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Subject[PATCH v3 1/5] regulator: Allow regulators to verify enabled during enable()
Date
Some regulators might need to verify that they have indeed been enabled
after the enable() call is made and enable_time delay has passed.

This is implemented by repeatedly checking is_enabled() upto
poll_enabled_time, waiting for the already calculated enable delay in
each iteration.

Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
---
drivers/regulator/core.c | 28 ++++++++++++++++++++++++++++
include/linux/regulator/driver.h | 5 +++++
2 files changed, 33 insertions(+)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 7486f6e4e613..06199f182114 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -2409,6 +2409,34 @@ static int _regulator_do_enable(struct regulator_dev *rdev)

_regulator_enable_delay(delay);

+ /* If set, poll upto poll_enabled_time uS to see if the regulator
+ * actually got enabled.
+ * For each iteration, wait for the enable_time delay calculated
+ * above already.
+ * If the regulator isn't enabled after poll_enabled_time has
+ * expired, return -ETIMEDOUT.
+ */
+ if (rdev->desc->poll_enabled_time) {
+ unsigned int time_remaining = rdev->desc->poll_enabled_time;
+
+ while (time_remaining > 0) {
+ /* We've already waited for enable_time above;
+ * so we can start with immediate check of the
+ * status of the regulator.
+ */
+ if (rdev->desc->ops->is_enabled(rdev))
+ break;
+
+ _regulator_enable_delay(delay);
+ time_remaining -= delay;
+ }
+
+ if (time_remaining <= 0) {
+ rdev_err(rdev, "Enabled check failed.\n");
+ return -ETIMEDOUT;
+ }
+ }
+
trace_regulator_enable_complete(rdev_get_name(rdev));

return 0;
diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index 29d920516e0b..bb50e943010f 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -322,6 +322,9 @@ enum regulator_type {
* @enable_time: Time taken for initial enable of regulator (in uS).
* @off_on_delay: guard time (in uS), before re-enabling a regulator
*
+ * @poll_enabled_time: Maximum time (in uS) to poll if the regulator is
+ * actually enabled, after enable() call
+ *
* @of_map_mode: Maps a hardware mode defined in a DeviceTree to a standard mode
*/
struct regulator_desc {
@@ -389,6 +392,8 @@ struct regulator_desc {

unsigned int off_on_delay;

+ unsigned int poll_enabled_time;
+
unsigned int (*of_map_mode)(unsigned int mode);
};

--
2.26.2
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