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media: i2c: dw9719: Fix power on/off sequence

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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 <val@packett.cool>
Signed-off-by: André Apitzsch <git@apitzsch.eu>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
This commit is contained in:
Val Packett
2025-09-20 14:03:47 +02:00
committed by Hans Verkuil
parent 5e18755738
commit a4b325c23e
1 changed files with 19 additions and 7 deletions
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26
drivers/media/i2c/dw9719.c
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@@ -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 */