linux-kernel - Re: [PATCH v2] hwmon: (pmbus/ibm-cffps) Add clear

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Date:   Sun, 13 Mar 2022 21:36:55 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Brandon Wyman <bjwyman@...il.com>, Joel Stanley <joel@....id.au>,
        openbmc@...ts.ozlabs.org, Eddie James <eajames@...ux.ibm.com>,
        Jean Delvare <jdelvare@...e.com>, linux-hwmon@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] hwmon: (pmbus/ibm-cffps) Add clear_faults debugfs
 entry

On 3/11/22 10:10, Brandon Wyman wrote:
> Add a clear_faults write-only debugfs entry for the ibm-cffps device
> driver.
> 
> Certain IBM power supplies require clearing some latched faults in order
> to indicate that the fault has indeed been observed/noticed.
> 

That is insufficient, sorry. Please provide the affected power supplies as
well as the affected faults, and confirm that the problem still exists
in v5.17-rc6 or later kernels - or, more specifically, in any kernel which
includes commit 35f165f08950 ("hwmon: (pmbus) Clear pmbus fault/warning
bits after read").

Thanks,
Guenter

> Signed-off-by: Brandon Wyman <bjwyman@...il.com>
> ---
> V1 -> V2: Explain why this change is needed
> 
>   drivers/hwmon/pmbus/ibm-cffps.c | 11 +++++++++++
>   1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/hwmon/pmbus/ibm-cffps.c b/drivers/hwmon/pmbus/ibm-cffps.c
> index e3294a1a54bb..3f02dde02a4b 100644
> --- a/drivers/hwmon/pmbus/ibm-cffps.c
> +++ b/drivers/hwmon/pmbus/ibm-cffps.c
> @@ -67,6 +67,7 @@ enum {
>   	CFFPS_DEBUGFS_CCIN,
>   	CFFPS_DEBUGFS_FW,
>   	CFFPS_DEBUGFS_ON_OFF_CONFIG,
> +	CFFPS_DEBUGFS_CLEAR_FAULTS,
>   	CFFPS_DEBUGFS_NUM_ENTRIES
>   };
>   
> @@ -274,6 +275,13 @@ static ssize_t ibm_cffps_debugfs_write(struct file *file,
>   		if (rc)
>   			return rc;
>   
> +		rc = 1;
> +		break;
> +	case CFFPS_DEBUGFS_CLEAR_FAULTS:
> +		rc = i2c_smbus_write_byte(psu->client, PMBUS_CLEAR_FAULTS);
> +		if (rc < 0)
> +			return rc;
> +
>   		rc = 1;
>   		break;
>   	default:
> @@ -607,6 +615,9 @@ static int ibm_cffps_probe(struct i2c_client *client)
>   	debugfs_create_file("on_off_config", 0644, ibm_cffps_dir,
>   			    &psu->debugfs_entries[CFFPS_DEBUGFS_ON_OFF_CONFIG],
>   			    &ibm_cffps_fops);
> +	debugfs_create_file("clear_faults", 0200, ibm_cffps_dir,
> +			    &psu->debugfs_entries[CFFPS_DEBUGFS_CLEAR_FAULTS],
> +			    &ibm_cffps_fops);
>   
>   	return 0;
>   }