[PATCH] drm/tinydrm: Move tinydrm_of_find_backlight into drm_of.c
Meghana Madhyastha
meghana.madhyastha at gmail.com
Fri Sep 29 03:47:41 UTC 2017
On Thu, Sep 28, 2017 at 11:38:36AM +0200, Daniel Vetter wrote:
> On Thu, Sep 28, 2017 at 11:27 AM, Meghana Madhyastha
> <meghana.madhyastha at gmail.com> wrote:
> > On Thu, Sep 28, 2017 at 09:15:39AM +0200, Daniel Vetter wrote:
> >> 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 at gmail.com>
> >> > > ---
> >> >
> >> > 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.
> >
> > I have a quick question on this. I did a git grep and found that the
> > other drivers used the function of_find_backlight_by_node defined in
> > video/backlight. This seems to be doing a different thing (taking
> > struct device_node* as a parameter instead of struct device*).
> > Basically, this function finds the backlight device by device-tree node.
> > How would you suggest converting these cases ?
>
> The function you're moving also uses of_find_backglight_by_node, but
> wraps it up to be more convenient for drm drivers. I didn't carefully
> audit all of them, but I'd assume a bunch of these other callers might
> be able to use the same convenience helper. But I might be wrong, and
> we need a drm_panel specific helper. Just something I've noticed and
> figured might be worth to check.
> -Daniel
Yes you are right. Sorry, I hadn't carefully looked into all of them,
but now having checked the calls, it looks like they can all be replaced by
of_find_backlight. The only thing extra of_find_backlight is doing is
setting the brightness to be the maximum brightness which makes sense here.
I can send in a patch to replace these.
> > Thanks and regards,
> > Meghana
> >
> >> 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
>
>
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
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