - DEBUG_LOCK_ALLOC && DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT


vim +/info +39 drivers/gpu/drm/drm_panel.c

    35	
    36	struct dp_aux_backlight {
    37		struct backlight_device *base;
    38		struct drm_dp_aux *aux;
  > 39		struct drm_edp_backlight_info info;
    40		bool enabled;
    41	};
    42	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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Re: [v5 1/5] drm/panel: add basic DP AUX backlight support

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 4261 bytes --]

Hi Rajeev,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on drm-intel/for-linux-next]
[also build test ERROR on drm-tip/drm-tip drm-exynos/exynos-drm-next tegra-drm/drm/tegra/for-next linus/master v5.13-rc3 next-20210528]
[cannot apply to drm/drm-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Rajeev-Nandan/drm-Support-basic-DPCD-backlight-in-panel-simple-and-add-a-new-panel-ATNA33XC20/20210530-235810
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
config: arm64-randconfig-r005-20210530 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project bc6799f2f79f0ae87e9f1ebf9d25ba799fbd25a9)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm64 cross compiling tool for clang build
        # apt-get install binutils-aarch64-linux-gnu
        # https://github.com/0day-ci/linux/commit/1cf1b3f6b1f766d4e932422d1cdec19354acdcc3
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Rajeev-Nandan/drm-Support-basic-DPCD-backlight-in-panel-simple-and-add-a-new-panel-ATNA33XC20/20210530-235810
        git checkout 1cf1b3f6b1f766d4e932422d1cdec19354acdcc3
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> drivers/gpu/drm/drm_panel.c:39:32: error: field has incomplete type 'struct drm_edp_backlight_info'
           struct drm_edp_backlight_info info;
                                         ^
   drivers/gpu/drm/drm_panel.c:39:9: note: forward declaration of 'struct drm_edp_backlight_info'
           struct drm_edp_backlight_info info;
                  ^
>> drivers/gpu/drm/drm_panel.c:362:4: error: implicit declaration of function 'drm_edp_backlight_enable' [-Werror,-Wimplicit-function-declaration]
                           drm_edp_backlight_enable(bl->aux, &bl->info, brightness);
                           ^
   drivers/gpu/drm/drm_panel.c:362:4: note: did you mean 'backlight_enable'?
   include/linux/backlight.h:363:19: note: 'backlight_enable' declared here
   static inline int backlight_enable(struct backlight_device *bd)
                     ^
>> drivers/gpu/drm/drm_panel.c:366:9: error: implicit declaration of function 'drm_edp_backlight_set_level' [-Werror,-Wimplicit-function-declaration]
                   ret = drm_edp_backlight_set_level(bl->aux, &bl->info, brightness);
                         ^
>> drivers/gpu/drm/drm_panel.c:369:4: error: implicit declaration of function 'drm_edp_backlight_disable' [-Werror,-Wimplicit-function-declaration]
                           drm_edp_backlight_disable(bl->aux, &bl->info);
                           ^
   drivers/gpu/drm/drm_panel.c:369:4: note: did you mean 'backlight_disable'?
   include/linux/backlight.h:379:19: note: 'backlight_disable' declared here
   static inline int backlight_disable(struct backlight_device *bd)
                     ^
>> drivers/gpu/drm/drm_panel.c:428:7: error: implicit declaration of function 'drm_edp_backlight_supported' [-Werror,-Wimplicit-function-declaration]
           if (!drm_edp_backlight_supported(edp_dpcd)) {
                ^
>> drivers/gpu/drm/drm_panel.c:433:8: error: implicit declaration of function 'drm_edp_backlight_init' [-Werror,-Wimplicit-function-declaration]
           ret = drm_edp_backlight_init(aux, &bl->info, 0, edp_dpcd,
                 ^
   6 errors generated.


vim +39 drivers/gpu/drm/drm_panel.c

    35	
    36	struct dp_aux_backlight {
    37		struct backlight_device *base;
    38		struct drm_dp_aux *aux;
  > 39		struct drm_edp_backlight_info info;
    40		bool enabled;
    41	};
    42	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 42938 bytes --]

Re: [v5 1/5] drm/panel: add basic DP AUX backlight support

[Doug Anderson]

