Re: [PATCH] regulator: core: Clean up on enable failure

[Brian Masney <bmasney@redhat.com>]

On Fri, Aug 19, 2022 at 02:43:36PM -0500, Andrew Halaney wrote:
> If regulator_enable() fails, enable_count is incremented still.
> A consumer, assuming no matching regulator_disable() is necessary on
> failure, will then get this error message upon regulator_put()
> since enable_count is non-zero:
> 
>     [    1.277418] WARNING: CPU: 3 PID: 1 at drivers/regulator/core.c:2304 _regulator_put.part.0+0x168/0x170
> 
> The consumer could try to fix this in their driver by cleaning up on
> error from regulator_enable() (i.e. call regulator_disable()), but that
> results in the following since regulator_enable() failed and didn't
> increment user_count:
> 
>     [    1.258112] unbalanced disables for vreg_l17c
>     [    1.262606] WARNING: CPU: 4 PID: 1 at drivers/regulator/core.c:2899 _regulator_disable+0xd4/0x190
> 
> Fix this by decrementing enable_count upon failure to enable.
> 
> With this in place, just the reason for failure to enable is printed
> as expected and developers can focus on the root cause of their issue
> instead of thinking their usage of the regulator consumer api is
> incorrect. For example, in my case:
> 
>     [    1.240426] vreg_l17c: invalid input voltage found
> 
> Fixes: 5451781dadf8 ("regulator: core: Only count load for enabled consumers")
> Signed-off-by: Andrew Halaney <ahalaney@redhat.com>

Reviewed-by: Brian Masney <bmasney@redhat.com>