On Fri, Oct 13, 2017 at 04:11:43PM +0530, Meghana Madhyastha wrote:
> Rename tinydrm_of_find_backlight to backlight_get and move it
> to linux/backlight.c so that it can be used by other drivers.
[apologies if this has been brought up in previous versions, I haven't been
following closely]
I don't think "backlight_get" is a good name for this function. How about
of_find_backlight_by_name (since there's already of_find_backlight_by_node)?
>
> Signed-off-by: Meghana Madhyastha <meghana.madhyastha@xxxxxxxxx>
> ---
> Changes in v13:
> -Add backlight_put to backlight.h in this patch
>
> 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..a932185 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 = backlight_get(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..c4e94d0 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
>
> +/**
> + * backlight_get - 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 *backlight_get(struct device *dev)
> +{
> + struct backlight_device *bd = NULL;
> + struct device_node *np;
> +
> + if (!dev)
> + return NULL;
> +
> + if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
I'm not really used to seeing IS_ENABLED(CONFIG_BLAH) inline. The common
patterns seems to be wrapping the actual implementation in #if
IS_ENABLED(CONFIG_BLAH) and then sticking a stub implementation in the #else.
I see below that you already have a stub if backlight is not enabled, so expand
that #if to include CONFIG_OF as well.
> + 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(backlight_get);
> +
> 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..987a6d7 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);
> +}
I'm not convinced this function needs to exist.
> +
> 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 *backlight_get(struct device *dev);
> +#else
> +static inline struct backlight_device *backlight_get(struct device *dev)
> +{
> + return NULL;
> +}
> +#endif
> +
> #endif
> --
> 2.7.4
>
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--
Sean Paul, Software Engineer, Google / Chromium OS
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