RE: [PATCH v2 6/8] input: goodix: add power management support

[Tirdea, Irina]

> -----Original Message-----
> From: Dmitry Torokhov [mailto:dmitry.torokhov@xxxxxxxxx]
> Sent: 09 June, 2015 21:16
> To: Tirdea, Irina
> Cc: Bastien Nocera; Mark Rutland; linux-input@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Rob
> Herring; Pawel Moll; Ian Campbell; Kumar Gala; Purdila, Octavian
> Subject: Re: [PATCH v2 6/8] input: goodix: add power management support
> 
> On Mon, Jun 08, 2015 at 05:37:51PM +0300, Irina Tirdea wrote:
> > Implement suspend/resume for goodix driver.
> >
> > This is based on Goodix datasheets for GT911 and GT9271
> > and on Goodix driver gt9xx.c for Android (publicly available
> > in Android kernel trees for various devices).
> >
> > Signed-off-by: Octavian Purdila <octavian.purdila@xxxxxxxxx>
> > Signed-off-by: Irina Tirdea <irina.tirdea@xxxxxxxxx>
> > ---
> >  drivers/input/touchscreen/goodix.c | 88 +++++++++++++++++++++++++++++++++++---
> >  1 file changed, 83 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
> > index 1ce9278..903c83d 100644
> > --- a/drivers/input/touchscreen/goodix.c
> > +++ b/drivers/input/touchscreen/goodix.c
> > @@ -38,6 +38,7 @@ struct goodix_ts_data {
> >  	unsigned int int_trigger_type;
> >  	struct gpio_desc *gpiod_int;
> >  	struct gpio_desc *gpiod_rst;
> > +	unsigned long irq_flags;
> >  };
> >
> >  #define GOODIX_GPIO_INT_NAME		"irq"
> > @@ -52,6 +53,9 @@ struct goodix_ts_data {
> >  #define GOODIX_CONFIG_MAX_LENGTH	240
> >
> >  /* Register defines */
> > +#define GOODIX_REG_COMMAND		0x8040
> > +#define GOODIX_CMD_SCREEN_OFF		0x05
> > +
> >  #define GOODIX_READ_COOR_ADDR		0x814E
> >  #define GOODIX_REG_CONFIG_DATA		0x8047
> >  #define GOODIX_REG_ID			0x8140
> > @@ -129,6 +133,11 @@ static int goodix_i2c_write(struct i2c_client *client, u16 reg, const u8 *buf,
> >  	return ret < 0 ? ret : (ret != 1 ? -EIO : 0);
> >  }
> >
> > +static int goodix_i2c_write_u8(struct i2c_client *client, u16 reg, u8 value)
> > +{
> > +	return goodix_i2c_write(client, reg, &value, sizeof(value));
> > +}
> > +
> >  static int goodix_ts_read_input_report(struct goodix_ts_data *ts, u8 *data)
> >  {
> >  	int touch_num;
> > @@ -226,6 +235,18 @@ static irqreturn_t goodix_ts_irq_handler(int irq, void *dev_id)
> >  	return IRQ_HANDLED;
> >  }
> >
> > +static void goodix_free_irq(struct goodix_ts_data *ts)
> > +{
> > +	devm_free_irq(&ts->client->dev, ts->client->irq, ts);
> > +}
> > +
> > +static int goodix_request_irq(struct goodix_ts_data *ts)
> > +{
> > +	return devm_request_threaded_irq(&ts->client->dev, ts->client->irq,
> > +					 NULL, goodix_ts_irq_handler,
> > +					 ts->irq_flags, ts->client->name, ts);
> > +}
> > +
> >  /**
> >   * goodix_check_cfg - Checks if config buffer is valid
> >   *
> > @@ -547,7 +568,6 @@ static int goodix_ts_probe(struct i2c_client *client,
> >  			   const struct i2c_device_id *id)
> >  {
> >  	struct goodix_ts_data *ts;
> > -	unsigned long irq_flags;
> >  	int error;
> >  	u16 version_info, id_info;
> >
> > @@ -599,10 +619,8 @@ static int goodix_ts_probe(struct i2c_client *client,
> >  	if (error)
> >  		return error;
> >
> > -	irq_flags = goodix_irq_flags[ts->int_trigger_type] | IRQF_ONESHOT;
> > -	error = devm_request_threaded_irq(&ts->client->dev, client->irq,
> > -					  NULL, goodix_ts_irq_handler,
> > -					  irq_flags, client->name, ts);
> > +	ts->irq_flags = goodix_irq_flags[ts->int_trigger_type] | IRQF_ONESHOT;
> > +	error = goodix_request_irq(ts);
> >  	if (error) {
> >  		dev_err(&client->dev, "request IRQ failed: %d\n", error);
> >  		return error;
> > @@ -611,6 +629,65 @@ static int goodix_ts_probe(struct i2c_client *client,
> >  	return 0;
> >  }
> >
> > +#ifdef CONFIG_PM_SLEEP
> > +static int goodix_suspend(struct device *dev)
> 
> Please drop #ifdef CONFIG_PM_SLEEP and annotate with __maybe_unused
> instead.
> 
Ok, will fix this.

