linux-kernel - Re: [PATCH v2 1/2] hwmon: (pmbus) add a function to check the presence of a block register

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Date:   Tue, 24 May 2022 06:32:41 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Adam Wujek <dev_public@...ek.eu>
Cc:     Jean Delvare <jdelvare@...e.com>, linux-hwmon@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] hwmon: (pmbus) add a function to check the
 presence of a block register

On 5/24/22 03:43, Adam Wujek wrote:
> Other functions (like pmbus_check_byte_register) cannot be used to check
> the presence of a block register, because it will generate error when PEC
> is used.
> 
> Signed-off-by: Adam Wujek <dev_public@...ek.eu>
> ---
> Notes:
>    Changes in v2:
>      - Use Phase 0xff when setting the page
> 
>   drivers/hwmon/pmbus/pmbus_core.c | 26 ++++++++++++++++++++++++++
>   1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index acf78d0829d9..2ff66f133d95 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -421,6 +421,18 @@ static int _pmbus_read_byte_data(struct i2c_client *client, int page, int reg)
>   	return pmbus_read_byte_data(client, page, reg);
>   }
> 
> +static int pmbus_read_block_data(struct i2c_client *client, int page, u8 reg,
> +				 char *data_buf)
> +{
> +	int rv;
> +
> +	rv = pmbus_set_page(client, page, 0xff);
> +	if (rv < 0)
> +		return rv;
> +
> +	return i2c_smbus_read_block_data(client, reg, data_buf);
> +}
> +
>   static struct pmbus_sensor *pmbus_find_sensor(struct pmbus_data *data, int page,
>   					      int reg)
>   {
> @@ -558,6 +570,20 @@ bool pmbus_check_word_register(struct i2c_client *client, int page, int reg)
>   }
>   EXPORT_SYMBOL_NS_GPL(pmbus_check_word_register, PMBUS);
> 
> +static bool pmbus_check_block_register(struct i2c_client *client, int page,
> +				       int reg)
> +{
> +	int rv;
> +	struct pmbus_data *data = i2c_get_clientdata(client);
> +	char data_buf[I2C_SMBUS_BLOCK_MAX + 2] = { 0 };

Unnecessary initialization.

> +
> +	rv = pmbus_read_block_data(client, page, reg, data_buf);
> +	if (rv >= 0 && !(data->flags & PMBUS_SKIP_STATUS_CHECK))
> +		rv = pmbus_check_status_cml(client);

How about PMBUS_READ_STATUS_AFTER_FAILED_CHECK ?

Thanks,
Guenter

> +	pmbus_clear_fault_page(client, -1);
> +	return rv >= 0;
> +}
> +
>   const struct pmbus_driver_info *pmbus_get_driver_info(struct i2c_client *client)
>   {
>   	struct pmbus_data *data = i2c_get_clientdata(client);
> --
> 2.17.1
> 
>