[PATCH 6.6 228/396] misc: lis3lv02d_i2c: Fix regulators getting en-/dis-abled twice on suspend/resume

Greg Kroah-Hartman
2024-04-01T16:47:17Z

From: Hans de Goede <hdegoede@redhat.com>

commit ac3e0384073b2408d6cb0d972fee9fcc3776053d upstream.

When not configured for wakeup lis3lv02d_i2c_suspend() will call
lis3lv02d_poweroff() even if the device has already been turned off
by the runtime-suspend handler and if configured for wakeup and
the device is runtime-suspended at this point then it is not turned
back on to serve as a wakeup source.

Before commit b1b9f7a49440 ("misc: lis3lv02d_i2c: Add missing setting
of the reg_ctrl callback"), lis3lv02d_poweroff() failed to disable
the regulators which as a side effect made calling poweroff() twice ok.

Now that poweroff() correctly disables the regulators, doing this twice
triggers a WARN() in the regulator core:

unbalanced disables for regulator-dummy
WARNING: CPU: 1 PID: 92 at drivers/regulator/core.c:2999 _regulator_disable
...

Fix lis3lv02d_i2c_suspend() to not call poweroff() a second time if
already runtime-suspended and add a poweron() call when necessary to
make wakeup work.

lis3lv02d_i2c_resume() has similar issues, with an added weirness that
it always powers on the device if it is runtime suspended, after which
the first runtime-resume will call poweron() again, causing the enabled
count for the regulator to increase by 1 every suspend/resume. These
unbalanced regulator_enable() calls cause the regulator to never
be turned off and trigger the following WARN() on driver unbind:

WARNING: CPU: 1 PID: 1724 at drivers/regulator/core.c:2396 _regulator_put

Fix this by making lis3lv02d_i2c_resume() mirror the new suspend().

Fixes: b1b9f7a49440 ("misc: lis3lv02d_i2c: Add missing setting of the reg_ctrl callback")
Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Closes: https://lore.kernel.org/regressions/5fc6da74-af0a-4aac-b4d5-a000b39a63a5@molgen.mpg.de/
Cc: stable@vger.kernel.org
Cc: regressions@lists.linux.dev
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Paul Menzel <pmenzel@molgen.mpg.de> # Dell XPS 15 7590
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Link: https://lore.kernel.org/r/20240220190035.53402-1-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/misc/lis3lv02d/lis3lv02d_i2c.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)

--- a/drivers/misc/lis3lv02d/lis3lv02d_i2c.c
+++ b/drivers/misc/lis3lv02d/lis3lv02d_i2c.c
@@ -198,8 +198,14 @@ static int lis3lv02d_i2c_suspend(struct
struct i2c_client *client = to_i2c_client(dev);
struct lis3lv02d *lis3 = i2c_get_clientdata(client);

- if (!lis3->pdata || !lis3->pdata->wakeup_flags)
+ /* Turn on for wakeup if turned off by runtime suspend */
+ if (lis3->pdata && lis3->pdata->wakeup_flags) {
+ if (pm_runtime_suspended(dev))
+ lis3lv02d_poweron(lis3);
+ /* For non wakeup turn off if not already turned off by runtime suspend */
+ } else if (!pm_runtime_suspended(dev))
lis3lv02d_poweroff(lis3);
+
return 0;
}

@@ -208,13 +214,12 @@ static int lis3lv02d_i2c_resume(struct d
struct i2c_client *client = to_i2c_client(dev);
struct lis3lv02d *lis3 = i2c_get_clientdata(client);

- /*
- * pm_runtime documentation says that devices should always
- * be powered on at resume. Pm_runtime turns them off after system
- * wide resume is complete.
- */
- if (!lis3->pdata || !lis3->pdata->wakeup_flags ||
- pm_runtime_suspended(dev))
+ /* Turn back off if turned on for wakeup and runtime suspended*/
+ if (lis3->pdata && lis3->pdata->wakeup_flags) {
+ if (pm_runtime_suspended(dev))
+ lis3lv02d_poweroff(lis3);
+ /* For non wakeup turn back on if not runtime suspended */
+ } else if (!pm_runtime_suspended(dev))
lis3lv02d_poweron(lis3);

return 0;