Hi,

On Sun, May 30, 2021 at 8:57 AM Rajeev Nandan <rajeevny@codeaurora.org> wrote:
>
> +static int dp_aux_backlight_update_status(struct backlight_device *bd)
> +{
> +       struct dp_aux_backlight *bl = bl_get_data(bd);
> +       u16 brightness = backlight_get_brightness(bd);
> +       int ret = 0;
> +
> +       if (brightness > 0) {
> +               if (!bl->enabled) {
> +                       drm_edp_backlight_enable(bl->aux, &bl->info, brightness);
> +                       bl->enabled = true;
> +                       return 0;
> +               }
> +               ret = drm_edp_backlight_set_level(bl->aux, &bl->info, brightness);
> +       } else {
> +               if (bl->enabled) {
> +                       drm_edp_backlight_disable(bl->aux, &bl->info);
> +                       bl->enabled = false;
> +               }
> +       }

I was trying to figure out if there are any races / locking problems /
problems trying to tweak the backlight when the panel is off. I don't
_think_ there are. Specifically:

1. Before turning the panel off, drm_panel will call
backlight_disable(). That will set BL_CORE_FBBLANK which is not set by
any other calls. Then it will call your
dp_aux_backlight_update_status().

2. Once BL_CORE_FBBLANK is set then backlight_get_brightness() will
always return 0.

This means that a transition from 0 -> non-zero (and enable) will
always only happen when the panel is on, which is good. It also means
that we'll always transition to 0 (disable the backlight) when the
panel turns off.

In terms of other races, it looks like the AUX transfer code handles
grabbing a mutex around transfers so we should be safe there.

So I guess the above is just a long-winded way of saying that this
looks right to me. :-)

BTW: we should probably make sure that the full set of people
identified by `./scripts/get_maintainer.pl -f
./drivers/video/backlight` are CCed on your series. I see Daniel
already and I've added the rest.


> +/**
> + * drm_panel_dp_aux_backlight - create and use DP AUX backlight
> + * @panel: DRM panel
> + * @aux: The DP AUX channel to use
> + *
> + * Use this function to create and handle backlight if your panel
> + * supports backlight control over DP AUX channel using DPCD
> + * registers as per VESA's standard backlight control interface.
> + *
> + * When the panel is enabled backlight will be enabled after a
> + * successful call to &drm_panel_funcs.enable()
> + *
> + * When the panel is disabled backlight will be disabled before the
> + * call to &drm_panel_funcs.disable().
> + *
> + * A typical implementation for a panel driver supporting backlight
> + * control over DP AUX will call this function at probe time.
> + * Backlight will then be handled transparently without requiring
> + * any intervention from the driver.
> + *
> + * drm_panel_dp_aux_backlight() must be called after the call to drm_panel_init().
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux)
> +{
> +       struct dp_aux_backlight *bl;
> +       struct backlight_properties props = { 0 };
> +       u16 current_level;
> +       u8 current_mode;
> +       u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE];
> +       int ret;
> +
> +       if (!panel || !panel->dev || !aux)
> +               return -EINVAL;
> +
> +       bl = devm_kzalloc(panel->dev, sizeof(*bl), GFP_KERNEL);
> +       if (!bl)
> +               return -ENOMEM;
> +
> +       bl->aux = aux;
> +
> +       ret = drm_dp_dpcd_read(aux, DP_EDP_DPCD_REV, edp_dpcd,
> +                              EDP_DISPLAY_CTL_CAP_SIZE);
> +       if (ret < 0)
> +               return ret;
> +
> +       if (!drm_edp_backlight_supported(edp_dpcd)) {
> +               DRM_DEV_INFO(panel->dev, "DP AUX backlight is not supported\n");
> +               return 0;
> +       }

nit: move this part up above the memory allocation. There's no reason
to allocate memory for "bl" if the backlight isn't supported.


> @@ -64,8 +65,8 @@ enum drm_panel_orientation;
>   * the panel. This is the job of the .unprepare() function.
>   *
>   * Backlight can be handled automatically if configured using
> - * drm_panel_of_backlight(). Then the driver does not need to implement the
> - * functionality to enable/disable backlight.
> + * drm_panel_of_backlight() or drm_panel_dp_aux_backlight(). Then the driver
> + * does not need to implement the functionality to enable/disable backlight.
>   */
>  struct drm_panel_funcs {
>         /**
> @@ -144,8 +145,8 @@ struct drm_panel {
>          * Backlight device, used to turn on backlight after the call
>          * to enable(), and to turn off backlight before the call to
>          * disable().
> -        * backlight is set by drm_panel_of_backlight() and drivers
> -        * shall not assign it.
> +        * backlight is set by drm_panel_of_backlight()/drm_panel_dp_aux_backlight()
> +        * and drivers shall not assign it.

