diff mbox series

[v4,07/10] Input: wacom_i2c - Add support for reset control

Message ID 20210326015229.141-7-alistair@alistair23.me (mailing list archive)
State Superseded
Headers show
Series [v4,01/10] dt-bindings: Add Wacom to vendor bindings | expand

Commit Message

Alistair Francis March 26, 2021, 1:52 a.m. UTC 
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(+)

Comments

Dmitry Torokhov March 29, 2021, 8:33 p.m. UTC | #1 
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?

> +
>  	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.
Alistair Francis April 27, 2021, 5:56 a.m. UTC | #2 
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
diff mbox series

Patch

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);
+
 	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);
+	}
+
 	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;