Commit 21d1611a authored by Marco Felsch's avatar Marco Felsch Committed by Dmitry Torokhov
Browse files

Input: edt-ft5x06 - improve power management operations 

It is possible to bring the device into a deep sleep state. To exit this
state the reset or wakeup pin must be toggeled as documented in [1].
Because of the poor documentation I used the several downstream kernels
[2] and other applications notes [3] to indentify the related registers.

Furthermore I added the support to disable the device completely which
is obviously the most effective power-saving mechanism. This mechanism
needs the reset pin to ensure the power-up/down sequence.

We can't apply any of these power-saving mechanism if both pins are
missing (not connected) or if it is a wakeup device.

[1] https://www.newhavendisplay.com/appnotes/datasheets/touchpanel/FT5x26.pdf
    https://www.newhavendisplay.com/appnotes/datasheets/touchpanel/FT5x06.pdf
[2] https://github.com/linux-sunxi/linux-sunxi/blob/sunxi-3.4/drivers/input/touchscreen/ft5x_ts.c
    https://github.com/Pablito2020/focaltech-touch-driver/blob/master/ft5336_driver.c
[3] https://www.newhavendisplay.com/appnotes/datasheets/touchpanel/FT5x16_registers.pdf



Signed-off-by: default avatarMarco Felsch <m.felsch@pengutronix.de>
Link: https://lore.kernel.org/r/20200227112819.16754-4-m.felsch@pengutronix.de


Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent f4ee52f3

drivers/input/touchscreen/edt-ft5x06.c

+132 −10
Original line number Diff line number Diff line
@@ -38,6 +38,9 @@ 
#define WORK_REGISTER_NUM_X		0x33

#define WORK_REGISTER_NUM_Y		0x34



#define PMOD_REGISTER_ACTIVE		0x00

#define PMOD_REGISTER_HIBERNATE		0x03



#define M09_REGISTER_THRESHOLD		0x80

#define M09_REGISTER_GAIN		0x92

#define M09_REGISTER_OFFSET		0x93
@@ -53,6 +56,7 @@ 


#define WORK_REGISTER_OPMODE		0x3c

#define FACTORY_REGISTER_OPMODE		0x01

#define PMOD_REGISTER_OPMODE		0xa5



#define TOUCH_EVENT_DOWN		0x00

#define TOUCH_EVENT_UP			0x01
@@ -65,6 +69,12 @@ 
#define EDT_RAW_DATA_RETRIES		100

#define EDT_RAW_DATA_DELAY		1000 /* usec */



enum edt_pmode {

	EDT_PMODE_NOT_SUPPORTED,

	EDT_PMODE_HIBERNATE,

	EDT_PMODE_POWEROFF,

};



enum edt_ver {

	EDT_M06,

	EDT_M09,
@@ -103,6 +113,7 @@ struct edt_ft5x06_ts_data { 


	struct mutex mutex;

	bool factory_mode;

	enum edt_pmode suspend_mode;

	int threshold;

	int gain;

	int offset;
@@ -767,8 +778,7 @@ static const struct file_operations debugfs_raw_data_fops = { 
	.read = edt_ft5x06_debugfs_raw_data_read,

};



static void

edt_ft5x06_ts_prepare_debugfs(struct edt_ft5x06_ts_data *tsdata,

static void edt_ft5x06_ts_prepare_debugfs(struct edt_ft5x06_ts_data *tsdata,

					  const char *debugfs_name)

{

	tsdata->debug_dir = debugfs_create_dir(debugfs_name, NULL);
@@ -782,8 +792,7 @@ edt_ft5x06_ts_prepare_debugfs(struct edt_ft5x06_ts_data *tsdata, 
			    tsdata->debug_dir, tsdata, &debugfs_raw_data_fops);

}



static void

edt_ft5x06_ts_teardown_debugfs(struct edt_ft5x06_ts_data *tsdata)

static void edt_ft5x06_ts_teardown_debugfs(struct edt_ft5x06_ts_data *tsdata)

{

	debugfs_remove_recursive(tsdata->debug_dir);

	kfree(tsdata->raw_buffer);
@@ -791,14 +800,17 @@ edt_ft5x06_ts_teardown_debugfs(struct edt_ft5x06_ts_data *tsdata) 


#else



static inline void

edt_ft5x06_ts_prepare_debugfs(struct edt_ft5x06_ts_data *tsdata,

static int edt_ft5x06_factory_mode(struct edt_ft5x06_ts_data *tsdata)

{

	return -ENOSYS;

}



static void edt_ft5x06_ts_prepare_debugfs(struct edt_ft5x06_ts_data *tsdata,

					  const char *debugfs_name)

{

}



static inline void

edt_ft5x06_ts_teardown_debugfs(struct edt_ft5x06_ts_data *tsdata)

static void edt_ft5x06_ts_teardown_debugfs(struct edt_ft5x06_ts_data *tsdata)

{

}
@@ -1125,6 +1137,19 @@ static int edt_ft5x06_ts_probe(struct i2c_client *client, 
		return error;

	}



	/*

	 * Check which sleep modes we can support. Power-off requieres the

	 * reset-pin to ensure correct power-down/power-up behaviour. Start with

	 * the EDT_PMODE_POWEROFF test since this is the deepest possible sleep

	 * mode.

