On Wed, Sep 27, 2017 at 05:08:07PM +0200, Noralf Trønnes wrote:
>
> Den 27.09.2017 15.54, skrev Meghana Madhyastha:
> > 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@xxxxxxxxx>
> > ---
>
> I suggest you split this patch in 2, one to add the function and one to
> use it in tinydrm.
In general I'd agree to split into 3 phases: 1) add new function 2)
convert drivers 3) remove old one.
But since there's only 1 caller this seems like overkill.
> > drivers/gpu/drm/drm_of.c | 41 ++++++++++++++++++++++++++
> > 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, 44 insertions(+), 42 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c
> > index 8dafbdf..d8cded3 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 +261,43 @@ 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.
>
> Please add a note here about the callers responsibility to call
> put_device() when releasing the resource.
> See the of_find_backlight_by_node() docs.
>
> > + *
> > + * 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);
>
> Can you also please add a devm_ version of this function. tinydrm uses
> devres[1] versions of functions for requiring device resources, so it
> would be nice to do this for backlight as well. tinydrm is currently
> broken in this respect, it doesn't put the backlight device.
>
> I had a devm_of_find_backlight() version lying around that I've adjusted
> to give you an idea of what I'm talking about:
>
> static void devm_drm_of_find_backlight_release(void *data)
> {
> put_device(data);
> }
>
> 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;
> }
Good idea for a follow up patch imo.
Another follow up patch series which would be really good is then
converting drivers over to using this (preferrably the devm_ version). A
quick git grep shows there's quite a few.
Either way, the patch that adds these to the core should also add a TODO
entry so we don't forget to complete this conversion.
Thanks, Daniel
>
> [1] https://www.kernel.org/doc/Documentation/driver-model/devres.txt
>
> Noralf.
>
> > 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)
> > 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);
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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