From: Val Packett <v...@packett.cool> The "jiggle" code was not actually expecting failure, which it should because that's what actually happens when the device wasn't already woken up by the regulator power-on (i.e. in the case of a shared regulator).
Also, do actually enter the internal suspend mode on shutdown, to save power in the case of a shared regulator. Also, wait a bit longer (2x tOPR) on waking up, 1x is not enough at least on the DW9718S as found on the motorola-nora smartphone. Signed-off-by: Val Packett <v...@packett.cool> Signed-off-by: André Apitzsch <g...@apitzsch.eu> --- drivers/media/i2c/dw9719.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) diff --git a/drivers/media/i2c/dw9719.c b/drivers/media/i2c/dw9719.c index a24594523030df7df7fb60afb5248472b4a8ea13..3627e78b8b6668933c4ecd92231465ce4105ff0c 100644 --- a/drivers/media/i2c/dw9719.c +++ b/drivers/media/i2c/dw9719.c @@ -95,12 +95,20 @@ struct dw9719_device { static int dw9719_power_down(struct dw9719_device *dw9719) { + u32 reg_pwr = dw9719->model == DW9718S ? DW9718S_PD : DW9719_CONTROL; + + /* + * Worth engaging the internal SHUTDOWN mode especially due to the + * regulator being potentially shared with other devices. + */ + if (cci_write(dw9719->regmap, reg_pwr, DW9719_SHUTDOWN, NULL)) + dev_err(dw9719->dev, "Error writing to power register\n"); return regulator_disable(dw9719->regulator); } static int dw9719_power_up(struct dw9719_device *dw9719, bool detect) { - u32 reg_pwr; + u32 reg_pwr = dw9719->model == DW9718S ? DW9718S_PD : DW9719_CONTROL; u64 val; int ret; int err; @@ -109,13 +117,17 @@ static int dw9719_power_up(struct dw9719_device *dw9719, bool detect) if (ret) return ret; - /* Jiggle SCL pin to wake up device */ - reg_pwr = dw9719->model == DW9718S ? DW9718S_PD : DW9719_CONTROL; - cci_write(dw9719->regmap, reg_pwr, DW9719_SHUTDOWN, &ret); - fsleep(100); + /* + * Need 100us to transition from SHUTDOWN to STANDBY. + * Jiggle the SCL pin to wake up the device (even when the regulator is + * shared) and wait double the time to be sure, as 100us is not enough + * at least on the DW9718S as found on the motorola-nora smartphone, + * then retry the write. + */ + cci_write(dw9719->regmap, reg_pwr, DW9719_STANDBY, NULL); + /* the jiggle is expected to fail, don't even log that as error */ + fsleep(200); cci_write(dw9719->regmap, reg_pwr, DW9719_STANDBY, &ret); - /* Need 100us to transit from SHUTDOWN to STANDBY */ - fsleep(100); if (detect) { /* This model does not have an INFO register */ -- 2.51.0