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: Marco Felsch <m.felsch@xxxxxxxxxxxxxx> --- v4: - improve suspend modi handling - restore configuration if poweroff suspend mode was selected - check return values during resume - add comments about the delays - adapt commit message v3: - drop enable/disable_irq_wake() v2: - adapt commit message - don't return errors during suspend/resume - replace dev_err() by dev_warn() - add support to disable the regulator too drivers/input/touchscreen/edt-ft5x06.c | 123 +++++++++++++++++++++++++ 1 file changed, 123 insertions(+) diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c index bb9107093796..0babe6a25fe3 100644 --- a/drivers/input/touchscreen/edt-ft5x06.c +++ b/drivers/input/touchscreen/edt-ft5x06.c @@ -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; @@ -1125,6 +1136,19 @@ 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 +1262,104 @@ 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); + +#ifdef CONFIG_DEBUG_FS + if (tsdata->factory_mode) + ret = edt_ft5x06_factory_mode(tsdata); +#endif + } 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 +1398,7 @@ 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, -- 2.20.1