Slight nit that I would have wrapped the drm_panel_dp_aux_backlight()
to the next line just to avoid one really long line followed by a
short one.

Other than the two nits (ordering of memory allocation and word
wrapping in a comment), this looks good to me. Feel free to add my
Reviewed-by tag when you fix the nits.

NOTE: Even though I have commit access to drm-misc now, I wouldn't
feel comfortable merging this to drm-misc myself without review
feedback from someone more senior. Obviously we're still blocked on my
and Lyude's series landing first, but even assuming those just land
as-is we'll need some more adult supervision before this can land. ;-)
That being said, I personally think this looks pretty nice now.


-Doug



>          */
>         struct backlight_device *backlight;
>
> @@ -208,11 +209,17 @@ static inline int of_drm_get_panel_orientation(const struct device_node *np,
>  #if IS_ENABLED(CONFIG_DRM_PANEL) && (IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \
>         (IS_MODULE(CONFIG_DRM) && IS_MODULE(CONFIG_BACKLIGHT_CLASS_DEVICE)))
>  int drm_panel_of_backlight(struct drm_panel *panel);
> +int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux);
>  #else
>  static inline int drm_panel_of_backlight(struct drm_panel *panel)
>  {
>         return 0;
>  }
> +static inline int drm_panel_dp_aux_backlight(struct drm_panel *panel,
> +                                            struct drm_dp_aux *aux)
> +{
> +       return 0;
> +}
>  #endif
>
>  #endif
> --
> 2.7.4
>

Re: [v5 1/5] drm/panel: add basic DP AUX backlight support

[rajeevny]

On 03-06-2021 05:35, Doug Anderson wrote:
> Hi,
> 
> On Sun, May 30, 2021 at 8:57 AM Rajeev Nandan <rajeevny@codeaurora.org> 
> wrote:
>> 

> 
> Other than the two nits (ordering of memory allocation and word
> wrapping in a comment), this looks good to me. Feel free to add my
> Reviewed-by tag when you fix the nits.
> 
> NOTE: Even though I have commit access to drm-misc now, I wouldn't
> feel comfortable merging this to drm-misc myself without review
> feedback from someone more senior. Obviously we're still blocked on my
> and Lyude's series landing first, but even assuming those just land
> as-is we'll need some more adult supervision before this can land. ;-)
> That being said, I personally think this looks pretty nice now.
> 
> 
> -Doug

Thank you, Doug.

I'll address the review comments of this patch and another patch (v5 
3/5)
in the next spin. I'll wait for Lyude to check this series, as she 
wanted
to review it in a few days.


Thanks,
Rajeev

[v5 2/5] drm/panel-simple: Support DP AUX backlight

[Rajeev Nandan]

If there is no backlight specified in the device tree and the panel
has access to the DP AUX channel then create a DP AUX backlight if
supported by the panel.

Signed-off-by: Rajeev Nandan <rajeevny@codeaurora.org>
---

This patch depends on [1] (drm/panel: panel-simple: Stash DP AUX bus;
allow using it for DDC) and the previous patch (2/5) of this series.

Changes in v4:
- New

Changes in v5:
- Address review comments and move backlight functions to drm_panel.c (Douglas)
- Create and register DP AUX backlight if there is no backlight specified in the
  device tree and panel has the DP AUX channel. (Douglas)
- The new drm_panel_dp_aux_backlight() will do the drm_edp_backlight_supported() check.

[1] https://lore.kernel.org/dri-devel/20210524165920.v8.7.I18e60221f6d048d14d6c50a770b15f356fa75092@changeid/

 drivers/gpu/drm/panel/panel-simple.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index b09be6e..047fad5 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -800,6 +800,12 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc,
 	if (err)
 		goto disable_pm_runtime;
 
+	if (!panel->base.backlight && panel->aux) {
+		err = drm_panel_dp_aux_backlight(&panel->base, panel->aux);
+		if (err)
+			goto disable_pm_runtime;
+	}
+
 	drm_panel_add(&panel->base);
 
 	return 0;
-- 
2.7.4

Re: [v5 2/5] drm/panel-simple: Support DP AUX backlight

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 9957 bytes --]

