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Message-ID: <CAMRc=MeKFG=gyogSn+WdUXwhHZE74-FwVfxgKrHNpScbFZFZrg@mail.gmail.com>
Date: Thu, 3 Oct 2019 10:42:21 +0200
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Daniel Thompson <daniel.thompson@...aro.org>
Cc: Yoshinori Sato <ysato@...rs.sourceforge.jp>,
Rich Felker <dalias@...c.org>,
Lee Jones <lee.jones@...aro.org>,
Jingoo Han <jingoohan1@...il.com>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
Linus Walleij <linus.walleij@...aro.org>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Jacopo Mondi <jacopo@...ndi.org>, linux-sh@...r.kernel.org,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
dri-devel@...ts.freedesktop.org, linux-fbdev@...r.kernel.org,
Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: Re: [PATCH v4 7/7] backlight: gpio: pull gpio_backlight_initial_power_state()
into probe
śr., 2 paź 2019 o 16:40 Daniel Thompson <daniel.thompson@...aro.org> napisał(a):
>
> On Wed, Oct 02, 2019 at 01:46:17PM +0200, Bartosz Golaszewski wrote:
> > śr., 2 paź 2019 o 12:33 Daniel Thompson <daniel.thompson@...aro.org> napisał(a):
> > >
> > > On Tue, Oct 01, 2019 at 02:58:37PM +0200, Bartosz Golaszewski wrote:
> > > > From: Bartosz Golaszewski <bgolaszewski@...libre.com>
> > > >
> > > > The probe function in the gpio-backlight driver is quite short. If we
> > > > pull gpio_backlight_initial_power_state() into probe we can drop two
> > > > more fields from struct gpio_backlight and shrink the driver code.
> > > >
> > > > Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
> > > > ---
> > > > drivers/video/backlight/gpio_backlight.c | 36 ++++++++----------------
> > > > 1 file changed, 12 insertions(+), 24 deletions(-)
> > > >
> > > > diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
> > > > index 6247687b6330..37ec184f0c5c 100644
> > > > --- a/drivers/video/backlight/gpio_backlight.c
> > > > +++ b/drivers/video/backlight/gpio_backlight.c
> > > > @@ -17,11 +17,8 @@
> > > > #include <linux/slab.h>
> > > >
> > > > struct gpio_backlight {
> > > > - struct device *dev;
> > > > struct device *fbdev;
> > > > -
> > > > struct gpio_desc *gpiod;
> > > > - int def_value;
> > > > };
> > > >
> > > > static int gpio_backlight_update_status(struct backlight_device *bl)
> > > > @@ -53,41 +50,24 @@ static const struct backlight_ops gpio_backlight_ops = {
> > > > .check_fb = gpio_backlight_check_fb,
> > > > };
> > > >
> > > > -static int gpio_backlight_initial_power_state(struct gpio_backlight *gbl)
> > >
> > > I'm inclined to view deleting this function as removing a comment (e.g.
> > > the function name helps us to read the code)!
> > >
> >
> > Right, but why not just add a comment then?
>
> I guess you could add a comment but keeping it pulled out in a function
> makes it easier to compare against equivalent code in other drivers
> (such as pwm_bl).
>
The pwm driver seems to be the only one that has this function and
it's also much more complicated. Unless it's a hard NACK, I think that
pulling all initialization into probe looks better and shrinks the
driver visually.
Bart
>
> Daniel.
>
>
> > The probe function is 50
> > lines long, there's really no need to split it. This will get inlined
> > anyway too.
> >
> > Bart
> >
> > > Removing the variables from the context structure is good but why not
> > > just pass them to the function and let the compiler decided whether or
> > > not to inline.
> > >
> > >
> > > Daniel.
> > >
> > >
> > > > -{
> > > > - struct device_node *node = gbl->dev->of_node;
> > > > -
> > > > - /* Not booted with device tree or no phandle link to the node */
> > > > - if (!node || !node->phandle)
> > > > - return gbl->def_value ? FB_BLANK_UNBLANK : FB_BLANK_POWERDOWN;
> > > > -
> > > > - /* if the enable GPIO is disabled, do not enable the backlight */
> > > > - if (gpiod_get_value_cansleep(gbl->gpiod) == 0)
> > > > - return FB_BLANK_POWERDOWN;
> > > > -
> > > > - return FB_BLANK_UNBLANK;
> > > > -}
> > > > -
> > > > -
> > > > static int gpio_backlight_probe(struct platform_device *pdev)
> > > > {
> > > > struct device *dev = &pdev->dev;
> > > > struct gpio_backlight_platform_data *pdata = dev_get_platdata(dev);
> > > > + struct device_node *of_node = dev->of_node;
> > > > struct backlight_properties props;
> > > > struct backlight_device *bl;
> > > > struct gpio_backlight *gbl;
> > > > - int ret;
> > > > + int ret, def_value;
> > > >
> > > > gbl = devm_kzalloc(dev, sizeof(*gbl), GFP_KERNEL);
> > > > if (gbl == NULL)
> > > > return -ENOMEM;
> > > >
> > > > - gbl->dev = dev;
> > > > -
> > > > if (pdata)
> > > > gbl->fbdev = pdata->fbdev;
> > > >
> > > > - gbl->def_value = device_property_read_bool(dev, "default-on");
> > > > + def_value = device_property_read_bool(dev, "default-on");
> > > >
> > > > gbl->gpiod = devm_gpiod_get(dev, NULL, GPIOD_ASIS);
> > > > if (IS_ERR(gbl->gpiod)) {
> > > > @@ -109,7 +89,15 @@ static int gpio_backlight_probe(struct platform_device *pdev)
> > > > return PTR_ERR(bl);
> > > > }
> > > >
> > > > - bl->props.power = gpio_backlight_initial_power_state(gbl);
> > > > + /* Not booted with device tree or no phandle link to the node */
> > > > + if (!of_node || !of_node->phandle)
> > > > + bl->props.power = def_value ? FB_BLANK_UNBLANK
> > > > + : FB_BLANK_POWERDOWN;
> > > > + else if (gpiod_get_value_cansleep(gbl->gpiod) == 0)
> > > > + bl->props.power = FB_BLANK_POWERDOWN;
> > > > + else
> > > > + bl->props.power = FB_BLANK_UNBLANK;
> > > > +
> > > > bl->props.brightness = 1;
> > > >
> > > > backlight_update_status(bl);
> > > > --
> > > > 2.23.0
> > > >
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