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Message-ID: <bedeec1d-d4eb-4154-a6f4-21b8d873a416@wolfvision.net>
Date: Tue, 28 May 2024 10:50:48 +0200
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH] drm/panel: sitronix-st7789v: Add check for
 of_drm_get_panel_orientation
To: Chen Ni <nichen@iscas.ac.cn>, neil.armstrong@linaro.org,
 quic_jesszhan@quicinc.com, sam@ravnborg.org,
 maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de,
 airlied@gmail.com, daniel@ffwll.ch, sre@kernel.org
Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
References: <20240528030832.2529471-1-nichen@iscas.ac.cn>
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From: Michael Riesch <michael.riesch@wolfvision.net>
Organization: WolfVision GmbH
In-Reply-To: <20240528030832.2529471-1-nichen@iscas.ac.cn>
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Hi Chen Ni,

On 5/28/24 05:08, Chen Ni wrote:
> Add check for the return value of of_drm_get_panel_orientation() and
> return the error if it fails in order to catch the error.
> 
> Fixes: b27c0f6d208d ("drm/panel: sitronix-st7789v: add panel orientation support")
> Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
> ---
>  drivers/gpu/drm/panel/panel-sitronix-st7789v.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/panel/panel-sitronix-st7789v.c b/drivers/gpu/drm/panel/panel-sitronix-st7789v.c
> index 88e80fe98112..8b15e225bf37 100644
> --- a/drivers/gpu/drm/panel/panel-sitronix-st7789v.c
> +++ b/drivers/gpu/drm/panel/panel-sitronix-st7789v.c
> @@ -643,7 +643,9 @@ static int st7789v_probe(struct spi_device *spi)
>  	if (ret)
>  		return dev_err_probe(dev, ret, "Failed to get backlight\n");
>  
> -	of_drm_get_panel_orientation(spi->dev.of_node, &ctx->orientation);
> +	ret = of_drm_get_panel_orientation(spi->dev.of_node, &ctx->orientation);
> +	if (ret)
> +		return dev_err_probe(&spi->dev, ret, "Failed to get orientation\n");
>  
>  	drm_panel_add(&ctx->panel);

I was worried that this effectively makes "rotation" a required property
(although it is not marked required in the bindings documentation) but
it turns out that of_drm_get_panel_orientation handles a missing
"rotation" property gracefully.

Also, all other panel drivers I checked handle the
of_drm_get_panel_orientation call as you suggested. Nice to see this
becoming aligned.

Reviewed-by: Michael Riesch <michael.riesch@wolfvision.net>

Thanks and best regards,
Michael