linux-kernel - Re: [PATCH v2 2/3] drm/stm: dsi: add support of an optional regulator

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Message-ID: <c1a7f401-a736-8145-2732-c7eea881ba37@st.com>
Date:   Fri, 10 May 2019 16:16:02 +0000
From:   Philippe CORNU <philippe.cornu@...com>
To:     Yannick FERTRE <yannick.fertre@...com>,
        Benjamin GAIGNARD <benjamin.gaignard@...com>,
        Vincent ABRIOU <vincent.abriou@...com>,
        "David Airlie" <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre TORGUE <alexandre.torgue@...com>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-stm32@...md-mailman.stormreply.com" 
        <linux-stm32@...md-mailman.stormreply.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/3] drm/stm: dsi: add support of an optional regulator

Dear Yannick,
Thank you for your patch,

I like better the new shorter commit heading, thank you.


On 5/10/19 4:20 PM, Yannick Fertré wrote:
> Add support of an optional regulator for the phy part of the DSI
> controller.
> 
> Signed-off-by: Yannick Fertré <yannick.fertre@...com>
> ---
>   drivers/gpu/drm/stm/dw_mipi_dsi-stm.c | 45 ++++++++++++++++++++++++++++++-----
>   1 file changed, 39 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c b/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
> index 1bef73e..22bd095 100644
> --- a/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
> +++ b/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
> @@ -9,6 +9,7 @@
>   #include <linux/clk.h>
>   #include <linux/iopoll.h>
>   #include <linux/module.h>
> +#include <linux/regulator/consumer.h>
>   #include <drm/drmP.h>
>   #include <drm/drm_mipi_dsi.h>
>   #include <drm/bridge/dw_mipi_dsi.h>
> @@ -76,6 +77,7 @@ struct dw_mipi_dsi_stm {
>   	u32 hw_version;
>   	int lane_min_kbps;
>   	int lane_max_kbps;
> +	struct regulator *vdd_supply;
>   };
>   
>   static inline void dsi_write(struct dw_mipi_dsi_stm *dsi, u32 reg, u32 val)
> @@ -318,17 +320,31 @@ static int dw_mipi_dsi_stm_probe(struct platform_device *pdev)
>   		return PTR_ERR(dsi->base);
>   	}
>   
> +	dsi->vdd_supply = devm_regulator_get_optional(dev, "phy-dsi");
> +	if (IS_ERR(dsi->vdd_supply)) {
> +		ret = PTR_ERR(dsi->vdd_supply);
> +		if (ret != -EPROBE_DEFER)
> +			DRM_ERROR("failed to request regulator: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = regulator_enable(dsi->vdd_supply);
> +	if (ret) {
> +		DRM_ERROR("failed to enable regulator: %d\n", ret);
> +		return ret;
> +	}
> +
>   	dsi->pllref_clk = devm_clk_get(dev, "ref");
>   	if (IS_ERR(dsi->pllref_clk)) {
>   		ret = PTR_ERR(dsi->pllref_clk);
> -		dev_err(dev, "Unable to get pll reference clock: %d\n", ret);
> -		return ret;
> +		DRM_ERROR("Unable to get pll reference clock: %d\n", ret);
> +		goto err_clk_get;
>   	}
>   
>   	ret = clk_prepare_enable(dsi->pllref_clk);
>   	if (ret) {
> -		dev_err(dev, "%s: Failed to enable pllref_clk\n", __func__);
> -		return ret;
> +		DRM_ERROR("%s: Failed to enable pllref_clk\n", __func__);
> +		goto err_clk_get;
>   	}
>   
>   	dw_mipi_dsi_stm_plat_data.base = dsi->base;
> @@ -339,11 +355,19 @@ static int dw_mipi_dsi_stm_probe(struct platform_device *pdev)
>   	dsi->dsi = dw_mipi_dsi_probe(pdev, &dw_mipi_dsi_stm_plat_data);
>   	if (IS_ERR(dsi->dsi)) {
>   		DRM_ERROR("Failed to initialize mipi dsi host\n");
> -		clk_disable_unprepare(dsi->pllref_clk);
> -		return PTR_ERR(dsi->dsi);
> +		ret = PTR_ERR(dsi->dsi);
> +		goto err_dsi_probe;
>   	}
>   
>   	return 0;
> +
> +err_dsi_probe:
> +	clk_disable_unprepare(dsi->pllref_clk);
> +err_clk_get:
> +	regulator_disable(dsi->vdd_supply);
> +
> +	return ret;
> +
>   }
>   
>   static int dw_mipi_dsi_stm_remove(struct platform_device *pdev)
> @@ -351,6 +375,7 @@ static int dw_mipi_dsi_stm_remove(struct platform_device *pdev)
>   	struct dw_mipi_dsi_stm *dsi = platform_get_drvdata(pdev);
>   
>   	clk_disable_unprepare(dsi->pllref_clk);
> +	regulator_disable(dsi->vdd_supply);
>   	dw_mipi_dsi_remove(dsi->dsi);

for a future patch: we may have a different order
	dw_mipi_dsi_remove(dsi->dsi);   	
	clk_disable_unprepare(dsi->pllref_clk);
	regulator_disable(dsi->vdd_supply);

>   
>   	return 0;
> @@ -363,6 +388,7 @@ static int __maybe_unused dw_mipi_dsi_stm_suspend(struct device *dev)
>   	DRM_DEBUG_DRIVER("\n");
>   
>   	clk_disable_unprepare(dsi->pllref_clk);
> +	regulator_disable(dsi->vdd_supply);
>   
>   	return 0;
>   }
> @@ -370,9 +396,16 @@ static int __maybe_unused dw_mipi_dsi_stm_suspend(struct device *dev)
>   static int __maybe_unudw_mipi_dsi_remove(dsi->dsi);sed dw_mipi_dsi_stm_resume(struct device *dev)
>   {
>   	struct dw_mipi_dsi_stm *dsi = dw_mipi_dsi_stm_plat_data.priv_data;
> +	int ret;
>   
>   	DRM_DEBUG_DRIVER("\n");
>   
> +	ret = regulator_enable(dsi->vdd_supply);
> +	if (ret) {
> +		DRM_ERROR("failed to enable regulator: %d\n", ret);
> +		return ret;
> +	}
> +
>   	clk_prepare_enable(dsi->pllref_clk);

for a future patch: we may check clk_prepare_enable return value.

>   
>   	return 0;
> 


Acked-by: Philippe Cornu <philippe.cornu@...com>

Philippe :)