linux-kernel - Re: [RESEND2,v4,2/2] drm/meson: dw-hdmi: Use devm_regulator_*get

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Message-ID: <6c865dd8-b6c3-4491-48ca-df3e3fa45a2d@samsung.com>
Date:   Mon, 9 Jan 2023 14:46:45 +0100
From:   Marek Szyprowski <m.szyprowski@...sung.com>
To:     Matti Vaittinen <mazziesaccount@...il.com>,
        Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
Cc:     Neil Armstrong <neil.armstrong@...aro.org>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Kevin Hilman <khilman@...libre.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Mark Brown <broonie@...nel.org>,
        linux-amlogic@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org,
        Jerome Brunet <jbrunet@...libre.com>
Subject: Re: [RESEND2,v4,2/2] drm/meson: dw-hdmi: Use
 devm_regulator_*get_enable*()

Hi Matti,

On 30.11.2022 10:23, Matti Vaittinen wrote:
> Simplify using the devm_regulator_get_enable_optional(). Also drop the
> now unused struct member 'hdmi_supply'.
>
> Signed-off-by: Matti Vaittinen <mazziesaccount@...il.com>
> Martin Blumenstingl <martin.blumenstingl@...glemail.com>
> ---
> v4 resend 2:
> Respinning unchanged code with the commit title changed as wa suggested
> by Robert Foss and commit message changed as was suggested by Martin.
>
> I am doing a clean-up for my local git and encountered this one.
> Respinning as it seems this one fell through the cracks.
> ---
>   drivers/gpu/drm/meson/meson_dw_hdmi.c | 23 +++--------------------
>   1 file changed, 3 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
> index 5cd2b2ebbbd3..7642f740272b 100644
> --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
> +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
> @@ -140,7 +140,6 @@ struct meson_dw_hdmi {
>   	struct reset_control *hdmitx_apb;
>   	struct reset_control *hdmitx_ctrl;
>   	struct reset_control *hdmitx_phy;
> -	struct regulator *hdmi_supply;
>   	u32 irq_stat;
>   	struct dw_hdmi *hdmi;
>   	struct drm_bridge *bridge;
> @@ -665,11 +664,6 @@ static void meson_dw_hdmi_init(struct meson_dw_hdmi *meson_dw_hdmi)
>   
>   }
>   
> -static void meson_disable_regulator(void *data)
> -{
> -	regulator_disable(data);
> -}
> -
>   static void meson_disable_clk(void *data)
>   {
>   	clk_disable_unprepare(data);
> @@ -723,20 +717,9 @@ static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
>   	meson_dw_hdmi->data = match;
>   	dw_plat_data = &meson_dw_hdmi->dw_plat_data;
>   
> -	meson_dw_hdmi->hdmi_supply = devm_regulator_get_optional(dev, "hdmi");
> -	if (IS_ERR(meson_dw_hdmi->hdmi_supply)) {
> -		if (PTR_ERR(meson_dw_hdmi->hdmi_supply) == -EPROBE_DEFER)
> -			return -EPROBE_DEFER;
> -		meson_dw_hdmi->hdmi_supply = NULL;
> -	} else {
> -		ret = regulator_enable(meson_dw_hdmi->hdmi_supply);
> -		if (ret)
> -			return ret;
> -		ret = devm_add_action_or_reset(dev, meson_disable_regulator,
> -					       meson_dw_hdmi->hdmi_supply);
> -		if (ret)
> -			return ret;
> -	}
> +	ret = devm_regulator_get_enable_optional(dev, "hdmi");
> +	if (ret != -ENODEV)

The above line should be "if (ret < 0)", otherwise it breaks hdmi support.

I've noticed this once this change has been merged to linux-next and all 
my Amlogic Meson based boards failed to initialize HDMI. Is it possible 
to fix this in drm tree or do I need to send the incremental fixup?

> +		return ret;
>   
>   	meson_dw_hdmi->hdmitx_apb = devm_reset_control_get_exclusive(dev,
>   						"hdmitx_apb");

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland