[lm-sensors] [PATCH 3/4] hwmon: (pmbus) Improve fan detection

[Jean Delvare]

Hi Guenter,

On Thu, 30 Jun 2011 10:29:52 -0700, Guenter Roeck wrote:
> Some PMBus devices return no error when reading fan speed registers, but don't
> really support fans. Strengthen fan detection by also checking if fan
> configuration registers exist.
> 
> Signed-off-by: Guenter Roeck <guenter.roeck at ericsson.com>
> ---
>  drivers/hwmon/pmbus.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwmon/pmbus.c b/drivers/hwmon/pmbus.c
> index 98e2e28..b0ea00b 100644
> --- a/drivers/hwmon/pmbus.c
> +++ b/drivers/hwmon/pmbus.c
> @@ -47,12 +47,14 @@ static void pmbus_find_sensor_groups(struct i2c_client *client,
>  	if (info->func[0]
>  	    && pmbus_check_byte_register(client, 0, PMBUS_STATUS_INPUT))
>  		info->func[0] |= PMBUS_HAVE_STATUS_INPUT;
> -	if (pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_1)) {
> +	if (pmbus_check_byte_register(client, 0, PMBUS_FAN_CONFIG_12) &&
> +	    pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_1)) {
>  		info->func[0] |= PMBUS_HAVE_FAN12;
>  		if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_12))
>  			info->func[0] |= PMBUS_HAVE_STATUS_FAN12;
>  	}
> -	if (pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_3)) {
> +	if (pmbus_check_byte_register(client, 0, PMBUS_FAN_CONFIG_34) &&
> +	    pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_3)) {
>  		info->func[0] |= PMBUS_HAVE_FAN34;
>  		if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_34))
>  			info->func[0] |= PMBUS_HAVE_STATUS_FAN34;

Then wouldn't it be sufficient to only test PMBUS_FAN_CONFIG_12 and
PMBUS_FAN_CONFIG_34, respectively? This would make the function
somewhat faster.

-- 
Jean Delvare