linux-kernel - Re: [PATCH 2/2] Input: cyttsp5

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Message-ID: <Y3ayb8b9vyQHRabc@google.com>
Date:   Thu, 17 Nov 2022 14:15:11 -0800
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>
Cc:     linmengbo0689@...tonmail.com, alistair@...stair23.me,
        devicetree@...r.kernel.org, krzysztof.kozlowski+dt@...aro.org,
        linus.walleij@...aro.org, linux-input@...r.kernel.org,
        linux-kernel@...r.kernel.org, robh+dt@...nel.org
Subject: Re: [PATCH 2/2] Input: cyttsp5 - add vddio regulator

On Thu, Nov 17, 2022 at 10:16:40PM +0100, Christophe JAILLET wrote:
> Le 17/11/2022 à 20:05, Lin, Meng-Bo a écrit :
> > The Samsung touchscreen controllers are often used with external pull-up
> > for the interrupt line and the I2C lines, so we might need to enable
> > a regulator to bring the lines into usable state. Otherwise, this might
> > cause spurious interrupts and reading from I2C will fail.
> > 
> > Implement support for a "vddio-supply" that is enabled by the cyttsp5
> > driver so that the regulator gets enabled when needed.
> > 
> > Signed-off-by: Lin, Meng-Bo <linmengbo0689-g/b1ySJe57IN+BqQ9rBEUg@...lic.gmane.org>
> > ---
> >   drivers/input/touchscreen/cyttsp5.c | 19 ++++++++++++-------
> >   1 file changed, 12 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/input/touchscreen/cyttsp5.c b/drivers/input/touchscreen/cyttsp5.c
> > index 24ab1df9fc07..d02fdb940edf 100644
> > --- a/drivers/input/touchscreen/cyttsp5.c
> > +++ b/drivers/input/touchscreen/cyttsp5.c
> > @@ -190,7 +190,7 @@ struct cyttsp5 {
> >   	int num_prv_rec;
> >   	struct regmap *regmap;
> >   	struct touchscreen_properties prop;
> > -	struct regulator *vdd;
> > +	struct regulator_bulk_data supplies[2];
> >   };
> >   /*
> > @@ -767,7 +767,7 @@ static void cyttsp5_cleanup(void *data)
> >   {
> >   	struct cyttsp5 *ts = data;
> > -	regulator_disable(ts->vdd);
> > +	regulator_bulk_disable(ARRAY_SIZE(ts->supplies), ts->supplies);
> >   }
> >   static int cyttsp5_probe(struct device *dev, struct regmap *regmap, int irq,
> > @@ -790,9 +790,12 @@ static int cyttsp5_probe(struct device *dev, struct regmap *regmap, int irq,
> >   	init_completion(&ts->cmd_done);
> >   	/* Power up the device */
> > -	ts->vdd = devm_regulator_get(dev, "vdd");
> > -	if (IS_ERR(ts->vdd)) {
> > -		error = PTR_ERR(ts->vdd);
> > +	ts->supplies[0].supply = "vdd";
> > +	ts->supplies[1].supply = "vddio";
> > +	error = devm_regulator_bulk_get(dev, ARRAY_SIZE(ts->supplies),
> > +				      ts->supplies);
> > +	if (error < 0) {
> > +		dev_err(ts->dev, "Failed to get regulators, error %d\n", error);
> 
> Hi,
> 
> dev_err_probe()?
> I think that devm_regulator_bulk_get() can return -EPROBE_DEFER;

No, I'd rather we avoid dev_err_probe().

Thanks.

-- 
Dmitry