Hi Rajeev,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on drm-intel/for-linux-next]
[also build test ERROR on drm-tip/drm-tip drm-exynos/exynos-drm-next tegra-drm/drm/tegra/for-next linus/master v5.13-rc3 next-20210528]
[cannot apply to drm/drm-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Rajeev-Nandan/drm-Support-basic-DPCD-backlight-in-panel-simple-and-add-a-new-panel-ATNA33XC20/20210530-235810
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
config: x86_64-randconfig-a006-20210530 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project bc6799f2f79f0ae87e9f1ebf9d25ba799fbd25a9)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install x86_64 cross compiling tool for clang build
        # apt-get install binutils-x86-64-linux-gnu
        # https://github.com/0day-ci/linux/commit/fedf88beabe2c179d593bbb61ff5df62ac909fa1
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Rajeev-Nandan/drm-Support-basic-DPCD-backlight-in-panel-simple-and-add-a-new-panel-ATNA33XC20/20210530-235810
        git checkout fedf88beabe2c179d593bbb61ff5df62ac909fa1
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> drivers/gpu/drm/panel/panel-simple.c:796:39: error: no member named 'aux' in 'struct panel_simple'
           if (!panel->base.backlight && panel->aux) {
                                         ~~~~~  ^
   include/linux/compiler.h:56:47: note: expanded from macro 'if'
   #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
                                                 ^~~~
   include/linux/compiler.h:58:52: note: expanded from macro '__trace_if_var'
   #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
                                                      ^~~~
>> drivers/gpu/drm/panel/panel-simple.c:796:39: error: no member named 'aux' in 'struct panel_simple'
           if (!panel->base.backlight && panel->aux) {
                                         ~~~~~  ^
   include/linux/compiler.h:56:47: note: expanded from macro 'if'
   #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
                                                 ^~~~
   include/linux/compiler.h:58:61: note: expanded from macro '__trace_if_var'
   #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
                                                               ^~~~
>> drivers/gpu/drm/panel/panel-simple.c:796:39: error: no member named 'aux' in 'struct panel_simple'
           if (!panel->base.backlight && panel->aux) {
                                         ~~~~~  ^
   include/linux/compiler.h:56:47: note: expanded from macro 'if'
   #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
                                                 ^~~~
   include/linux/compiler.h:58:86: note: expanded from macro '__trace_if_var'
   #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
                                                                                        ^~~~
   include/linux/compiler.h:69:3: note: expanded from macro '__trace_if_value'
           (cond) ?                                        \
            ^~~~
   drivers/gpu/drm/panel/panel-simple.c:797:57: error: no member named 'aux' in 'struct panel_simple'
                   err = drm_panel_dp_aux_backlight(&panel->base, panel->aux);
                                                                  ~~~~~  ^
   4 errors generated.


