Re: [PATCH v19 10/10] drm/omapdrm: Use of_find_backlight helper

From: Sean Paul
Date: Wed Jan 24 2018 - 14:26:56 EST


On Wed, Jan 24, 2018 at 02:23:46PM -0500, Sean Paul wrote:
> On Wed, Jan 24, 2018 at 04:41:38PM +0000, Meghana Madhyastha wrote:
> > Replace of_find_backlight_by_node and of the code around it
> > with of_find_backlight helper to avoid repetition of code.
> >
> > Signed-off-by: Meghana Madhyastha <meghana.madhyastha@xxxxxxxxx>
> > ---
> > Changes in v19:
> > -Changed to devm version of of_find_backlight in omapdrm (patch 10)
> > -removed assigning pdev->dev to variable dev in omapdrm (patch 10)
> >
> > drivers/gpu/drm/omapdrm/displays/panel-dpi.c | 25 +++++--------------------
> > 1 file changed, 5 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/omapdrm/displays/panel-dpi.c b/drivers/gpu/drm/omapdrm/displays/panel-dpi.c
> > index ac9596251..b4a4006a2 100644
> > --- a/drivers/gpu/drm/omapdrm/displays/panel-dpi.c
> > +++ b/drivers/gpu/drm/omapdrm/displays/panel-dpi.c
> > @@ -157,7 +157,6 @@ static int panel_dpi_probe_of(struct platform_device *pdev)
> > {
> > struct panel_drv_data *ddata = platform_get_drvdata(pdev);
> > struct device_node *node = pdev->dev.of_node;
> > - struct device_node *bl_node;
> > struct omap_dss_device *in;
> > int r;
> > struct display_timing timing;
> > @@ -183,19 +182,15 @@ static int panel_dpi_probe_of(struct platform_device *pdev)
> > if (IS_ERR(ddata->vcc_supply))
> > return PTR_ERR(ddata->vcc_supply);
> >
> > - bl_node = of_parse_phandle(node, "backlight", 0);
> > - if (bl_node) {
> > - ddata->backlight = of_find_backlight_by_node(bl_node);
> > - of_node_put(bl_node);
> > + ddata->backlight = devm_of_find_backlight(&pdev->dev);
> >
> > - if (!ddata->backlight)
> > - return -EPROBE_DEFER;
> > - }
> > + if (IS_ERR(ddata->backlight))
>
> AFAICT, devm_of_find_backlight can return NULL. As such, you should be checking
> IS_ERR_OR_NULL here instead of just IS_ERR. Looks like you also made this
> same mistake in other patches in the series, so please fix those up as well.
>

annnd I should spend more time reading the context of the code. Looks like
backlight is optional here, so this is a valid code path. I'm sorry about that.

So,

Reviewed-by: Sean Paul <seanpaul@xxxxxxxxxxxx>

I think every other patch has R-b, so if no one objects in the next day or so,
I'll apply this to drm-misc-next

Sean


> Sean
>
> > + return PTR_ERR(ddata->backlight);
> >
> > r = of_get_display_timing(node, "panel-timing", &timing);
> > if (r) {
> > dev_err(&pdev->dev, "failed to get video timing\n");
> > - goto error_free_backlight;
> > + return r;
> > }
> >
> > videomode_from_timing(&timing, &ddata->vm);
> > @@ -203,19 +198,12 @@ static int panel_dpi_probe_of(struct platform_device *pdev)
> > in = omapdss_of_find_source_for_first_ep(node);
> > if (IS_ERR(in)) {
> > dev_err(&pdev->dev, "failed to find video source\n");
> > - r = PTR_ERR(in);
> > - goto error_free_backlight;
> > + return PTR_ERR(in);
> > }
> >
> > ddata->in = in;
> >
> > return 0;
> > -
> > -error_free_backlight:
> > - if (ddata->backlight)
> > - put_device(&ddata->backlight->dev);
> > -
> > - return r;
> > }
> >
> > static int panel_dpi_probe(struct platform_device *pdev)
> > @@ -270,9 +258,6 @@ static int __exit panel_dpi_remove(struct platform_device *pdev)
> >
> > omap_dss_put_device(in);
> >
> > - if (ddata->backlight)
> > - put_device(&ddata->backlight->dev);
> > -
> > return 0;
> > }
> >
> > --
> > 2.11.0
> >
>
> --
> Sean Paul, Software Engineer, Google / Chromium OS

--
Sean Paul, Software Engineer, Google / Chromium OS