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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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