linux-kernel - Re: [PATCH v10] staging: fbtft: add tearing signal detect

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Message-ID: <CAMuHMdX50YJ6_=maJveDk=dh+suFeCEtarWrqoP_gNMP9k922Q@mail.gmail.com>
Date:   Thu, 28 Jan 2021 12:15:28 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     carlis <zhangxuezhi3@...il.com>
Cc:     Kari Argillander <kari.argillander@...il.com>,
        Greg KH <gregkh@...uxfoundation.org>,
        Colin King <colin.king@...onical.com>,
        oliver.graute@...oconnector.com, zhangxuezhi1@...ong.com,
        mh12gx2825@...il.com, Stefano Brivio <sbrivio@...hat.com>,
        DRI Development <dri-devel@...ts.freedesktop.org>,
        Linux Fbdev development list <linux-fbdev@...r.kernel.org>,
        driverdevel <devel@...verdev.osuosl.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v10] staging: fbtft: add tearing signal detect

Hi Carlis,

On Thu, Jan 28, 2021 at 12:03 PM carlis <zhangxuezhi3@...il.com> wrote:
> On Thu, 28 Jan 2021 10:42:54 +0100
> Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
> > On Thu, Jan 28, 2021 at 7:53 AM Kari Argillander
> > <kari.argillander@...il.com> wrote:
> > > On Thu, Jan 28, 2021 at 09:42:58AM +0800, carlis wrote:
> > > > On Thu, 28 Jan 2021 00:32:22 +0200
> > > > Kari Argillander <kari.argillander@...il.com> wrote:
> > > > > >  #include "fbtft.h"
> > > > > >
> > > > > >  #define DRVNAME "fb_st7789v"
> > > > > > @@ -66,6 +69,32 @@ enum st7789v_command {
> > > > > >  #define MADCTL_MX BIT(6) /* bitmask for column address order
> > > > > > */ #define MADCTL_MY BIT(7) /* bitmask for page address order
> > > > > > */
> > > > > >
> > > > > > +#define SPI_PANEL_TE_TIMEOUT     400 /* msecs */
> > > > > > +static struct mutex te_mutex;/* mutex for set te gpio irq
> > > > > > status */
> > > > >
> > > > > Space after ;
> > > > hi, i have fix it in the patch v11
> > > > >
> > >
> > > Yeah sorry. I accidentally review wrong patch. But mostly stuff are
> > > still relevant.
> > >
> > > > > > @@ -82,6 +111,33 @@ enum st7789v_command {
> > > > > >   */
> > > > > >  static int init_display(struct fbtft_par *par)
> > > > > >  {
> > > > > > + int rc;
> > > > > > + struct device *dev = par->info->device;
> > > > > > +
> > > > > > + par->gpio.te = devm_gpiod_get_index_optional(dev, "te", 0,
> > > > > > GPIOD_IN);
> > > > > > + if (IS_ERR(par->gpio.te)) {
> > > > > > +         rc = PTR_ERR(par->gpio.te);
> > > > > > +         dev_err(par->info->device, "Failed to request te
> > > > > > gpio: %d\n", rc);
> > > > > > +         return rc;
> > > > > > + }
> > > > >
> > > > > You request with optinal and you still want to error out? We
> > > > > could just continue and not care about that error. User will be
> > > > > happier if device still works somehow.
> >
> > devm_gpiod_get_index_optional() returns NULL, not an error, if the
> > GPIO is not found.  So if IS_ERR() is the right check.
> >
> > And checks for -EPROBE_DEFER can be handled automatically
> > by using dev_err_probe() instead of dev_err().
> >
> hi, i fix it like below!?
>         par->gpio.te = devm_gpiod_get_index_optional(dev, "te", 0,
>         GPIOD_IN); if (IS_ERR(par->gpio.te)) {
>                 rc = PTR_ERR(par->gpio.te);
>                 dev_err_probe(par->info->device, rc, "Failed to request
>         te gpio\n"); return rc;
>         }
>         if (par->gpio.te) {
>                 init_completion(&spi_panel_te);
>                 rc = devm_request_irq(dev,
>                                       gpiod_to_irq(par->gpio.te),
>                                      spi_panel_te_handler,
>         IRQF_TRIGGER_RISING, "TE_GPIO", par);
>                 if (rc) {
>                         dev_err(par->info->device, "TE request_irq
>         failed.\n"); return rc;

dev_err_probe()

>                 }
>
>                 disable_irq_nosync(gpiod_to_irq(par->gpio.te));
>         } else {
>                 dev_info(par->info->device, "%s:%d, TE gpio not
>                 specified\n", __func__, __LINE__);
>         }

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds