linux-kernel - Re: [PATCH v3 4/6] hwmon: (pmbus/core) clear faults after setting smbalert mask

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Message-ID: <1jo72v5rnp.fsf@starbuckisacylon.baylibre.com>
Date: Mon, 04 Nov 2024 09:28:42 +0100
From: Jerome Brunet <jbrunet@...libre.com>
To: Guenter Roeck <linux@...ck-us.net>
Cc: Jean Delvare <jdelvare@...e.com>,  Jonathan Corbet <corbet@....net>,
  Patrick Rudolph <patrick.rudolph@...ements.com>,  Naresh Solanki
 <naresh.solanki@...ements.com>,  Rob Herring <robh@...nel.org>,  Krzysztof
 Kozlowski <krzk+dt@...nel.org>,  Conor Dooley <conor+dt@...nel.org>,
  Delphine CC Chiu <Delphine_CC_Chiu@...ynn.com>,
  linux-hwmon@...r.kernel.org,  linux-kernel@...r.kernel.org,
  linux-doc@...r.kernel.org,  devicetree@...r.kernel.org,
  linux-i2c@...r.kernel.org
Subject: Re: [PATCH v3 4/6] hwmon: (pmbus/core) clear faults after setting
 smbalert mask

On Fri 01 Nov 2024 at 08:10, Guenter Roeck <linux@...ck-us.net> wrote:

> On Thu, Oct 24, 2024 at 08:10:38PM +0200, Jerome Brunet wrote:
>> pmbus_write_smbalert_mask() ignores the errors if the chip can't set
>> smbalert mask the standard way. It is not necessarily a problem for the irq
>> support if the chip is otherwise properly setup but it may leave an
>> uncleared fault behind.
>> 
>> pmbus_core will pick the fault on the next register_check(). The register
>> check will fails regardless of the actual register support by the chip.
>> 
>> This leads to missing attributes or debugfs entries for chips that should
>> provide them.
>> 
>> We cannot rely on register_check() as PMBUS_SMBALERT_MASK may be read-only.
>> 
>> Unconditionally clear the page fault after setting PMBUS_SMBALERT_MASK to
>> avoid the problem.
>> 
>> Suggested-by: Guenter Roeck <linux@...ck-us.net>
>> Fixes: 221819ca4c36 ("hwmon: (pmbus/core) Add interrupt support")
>> Signed-off-by: Jerome Brunet <jbrunet@...libre.com>
>> ---
>>  drivers/hwmon/pmbus/pmbus_core.c | 7 ++++++-
>>  1 file changed, 6 insertions(+), 1 deletion(-)
>> 
>> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
>> index ce697ca03de01c0e5a352f8f6b72671137721868..a0a397d571caa1a6620ef095f9cf63d94e8bda1d 100644
>> --- a/drivers/hwmon/pmbus/pmbus_core.c
>> +++ b/drivers/hwmon/pmbus/pmbus_core.c
>> @@ -3346,7 +3346,12 @@ static int pmbus_regulator_notify(struct pmbus_data *data, int page, int event)
>>  
>>  static int pmbus_write_smbalert_mask(struct i2c_client *client, u8 page, u8 reg, u8 val)
>>  {
>> -	return _pmbus_write_word_data(client, page, PMBUS_SMBALERT_MASK, reg | (val << 8));
>> +	int ret;
>> +
>> +	ret = _pmbus_write_word_data(client, page, PMBUS_SMBALERT_MASK, reg | (val << 8));
>> +	pmbus_clear_fault_page(client, -1);
>
> Why -1 and not page ?

The idea was to clear the fault on the page we are on, basically just skipping
setting the page again.

I'll change to 'page'

>
> Guenter

-- 
Jerome