diff mbox series

[v4,1/5] regulator: Allow regulators to verify enabled during enable()

Message ID 20200602100924.26256-2-sumit.semwal@linaro.org (mailing list archive)
State Superseded
Headers show
Series Qualcomm labibb regulator driver | expand

Commit Message

Sumit Semwal June 2, 2020, 10:09 a.m. UTC
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>
--
v2: Address review comments, including swapping enable_time and poll_enabled_time.
---
 drivers/regulator/core.c         | 58 +++++++++++++++++++++++++++++++-
 include/linux/regulator/driver.h |  5 +++
 2 files changed, 62 insertions(+), 1 deletion(-)

Comments

Mark Brown June 2, 2020, 11:24 a.m. UTC | #1
On Tue, Jun 02, 2020 at 03:39:20PM +0530, Sumit Semwal wrote:

> +
> +		if (time_remaining <= 0) {
> +			rdev_err(rdev, "Enabled check failed.\n");
> +			return -ETIMEDOUT;

s/failed/timed out/

> + * @poll_enabled_time: Maximum time (in uS) to poll if the regulator is
> + *                          actually enabled, after enable() call
> + *

This comment needs updating to reflect the new implementation.
Sumit Semwal June 2, 2020, 11:57 a.m. UTC | #2
Hi Mark,

Thanks for the review!

On Tue, 2 Jun 2020 at 16:54, Mark Brown <broonie@kernel.org> wrote:
>
> On Tue, Jun 02, 2020 at 03:39:20PM +0530, Sumit Semwal wrote:
>
> > +
> > +             if (time_remaining <= 0) {
> > +                     rdev_err(rdev, "Enabled check failed.\n");
> > +                     return -ETIMEDOUT;
>
> s/failed/timed out/
Ack
>
> > + * @poll_enabled_time: Maximum time (in uS) to poll if the regulator is
> > + *                          actually enabled, after enable() call
> > + *
>
> This comment needs updating to reflect the new implementation.
Yes, I will update.

Best,
Sumit.
Bjorn Andersson June 18, 2020, 11:44 p.m. UTC | #3
On Tue 02 Jun 03:09 PDT 2020, Sumit Semwal wrote:

> 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>
> --
> v2: Address review comments, including swapping enable_time and poll_enabled_time.
> ---
>  drivers/regulator/core.c         | 58 +++++++++++++++++++++++++++++++-
>  include/linux/regulator/driver.h |  5 +++
>  2 files changed, 62 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
> index 7486f6e4e613..d9ab888da95f 100644
> --- a/drivers/regulator/core.c
> +++ b/drivers/regulator/core.c
> @@ -2347,6 +2347,32 @@ static void _regulator_enable_delay(unsigned int delay)
>  		udelay(us);
>  }
>  
> +/* _regulator_check_status_enabled

Please make all your kerneldoc follow:
https://www.kernel.org/doc/html/latest/doc-guide/kernel-doc.html#function-documentation