vim +796 drivers/gpu/drm/panel/panel-simple.c

   659	
   660	static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
   661	{
   662		struct panel_simple *panel;
   663		struct display_timing dt;
   664		struct device_node *ddc;
   665		int connector_type;
   666		u32 bus_flags;
   667		int err;
   668	
   669		panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
   670		if (!panel)
   671			return -ENOMEM;
   672	
   673		panel->enabled = false;
   674		panel->prepared_time = 0;
   675		panel->desc = desc;
   676	
   677		panel->no_hpd = of_property_read_bool(dev->of_node, "no-hpd");
   678		if (!panel->no_hpd) {
   679			err = panel_simple_get_hpd_gpio(dev, panel);
   680			if (err)
   681				return err;
   682		}
   683	
   684		panel->supply = devm_regulator_get(dev, "power");
   685		if (IS_ERR(panel->supply))
   686			return PTR_ERR(panel->supply);
   687	
   688		panel->enable_gpio = devm_gpiod_get_optional(dev, "enable",
   689							     GPIOD_OUT_LOW);
   690		if (IS_ERR(panel->enable_gpio)) {
   691			err = PTR_ERR(panel->enable_gpio);
   692			if (err != -EPROBE_DEFER)
   693				dev_err(dev, "failed to request GPIO: %d\n", err);
   694			return err;
   695		}
   696	
   697		err = of_drm_get_panel_orientation(dev->of_node, &panel->orientation);
   698		if (err) {
   699			dev_err(dev, "%pOF: failed to get orientation %d\n", dev->of_node, err);
   700			return err;
   701		}
   702	
   703		ddc = of_parse_phandle(dev->of_node, "ddc-i2c-bus", 0);
   704		if (ddc) {
   705			panel->ddc = of_find_i2c_adapter_by_node(ddc);
   706			of_node_put(ddc);
   707	
   708			if (!panel->ddc)
   709				return -EPROBE_DEFER;
   710		}
   711	
   712		if (desc == &panel_dpi) {
   713			/* Handle the generic panel-dpi binding */
   714			err = panel_dpi_probe(dev, panel);
   715			if (err)
   716				goto free_ddc;
   717		} else {
   718			if (!of_get_display_timing(dev->of_node, "panel-timing", &dt))
   719				panel_simple_parse_panel_timing_node(dev, panel, &dt);
   720		}
   721	
   722		connector_type = desc->connector_type;
   723		/* Catch common mistakes for panels. */
   724		switch (connector_type) {
   725		case 0:
   726			dev_warn(dev, "Specify missing connector_type\n");
   727			connector_type = DRM_MODE_CONNECTOR_DPI;
   728			break;
   729		case DRM_MODE_CONNECTOR_LVDS:
   730			WARN_ON(desc->bus_flags &
   731				~(DRM_BUS_FLAG_DE_LOW |
   732				  DRM_BUS_FLAG_DE_HIGH |
   733				  DRM_BUS_FLAG_DATA_MSB_TO_LSB |
   734				  DRM_BUS_FLAG_DATA_LSB_TO_MSB));
   735			WARN_ON(desc->bus_format != MEDIA_BUS_FMT_RGB666_1X7X3_SPWG &&
   736				desc->bus_format != MEDIA_BUS_FMT_RGB888_1X7X4_SPWG &&
   737				desc->bus_format != MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA);
   738			WARN_ON(desc->bus_format == MEDIA_BUS_FMT_RGB666_1X7X3_SPWG &&
   739				desc->bpc != 6);
   740			WARN_ON((desc->bus_format == MEDIA_BUS_FMT_RGB888_1X7X4_SPWG ||
   741				 desc->bus_format == MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA) &&
   742				desc->bpc != 8);
   743			break;
   744		case DRM_MODE_CONNECTOR_eDP:
   745			if (desc->bus_format == 0)
   746				dev_warn(dev, "Specify missing bus_format\n");
   747			if (desc->bpc != 6 && desc->bpc != 8)
   748				dev_warn(dev, "Expected bpc in {6,8} but got: %u\n", desc->bpc);
   749			break;
   750		case DRM_MODE_CONNECTOR_DSI:
   751			if (desc->bpc != 6 && desc->bpc != 8)
   752				dev_warn(dev, "Expected bpc in {6,8} but got: %u\n", desc->bpc);
   753			break;
   754		case DRM_MODE_CONNECTOR_DPI:
   755			bus_flags = DRM_BUS_FLAG_DE_LOW |
   756				    DRM_BUS_FLAG_DE_HIGH |
   757				    DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE |
   758				    DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE |
   759				    DRM_BUS_FLAG_DATA_MSB_TO_LSB |
   760				    DRM_BUS_FLAG_DATA_LSB_TO_MSB |
   761				    DRM_BUS_FLAG_SYNC_SAMPLE_POSEDGE |
   762				    DRM_BUS_FLAG_SYNC_SAMPLE_NEGEDGE;
   763			if (desc->bus_flags & ~bus_flags)
   764				dev_warn(dev, "Unexpected bus_flags(%d)\n", desc->bus_flags & ~bus_flags);
   765			if (!(desc->bus_flags & bus_flags))
   766				dev_warn(dev, "Specify missing bus_flags\n");
   767			if (desc->bus_format == 0)
   768				dev_warn(dev, "Specify missing bus_format\n");
   769			if (desc->bpc != 6 && desc->bpc != 8)
   770				dev_warn(dev, "Expected bpc in {6,8} but got: %u\n", desc->bpc);
   771			break;
   772		default:
   773			dev_warn(dev, "Specify a valid connector_type: %d\n", desc->connector_type);
   774			connector_type = DRM_MODE_CONNECTOR_DPI;
   775			break;
   776		}
   777	
   778		dev_set_drvdata(dev, panel);
   779	
   780		/*
   781		 * We use runtime PM for prepare / unprepare since those power the panel
   782		 * on and off and those can be very slow operations. This is important
   783		 * to optimize powering the panel on briefly to read the EDID before
   784		 * fully enabling the panel.
   785		 */
   786		pm_runtime_enable(dev);
   787		pm_runtime_set_autosuspend_delay(dev, 1000);
   788		pm_runtime_use_autosuspend(dev);
   789	
   790		drm_panel_init(&panel->base, dev, &panel_simple_funcs, connector_type);
   791	
   792		err = drm_panel_of_backlight(&panel->base);
   793		if (err)
   794			goto disable_pm_runtime;
   795	
 > 796		if (!panel->base.backlight && panel->aux) {
   797			err = drm_panel_dp_aux_backlight(&panel->base, panel->aux);
   798			if (err)
   799				goto disable_pm_runtime;
   800		}
   801	
   802		drm_panel_add(&panel->base);
   803	
   804		return 0;
   805	
   806	disable_pm_runtime:
   807		pm_runtime_disable(dev);
   808	free_ddc:
   809		if (panel->ddc)
   810			put_device(&panel->ddc->dev);
   811	
   812		return err;
   813	}
   814	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 41588 bytes --]

