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SubjectRe: [PATCH v4 07/10] Input: wacom_i2c - Add support for reset control
On Tue, Mar 30, 2021 at 6:33 AM Dmitry Torokhov
<dmitry.torokhov@gmail.com> wrote:
>
> Hi Alistair,
>
> On Thu, Mar 25, 2021 at 09:52:27PM -0400, Alistair Francis wrote:
> > From: Alistair Francis <alistair@alistair22.me>
> >
> > Signed-off-by: Alistair Francis <alistair@alistair22.me>
> > ---
> > v4:
> > - Initial commit
> >
> > drivers/input/touchscreen/wacom_i2c.c | 11 +++++++++++
> > 1 file changed, 11 insertions(+)
> >
> > diff --git a/drivers/input/touchscreen/wacom_i2c.c b/drivers/input/touchscreen/wacom_i2c.c
> > index 84c7ccb737bd..28004b1180c9 100644
> > --- a/drivers/input/touchscreen/wacom_i2c.c
> > +++ b/drivers/input/touchscreen/wacom_i2c.c
> > @@ -55,6 +55,7 @@ struct wacom_features {
> > struct wacom_i2c {
> > struct i2c_client *client;
> > struct input_dev *input;
> > + struct reset_control *rstc;
> > struct touchscreen_properties props;
> > u8 data[WACOM_QUERY_SIZE];
> > bool prox;
> > @@ -175,6 +176,8 @@ static int wacom_i2c_open(struct input_dev *dev)
> > struct wacom_i2c *wac_i2c = input_get_drvdata(dev);
> > struct i2c_client *client = wac_i2c->client;
> >
> > + reset_control_reset(wac_i2c->rstc);
>
> Why does this device need to be reset on every open compared to doing it
> in probe?
>
> > +
> > enable_irq(client->irq);
> >
> > return 0;
> > @@ -193,6 +196,7 @@ static int wacom_i2c_probe(struct i2c_client *client,
> > {
> > struct wacom_i2c *wac_i2c;
> > struct input_dev *input;
> > + struct reset_control *rstc;
> > struct wacom_features features = { 0 };
> > int error;
> >
> > @@ -201,6 +205,12 @@ static int wacom_i2c_probe(struct i2c_client *client,
> > return -EIO;
> > }
> >
> > + rstc = devm_reset_control_get_optional_exclusive(&client->dev, NULL);
> > + if (IS_ERR(rstc)) {
> > + dev_err(&client->dev, "Failed to get reset control before init\n");
> > + return PTR_ERR(rstc);
> > + }
>
> I think majority users will have this controller reset line connected to
> a GPIO. I briefly looked into reset controller code and I do not see it
> supporting this case. How is this device connected on your board?

That's a good question. I am going to drop this patch as I'm not
convinced it's required.

Alistair

>
> > +
> > error = wacom_query_device(client, &features);
> > if (error)
> > return error;
> > @@ -214,6 +224,7 @@ static int wacom_i2c_probe(struct i2c_client *client,
> >
> > wac_i2c->client = client;
> > wac_i2c->input = input;
> > + wac_i2c->rstc = rstc;
> >
> > input->name = "Wacom I2C Digitizer";
> > input->id.bustype = BUS_I2C;
> > --
> > 2.31.0
> >
>
> Thanks.
>
> --
> Dmitry

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