Re: [PATCH v2 04/11] media: i2c: max9286: Add support for port regulators

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Jacopo Mondi <jacopo@jmondi.org>
Cc: linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
	"Kieran Bingham" <kieran.bingham@ideasonboard.com>,
	"Niklas Söderlund" <niklas.soderlund@ragnatech.se>,
	"Thomas Nizan" <tnizan@witekio.com>,
	"Mark Brown" <broonie@kernel.org>,
	"Liam Girdwood" <lgirdwood@gmail.com>
Subject: Re: [PATCH v2 04/11] media: i2c: max9286: Add support for port regulators
Date: Mon, 10 Jan 2022 01:16:52 +0200	[thread overview]
Message-ID: <Ydts5Da3mHdvBIng@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20220109100412.z2twzgkeum4fzbaw@uno.localdomain>

Hi Jacopo,

On Sun, Jan 09, 2022 at 11:04:12AM +0100, Jacopo Mondi wrote:
> On Sat, Jan 01, 2022 at 08:27:59PM +0200, Laurent Pinchart wrote:
> > From: Thomas Nizan <tnizan@witekio.com>
> >
> > Allow users to use one PoC regulator per port, instead of a global
> > regulator.
> >
> > The properties '^port[0-3]-poc-supply$' in the DT node are used to
> > indicate the regulators for individual ports.
> >
> > Signed-off-by: Thomas Nizan <tnizan@witekio.com>
> > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> 
> The patch looks almost good, but it will really conflict with gpio-poc work I
> have on the list. Should we decide an ordering and send a single
> series with both efforts in to ease collecting it ?

I'm fine with any order, and I'm also fine merging the two series. I
don't mind rebasing on top of your gpio-poc series at all, would that
help ?

> > ---
> > Changes since v1:
> >
> > - Use to_index()
> > - Use dev_err_probe()
> > - Fix error path in probe()
> > - Use devm_regulator_get_optional() instead of
> >   devm_regulator_get_exclusive()
> > ---
> >  drivers/media/i2c/max9286.c | 107 +++++++++++++++++++++++++++++++-----
> >  1 file changed, 94 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
> > index eb2b8e42335b..15c80034e3a4 100644
> > --- a/drivers/media/i2c/max9286.c
> > +++ b/drivers/media/i2c/max9286.c
> > @@ -138,6 +138,7 @@
> >  struct max9286_source {
> >  	struct v4l2_subdev *sd;
> >  	struct fwnode_handle *fwnode;
> > +	struct regulator *regulator;
> >  };
> >
> >  struct max9286_asd {
> > @@ -1071,6 +1072,49 @@ static int max9286_register_gpio(struct max9286_priv *priv)
> >  	return ret;
> >  }
> >
> > +static int max9286_poc_power_on(struct max9286_priv *priv)
> > +{
> > +	struct max9286_source *source;
> > +	unsigned int enabled = 0;
> > +	int ret;
> > +
> > +	/* Enable the global regulator if available. */
> > +	if (priv->regulator)
> > +		return regulator_enable(priv->regulator);
> > +
> > +	/* Otherwise use the per-port regulators. */
> > +	for_each_source(priv, source) {
> > +		ret = regulator_enable(source->regulator);
> > +		if (ret < 0)
> > +			goto error;
> > +
> > +		enabled |= BIT(to_index(priv, source));
> > +	}
> > +
> > +	return 0;
> > +
> > +error:
> > +	for_each_source(priv, source) {
> > +		if (enabled & BIT(to_index(priv, source)))
> > +			regulator_disable(source->regulator);
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> > +static void max9286_poc_power_off(struct max9286_priv *priv)
> > +{
> > +	struct max9286_source *source;
> > +
> > +	if (priv->regulator) {
> > +		regulator_disable(priv->regulator);
> > +		return;
> > +	}
> > +
> > +	for_each_source(priv, source)
> > +		regulator_disable(source->regulator);
> > +}
> > +
> >  static int max9286_init(struct device *dev)
> >  {
> >  	struct max9286_priv *priv;
> > @@ -1081,9 +1125,9 @@ static int max9286_init(struct device *dev)
> >  	priv = i2c_get_clientdata(client);
> >
> >  	/* Enable the bus power. */
> > -	ret = regulator_enable(priv->regulator);
> > +	ret = max9286_poc_power_on(priv);
> >  	if (ret < 0) {
> > -		dev_err(&client->dev, "Unable to turn PoC on\n");
> > +		dev_err(dev, "Unable to turn PoC on\n");
> >  		return ret;
> >  	}
> >
> > @@ -1117,7 +1161,7 @@ static int max9286_init(struct device *dev)
> >  err_v4l2_register:
> >  	max9286_v4l2_unregister(priv);
> >  err_regulator:
> > -	regulator_disable(priv->regulator);
> > +	max9286_poc_power_off(priv);
> >
> >  	return ret;
> >  }
> > @@ -1248,6 +1292,47 @@ static int max9286_parse_dt(struct max9286_priv *priv)
> >  	return 0;
> >  }
> >
> > +static int max9286_get_poc_supplies(struct max9286_priv *priv)
> > +{
> > +	struct device *dev = &priv->client->dev;
> > +	struct max9286_source *source;
> > +	int ret;
> > +
> > +	/* Start by getting the global regulator. */
> > +	priv->regulator = devm_regulator_get_optional(dev, "poc");
> > +	if (!IS_ERR(priv->regulator))
> > +		return 0;
> > +
> > +	if (PTR_ERR(priv->regulator) != -ENODEV) {
> > +		if (PTR_ERR(priv->regulator) != -EPROBE_DEFER)
> > +			dev_err(dev, "Unable to get PoC regulator: %ld\n",
> > +				PTR_ERR(priv->regulator));
> > +		return PTR_ERR(priv->regulator);
> > +	}
> > +
> > +	/* If there's no global regulator, get per-port regulators. */
> > +	dev_dbg(dev,
> > +		"No global PoC regulator, looking for per-port regulators\n");
> > +	priv->regulator = NULL;
> > +
> > +	for_each_source(priv, source) {
> > +		unsigned int index = to_index(priv, source);
> > +		char name[10];
> > +
> > +		snprintf(name, sizeof(name), "port%u-poc", index);
> > +		source->regulator = devm_regulator_get(dev, name);
> 
> Are you ok with a dummy being returned ?

