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 | 23 ++++++++++++++++-------
1 file changed, 16 insertions(+), 7 deletions(-)
diff --git a/drivers/media/i2c/dw9719.c b/drivers/media/i2c/dw9719.c
index
63c7fd4ab70a0e02518252b23b89c45df4ba273d..dd28a0223d6ac980084b1f661bd029ea6b0be503
100644
--- a/drivers/media/i2c/dw9719.c
+++ b/drivers/media/i2c/dw9719.c
@@ -95,12 +95,19 @@ 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.
+ */
+ cci_write(dw9719->regmap, reg_pwr, DW9719_SHUTDOWN, NULL);
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 +116,15 @@ 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, then retry the write.
+ */
+ cci_write(dw9719->regmap, reg_pwr, DW9719_STANDBY, &ret);
+ ret = 0; /* 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 */
--
2.50.1
