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Date:   Sun, 12 Jun 2022 09:53:33 +0100
From:   Jonathan Cameron <jic23@kernel.org>
To:     "Luca Weiss" <luca.weiss@fairphone.com>
Cc:     "Markuss Broks" <markuss.broks@gmail.com>,
        <linux-kernel@vger.kernel.org>,
        <~postmarketos/upstreaming@lists.sr.ht>,
        <phone-devel@vger.kernel.org>,
        "Konrad Dybcio" <konrad.dybcio@somainline.org>,
        "Marijn Suijten" <marijn.suijten@somainline.org>,
        "AngeloGioacchino Del Regno" 
        <angelogioacchino.delregno@somainline.org>,
        "Song Qiang" <songqiang1304521@gmail.com>,
        "Lars-Peter Clausen" <lars@metafoo.de>,
        "Rob Herring" <robh+dt@kernel.org>,
        "Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
        "Andy Gross" <agross@kernel.org>,
        "Bjorn Andersson" <bjorn.andersson@linaro.org>,
        "Liam Girdwood" <lgirdwood@gmail.com>,
        "Mark Brown" <broonie@kernel.org>, <linux-iio@vger.kernel.org>,
        <devicetree@vger.kernel.org>, <linux-arm-msm@vger.kernel.org>
Subject: Re: [PATCH 3/5] proximity: vl53l0x: Handle the VDD regulator
Message-ID: <20220612095333.1479464c@jic23-huawei>
In-Reply-To: <CKKOCWP2NYO5.GH08U776B1KU@otso>
References: <20220523175344.5845-1-markuss.broks@gmail.com>
        <20220523175344.5845-4-markuss.broks@gmail.com>
        <CKKOCWP2NYO5.GH08U776B1KU@otso>
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On Wed, 08 Jun 2022 12:18:52 +0200
"Luca Weiss" <luca.weiss@fairphone.com> wrote:

> Hi Markuss,
> 
> On Mon May 23, 2022 at 7:53 PM CEST, Markuss Broks wrote:
> > Handle the regulator supplying the VDD pin of VL53L0X.
> >
> > Signed-off-by: Markuss Broks <markuss.broks@gmail.com>
> > ---
> >  drivers/iio/proximity/vl53l0x-i2c.c | 37 +++++++++++++++++++++++++++++
> >  1 file changed, 37 insertions(+)
> >
> > diff --git a/drivers/iio/proximity/vl53l0x-i2c.c b/drivers/iio/proximity/vl53l0x-i2c.c
> > index 12a3e2eff464..8581a873919f 100644
> > --- a/drivers/iio/proximity/vl53l0x-i2c.c
> > +++ b/drivers/iio/proximity/vl53l0x-i2c.c
> > @@ -43,6 +43,7 @@
> >  struct vl53l0x_data {
> >  	struct i2c_client *client;
> >  	struct completion completion;
> > +	struct regulator *vdd_supply;
> >  };
> >  
> >  static irqreturn_t vl53l0x_handle_irq(int irq, void *priv)
> > @@ -192,10 +193,31 @@ static const struct iio_info vl53l0x_info = {
> >  	.read_raw = vl53l0x_read_raw,
> >  };
> >  
> > +static void vl53l0x_power_off(void *_data)
> > +{
> > +	struct vl53l0x_data *data = _data;
> > +
> > +	regulator_disable(data->vdd_supply);
> > +}
> > +
> > +static int vl53l0x_power_on(struct vl53l0x_data *data)
> > +{
> > +	int ret;
> > +
> > +	ret = regulator_enable(data->vdd_supply);
> > +	if (ret)
> > +		return ret;
> > +
> > +	usleep_range(3200, 5000);
> > +
> > +	return 0;
> > +}
> > +
> >  static int vl53l0x_probe(struct i2c_client *client)
> >  {
> >  	struct vl53l0x_data *data;
> >  	struct iio_dev *indio_dev;
> > +	int error;
> >  
> >  	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> >  	if (!indio_dev)
> > @@ -210,6 +232,21 @@ static int vl53l0x_probe(struct i2c_client *client)
> >  				     I2C_FUNC_SMBUS_BYTE_DATA))
> >  		return -EOPNOTSUPP;
> >  
> > +	data->vdd_supply = devm_regulator_get_optional(&client->dev, "vdd");
> > +	if (IS_ERR(data->vdd_supply))
> > +		return dev_err_probe(&client->dev, PTR_ERR(data->vdd_supply),
> > +				     "Unable to get VDD regulator\n");  
> 
> It looks like this optional regulator is not actually optional.
> 
> [    1.919995] vl53l0x-i2c 1-0029: error -ENODEV: Unable to get VDD regulator
> 
> When using devm_regulator_get instead, a dummy regulator gets returned
> which I think is what we want here:
> 
> [    1.905518] vl53l0x-i2c 1-0029: supply vdd not found, using dummy regulator
> 
> Can you fix this up or should I send a patch?

Hi Luca,

Please send a patch.

Jonathan

> 
> Regards
> Luca
> 
> 
> > +
> > +	error = vl53l0x_power_on(data);
> > +	if (error)
> > +		return dev_err_probe(&client->dev, error,
> > +				     "Failed to power on the chip\n");
> > +
> > +	error = devm_add_action_or_reset(&client->dev, vl53l0x_power_off, data);
> > +	if (error)
> > +		return dev_err_probe(&client->dev, error,
> > +				     "Failed to install poweroff action\n");
> > +
> >  	indio_dev->name = "vl53l0x";
> >  	indio_dev->info = &vl53l0x_info;
> >  	indio_dev->channels = vl53l0x_channels;
> > -- 
> > 2.36.1  
>