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

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Message-ID: <fa3ccd3b-7dab-45b2-92ec-49400e39114c@roeck-us.net>
Date: Fri, 1 Nov 2024 08:10:27 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Jerome Brunet <jbrunet@...libre.com>
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 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 ?

Guenter