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Subject: Re: [PATCH v18 10/10] drm/omapdrm: Use of_find_backlight helper
To:     Meghana Madhyastha <meghana.madhyastha@gmail.com>,
        Lee Jones <lee.jones@linaro.org>,
        Daniel Thompson <daniel.thompson@linaro.org>,
        Jingoo Han <jingoohan1@gmail.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Tomi Valkeinen <tomi.valkeinen@ti.com>,
        Daniel Vetter <daniel.vetter@intel.com>,
        Sean Paul <seanpaul@chromium.org>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
References: <cover.1516632387.git.meghana.madhyastha@gmail.com>
 <69379bffdebdddf49952eabeaaee7f1dd7cff99c.1516632388.git.meghana.madhyastha@gmail.com>
From:   =?UTF-8?Q?Noralf_Tr=c3=b8nnes?= <noralf@tronnes.org>
Message-ID: <394a73f6-3459-449f-6d9f-4cb52a1d3328@tronnes.org>
Date:   Tue, 23 Jan 2018 15:37:38 +0100
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Den 22.01.2018 15.56, skrev Meghana Madhyastha:
> Replace of_find_backlight_by_node and of the code around it
> with of_find_backlight helper to avoid repetition of code.
>
> Signed-off-by: Meghana Madhyastha <meghana.madhyastha@gmail.com>
> ---
> Changes in v18:
> -Fixed warnings resulting from passing device_node* to of_find_backlight.
>   Fixed it by passing struct device* to of_find_backlight
>
>   drivers/gpu/drm/omapdrm/displays/panel-dpi.c | 33 ++++++++++------------------
>   1 file changed, 11 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/gpu/drm/omapdrm/displays/panel-dpi.c b/drivers/gpu/drm/omapdrm/displays/panel-dpi.c
> index ac9596251..93b7a176d 100644
> --- a/drivers/gpu/drm/omapdrm/displays/panel-dpi.c
> +++ b/drivers/gpu/drm/omapdrm/displays/panel-dpi.c
> @@ -156,14 +156,14 @@ static struct omap_dss_driver panel_dpi_ops = {
>   static int panel_dpi_probe_of(struct platform_device *pdev)
>   {
>   	struct panel_drv_data *ddata = platform_get_drvdata(pdev);
> +	struct device *dev = &pdev->dev;
>   	struct device_node *node = pdev->dev.of_node;
> -	struct device_node *bl_node;
>   	struct omap_dss_device *in;
>   	int r;
>   	struct display_timing timing;
>   	struct gpio_desc *gpio;
>   
> -	gpio = devm_gpiod_get_optional(&pdev->dev, "enable", GPIOD_OUT_LOW);
> +	gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_LOW);

Please don't make unrelated changes like this. It clutters the patch.
You can just as well use &pdev->dev when getting the backlight also.

>   	if (IS_ERR(gpio))
>   		return PTR_ERR(gpio);
>   
> @@ -175,47 +175,36 @@ static int panel_dpi_probe_of(struct platform_device *pdev)
>   	 * timing and order relative to the enable gpio. So for now it's just
>   	 * ensured that the reset line isn't active.
>   	 */
> -	gpio = devm_gpiod_get_optional(&pdev->dev, "reset", GPIOD_OUT_LOW);
> +	gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
>   	if (IS_ERR(gpio))
>   		return PTR_ERR(gpio);
>   
> -	ddata->vcc_supply = devm_regulator_get(&pdev->dev, "vcc");
> +	ddata->vcc_supply = devm_regulator_get(dev, "vcc");
>   	if (IS_ERR(ddata->vcc_supply))
>   		return PTR_ERR(ddata->vcc_supply);
>   
> -	bl_node = of_parse_phandle(node, "backlight", 0);
> -	if (bl_node) {
> -		ddata->backlight = of_find_backlight_by_node(bl_node);
> -		of_node_put(bl_node);
> +	ddata->backlight = of_find_backlight(dev);

Any reason you don't use the devm_ version here?
You do remove error_free_backlight...

With the devm_ version remember to drop the put_device in 
panel_dpi_remove().

Noralf.

>   
> -		if (!ddata->backlight)
> -			return -EPROBE_DEFER;
> -	}
> +	if (IS_ERR(ddata->backlight))
> +		return PTR_ERR(ddata->backlight);
>   
>   	r = of_get_display_timing(node, "panel-timing", &timing);
>   	if (r) {
> -		dev_err(&pdev->dev, "failed to get video timing\n");
> -		goto error_free_backlight;
> +		dev_err(dev, "failed to get video timing\n");
> +		return r;
>   	}
>   
>   	videomode_from_timing(&timing, &ddata->vm);
>   
>   	in = omapdss_of_find_source_for_first_ep(node);
>   	if (IS_ERR(in)) {
> -		dev_err(&pdev->dev, "failed to find video source\n");
> -		r = PTR_ERR(in);
> -		goto error_free_backlight;
> +		dev_err(dev, "failed to find video source\n");
> +		return PTR_ERR(in);
>   	}
>   
>   	ddata->in = in;
>   
>   	return 0;
> -
> -error_free_backlight:
> -	if (ddata->backlight)
> -		put_device(&ddata->backlight->dev);
> -
> -	return r;
>   }
>   
>   static int panel_dpi_probe(struct platform_device *pdev)