Den 30.09.2017 11.05, skrev Meghana Madhyastha:

Add devm_drm_of_find_backlight and the corresponding release function because some drivers such as tinydrm use devres versions of functions for requiring device resources.

Signed-off-by: Meghana Madhyastha meghana.madhyastha@gmail.com

Changes in v5: -None

drivers/gpu/drm/drm_of.c | 47 ++++++++++++++++++++++++++++++++++++++ drivers/gpu/drm/tinydrm/mi0283qt.c | 2 +- include/drm/drm_of.h | 1 + 3 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c index d878d3a..cd80dfc 100644 --- a/drivers/gpu/drm/drm_of.c +++ b/drivers/gpu/drm/drm_of.c @@ -304,3 +304,50 @@ struct backlight_device *drm_of_find_backlight(struct device *dev) return backlight; } EXPORT_SYMBOL(drm_of_find_backlight);

+/**

• • devm_drm_of_find_backlight_release - Release backlight device
• • @dev: Device
• • This is the release function corresponding to the devm_drm_of_find_backlight.
• • Each devres entry is associated with a release function.
• */

No docs on internal functions.

+static void devm_drm_of_find_backlight_release(void *data) +{

• put_device(data);

+}

+/**

• • devm_drm_of_find_backlight - Find backlight device in device-tree
• • devres version of the function
• • @dev: Device
• • This is the devres version of the function drm_of_find_backlight.
• • Some drivers use devres versions of functions for
• • requiring device resources.
• • Returns:
• • NULL if there's no backlight property.
• • Error pointer -EPROBE_DEFER if the DT node is found, but no backlight device
• • is found.
• • If the backlight device is found, a pointer to the structure is returned.
• */

+struct backlight_device *devm_drm_of_find_backlight(struct device *dev) +{

• struct backlight_device *backlight;
• int ret;
• backlight = drm_of_find_backlight(dev);
• if (IS_ERR_OR_NULL(backlight))

• return backlight;
  

• ret = devm_add_action(dev, devm_drm_of_find_backlight_release,

• 	      &backlight->dev);
  

• if (ret) {

• put_device(&backlight->dev);
  

• return ERR_PTR(ret);
  

• }
• return backlight;

+} +EXPORT_SYMBOL(devm_drm_of_find_backlight); diff --git a/drivers/gpu/drm/tinydrm/mi0283qt.c b/drivers/gpu/drm/tinydrm/mi0283qt.c index 5e3d635..d37f658 100644 --- a/drivers/gpu/drm/tinydrm/mi0283qt.c +++ b/drivers/gpu/drm/tinydrm/mi0283qt.c @@ -190,7 +190,7 @@ static int mi0283qt_probe(struct spi_device *spi) if (IS_ERR(mipi->regulator)) return PTR_ERR(mipi->regulator);

• mipi->backlight = drm_of_find_backlight(dev);

• mipi->backlight = devm_drm_of_find_backlight(dev); if (IS_ERR(mipi->backlight)) return PTR_ERR(mipi->backlight);

diff --git a/include/drm/drm_of.h b/include/drm/drm_of.h index e8fba5b..b2d6e0c 100644 --- a/include/drm/drm_of.h +++ b/include/drm/drm_of.h @@ -30,6 +30,7 @@ int drm_of_find_panel_or_bridge(const struct device_node *np, struct drm_panel **panel, struct drm_bridge **bridge); struct backlight_device *drm_of_find_backlight(struct device *dev); +struct backlight_device *devm_drm_of_find_backlight(struct device *dev); #else static inline uint32_t drm_of_find_possible_crtcs(struct drm_device *dev, struct device_node *port)

Den 30.09.2017 11.07, skrev Meghana Madhyastha:

Add the dummy versions (function definition returning -EINVAL) of drm_of_find_backlight and devm_drm_of_find_backlight in the #else part of the conditional directive in drm_of.h. This is needed for drivers where CONFIG_OF is optional.

Signed-off-by: Meghana Madhyastha meghana.madhyastha@gmail.com

You have to fold this into the previous patches, or else someone bisecting might end up with a broken build. And you need to return NULL. This shows that you haven't tried building with CONFIG_OF=n ;-)

Noralf.

Changes in v5: -Fix the kbuild errors and warnings such as return 0 instead of -EINVAL.

include/drm/drm_of.h | 13 +++++++++++++ 1 file changed, 13 insertions(+)

diff --git a/include/drm/drm_of.h b/include/drm/drm_of.h index b2d6e0c..55c9304 100644 --- a/include/drm/drm_of.h +++ b/include/drm/drm_of.h @@ -60,6 +60,7 @@ static inline int drm_of_encoder_active_endpoint(struct device_node *node, { return -EINVAL; }

• static inline int drm_of_find_panel_or_bridge(const struct device_node *np, int port, int endpoint, struct drm_panel **panel,

@@ -67,6 +68,18 @@ static inline int drm_of_find_panel_or_bridge(const struct device_node *np, { return -EINVAL; }

+static inline struct backlight_device *drm_of_find_backlight(

• 			struct device *dev)
  

+{

• return 0;

+}

+static inline struct backlight_device *devm_drm_of_find_backlight(

• 				struct device *dev)
  

+{

• return 0;

+} #endif

static inline int drm_of_encoder_active_endpoint_id(struct device_node *node,

Den 30.09.2017 11.10, skrev Meghana Madhyastha:

Add select BACKLIGHT_LCD_SUPPORT, BACKLIGHT_CLASS_DEVICE to the Kconfig of drm. This is required for the successful build of drm_of_find_backlight helpers.

Signed-off-by: Meghana Madhyastha meghana.madhyastha@gmail.com

Changes in v5: -This commit was not present in v4. Selecting BACKLIGHT_LCD_SUPPORT, BACKLIGHT_CLASS_DEVICE in the Kconfig file under the symbol DRM seems to fix the Kbuild error drm_of.c:(.text+0x3bc): undefined reference to `of_find_backlight_by_node'.

drivers/gpu/drm/Kconfig | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index 83cb2a8..3ba5632 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -7,6 +7,8 @@ menuconfig DRM tristate "Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)" depends on (AGP || AGP=n) && !EMULATED_CMPXCHG && HAS_DMA

• select BACKLIGHT_LCD_SUPPORT
• select BACKLIGHT_CLASS_DEVICE select HDMI select FB_CMDLINE select I2C

A night's sleep has made this more clear, we don't need 'depends on' or select as you have tried here, it's enough that we make a change in the backlight subsystem as I outlined earlier:

include/linux/backlight.h:

-#ifdef CONFIG_OF +#if defined(CONFIG_OF) && IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)  struct backlight_device *of_find_backlight_by_node(struct device_node *node);  #else  static inline struct backlight_device *  of_find_backlight_by_node(struct device_node *node)  {      return NULL;  }  #endif

Now we don't have to care about backlight being built-in, module or disabled.

This patch has to be the first in the patchset. No single patch can break anything even if it's fixed later. This is so people can bisect.

Noralf.