regulator: core: add guard delay between calling regulator_disable and _enable

Some regulator require a minimum delay between its disable and next enable.
This is to avoid damages when out-of-range frequent disable/enable of a
single regulator can bring to the regulator chip.

Add @off_on_delay to struct regulator_desc. Device drivers' can use this field
to set this guard time.

Add @last_off_jiffy to struct regulator_dev. When @off_on_delay is set by
driver, regulator core can store its last off (disable) time into this field.

Signed-off-by: Guodong Xu <guodong.xu@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index 4b628139a9cb..efe058f8f746 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -238,6 +238,7 @@ enum regulator_type {
  * @bypass_val_off: Disabling value for control when using regmap set_bypass
  *
  * @enable_time: Time taken for initial enable of regulator (in uS).
+ * @off_on_delay: guard time (in uS), before re-enabling a regulator
  */
 struct regulator_desc {
         const char *name;
@@ -276,6 +277,8 @@ struct regulator_desc {
         unsigned int bypass_val_off;
 
         unsigned int enable_time;
+
+        unsigned int off_on_delay;
 };
 
 /**
@@ -348,6 +351,9 @@ struct regulator_dev {
 
         struct regulator_enable_gpio *ena_pin;
         unsigned int ena_gpio_state:1;
+
+        /* time when this regulator was disabled last time */
+        unsigned long last_off_jiffy;
 };
 
 struct regulator_dev *