linux-kernel - Re: [PATCH v16 09/10] drm/panel: Use of_find

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Date:   Tue, 16 Jan 2018 18:08:53 +0100
From:   Noralf Trønnes <noralf@...nnes.org>
To:     Meghana Madhyastha <meghana.madhyastha@...il.com>,
        Lee Jones <lee.jones@...aro.org>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Jingoo Han <jingoohan1@...il.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Tomi Valkeinen <tomi.valkeinen@...com>,
        Daniel Vetter <daniel.vetter@...el.com>,
        Sean Paul <seanpaul@...omium.org>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v16 09/10] drm/panel: Use of_find_backlight helper


Den 16.01.2018 11.36, 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@...il.com>
> ---
>   drivers/gpu/drm/panel/panel-innolux-p079zca.c   | 10 +++-------
>   drivers/gpu/drm/panel/panel-sharp-lq101r1sx01.c | 10 +++-------
>   drivers/gpu/drm/panel/panel-sharp-ls043t1le01.c | 10 +++-------
>   3 files changed, 9 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/gpu/drm/panel/panel-innolux-p079zca.c b/drivers/gpu/drm/panel/panel-innolux-p079zca.c
> index 4c1b29eec..a69b0530f 100644
> --- a/drivers/gpu/drm/panel/panel-innolux-p079zca.c
> +++ b/drivers/gpu/drm/panel/panel-innolux-p079zca.c
> @@ -230,14 +230,10 @@ static int innolux_panel_add(struct innolux_panel *innolux)
>   		innolux->enable_gpio = NULL;
>   	}
>   
> -	np = of_parse_phandle(dev->of_node, "backlight", 0);
> -	if (np) {
> -		innolux->backlight = of_find_backlight_by_node(np);
> -		of_node_put(np);
> +	innolux->backlight = devm_of_find_backlight(np);

This driver isn't broken like tinydrm was, so it does put the backlight
device on cleanup like it should. So when you're using the devm_ version,
the result is a double put. Just remove the put_device() in
innolux_panel_add/del() and you're good.

I haven't checked the other drivers.

Noralf.

PS:
Give people a few days (one week?) to respond before respinning a new
version, so we avoid a fragmented discussion.

>   
> -		if (!innolux->backlight)
> -			return -EPROBE_DEFER;
> -	}
> +	if (IS_ERR(innolux->backlight))
> +		return PTR_ERR(innolux->backlight);
>   
>   	drm_panel_init(&innolux->base);
>   	innolux->base.funcs = &innolux_panel_funcs;
> diff --git a/drivers/gpu/drm/panel/panel-sharp-lq101r1sx01.c b/drivers/gpu/drm/panel/panel-sharp-lq101r1sx01.c
> index 1512ec4f3..d5450c9d9 100644
> --- a/drivers/gpu/drm/panel/panel-sharp-lq101r1sx01.c
> +++ b/drivers/gpu/drm/panel/panel-sharp-lq101r1sx01.c
> @@ -329,14 +329,10 @@ static int sharp_panel_add(struct sharp_panel *sharp)
>   	if (IS_ERR(sharp->supply))
>   		return PTR_ERR(sharp->supply);
>   
> -	np = of_parse_phandle(sharp->link1->dev.of_node, "backlight", 0);
> -	if (np) {
> -		sharp->backlight = of_find_backlight_by_node(np);
> -		of_node_put(np);
> +	sharp->backlight = devm_of_find_backlight(np);
>   
> -		if (!sharp->backlight)
> -			return -EPROBE_DEFER;
> -	}
> +	if (IS_ERR(sharp->backlight))
> +		return PTR_ERR(sharp->backlight);
>   
>   	drm_panel_init(&sharp->base);
>   	sharp->base.funcs = &sharp_panel_funcs;
> diff --git a/drivers/gpu/drm/panel/panel-sharp-ls043t1le01.c b/drivers/gpu/drm/panel/panel-sharp-ls043t1le01.c
> index a6af3257f..db31d8268 100644
> --- a/drivers/gpu/drm/panel/panel-sharp-ls043t1le01.c
> +++ b/drivers/gpu/drm/panel/panel-sharp-ls043t1le01.c
> @@ -273,14 +273,10 @@ static int sharp_nt_panel_add(struct sharp_nt_panel *sharp_nt)
>   		gpiod_set_value(sharp_nt->reset_gpio, 0);
>   	}
>   
> -	np = of_parse_phandle(dev->of_node, "backlight", 0);
> -	if (np) {
> -		sharp_nt->backlight = of_find_backlight_by_node(np);
> -		of_node_put(np);
> +	sharp_nt->backlight = devm_of_find_backlight(np);
>   
> -		if (!sharp_nt->backlight)
> -			return -EPROBE_DEFER;
> -	}
> +	if (IS_ERR(sharp_nt->backlight))
> +		return PTR_ERR(sharp_nt->backlight);
>   
>   	drm_panel_init(&sharp_nt->base);
>   	sharp_nt->base.funcs = &sharp_nt_panel_funcs;