On 4/28/23 02:39, Tim Harvey wrote:
On Wed, Apr 19, 2023 at 6:45 AM Eugen Hristev
<eugen.hris...@collabora.com> wrote:
Some devices share a regulator supply, when the first one will request
regulator disable, the second device will have it's supply cut off before
graciously shutting down. Hence there will be timeouts and other failed
operations.
Implement a reference counter mechanism similar with what is done in
Linux, to keep track of enable and disable requests, and only disable the
regulator when the last of the consumers has requested shutdown.
Signed-off-by: Eugen Hristev <eugen.hris...@collabora.com>
Reviewed-by: Simon Glass <s...@chromium.org>
---
Changes in v5:
- none
Changes in v4:
- add documentation for error codes
Changes in v3:
- add error return codes
Changes in v2:
- add info in header regarding the function
drivers/power/regulator/regulator_common.c | 22 ++++++++++++++++++++++
drivers/power/regulator/regulator_common.h | 21 +++++++++++++++++++++
2 files changed, 43 insertions(+)
diff --git a/drivers/power/regulator/regulator_common.c
b/drivers/power/regulator/regulator_common.c
index 93d8196b381e..484a4fc31ef7 100644
--- a/drivers/power/regulator/regulator_common.c
+++ b/drivers/power/regulator/regulator_common.c
@@ -73,6 +73,23 @@ int regulator_common_set_enable(const struct udevice *dev,
return 0;
}
+ /* If previously enabled, increase count */
+ if (enable && dev_pdata->enable_count > 0) {
+ dev_pdata->enable_count++;
+ return -EALREADY;
+ }
+
+ if (!enable) {
+ if (dev_pdata->enable_count > 1) {
+ /* If enabled multiple times, decrease count */
+ dev_pdata->enable_count--;
+ return -EBUSY;
+ } else if (!dev_pdata->enable_count) {
+ /* If already disabled, do nothing */
+ return -EALREADY;
+ }
+ }
+
Eugen,
Thank you for working on this series!
Hi Tim,
Thank you for testing and having a look on my patches.
I wonder if instead of returning a failure you should print an error
here but return 0 in order to not break unbalanced regulator calls
Initially I did that, but Simon forced me to return error as you see now.
(like what is done in clk_disable()). I see that you have another
patch in this series which handles htis for
regulator_set_enable_if_allowed() but that doesn't cover drivers that
call regulator_common_set_enable() directly such as
drivers/power/regulator/fixed.c and
drivers/power/regulator/gpio-regulator.c.
I believe Jonas (in CC) fixed those with a patch, but at the moment I am
lost in providing you a link to it
I know there is an unbalanced call currently on imx8mm that this patch
causes a failure where it previously did not:
u-boot=> usb start && usb tree
starting USB...
Bus usb@32e40000: Bus usb@32e50000: Error enabling VBUS supply (ret=-114)
probe failed, error -114
That's a good catch.
I expected such things would happen if I would return error in those
cases, so it might be that this is not the only case.
If you are able to test that board, do you wish me to send you a patch
that changes the code to using regulator_set_enable_if_allowed() ?
Best Regards,
Tim
