Re: [PATCH v2 1/2] Input: edt-ft5x06 - Add support for regulator

From: Dmitry Torokhov
Date: Tue Jan 23 2018 - 12:58:39 EST

On Tue, Jan 23, 2018 at 10:10:55AM +0100, Mylene Josserand wrote:
> Hello Dimitry,
>
> Thank you for the review!
>
> Le Mon, 22 Jan 2018 09:42:08 -0800,
> Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> a écrit :
>
> > Hi Mylène,
> >
> > On Thu, Dec 28, 2017 at 8:33 AM, Mylène Josserand
> > <mylene.josserand@xxxxxxxxxxxxxxxxxx> wrote:
> > > Add the support of regulator to use it as VCC source.
> > >
> > > Signed-off-by: Mylène Josserand <mylene.josserand@xxxxxxxxxxxxxxxxxx>
> > > ---
> > > .../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?

If you take a look at edt_ft5x06_work_mode() at the end ther eis code to
restore parameters. You want to factor it out and apply to the device
when resuming. You probably also want to see what mode (factory/normal)
the device was before suspend and restore the previous mode on resume.

>
> >
> > > + }
> > > +
> > > 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?

See if Simon Budig <simon.budig@xxxxxxxxxxxxxxxxx> can help us here.

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

It all depends on the patch shape...

Thanks.

--
Dmitry