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Date:   Tue, 23 Jan 2018 10:10:55 +0100
From:   Mylene Josserand <mylene.josserand@free-electrons.com>
To:     Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc:     Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Russell King - ARM Linux <linux@armlinux.org.uk>,
        Maxime Ripard <maxime.ripard@free-electrons.com>,
        Chen-Yu Tsai <wens@csie.org>,
        linux-arm-kernel@lists.infradead.org,
        "linux-input@vger.kernel.org" <linux-input@vger.kernel.org>,
        devicetree@vger.kernel.org, lkml <linux-kernel@vger.kernel.org>,
        Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
        Quentin Schulz <quentin.schulz@free-electrons.com>
Subject: Re: [PATCH v2 1/2] Input: edt-ft5x06 - Add support for regulator
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Hello Dimitry,

Thank you for the review!

Le Mon, 22 Jan 2018 09:42:08 -0800,
Dmitry Torokhov <dmitry.torokhov@gmail.com> a écrit :

> Hi Mylène,
> 
> On Thu, Dec 28, 2017 at 8:33 AM, Mylène Josserand
> <mylene.josserand@free-electrons.com> wrote:
> > Add the support of regulator to use it as VCC source.
> >
> > Signed-off-by: Mylène Josserand <mylene.josserand@free-electrons.com>
> > ---
> >  .../bindings/input/touchscreen/edt-ft5x06.txt      |  1 +
> >  drivers/input/touchscreen/edt-ft5x06.c             | 33 ++++++++++++++++++++++
> >  2 files changed, 34 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt b/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt
> > index 025cf8c9324a..48e975b9c1aa 100644
> > --- a/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt
> > +++ b/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt
> > @@ -30,6 +30,7 @@ Required properties:
> >  Optional properties:
> >   - reset-gpios: GPIO specification for the RESET input
> >   - wake-gpios:  GPIO specification for the WAKE input
> > + - vcc-supply:  Regulator that supplies the touchscreen
> >
> >   - pinctrl-names: should be "default"
> >   - pinctrl-0:   a phandle pointing to the pin settings for the
> > diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c
> > index c53a3d7239e7..5ee14a25a382 100644
> > --- a/drivers/input/touchscreen/edt-ft5x06.c
> > +++ b/drivers/input/touchscreen/edt-ft5x06.c
> > @@ -39,6 +39,7 @@
> >  #include <linux/input/mt.h>
> >  #include <linux/input/touchscreen.h>
> >  #include <linux/of_device.h>
> > +#include <linux/regulator/consumer.h>
> >
> >  #define WORK_REGISTER_THRESHOLD                0x00
> >  #define WORK_REGISTER_REPORT_RATE      0x08
> > @@ -91,6 +92,7 @@ struct edt_ft5x06_ts_data {
> >         struct touchscreen_properties prop;
> >         u16 num_x;
> >         u16 num_y;
> > +       struct regulator *vcc;
> >
> >         struct gpio_desc *reset_gpio;
> >         struct gpio_desc *wake_gpio;
> > @@ -993,6 +995,23 @@ static int edt_ft5x06_ts_probe(struct i2c_client *client,
> >
> >         tsdata->max_support_points = chip_data->max_support_points;
> >
> > +       tsdata->vcc = devm_regulator_get(&client->dev, "vcc");
> > +       if (IS_ERR(tsdata->vcc)) {
> > +               error = PTR_ERR(tsdata->vcc);
> > +               dev_err(&client->dev, "failed to request regulator: %d\n",
> > +                       error);
> > +               return error;
> > +       };  
> 
> As 0-day pounted out, this semicolon is not needed.

Yes, thanks, I will fix that in next version.

> 
> > +
> > +       if (tsdata->vcc) {  
> 
> You do not need to check for non-NULL here, devm_regulator_get() wil
> lnever give you a NULL. If regulator is not defined in DT/board
> mappings, then dummy regulator will be provided. You can call
> regulator_enable() and regulator_disable() and other regulator APIs
> with dummy regulator.

Okay, thanks for the explanation, I will remove that.

> 
> > +               error = regulator_enable(tsdata->vcc);
> > +               if (error < 0) {
> > +                       dev_err(&client->dev, "failed to enable vcc: %d\n",
> > +                               error);
> > +                       return error;
> > +               }
> > +       }
> > +
> >         tsdata->reset_gpio = devm_gpiod_get_optional(&client->dev,
> >                                                      "reset", GPIOD_OUT_HIGH);
> >         if (IS_ERR(tsdata->reset_gpio)) {
> > @@ -1122,20 +1141,34 @@ static int edt_ft5x06_ts_remove(struct i2c_client *client)
> >  static int __maybe_unused edt_ft5x06_ts_suspend(struct device *dev)
> >  {
> >         struct i2c_client *client = to_i2c_client(dev);
> > +       struct edt_ft5x06_ts_data *tsdata = i2c_get_clientdata(client);
> >
> >         if (device_may_wakeup(dev))
> >                 enable_irq_wake(client->irq);
> >
> > +       if (tsdata->vcc)  
> 
> Same here.

yep

> 
> > +               regulator_disable(tsdata->vcc);
> > +
> >         return 0;
> >  }
> >
> >  static int __maybe_unused edt_ft5x06_ts_resume(struct device *dev)
> >  {
> >         struct i2c_client *client = to_i2c_client(dev);
> > +       struct edt_ft5x06_ts_data *tsdata = i2c_get_clientdata(client);
> > +       int ret;
> >
> >         if (device_may_wakeup(dev))
> >                 disable_irq_wake(client->irq);
> >
> > +       if (tsdata->vcc) {  
> 
> And here.

yep

> 
> > +               ret = regulator_enable(tsdata->vcc);
> > +               if (ret < 0) {
> > +                       dev_err(dev, "failed to enable vcc: %d\n", ret);
> > +                       return ret;
> > +               }  
> 
> Since power to the device may have been cut, I think you need to
> restore the register settings to whatever it was (factory vs work
> mode, threshold, gain and offset registers, etc, etc).

Okay. Could you tell me how can I do that?

> 
> > +       }
> > +
> >         return 0;
> >  }
> >
> > --
> > 2.11.0
> >  
> 
> Thanks.
> 

About your V2's review, you suggested to add support for wake/reset in
suspend/resume (that I forgot in this version). I wanted to add it but
with my board, I can't test suspend/resume. What should I do about
that?

If I send a V3 in next few days, do you think you will have time to
merge it for v4.16?

Thank you in advance,

Best regards,

Mylène

-- 
Mylène Josserand, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com