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. This is the most effective power-saving mechanism. Disabling the device don't change the suspend logic because the hibernate mode needs a hardware reset anyway. [1] https://www.newhavendisplay.com/appnotes/datasheets/touchpanel/FT5x26.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> --- 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 | 49 ++++++++++++++++++++++++-- 1 file changed, 47 insertions(+), 2 deletions(-) diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c index 8d2ec7947f0e..0bdd3440f684 100644 --- a/drivers/input/touchscreen/edt-ft5x06.c +++ b/drivers/input/touchscreen/edt-ft5x06.c @@ -39,6 +39,9 @@ #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 @@ -54,6 +57,7 @@ #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 @@ -1235,9 +1239,29 @@ static int edt_ft5x06_ts_remove(struct i2c_client *client) 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); + int ret; - if (device_may_wakeup(dev)) + if (device_may_wakeup(dev)) { enable_irq_wake(client->irq); + return 0; + } + + /* + * Hibernate mode requires reset or wake signal to recover to active + * state. + */ + if (!tsdata->wake_gpio && !tsdata->reset_gpio) + return 0; + + ret = edt_ft5x06_register_write(tsdata, PMOD_REGISTER_OPMODE, + PMOD_REGISTER_HIBERNATE); + if (ret) + dev_warn(dev, "Failed to set hibernate mode\n"); + + ret = regulator_disable(tsdata->vcc); + if (ret) + dev_warn(dev, "Failed to disable vcc\n"); return 0; } @@ -1245,9 +1269,30 @@ static int __maybe_unused edt_ft5x06_ts_suspend(struct device *dev) 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; - if (device_may_wakeup(dev)) + if (device_may_wakeup(dev)) { disable_irq_wake(client->irq); + return 0; + } + + ret = regulator_enable(tsdata->vcc); + if (ret) + dev_warn(dev, "Failed to enable vcc\n"); + + /* Recover from hibernate mode if hardware supports it */ + if (tsdata->wake_gpio) { + gpiod_set_value_cansleep(tsdata->wake_gpio, 0); + usleep_range(5000, 6000); + gpiod_set_value_cansleep(tsdata->wake_gpio, 1); + msleep(300); + } else if (tsdata->reset_gpio) { + gpiod_set_value_cansleep(tsdata->reset_gpio, 1); + usleep_range(5000, 6000); + gpiod_set_value_cansleep(tsdata->reset_gpio, 0); + msleep(300); + } return 0; } -- 2.20.1
