linux-kernel - Re: [PATCH v3 2/4] Input: goodix - Add AVDD28-supply regulator support

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Message-ID: <CAKdAkRR8MQvh2CQ6+6d1LcX28CmRASXvmqc3QoJaoMEz92=uxg@mail.gmail.com>
Date:   Fri, 1 Feb 2019 00:18:35 -0800
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Jagan Teki <jagan@...rulasolutions.com>
Cc:     Chen-Yu Tsai <wens@...e.org>,
        "linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Michael Trimarchi <michael@...rulasolutions.com>,
        linux-amarula@...rulasolutions.com
Subject: Re: [PATCH v3 2/4] Input: goodix - Add AVDD28-supply regulator support

On Thu, Jan 31, 2019 at 12:00 PM Jagan Teki <jagan@...rulasolutions.com> wrote:
>
> On Wed, Jan 9, 2019 at 1:10 PM Dmitry Torokhov
> <dmitry.torokhov@...il.com> wrote:
> >
> > Hi Jagan,
> >
> > On Sat, Dec 15, 2018 at 08:48:00PM +0530, Jagan Teki wrote:
> > > Goodix CTP controllers have AVDD28 pin connected to voltage
> > > regulator which may not be turned on by default, like for GT5663.
> > >
> > > Add support for such ctp used boards by adding voltage regulator
> > > handling code to goodix ctp driver.
> > >
> > > Signed-off-by: Jagan Teki <jagan@...rulasolutions.com>
> > > ---
> > >  drivers/input/touchscreen/goodix.c | 33 +++++++++++++++++++++++++-----
> > >  1 file changed, 28 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
> > > index f2d9c2c41885..7371f6946098 100644
> > > --- a/drivers/input/touchscreen/goodix.c
> > > +++ b/drivers/input/touchscreen/goodix.c
> > > @@ -27,6 +27,7 @@
> > >  #include <linux/delay.h>
> > >  #include <linux/irq.h>
> > >  #include <linux/interrupt.h>
> > > +#include <linux/regulator/consumer.h>
> > >  #include <linux/slab.h>
> > >  #include <linux/acpi.h>
> > >  #include <linux/of.h>
> > > @@ -47,6 +48,7 @@ struct goodix_ts_data {
> > >       struct touchscreen_properties prop;
> > >       unsigned int max_touch_num;
> > >       unsigned int int_trigger_type;
> > > +     struct regulator *avdd28;
> > >       struct gpio_desc *gpiod_int;
> > >       struct gpio_desc *gpiod_rst;
> > >       u16 id;
> > > @@ -786,25 +788,41 @@ static int goodix_ts_probe(struct i2c_client *client,
> > >       if (error)
> > >               return error;
> > >
> > > +     ts->avdd28 = devm_regulator_get(&client->dev, "AVDD28");
> > > +     if (IS_ERR(ts->avdd28)) {
> > > +             error = PTR_ERR(ts->avdd28);
> > > +             if (error != -EPROBE_DEFER)
> > > +                     dev_err(&client->dev,
> > > +                             "Failed to get AVDD28 regulator: %d\n", error);
> > > +             return error;
> > > +     }
> > > +
> > > +     /* power the controller */
> > > +     error = regulator_enable(ts->avdd28);
> > > +     if (error) {
> > > +             dev_err(&client->dev, "Controller fail to enable AVDD28\n");
> > > +             return error;
> > > +     }
> > > +
> > >       if (ts->gpiod_int && ts->gpiod_rst) {
> > >               /* reset the controller */
> > >               error = goodix_reset(ts);
> > >               if (error) {
> > >                       dev_err(&client->dev, "Controller reset failed.\n");
> > > -                     return error;
> > > +                     goto error;
> > >               }
> > >       }
> > >
> > >       error = goodix_i2c_test(client);
> > >       if (error) {
> > >               dev_err(&client->dev, "I2C communication failure: %d\n", error);
> > > -             return error;
> > > +             goto error;
> > >       }
> > >
> > >       error = goodix_read_version(ts);
> > >       if (error) {
> > >               dev_err(&client->dev, "Read version failed.\n");
> > > -             return error;
> > > +             goto error;
> > >       }
> > >
> > >       ts->chip = goodix_get_chip_data(ts->id);
> > > @@ -823,23 +841,28 @@ static int goodix_ts_probe(struct i2c_client *client,
> > >                       dev_err(&client->dev,
> > >                               "Failed to invoke firmware loader: %d\n",
> > >                               error);
> > > -                     return error;
> > > +                     goto error;
> > >               }
> > >
> > >               return 0;
> > >       } else {
> > >               error = goodix_configure_dev(ts);
> > >               if (error)
> > > -                     return error;
> > > +                     goto error;
> > >       }
> > >
> > >       return 0;
> > > +
> > > +error:
> > > +     regulator_disable(ts->avdd28);
> > > +     return error;
> > >  }
> > >
> > >  static int goodix_ts_remove(struct i2c_client *client)
> > >  {
> > >       struct goodix_ts_data *ts = i2c_get_clientdata(client);
> > >
> > > +     regulator_disable(ts->avdd28);
> >
> > This may be disabling the regulator too early. Please use
> > devm_add_action_or_reset() to install a custom devm handler that would
> > disable the regulator in line with the rest of devm unwinding flow.
>
> Like handler with only regulator_disable?

Right.

> and would that call from suspend or not need?

No, it will only be called when device is unbound from the driver or
when probe fails. If you need to control regulator in suspend/resume
you can do it with normal regulator_enable() and regulator_disable()
calls.

Thanks.

-- 
Dmitry