Re: [PATCH] regulator: core: Limit propagation of parent voltage count and list

From: Brian Norris
Date: Fri Mar 24 2017 - 16:38:38 EST


On Fri, Mar 24, 2017 at 01:09:52PM -0700, Matthias Kaehlcke wrote:
> diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
> index 53d4fc70dbd0..121838e0125b 100644
> --- a/drivers/regulator/core.c
> +++ b/drivers/regulator/core.c
> @@ -2487,6 +2487,10 @@ static int _regulator_list_voltage(struct regulator *regulator,
> if (lock)
> mutex_unlock(&rdev->mutex);
> } else if (rdev->supply) {
> + // Limit propagation of parent values to switch regulators

The kernel doesn't use C99 comments. Oddly enough, this isn't actually
in the coding style doc (Documentation/process/coding-style.rst), nor is
it caught by scripts/checkpatch.pl (even though it clearly has a 'C99
comment' rule).

> + if (ops->get_voltage || ops->get_voltage_sel)
> + return -EINVAL;
> +
> ret = _regulator_list_voltage(rdev->supply, selector, lock);
> } else {
> return -EINVAL;
> @@ -2540,6 +2544,7 @@ EXPORT_SYMBOL_GPL(regulator_is_enabled);
> int regulator_count_voltages(struct regulator *regulator)
> {
> struct regulator_dev *rdev = regulator->rdev;
> + const struct regulator_ops *ops = rdev->desc->ops;
>
> if (rdev->desc->n_voltages)
> return rdev->desc->n_voltages;
> @@ -2547,6 +2552,10 @@ int regulator_count_voltages(struct regulator *regulator)
> if (!rdev->supply)
> return -EINVAL;
>
> + // Limit propagation of parent value to switch regulators

Same here.

> + if (ops->get_voltage || ops->get_voltage_sel || ops->list_voltage)
> + return -EINVAL;
> +
> return regulator_count_voltages(rdev->supply);
> }
> EXPORT_SYMBOL_GPL(regulator_count_voltages);

I'm not very familiar with this code, but judging by your problem
description in previous threads and by comparing with the logic in
_regulator_get_voltage() (for when to reference the ->supply), this
seems resonable. So:

Reviewed-by: Brian Norris <briannorris@xxxxxxxxxxxx>

It's probably worth verifying that this doesn't break whatever Javier
was supporting in the first place, as a sanity check.

Brian