On Tue, Oct 24, 2017 at 04:56:59PM +0100, Daniel Thompson wrote:
On 24/10/17 16:38, Sean Paul wrote:
On Sat, Oct 21, 2017 at 05:27:33PM +0530, Meghana Madhyastha wrote:
Rename tinydrm_of_find_backlight to of_find_backlight and move it to linux/backlight.c so that it can be used by other drivers.
Signed-off-by: Meghana Madhyastha meghana.madhyastha@gmail.com
Changes in v14: -s/backlight_get/of_find_backlight/
drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c | 40 -------------------------- drivers/gpu/drm/tinydrm/mi0283qt.c | 3 +- drivers/video/backlight/backlight.c | 37 ++++++++++++++++++++++++ include/drm/tinydrm/tinydrm-helpers.h | 2 -- include/linux/backlight.h | 19 ++++++++++++ 5 files changed, 58 insertions(+), 43 deletions(-)
diff --git a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c index a42dee6..cb1a01a 100644 --- a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c +++ b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c @@ -236,46 +236,6 @@ void tinydrm_xrgb8888_to_gray8(u8 *dst, void *vaddr, struct drm_framebuffer *fb, } EXPORT_SYMBOL(tinydrm_xrgb8888_to_gray8); -/**
- tinydrm_of_find_backlight - Find backlight device in device-tree
- @dev: Device
- This function looks for a DT node pointed to by a property named 'backlight'
- and uses of_find_backlight_by_node() to get the backlight device.
- Additionally if the brightness property is zero, it is set to
- max_brightness.
- 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 *tinydrm_of_find_backlight(struct device *dev) -{
- struct backlight_device *backlight;
- struct device_node *np;
- np = of_parse_phandle(dev->of_node, "backlight", 0);
- if (!np)
return NULL;- backlight = of_find_backlight_by_node(np);
- of_node_put(np);
- if (!backlight)
return ERR_PTR(-EPROBE_DEFER);- if (!backlight->props.brightness) {
backlight->props.brightness = backlight->props.max_brightness;DRM_DEBUG_KMS("Backlight brightness set to %d\n",backlight->props.brightness);- }
- return backlight;
-} -EXPORT_SYMBOL(tinydrm_of_find_backlight);
- #if IS_ENABLED(CONFIG_SPI) /**
diff --git a/drivers/gpu/drm/tinydrm/mi0283qt.c b/drivers/gpu/drm/tinydrm/mi0283qt.c index 7fd2691..53ab5a0 100644 --- a/drivers/gpu/drm/tinydrm/mi0283qt.c +++ b/drivers/gpu/drm/tinydrm/mi0283qt.c @@ -12,6 +12,7 @@ #include <drm/tinydrm/ili9341.h> #include <drm/tinydrm/mipi-dbi.h> #include <drm/tinydrm/tinydrm-helpers.h> +#include <linux/backlight.h> #include <linux/delay.h> #include <linux/gpio/consumer.h> #include <linux/module.h> @@ -188,7 +189,7 @@ static int mi0283qt_probe(struct spi_device *spi) if (IS_ERR(mipi->regulator)) return PTR_ERR(mipi->regulator);
- mipi->backlight = tinydrm_of_find_backlight(dev);
- mipi->backlight = of_find_backlight(dev); if (IS_ERR(mipi->backlight)) return PTR_ERR(mipi->backlight);
diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c index 8049e76..76d46c3 100644 --- a/drivers/video/backlight/backlight.c +++ b/drivers/video/backlight/backlight.c @@ -580,6 +580,43 @@ struct backlight_device *of_find_backlight_by_node(struct device_node *node) EXPORT_SYMBOL(of_find_backlight_by_node); #endif +/**
- of_find_backlight - Get backlight device
- @dev: Device
- This function looks for a property named 'backlight' on the DT node
- connected to @dev and looks up the backlight device.
- Call backlight_put() to drop the reference on the backlight device.
- Returns:
- A pointer to the backlight device if found.
- Error pointer -EPROBE_DEFER if the DT property is set, but no backlight
- device is found.
- NULL if there's no backlight property.
- */
+struct backlight_device *of_find_backlight(struct device *dev) +{
- struct backlight_device *bd = NULL;
- struct device_node *np;
- if (!dev)
return NULL;- if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
np = of_parse_phandle(dev->of_node, "backlight", 0);if (np) {bd = of_find_backlight_by_node(np);of_node_put(np);if (!bd)return ERR_PTR(-EPROBE_DEFER);}- }
- return bd;
+} +EXPORT_SYMBOL(of_find_backlight);
- static void __exit backlight_class_exit(void) { class_destroy(backlight_class);
diff --git a/include/drm/tinydrm/tinydrm-helpers.h b/include/drm/tinydrm/tinydrm-helpers.h index f54fae0..0a4ddbc 100644 --- a/include/drm/tinydrm/tinydrm-helpers.h +++ b/include/drm/tinydrm/tinydrm-helpers.h @@ -46,8 +46,6 @@ void tinydrm_xrgb8888_to_rgb565(u16 *dst, void *vaddr, void tinydrm_xrgb8888_to_gray8(u8 *dst, void *vaddr, struct drm_framebuffer *fb, struct drm_clip_rect *clip); -struct backlight_device *tinydrm_of_find_backlight(struct device *dev);
- size_t tinydrm_spi_max_transfer_size(struct spi_device *spi, size_t max_len); bool tinydrm_spi_bpw_supported(struct spi_device *spi, u8 bpw); int tinydrm_spi_transfer(struct spi_device *spi, u32 speed_hz,
diff --git a/include/linux/backlight.h b/include/linux/backlight.h index b88fabb..f98b684 100644 --- a/include/linux/backlight.h +++ b/include/linux/backlight.h @@ -159,6 +159,16 @@ static inline int backlight_disable(struct backlight_device *bd) return backlight_update_status(bd); } +/**
- backlight_put - Drop backlight reference
- @bd: the backlight device to put
- */
+static inline void backlight_put(struct backlight_device *bd) +{
- if (bd)
put_device(&bd->dev);+}
As I mentioned in my last review, I don't think we need this function.
Just to check... some DRM drivers do allow themselves to work if CONFIG_BACKLIGHT_CLASS_DEVICE isn't enabled (as discussed earlier in the thread ;-). Did you consider what happens when this happens.
Wrapped up with backlight_put() we are sure never to accidentally dereference bd in DRM de-init paths when CONFIG_BACKLIGHT_CLASS_DEVICVE if it is not set. With a raw put_device() all that conditional logic ends up on the driver.
Thanks for pointing that out, definitely a fair point.
I don't really mind putting the NULL check in the driver code. The return values of of_find_backlight are well documented, so it shouldn't be too much of a problem.
That said, this is your rodeo, so if you prefer to supply the put helper, that's A-Ok with me.
Sean
Daniel.
- extern struct backlight_device *backlight_device_register(const char *name, struct device *dev, void *devdata, const struct backlight_ops *ops, const struct backlight_properties *props);
@@ -202,4 +212,13 @@ of_find_backlight_by_node(struct device_node *node) } #endif +#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE) +struct backlight_device *of_find_backlight(struct device *dev); +#else +static inline struct backlight_device *of_find_backlight(struct device *dev) +{
- return NULL;
+} +#endif
- #endif
-- 2.7.4
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