linux-kernel - Re: [PATCH 3/5] proximity: vl53l0x: Handle the VDD regulator

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Date:   Tue, 14 Jun 2022 11:48:53 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     Luca Weiss <luca@...tu.xyz>
Cc:     Luca Weiss <luca.weiss@...rphone.com>,
        ~postmarketos/upstreaming@...ts.sr.ht,
        Markuss Broks <markuss.broks@...il.com>,
        linux-kernel@...r.kernel.org, phone-devel@...r.kernel.org,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...ainline.org>,
        Song Qiang <songqiang1304521@...il.com>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>, linux-iio@...r.kernel.org,
        devicetree@...r.kernel.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH 3/5] proximity: vl53l0x: Handle the VDD regulator

On Sun, 12 Jun 2022 11:28:22 +0200
Luca Weiss <luca@...tu.xyz> wrote:

> Hi Jonathan,
> 
> On Sonntag, 12. Juni 2022 10:53:33 CEST Jonathan Cameron wrote:
> > On Wed, 08 Jun 2022 12:18:52 +0200
> > 
> > "Luca Weiss" <luca.weiss@...rphone.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@...il.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.  
> 
> Which commit sha can I use for Fixes: here?
> Based your togreg[0] branch currently shows "Age: 20 hours" I guess it was 
> rebased recently?

It was rebased onto rc1 as you noticed.

In theory it is now stable, assuming nothing nasty shows up.
Fixes tag doesn't matter strongly given both will go into mainline via
the same pull request, so maybe just skip adding one to make my life
easier :)

Thanks,

Jonathan

> 
> Regards
> Luca
> 
> [0]https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git/log/?h=togreg
> 
> > 
> > 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;  
> 
> 
> 
>