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Date:   Wed, 27 Jan 2021 08:45:23 +0300
From:   Dan Carpenter <dan.carpenter@oracle.com>
To:     Carlis <zhangxuezhi3@gmail.com>
Cc:     gregkh@linuxfoundation.org, devel@driverdev.osuosl.org,
        linux-fbdev@vger.kernel.org, mh12gx2825@gmail.com,
        oliver.graute@kococonnector.com, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org, sbrivio@redhat.com,
        colin.king@canonical.com, zhangxuezhi1@yulong.com
Subject: Re: [PATCH v5] fbtft: add tearing signal detect
Message-ID: <20210127054523.GA2696@kadam>
References: <1611711140-68260-1-git-send-email-zhangxuezhi3@gmail.com>
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In-Reply-To: <1611711140-68260-1-git-send-email-zhangxuezhi3@gmail.com>
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Precedence: bulk

On Wed, Jan 27, 2021 at 09:32:20AM +0800, Carlis wrote:
> @@ -82,6 +111,29 @@ 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 (par->gpio.te) {
> +		init_completion(&spi_panel_te);
> +		mutex_init(&te_mutex);
> +		rc = devm_request_irq(dev,
> +				      gpiod_to_irq(par->gpio.te),
> +				     spi_panel_te_handler, IRQF_TRIGGER_RISING,
> +				     "TE_GPIO", par);
> +		if (rc) {
> +			pr_err("TE request_irq failed.\n");
> +			devm_gpiod_put(dev, par->gpio.te);
> +			par->gpio.te = NULL;
> +		} else {
> +			disable_irq_nosync(gpiod_to_irq(par->gpio.te));
> +			pr_info("TE request_irq completion.\n");
> +		}
> +	} else {
> +		pr_info("%s:%d, TE gpio not specified\n",
> +			__func__, __LINE__);
> +	}

I'm sorry that I was not clear before.  This code will crash if
devm_gpiod_get_index_optional() returns an error.  You *NEED* to check
for error pointers and return the error code.  Write it exactly like
this:

	par->gpio.te = devm_gpiod_get_index_optional(dev, "te", 0, GPIOD_IN);
	if (IS_ERR(par->gpio.te))
		return PTR_ERR(par->gpio.te);

	if (par->gpio.te) {
		init_completion(&spi_panel_te);


regards,
dan carpenter