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From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Philippe Cornu <philippe.cornu@st.com>
Cc:     Archit Taneja <architt@codeaurora.org>,
        Andrzej Hajda <a.hajda@samsung.com>,
        David Airlie <airlied@linux.ie>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Yannick Fertre <yannick.fertre@st.com>,
        Benjamin Gaignard <benjamin.gaignard@linaro.org>,
        Alexandre Torgue <alexandre.torgue@st.com>
Subject: Re: [PATCH 2/2] drm/bridge: sii902x: add optional power supplies
Date:   Thu, 19 Apr 2018 11:20:37 +0300
Message-ID: <3775994.jviQhGlOpf@avalon>
Organization: Ideas on Board Oy
In-Reply-To: <20180410051927.8268-3-philippe.cornu@st.com>
References: <20180410051927.8268-1-philippe.cornu@st.com> <20180410051927.8268-3-philippe.cornu@st.com>
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Sender: linux-kernel-owner@vger.kernel.org
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Hi Philippe,

Thank you for the patch.

On Tuesday, 10 April 2018 08:19:27 EEST Philippe Cornu wrote:
> Add the 3 optional power supplies using the exact description
> found in the document named
> "SiI9022A/SiI9024A HDMI Transmitter Data Sheet (August 2016)".
> 
> Signed-off-by: Philippe Cornu <philippe.cornu@st.com>
> ---
> drivers/gpu/drm/bridge/sii902x.c | 39 +++++++++++++++++++++++++++++++++----
> 1 file changed, 35 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/sii902x.c
> b/drivers/gpu/drm/bridge/sii902x.c index 60373d7eb220..e17ba6db1ec8 100644
> --- a/drivers/gpu/drm/bridge/sii902x.c
> +++ b/drivers/gpu/drm/bridge/sii902x.c
> @@ -24,6 +24,7 @@
>  #include <linux/i2c.h>
>  #include <linux/module.h>
>  #include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> 
>  #include <drm/drmP.h>
>  #include <drm/drm_atomic_helper.h>
> @@ -86,6 +87,7 @@ struct sii902x {
>  	struct drm_bridge bridge;
>  	struct drm_connector connector;
>  	struct gpio_desc *reset_gpio;
> +	struct regulator_bulk_data supplies[3];
>  };
> 
>  static inline struct sii902x *bridge_to_sii902x(struct drm_bridge *bridge)
> @@ -392,23 +394,43 @@ static int sii902x_probe(struct i2c_client *client,
>  		return PTR_ERR(sii902x->reset_gpio);
>  	}
> 
> +	sii902x->supplies[0].supply = "iovcc";
> +	sii902x->supplies[1].supply = "avcc12";
> +	sii902x->supplies[2].supply = "cvcc12";
> +	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(sii902x->supplies),
> +				      sii902x->supplies);
> +	if (ret) {
> +		dev_err(dev, "regulator_bulk_get failed\n");

Maybe "failed to get power supplies" to be a bit more explicit ? And while at 
it, printing the value of ret too ?

> +		return ret;
> +	}
> +
> +	ret = regulator_bulk_enable(ARRAY_SIZE(sii902x->supplies),
> +				    sii902x->supplies);
> +	if (ret) {
> +		dev_err(dev, "regulator_bulk_enable failed\n");

Same here ?

> +		return ret;
> +	}
> +
> +	usleep_range(10000, 20000);
> +
>  	sii902x_reset(sii902x);
> 
>  	ret = regmap_write(sii902x->regmap, SII902X_REG_TPI_RQB, 0x0);
>  	if (ret)
> -		return ret;
> +		goto err_disable_regulator;
> 
>  	ret = regmap_bulk_read(sii902x->regmap, SII902X_REG_CHIPID(0),
>  			       &chipid, 4);
>  	if (ret) {
>  		dev_err(dev, "regmap_read failed %d\n", ret);
> -		return ret;
> +		goto err_disable_regulator;
>  	}
> 
>  	if (chipid[0] != 0xb0) {
>  		dev_err(dev, "Invalid chipid: %02x (expecting 0xb0)\n",
>  			chipid[0]);
> -		return -EINVAL;
> +		ret = -EINVAL;
> +		goto err_disable_regulator;
>  	}
> 
>  	/* Clear all pending interrupts */
> @@ -424,7 +446,7 @@ static int sii902x_probe(struct i2c_client *client,
>  						IRQF_ONESHOT, dev_name(dev),
>  						sii902x);
>  		if (ret)
> -			return ret;
> +			goto err_disable_regulator;
>  	}
> 
>  	sii902x->bridge.funcs = &sii902x_bridge_funcs;
> @@ -434,6 +456,12 @@ static int sii902x_probe(struct i2c_client *client,
>  	i2c_set_clientdata(client, sii902x);
> 
>  	return 0;
> +
> +err_disable_regulator:
> +	regulator_bulk_disable(ARRAY_SIZE(sii902x->supplies),
> +			       sii902x->supplies);
> +
> +	return ret;
>  }
> 
>  static int sii902x_remove(struct i2c_client *client)
> @@ -443,6 +471,9 @@ static int sii902x_remove(struct i2c_client *client)
> 
>  	drm_bridge_remove(&sii902x->bridge);
> 
> +	regulator_bulk_disable(ARRAY_SIZE(sii902x->supplies),
> +			       sii902x->supplies);
> +

While this seems functionally correct, would it be useful to only enable power 
supplies when needed to save power ?

>  	return 0;
>  }

-- 
Regards,

Laurent Pinchart