Re: [v5 2/5] drm/panel-simple: Support DP AUX backlight

[Doug Anderson]

Hi,

On Sun, May 30, 2021 at 8:57 AM Rajeev Nandan <rajeevny@codeaurora.org> wrote:
>
> If there is no backlight specified in the device tree and the panel
> has access to the DP AUX channel then create a DP AUX backlight if
> supported by the panel.
>
> Signed-off-by: Rajeev Nandan <rajeevny@codeaurora.org>
> ---
>
> This patch depends on [1] (drm/panel: panel-simple: Stash DP AUX bus;
> allow using it for DDC) and the previous patch (2/5) of this series.
>
> Changes in v4:
> - New
>
> Changes in v5:
> - Address review comments and move backlight functions to drm_panel.c (Douglas)
> - Create and register DP AUX backlight if there is no backlight specified in the
>   device tree and panel has the DP AUX channel. (Douglas)
> - The new drm_panel_dp_aux_backlight() will do the drm_edp_backlight_supported() check.
>
> [1] https://lore.kernel.org/dri-devel/20210524165920.v8.7.I18e60221f6d048d14d6c50a770b15f356fa75092@changeid/
>
>  drivers/gpu/drm/panel/panel-simple.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
> index b09be6e..047fad5 100644
> --- a/drivers/gpu/drm/panel/panel-simple.c
> +++ b/drivers/gpu/drm/panel/panel-simple.c
> @@ -800,6 +800,12 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc,
>         if (err)
>                 goto disable_pm_runtime;
>
> +       if (!panel->base.backlight && panel->aux) {
> +               err = drm_panel_dp_aux_backlight(&panel->base, panel->aux);
> +               if (err)
> +                       goto disable_pm_runtime;
> +       }

It's so nice now!

Reviewed-by: Douglas Anderson <dianders@chromium.org>

[v5 3/5] drm/panel-simple: Support for delays between GPIO & regulator

[Rajeev Nandan]

Some panels datasheets may specify a delay between the enable GPIO and
the regulator. Support this in panel-simple.

Signed-off-by: Rajeev Nandan <rajeevny@codeaurora.org>
---

Changes in v4:
- New

Changes in v5:
- Update description (Douglas)
- Warn if "power_to_enable" or "disable_to_power_off" is non-zero and panel->enable_gpio
  is NULL (Douglas)

 drivers/gpu/drm/panel/panel-simple.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index 047fad5..e3f5b7e 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -133,6 +133,22 @@ struct panel_desc {
 		unsigned int prepare_to_enable;
 
 		/**
+		 * @delay.power_to_enable: Time for the power to enable the display on.
+		 *
+		 * The time (in milliseconds) to wait after powering up the display
+		 * before asserting its enable pin.
+		 */
+		unsigned int power_to_enable;
+
+		/**
+		 * @delay.disable_to_power_off: Time for the disable to power the display off.
+		 *
+		 * The time (in milliseconds) to wait before powering off the display
+		 * after deasserting its enable pin.
+		 */
+		unsigned int disable_to_power_off;
+
+		/**
 		 * @delay.enable: Time for the panel to display a valid frame.
 		 *
 		 * The time (in milliseconds) that it takes for the panel to
@@ -347,6 +363,10 @@ static int panel_simple_suspend(struct device *dev)
 	struct panel_simple *p = dev_get_drvdata(dev);
 
 	gpiod_set_value_cansleep(p->enable_gpio, 0);
+
+	if (p->desc->delay.disable_to_power_off)
+		msleep(p->desc->delay.disable_to_power_off);
+
 	regulator_disable(p->supply);
 	p->unprepared_time = ktime_get();
 