	 */

	if (tsdata->reset_gpio)

		tsdata->suspend_mode = EDT_PMODE_POWEROFF;

	else if (tsdata->wake_gpio)

		tsdata->suspend_mode = EDT_PMODE_HIBERNATE;

	else

		tsdata->suspend_mode = EDT_PMODE_NOT_SUPPORTED;



	if (tsdata->wake_gpio) {

		usleep_range(5000, 6000);

		gpiod_set_value_cansleep(tsdata->wake_gpio, 1);
@@ -1238,6 +1263,102 @@ static int edt_ft5x06_ts_remove(struct i2c_client *client) 
	return 0;

}



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);

	struct gpio_desc *reset_gpio = tsdata->reset_gpio;

	int ret;



	if (device_may_wakeup(dev))

		return 0;



	if (tsdata->suspend_mode == EDT_PMODE_NOT_SUPPORTED)

		return 0;



	/* Enter hibernate mode. */

	ret = edt_ft5x06_register_write(tsdata, PMOD_REGISTER_OPMODE,

					PMOD_REGISTER_HIBERNATE);

	if (ret)

		dev_warn(dev, "Failed to set hibernate mode\n");



	if (tsdata->suspend_mode == EDT_PMODE_HIBERNATE)

		return 0;



	/*

	 * Power-off according the datasheet. Cut the power may leaf the irq

	 * line in an undefined state depending on the host pull resistor

	 * settings. Disable the irq to avoid adjusting each host till the

	 * device is back in a full functional state.

	 */

	disable_irq(tsdata->client->irq);



	gpiod_set_value_cansleep(reset_gpio, 1);

	usleep_range(1000, 2000);



	ret = regulator_disable(tsdata->vcc);

	if (ret)

		dev_warn(dev, "Failed to disable vcc\n");



	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 = 0;



	if (device_may_wakeup(dev))

		return 0;



	if (tsdata->suspend_mode == EDT_PMODE_NOT_SUPPORTED)

		return 0;



	if (tsdata->suspend_mode == EDT_PMODE_POWEROFF) {

		struct gpio_desc *reset_gpio = tsdata->reset_gpio;



		/*

		 * We can't check if the regulator is a dummy or a real

		 * regulator. So we need to specify the 5ms reset time (T_rst)

		 * here instead of the 100us T_rtp time. We also need to wait

		 * 300ms in case it was a real supply and the power was cutted

		 * of. Toggle the reset pin is also a way to exit the hibernate

		 * mode.

		 */

		gpiod_set_value_cansleep(reset_gpio, 1);

		usleep_range(5000, 6000);



		ret = regulator_enable(tsdata->vcc);

		if (ret) {

			dev_err(dev, "Failed to enable vcc\n");

			return ret;

		}



		usleep_range(1000, 2000);

		gpiod_set_value_cansleep(reset_gpio, 0);

		msleep(300);



		edt_ft5x06_restore_reg_parameters(tsdata);

		enable_irq(tsdata->client->irq);



		if (tsdata->factory_mode)

			ret = edt_ft5x06_factory_mode(tsdata);

	} else {

		struct gpio_desc *wake_gpio = tsdata->wake_gpio;



		gpiod_set_value_cansleep(wake_gpio, 0);

		usleep_range(5000, 6000);

		gpiod_set_value_cansleep(wake_gpio, 1);

	}





	return ret;

}



static SIMPLE_DEV_PM_OPS(edt_ft5x06_ts_pm_ops,

			 edt_ft5x06_ts_suspend, edt_ft5x06_ts_resume);



static const struct edt_i2c_chip_data edt_ft5x06_data = {

	.max_support_points = 5,

};
@@ -1276,6 +1397,7 @@ static struct i2c_driver edt_ft5x06_ts_driver = { 
	.driver = {

		.name = "edt_ft5x06",

		.of_match_table = edt_ft5x06_of_match,

		.pm = &edt_ft5x06_ts_pm_ops,

	},

	.id_table = edt_ft5x06_ts_id,

	.probe    = edt_ft5x06_ts_probe,