linux-kernel - Re: [PATCH 4/5] hwmon: (pmbus/core) improve handling of write protected regulators

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Message-ID: <1j5xq2sr0s.fsf@starbuckisacylon.baylibre.com>
Date: Tue, 08 Oct 2024 14:44:35 +0200
From: Jerome Brunet <jbrunet@...libre.com>
To: Guenter Roeck <linux@...ck-us.net>
Cc: Mark Brown <broonie@...nel.org>,  Liam Girdwood <lgirdwood@...il.com>,
  Jean Delvare <jdelvare@...e.com>,  Jonathan Corbet <corbet@....net>,
  linux-kernel@...r.kernel.org,  linux-hwmon@...r.kernel.org,
  linux-doc@...r.kernel.org
Subject: Re: [PATCH 4/5] hwmon: (pmbus/core) improve handling of write
 protected regulators

On Mon 23 Sep 2024 at 09:44, Guenter Roeck <linux@...ck-us.net> wrote:

> On 9/23/24 06:21, Mark Brown wrote:
>> On Fri, Sep 20, 2024 at 06:47:05PM +0200, Jerome Brunet wrote:
>> 
>>> +int pmbus_regulator_init_cb(struct regulator_dev *rdev,
>>> +			    struct regulator_config *config)
>>> +{
>>> +	struct pmbus_data *data = config->driver_data;
>>> +	struct regulation_constraints *constraints = rdev->constraints;
>>> +
>>> +	if (data->flags & PMBUS_OP_PROTECTED)
>>> +		constraints->valid_ops_mask &= ~REGULATOR_CHANGE_STATUS;
>>> +
>>> +	if (data->flags & PMBUS_VOUT_PROTECTED)
>>> +		constraints->valid_ops_mask &= ~REGULATOR_CHANGE_VOLTAGE;
>>> +
>>> +	return 0;
>>> +}
>>> +EXPORT_SYMBOL_NS_GPL(pmbus_regulator_init_cb, PMBUS);
>> I'm fairly comfortable with this from a regulator point of view, modulo
>> the suggestion I posted in the other message about registering separate
>> ops.  The fact that there's three combinations of ops is annoying but
>> doesn't feel too bad, though I didn't actually write it out so perhaps
>> it looks horrible.  In general removing permissions is safe, and without
>> separate steps to remove write protect (which I see in your patch 5) the
>> writes wouldn't actually work anyway.
>
>
> I still consider the callback to be unnecessary, but I don't really have time
> to implement a better solution myself. If you accept the regulator patches,
> I'll have another look at the series as-is.

I'll group the regulator patches and resend to Mark, adjusted as
requested.

Guenter, should I the resend the hwmon patches here grouped with the
tps25990 series ? Or is there something you'd like me change before ?

>
> Guenter

-- 
Jerome