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From:   Stephen Boyd <swboyd@chromium.org>
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Date:   Fri, 22 Apr 2022 11:39:18 -0700
Message-ID: <CAE-0n52nFSUA-3CWa81mE-WUFW8pjOwYsFp-eGOkzupg2cZ9Yg@mail.gmail.com>
Subject: Re: [PATCH] drm/msm/dp: fix error check return value of irq_of_parse_and_map()
To:     cgel.zte@gmail.com, quic_abhinavk@quicinc.com, robdclark@gmail.com,
        sean@poorly.run
Cc:     airlied@linux.ie, daniel@ffwll.ch, dmitry.baryshkov@linaro.org,
        quic_khsieh@quicinc.com, bjorn.andersson@linaro.org,
        linux@roeck-us.net, linux-arm-msm@vger.kernel.org,
        dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, Lv Ruyi <lv.ruyi@zte.com.cn>,
        Zeal Robot <zealci@zte.com.cn>
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Quoting cgel.zte@gmail.com (2022-04-22 01:49:51)
> From: Lv Ruyi <lv.ruyi@zte.com.cn>
>
> The irq_of_parse_and_map() function returns 0 on failure, and does not
> return an negative value.
>
> Fixes:  8ede2ecc3e5e ("drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets")
> Reported-by: Zeal Robot <zealci@zte.com.cn>
> Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn>
> ---
>  drivers/gpu/drm/msm/dp/dp_display.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index a42732b67349..3926d2ac107d 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -1239,7 +1239,7 @@ int dp_display_request_irq(struct msm_dp *dp_display)
>         dp = container_of(dp_display, struct dp_display_private, dp_display);
>
>         dp->irq = irq_of_parse_and_map(dp->pdev->dev.of_node, 0);

Why can't platform_get_irq() be used?

> -       if (dp->irq < 0) {
> +       if (!dp->irq) {
>                 rc = dp->irq;

zero as an error return value is an error?

>                 DRM_ERROR("failed to get irq: %d\n", rc);
>                 return rc;