@@ -407,6 +427,9 @@ static int panel_simple_prepare_once(struct panel_simple *p)
 		return err;
 	}
 
+	if (p->desc->delay.power_to_enable)
+		msleep(p->desc->delay.power_to_enable);
+
 	gpiod_set_value_cansleep(p->enable_gpio, 1);
 
 	delay = p->desc->delay.prepare;
@@ -782,6 +805,11 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc,
 		break;
 	}
 
+	if (!panel->enable_gpio && desc->delay.disable_to_power_off)
+		dev_warn(dev, "Specify enable_gpio when using disable_to_power_off delay\n");
+	if (!panel->enable_gpio && desc->delay.power_to_enable)
+		dev_warn(dev, "Specify enable_gpio when using power_to_enable delay\n");
+
 	dev_set_drvdata(dev, panel);
 
 	/*
-- 
2.7.4

Re: [v5 3/5] drm/panel-simple: Support for delays between GPIO & regulator

[Doug Anderson]

Hi,

On Sun, May 30, 2021 at 8:57 AM Rajeev Nandan <rajeevny@codeaurora.org> wrote:
>
> Some panels datasheets may specify a delay between the enable GPIO and
> the regulator. Support this in panel-simple.
>
> Signed-off-by: Rajeev Nandan <rajeevny@codeaurora.org>
> ---
>
> Changes in v4:
> - New
>
> Changes in v5:
> - Update description (Douglas)
> - Warn if "power_to_enable" or "disable_to_power_off" is non-zero and panel->enable_gpio
>   is NULL (Douglas)
>
>  drivers/gpu/drm/panel/panel-simple.c | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
>
> diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
> index 047fad5..e3f5b7e 100644
> --- a/drivers/gpu/drm/panel/panel-simple.c
> +++ b/drivers/gpu/drm/panel/panel-simple.c
> @@ -133,6 +133,22 @@ struct panel_desc {
>                 unsigned int prepare_to_enable;
>
>                 /**
> +                * @delay.power_to_enable: Time for the power to enable the display on.
> +                *
> +                * The time (in milliseconds) to wait after powering up the display
> +                * before asserting its enable pin.
> +                */
> +               unsigned int power_to_enable;
> +
> +               /**
> +                * @delay.disable_to_power_off: Time for the disable to power the display off.
> +                *
> +                * The time (in milliseconds) to wait before powering off the display
> +                * after deasserting its enable pin.
> +                */
> +               unsigned int disable_to_power_off;
> +
> +               /**
>                  * @delay.enable: Time for the panel to display a valid frame.
>                  *
>                  * The time (in milliseconds) that it takes for the panel to
> @@ -347,6 +363,10 @@ static int panel_simple_suspend(struct device *dev)
>         struct panel_simple *p = dev_get_drvdata(dev);
>
>         gpiod_set_value_cansleep(p->enable_gpio, 0);
> +
> +       if (p->desc->delay.disable_to_power_off)
> +               msleep(p->desc->delay.disable_to_power_off);
> +
>         regulator_disable(p->supply);
>         p->unprepared_time = ktime_get();
>
> @@ -407,6 +427,9 @@ static int panel_simple_prepare_once(struct panel_simple *p)
>                 return err;
>         }
>
> +       if (p->desc->delay.power_to_enable)
> +               msleep(p->desc->delay.power_to_enable);
> +
>         gpiod_set_value_cansleep(p->enable_gpio, 1);
>
>         delay = p->desc->delay.prepare;
> @@ -782,6 +805,11 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc,
>                 break;
>         }
>
> +       if (!panel->enable_gpio && desc->delay.disable_to_power_off)
> +               dev_warn(dev, "Specify enable_gpio when using disable_to_power_off delay\n");
> +       if (!panel->enable_gpio && desc->delay.power_to_enable)
> +               dev_warn(dev, "Specify enable_gpio when using power_to_enable delay\n");

Last nit is that the warning messages could be a little confusing to
someone reading the logs. I guess the target audience of the error
message is probably someone doing bringup. That person specified a
panel in their device tree and maybe isn't even aware that they're
using "disable_to_power_off" or "power_to_enable". Maybe wording
instead:

Need a delay after disabling panel GPIO, but a GPIO wasn't provided.
Need a delay after enabling panel GPIO, but a GPIO wasn't provided.

