On Wed, Oct 18, 2017 at 1:11 PM, Meghana Madhyastha
<meghana.madhyastha@xxxxxxxxx> wrote:
> On Mon, Oct 16, 2017 at 02:26:00PM -0400, Sean Paul wrote:
>> On Fri, Oct 13, 2017 at 6:42 PM, Noralf Trønnes <noralf@xxxxxxxxxxx> wrote:
>> >
>> > Den 13.10.2017 22.25, skrev Sean Paul:
>> >>
>> >> 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)?
>> >
>> >
>> > I came up with that name modelled after gpiod_get() and gpiod_put() and I
>> > deliberately kept the of_ part out of the name like the gpio functions.
>> > gpiod_get() checks OF, ACPI and platform for gpios and calling it
>> > backlight_get() would keep the door open for other ways of connecting
>> > backlight devices in the future, other than Device Tree.
>> >
>>
>> Thanks for the background, Noralf! Apologies for stepping on top of
>> your previous reviews.
>>
>> > I think of_find_backlight() would be better than *_by_name(), since
>> > 'backlight' is the common DT property name, so it wouldn't make much sense
>> > to require every caller to pass in the same name.
>> >
>>
>> of_find_backlight() sounds like a good compromise.
>>
>> Sean
>
> Are there any changes that need to be made to this patchset now ?
>
I still prefer s/backlight_get/of_find_backlight/ and it seems Noralf
is Ok with that too. I think there were also review comments
surrounding the _put function?
Sean
> Regards,
> Meghana
>
>>
>> > Either way is fine with me.
>> >
>> > Noralf.
>> >
>> >
>> >
>> >>> 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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>> >>> https://groups.google.com/d/msgid/outreachy-kernel/e2ef05bf46438427d08c6a61fe5058156800db95.1507890285.git.meghana.madhyastha%40gmail.com.
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>> >
>> >
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