> + *
> + * returns:
> + *          1 if status shows regulator is in enabled state
> + *          0 if not enabled state
> + *          else, error value as received from ops->get_status()
> + */
> +static inline int _regulator_check_status_enabled(struct regulator_dev *rdev)
> +{
> +	int ret = rdev->desc->ops->get_status(rdev);
> +
> +	if (ret < 0) {
> +		rdev_info(rdev, "get_status returned error: %d\n", ret);
> +		return ret;
> +	}
> +
> +	switch (ret) {
> +	case REGULATOR_STATUS_OFF:
> +	case REGULATOR_STATUS_ERROR:
> +	case REGULATOR_STATUS_UNDEFINED:
> +		return 0;
> +	default:
> +		return 1;
> +	}
> +}
> +
>  static int _regulator_do_enable(struct regulator_dev *rdev)
>  {
>  	int ret, delay;
> @@ -2407,7 +2433,37 @@ static int _regulator_do_enable(struct regulator_dev *rdev)
>  	 * together.  */
>  	trace_regulator_enable_delay(rdev_get_name(rdev));
>  
> -	_regulator_enable_delay(delay);
> +	/* If poll_enabled_time is set, poll upto the delay calculated
> +	 * above, delaying poll_enabled_time uS to check if the regulator
> +	 * actually got enabled.
> +	 * If the regulator isn't enabled after enable_delay has
> +	 * expired, return -ETIMEDOUT.
> +	 */
> +	if (rdev->desc->poll_enabled_time) {
> +		unsigned int time_remaining = delay;
> +
> +		while (time_remaining > 0) {
> +			_regulator_enable_delay(rdev->desc->poll_enabled_time);
> +
> +			if (rdev->desc->ops->get_status) {
> +				ret = _regulator_check_status_enabled(rdev);
> +				if (ret < 0)
> +					return ret;
> +				else if (ret)
> +					break;
> +			} else if (rdev->desc->ops->is_enabled(rdev))
> +				break;
> +
> +			time_remaining -= rdev->desc->poll_enabled_time;
> +		}
> +
> +		if (time_remaining <= 0) {
> +			rdev_err(rdev, "Enabled check failed.\n");
> +			return -ETIMEDOUT;
> +		}
> +	} else {
> +		_regulator_enable_delay(delay);
> +	}
>  
>  	trace_regulator_enable_complete(rdev_get_name(rdev));
>  
> 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

I read this as "how long should we stay in the poll loop". I think it
would be better describes as something like "The polling interval to use
while checking that the regulator was actually enabled".

Regards,
Bjorn

> + *
>   * @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
>
diff mbox series

Patch

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 7486f6e4e613..d9ab888da95f 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -2347,6 +2347,32 @@  static void _regulator_enable_delay(unsigned int delay)
 		udelay(us);
 }
 
+/* _regulator_check_status_enabled
+ *
+ * returns:
+ *          1 if status shows regulator is in enabled state
+ *          0 if not enabled state
+ *          else, error value as received from ops->get_status()
+ */
+static inline int _regulator_check_status_enabled(struct regulator_dev *rdev)
+{
+	int ret = rdev->desc->ops->get_status(rdev);
+
+	if (ret < 0) {
+		rdev_info(rdev, "get_status returned error: %d\n", ret);
+		return ret;
+	}
+
+	switch (ret) {
+	case REGULATOR_STATUS_OFF:
+	case REGULATOR_STATUS_ERROR:
+	case REGULATOR_STATUS_UNDEFINED:
+		return 0;
+	default:
+		return 1;
+	}
+}
+
 static int _regulator_do_enable(struct regulator_dev *rdev)
 {
 	int ret, delay;
@@ -2407,7 +2433,37 @@  static int _regulator_do_enable(struct regulator_dev *rdev)
 	 * together.  */
 	trace_regulator_enable_delay(rdev_get_name(rdev));
 
-	_regulator_enable_delay(delay);
+	/* If poll_enabled_time is set, poll upto the delay calculated
+	 * above, delaying poll_enabled_time uS to check if the regulator
+	 * actually got enabled.
+	 * If the regulator isn't enabled after enable_delay has
+	 * expired, return -ETIMEDOUT.
+	 */
+	if (rdev->desc->poll_enabled_time) {
+		unsigned int time_remaining = delay;
+
+		while (time_remaining > 0) {
+			_regulator_enable_delay(rdev->desc->poll_enabled_time);
+
+			if (rdev->desc->ops->get_status) {
+				ret = _regulator_check_status_enabled(rdev);
+				if (ret < 0)
+					return ret;
+				else if (ret)
+					break;
+			} else if (rdev->desc->ops->is_enabled(rdev))
+				break;
+
+			time_remaining -= rdev->desc->poll_enabled_time;
+		}
+
+		if (time_remaining <= 0) {
+			rdev_err(rdev, "Enabled check failed.\n");
+			return -ETIMEDOUT;
+		}
+	} else {
+		_regulator_enable_delay(delay);
+	}
 
 	trace_regulator_enable_complete(rdev_get_name(rdev));
 
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);
 };