Re: [PATCH v12] staging: fbtft: add tearing signal detect

From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Carlis <zhangxuezhi3@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Colin King <colin.king@canonical.com>,
	oliver.graute@kococonnector.com, zhangxuezhi1@yulong.com,
	Deepak R Varma <mh12gx2825@gmail.com>,
	Stefano Brivio <sbrivio@redhat.com>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	"open list:FRAMEBUFFER LAYER" <linux-fbdev@vger.kernel.org>,
	"open list:STAGING SUBSYSTEM" <devel@driverdev.osuosl.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v12] staging: fbtft: add tearing signal detect
Date: Thu, 28 Jan 2021 16:44:02 +0200	[thread overview]
Message-ID: <CAHp75VcRxPVs0KHwaY8QZima489D2_hntuW0eUqdfK8HJ-gnKA@mail.gmail.com> (raw)
In-Reply-To: <CAHp75Vd=ijxnamuSYuxNLeyhGMCod=HaXWrQ0W0+3QCsQAychg@mail.gmail.com>

On Thu, Jan 28, 2021 at 4:33 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Thu, Jan 28, 2021 at 2:58 PM Carlis <zhangxuezhi3@gmail.com> wrote:

...

> Taking all together you probably need to create a helper and use it
> inside init_display(), like
>
> static int init_tearing_effect_line(struct fbtft_par *par)
> {
>   struct device *dev = par->info->device;
>   struct gpio_desc *te;
>   int irq, rc;
>
>   te = gpiod_get_optional(dev, "te", GPIOD_IN);
>   if (IS_ERR(te))
>            return dev_err_probe(dev, PTR_ERR(te), "Failed to request
> te GPIO\n");

Sorry, here I missed the following:

  /* Absence of TE IRQ is not critical */
  if (!te)
    return 0;

>   irq = gpiod_to_irq(te); // this value you have to save in the
> driver's (per device) data structure.
>
>   /* GPIO is locked as an IRQ, we may drop the reference */
>   gpiod_put(te);

...and here:

  if (irq < 0)
    return irq;

>   init_completion(&spi_panel_te); // should be in the (per device)
> data structure
>   rc = devm_request_irq(dev, irq,  spi_panel_te_handler,
> IRQF_TRIGGER_RISING, "TE_GPIO", par);
>   if (rc)
>                 return dev_err_probe(dev, rc, "TE IRQ request failed.\n");
>   disable_irq_nosync(irq);
>   return irq;
> }

-- 
With Best Regards,
Andy Shevchenko