linux-kernel - Re: [RESEND][PATCH] video: fbdev: atmel_lcdfb: convert to use GPIO descriptors

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Date:   Mon, 5 Feb 2018 16:31:37 +0100
From:   Ludovic Desroches <ludovic.desroches@...rochip.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
CC:     Ludovic Desroches <ludovic.desroches@...rochip.com>,
        <linux-fbdev@...r.kernel.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        <dri-devel@...ts.freedesktop.org>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [RESEND][PATCH] video: fbdev: atmel_lcdfb: convert to use GPIO
 descriptors

On Mon, Feb 05, 2018 at 03:06:33PM +0200, Andy Shevchenko wrote:
> On Mon, Feb 5, 2018 at 10:47 AM, Ludovic Desroches
> <ludovic.desroches@...rochip.com> wrote:
> > Use GPIO descriptors instead of relying on the old method.
> 
> Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
> 
> Though few nitpicks below.
> 
> 
> > --- a/drivers/video/fbdev/atmel_lcdfb.c
> > +++ b/drivers/video/fbdev/atmel_lcdfb.c
> > @@ -18,6 +18,7 @@
> >  #include <linux/delay.h>
> >  #include <linux/backlight.h>
> >  #include <linux/gfp.h>
> 
> > +#include <linux/gpio/consumer.h>
> 
> I think you forgot to remove of_gpio.h.

Right. I'll remove it.

> 
> >  #include <linux/module.h>
> >  #include <linux/of.h>
> >  #include <linux/of_device.h>
> 
> >         struct device_node *display_np;
> >         struct device_node *timings_np;
> >         struct display_timings *timings;
> > -       enum of_gpio_flags flags;
> >         struct atmel_lcdfb_power_ctrl_gpio *og;
> >         bool is_gpio_power = false;
> >         int ret = -ENOENT;
> > -       int i, gpio;
> > +       int i;
> > +       struct gpio_desc *gpiod;
> 
> I would rather preserve reversed tree style, i.e. put longer line upper.

Ok.

> 
> 
> > +       for (i = 0; i < gpiod_count(dev, "atmel,power-control"); i++) {
> > +               gpiod = devm_gpiod_get_index_optional(dev,
> > +                               "atmel,power-control", i, GPIOD_ASIS);
> > +               if (!gpiod)
> >                         continue;
> 
> What about IS_ERR() case?

if (!gpiod || IS_ERR(gpiod))
	continue;

Thanks.

> 
> >
> >                 og = devm_kzalloc(dev, sizeof(*og), GFP_KERNEL);
> >                 if (!og)
> >                         goto put_display_node;
> >
> > +               og->gpiod = gpiod;
> >                 is_gpio_power = true;
> >
> > +               ret = gpiod_direction_output(gpiod, gpiod_is_active_low(gpiod));
> >                 if (ret) {
> 
> I'm not sure this will be needed if you check IS_ERR() above.
> 

When in doubt, I keep it.

Regards

Ludovic

> > +                       dev_err(dev, "set direction output gpio atmel,power-control[%d] failed\n", i);
> >                         goto put_display_node;
> >                 }
> 
> 
> -- 
> With Best Regards,
> Andy Shevchenko
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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