That's definitely getting into nittiness, though and I wouldn't be
upset if the patch landed with the existing messages. Thus, with or
without the change to the error message:

Reviewed-by: Douglas Anderson <dianders@chromium.org>

[v5 4/5] dt-bindings: display: simple: Add Samsung ATNA33XC20

[Rajeev Nandan]

Add Samsung 13.3" FHD eDP AMOLED panel.

Signed-off-by: Rajeev Nandan <rajeevny@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
---

(no changes since v4)

Changes in v4:
- New

 Documentation/devicetree/bindings/display/panel/panel-simple.yaml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/panel-simple.yaml b/Documentation/devicetree/bindings/display/panel/panel-simple.yaml
index 4a0a5e1..f5acfd6 100644
--- a/Documentation/devicetree/bindings/display/panel/panel-simple.yaml
+++ b/Documentation/devicetree/bindings/display/panel/panel-simple.yaml
@@ -242,6 +242,8 @@ properties:
       - rocktech,rk101ii01d-ct
         # Rocktech Display Ltd. RK070ER9427 800(RGB)x480 TFT LCD panel
       - rocktech,rk070er9427
+        # Samsung 13.3" FHD (1920x1080 pixels) eDP AMOLED panel
+      - samsung,atna33xc20
         # Samsung 12.2" (2560x1600 pixels) TFT LCD panel
       - samsung,lsn122dl01-c01
         # Samsung Electronics 10.1" WSVGA TFT LCD panel
-- 
2.7.4

Re: [v5 4/5] dt-bindings: display: simple: Add Samsung ATNA33XC20

[Rob Herring]

On Sun, 30 May 2021 21:26:11 +0530, Rajeev Nandan wrote:
> Add Samsung 13.3" FHD eDP AMOLED panel.
> 
> Signed-off-by: Rajeev Nandan <rajeevny@codeaurora.org>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
> ---
> 
> (no changes since v4)
> 
> Changes in v4:
> - New
> 
>  Documentation/devicetree/bindings/display/panel/panel-simple.yaml | 2 ++
>  1 file changed, 2 insertions(+)
> 

Acked-by: Rob Herring <robh@kernel.org>

[v5 5/5] drm/panel-simple: Add Samsung ATNA33XC20

[Rajeev Nandan]

Add Samsung 13.3" FHD eDP AMOLED panel.

Signed-off-by: Rajeev Nandan <rajeevny@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
---

Changes in v4:
- New

Changes in v5:
- Remove "uses_dpcd_backlight" property, not required now. (Douglas)

 drivers/gpu/drm/panel/panel-simple.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index e3f5b7e..ce60517 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -3562,6 +3562,36 @@ static const struct panel_desc rocktech_rk101ii01d_ct = {
 	.connector_type = DRM_MODE_CONNECTOR_LVDS,
 };
 
+static const struct drm_display_mode samsung_atna33xc20_mode = {
+	.clock = 138770,
+	.hdisplay = 1920,
+	.hsync_start = 1920 + 48,
+	.hsync_end = 1920 + 48 + 32,
+	.htotal = 1920 + 48 + 32 + 80,
+	.vdisplay = 1080,
+	.vsync_start = 1080 + 8,
+	.vsync_end = 1080 + 8 + 8,
+	.vtotal = 1080 + 8 + 8 + 16,
+	.flags = DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_NVSYNC,
+};
+
+static const struct panel_desc samsung_atna33xc20 = {
+	.modes = &samsung_atna33xc20_mode,
+	.num_modes = 1,
+	.bpc = 10,
+	.size = {
+		.width = 294,
+		.height = 165,
+	},
+	.delay = {
+		.disable_to_power_off = 150,
+		.power_to_enable = 150,
+		.hpd_absent_delay = 200,
+		.unprepare = 500,
+	},
+	.connector_type = DRM_MODE_CONNECTOR_eDP,
+};
+
 static const struct drm_display_mode samsung_lsn122dl01_c01_mode = {
 	.clock = 271560,
 	.hdisplay = 2560,
@@ -4563,6 +4593,9 @@ static const struct of_device_id platform_of_match[] = {
 		.compatible = "rocktech,rk101ii01d-ct",
 		.data = &rocktech_rk101ii01d_ct,
 	}, {
+		.compatible = "samsung,atna33xc20",
+		.data = &samsung_atna33xc20,
+	}, {
 		.compatible = "samsung,lsn122dl01-c01",
 		.data = &samsung_lsn122dl01_c01,
 	}, {
-- 
2.7.4