> > +{
> > +	struct i2c_client *client = to_i2c_client(dev);
> > +	struct goodix_ts_data *ts = i2c_get_clientdata(client);
> > +	int ret;
> > +
> > +	goodix_free_irq(ts);
> 
> Why do we need to free IRQ here?
> 

The suspend sequence described in Goodix datasheets requires using the irq pin as output pin.
If the interrupt is not released, gpiod_direction_output(ts->gpiod_int, 0) will fail with the message
"tried to set a GPIO tied to an IRQ as output".  Initially I used gpiod_lock/unlock_as_irq, but this API
is no longer available (and gpiochip_lock_as_irq is only available for gpio chips). Is there a better way
to do this?

> > +	/* Output LOW on the INT pin for 5 ms */
> > +	ret = gpiod_direction_output(ts->gpiod_int, 0);
> > +	if (ret) {
> > +		goodix_request_irq(ts);
> > +		return ret;
> > +	}
> > +	usleep_range(5000, 6000);
> > +
> > +	ret = goodix_i2c_write_u8(ts->client, GOODIX_REG_COMMAND,
> > +				  GOODIX_CMD_SCREEN_OFF);
> > +	if (ret) {
> > +		dev_err(&ts->client->dev, "Screen off command failed\n");
> > +		gpiod_direction_input(ts->gpiod_int);
> > +		goodix_request_irq(ts);
> > +		return -EAGAIN;
> > +	}
> > +
> > +	/*
> > +	 * The datasheet specifies that the interval between sending screen-off
> > +	 * command and wake-up should be longer than 58 ms. To avoid waking up
> > +	 * sooner, delay 58ms here.
> > +	 */
> > +	msleep(58);
> > +	return 0;
> > +}
> > +
> > +static int goodix_resume(struct device *dev)
> 
> __maybe_unused
Ok.
> 
> > +{
> > +	struct i2c_client *client = to_i2c_client(dev);
> > +	struct goodix_ts_data *ts = i2c_get_clientdata(client);
> > +	int ret;
> > +
> > +	/*
> > +	 * Exit sleep mode by outputting HIGH level to INT pin
> > +	 * for 2ms~5ms.
> > +	 */
> > +	ret = gpiod_direction_output(ts->gpiod_int, 1);
> > +	if (ret)
> > +		return ret;
> > +	usleep_range(2000, 5000);
> > +
> > +	ret = goodix_int_sync(ts);
> > +	if (ret)
> > +		return ret;
> > +
> > +	return goodix_request_irq(ts);
> > +}
> > +#endif
> > +
> > +static SIMPLE_DEV_PM_OPS(goodix_pm_ops, goodix_suspend, goodix_resume);
> > +
> >  static const struct i2c_device_id goodix_ts_id[] = {
> >  	{ "GDIX1001:00", 0 },
> >  	{ }
> > @@ -646,6 +723,7 @@ static struct i2c_driver goodix_ts_driver = {
> >  		.owner = THIS_MODULE,
> >  		.acpi_match_table = ACPI_PTR(goodix_acpi_match),
> >  		.of_match_table = of_match_ptr(goodix_of_match),
> > +		.pm = &goodix_pm_ops,
> >  	},
> >  };
> >  module_i2c_driver(goodix_ts_driver);
> > --
> > 1.9.1
> >
> 

Thanks,
Irina

> Thanks.
> 
> --
> Dmitry
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