I think that's fine. It would mean that there's no global regulator nor
per-port regulator specified in DT, which shouldn't happen even if the
supply is alwaus on. From a driver point of view it won't hurt I think.

> > +		if (IS_ERR(source->regulator)) {
> > +			ret = PTR_ERR(source->regulator);
> > +			dev_err_probe(dev, ret,
> > +				      "Unable to get port %u PoC regulator\n",
> > +				      index);
> > +			return ret;
> > +		}
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> >  static int max9286_probe(struct i2c_client *client)
> >  {
> >  	struct max9286_priv *priv;
> > @@ -1292,17 +1377,13 @@ static int max9286_probe(struct i2c_client *client)
> >  	if (ret)
> >  		goto err_powerdown;
> >
> > -	priv->regulator = devm_regulator_get(&client->dev, "poc");
> > -	if (IS_ERR(priv->regulator)) {
> > -		ret = PTR_ERR(priv->regulator);
> > -		dev_err_probe(&client->dev, ret,
> > -			      "Unable to get PoC regulator\n");
> > -		goto err_powerdown;
> > -	}
> > -
> >  	ret = max9286_parse_dt(priv);
> >  	if (ret)
> > -		goto err_powerdown;
> > +		goto err_cleanup_dt;
> 
> Shouldn't this be still err_powerdown ?

I don't think so, max9286_parse_dt() may have populated the fwnode of
part of the sources before failing.

> > +
> > +	ret = max9286_get_poc_supplies(priv);
> > +	if (ret)
> > +		goto err_cleanup_dt;
> >
> >  	ret = max9286_init(&client->dev);
> >  	if (ret < 0)
> > @@ -1326,7 +1407,7 @@ static int max9286_remove(struct i2c_client *client)
> >
> >  	max9286_v4l2_unregister(priv);
> >
> > -	regulator_disable(priv->regulator);
> > +	max9286_poc_power_off(priv);
> >
> >  	gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
> >

-- 
Regards,

Laurent Pinchart