[PATCH v3 1/2] drm/tinydrm: Move tinydrm_of_find_backlight into drm_of.c
Noralf Trønnes
noralf at tronnes.org
Thu Sep 28 16:02:27 UTC 2017
Den 28.09.2017 16.08, skrev Daniel Vetter:
> On Thu, Sep 28, 2017 at 02:44:34PM +0530, Meghana Madhyastha wrote:
>> Rename tinydrm_of_find_backlight to drm_of_find_backlight
>> and move it into drm_of.c from tinydrm-helpers.c. This is
>> because other drivers in the drm subsystem might need to call
>> this function. In that case and otherwise, it is better from
>> an organizational point of view to move it into drm_of.c along
>> with the other _of.c functions.
>>
>> Signed-off-by: Meghana Madhyastha <meghana.madhyastha at gmail.com>
>> ---
>> Changes in v3:
>> -Change it back to a single patch from two patches in v2
>>
>> drivers/gpu/drm/drm_of.c | 44 ++++++++++++++++++++++++++
>> drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c | 40 -----------------------
>> drivers/gpu/drm/tinydrm/mi0283qt.c | 3 +-
>> include/drm/drm_of.h | 1 +
>> include/drm/tinydrm/tinydrm-helpers.h | 1 -
>> 5 files changed, 47 insertions(+), 42 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c
>> index 8dafbdf..d878d3a 100644
>> --- a/drivers/gpu/drm/drm_of.c
>> +++ b/drivers/gpu/drm/drm_of.c
>> @@ -1,6 +1,7 @@
>> #include <linux/component.h>
>> #include <linux/export.h>
>> #include <linux/list.h>
>> +#include <linux/backlight.h>
>> #include <linux/of_graph.h>
>> #include <drm/drmP.h>
>> #include <drm/drm_bridge.h>
>> @@ -260,3 +261,46 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
>> return ret;
>> }
>> EXPORT_SYMBOL_GPL(drm_of_find_panel_or_bridge);
>> +
>> +/**
>> + * drm_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.
>> + *
>> + * Note: It is the responsibility of the caller to call put_device() when
>> + * releasing the resource.
>> + *
>> + * 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 *drm_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(drm_of_find_backlight);
>> diff --git a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
>> index bd6cce0..cd4c6a5 100644
>> --- a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
>> +++ b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
>> @@ -237,46 +237,6 @@ 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);
>> -
>> -/**
>> * tinydrm_enable_backlight - Enable backlight helper
>> * @backlight: Backlight device
>> *
>> diff --git a/drivers/gpu/drm/tinydrm/mi0283qt.c b/drivers/gpu/drm/tinydrm/mi0283qt.c
>> index 7e5bb7d..5e3d635 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 <drm/drm_of.h>
>> #include <linux/delay.h>
>> #include <linux/gpio/consumer.h>
>> #include <linux/module.h>
>> @@ -189,7 +190,7 @@ 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 = 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 104dd51..e8fba5b 100644
>> --- a/include/drm/drm_of.h
>> +++ b/include/drm/drm_of.h
>> @@ -29,6 +29,7 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
>> int port, int endpoint,
>> struct drm_panel **panel,
>> struct drm_bridge **bridge);
>> +struct backlight_device *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)
> Minor detail I missed: The dummy version for the #else here is missing.
> Not a problem for tinydrm, but might be an issue for a driver where
> CONFIG_OF is optional.
Yeah, we need a dummy version. tinydrm can in theory be used on non-DT
platforms. The only resource that isn't available there is backlight
since there is no platform or ACPI way of describing that dependency.
Another problem I discovered when trying to compile this, is that if
DRM is builtin and LCD_CLASS_DEVICE is a module:
drivers/gpu/drm/drm_of.c:292: undefined reference to
`of_find_backlight_by_node'
I see that I solved this in tinydrm by just selecting
BACKLIGHT_LCD_SUPPORT and LCD_CLASS_DEVICE. I'm not aware of a way to
force LCD_CLASS_DEVICE to be builtin if DRM is builtin.
Arnd fixed a similar type of dependecy in the repaper driver by forcing
repaper to be a module if necessary. To be honest, I don't know why his
fix works:
https://github.com/torvalds/linux/commit/8312a3fe84b96e30a010fa20f933606d976ac002
Another way of solving this is to put the function in
drivers/gpu/drm/drm_backlight.c and add a DRM_BACKLIGHT konfig option
that does the selection.
Noralf.
> Otherwise I think this patch looks good.
> -Daniel
>
>> diff --git a/include/drm/tinydrm/tinydrm-helpers.h b/include/drm/tinydrm/tinydrm-helpers.h
>> index d554ded..e40ef2d 100644
>> --- a/include/drm/tinydrm/tinydrm-helpers.h
>> +++ b/include/drm/tinydrm/tinydrm-helpers.h
>> @@ -46,7 +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);
>> int tinydrm_enable_backlight(struct backlight_device *backlight);
>> int tinydrm_disable_backlight(struct backlight_device *backlight);
>>
>> --
>> 2.7.4
>>
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