linux-kernel - Re: [PATCH v3 16/25] drm/sun4i: sun6i_mipi_dsi: Add support for VCC-DSI voltage regulator

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Date:   Mon, 29 Oct 2018 10:31:42 +0100
From:   Maxime Ripard <maxime.ripard@...tlin.com>
To:     Jagan Teki <jagan@...rulasolutions.com>
Cc:     Chen-Yu Tsai <wens@...e.org>, Icenowy Zheng <icenowy@...c.io>,
        Jernej Skrabec <jernej.skrabec@...l.net>,
        Vasily Khoruzhick <anarsoul@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        David Airlie <airlied@...ux.ie>,
        dri-devel@...ts.freedesktop.org,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, linux-clk@...r.kernel.org,
        Michael Trimarchi <michael@...rulasolutions.com>,
        linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-sunxi@...glegroups.com
Subject: Re: [PATCH v3 16/25] drm/sun4i: sun6i_mipi_dsi: Add support for
 VCC-DSI voltage regulator

On Fri, Oct 26, 2018 at 08:13:35PM +0530, Jagan Teki wrote:
> Some boards have VCC-DSI pin connected to voltage regulator which may
> not be turned on by default.
> 
> Add support for such boards by adding voltage regulator handling code to
> MIPI DSI driver.
> 
> Signed-off-by: Jagan Teki <jagan@...rulasolutions.com>
> Tested-by: Jagan Teki <jagan@...rulasolutions.com>
> ---
> Changes for v3:
> - new patch
> Changes for v2:
> - none
> 
>  drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 14 ++++++++++++++
>  drivers/gpu/drm/sun4i/sun6i_mipi_dsi.h |  3 +++
>  2 files changed, 17 insertions(+)
> 
> diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> index 42bd7506abaf..bc57343592e0 100644
> --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> @@ -949,6 +949,12 @@ static int sun6i_dsi_bind(struct device *dev, struct device *master,
>  
>  	dsi->drv = drv;
>  
> +	ret = regulator_enable(dsi->regulator);
> +	if (ret) {
> +		dev_err(dev, "Failed to enable regulator\n");
> +		return ret;
> +	}
> +

The regulator should be enabled only when the device is in use.

>  	drm_encoder_helper_add(&dsi->encoder,
>  			       &sun6i_dsi_enc_helper_funcs);
>  	ret = drm_encoder_init(drm,
> @@ -980,6 +986,7 @@ static int sun6i_dsi_bind(struct device *dev, struct device *master,
>  
>  err_cleanup_connector:
>  	drm_encoder_cleanup(&dsi->encoder);
> +	regulator_disable(dsi->regulator);
>  	return ret;
>  }
>  
> @@ -989,6 +996,7 @@ static void sun6i_dsi_unbind(struct device *dev, struct device *master,
>  	struct sun6i_dsi *dsi = dev_get_drvdata(dev);
>  
>  	drm_panel_detach(dsi->panel);
> +	regulator_disable(dsi->regulator);
>  }
>  
>  static const struct component_ops sun6i_dsi_ops = {
> @@ -1022,6 +1030,12 @@ static int sun6i_dsi_probe(struct platform_device *pdev)
>  		return PTR_ERR(base);
>  	}
>  
> +	dsi->regulator = devm_regulator_get(dev, "vcc-dsi");
> +	if (IS_ERR(dsi->regulator)) {
> +		dev_err(dev, "Couldn't get regulator\n");
> +		return PTR_ERR(dsi->regulator);
> +	}
> +

You haven't updated the DT bindings accordingly.

Maxime

-- 
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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