[lm-sensors] [PATCH] hwmon: (lm63) LM64 has a dedicated pin for tachometer

[Guenter Roeck]

On Fri, Jan 13, 2012 at 04:13:21AM -0500, Jean Delvare wrote:
> On the LM64, the tachometer function has a dedicated pin and fan speed
> monitoring is always enabled.
> 
> Signed-off-by: Jean Delvare <khali at linux-fr.org>
> ---
>  Documentation/hwmon/lm63 |    4 +++-
>  drivers/hwmon/lm63.c     |    3 ++-
>  2 files changed, 5 insertions(+), 2 deletions(-)
> 
> --- linux-3.3-rc0.orig/Documentation/hwmon/lm63	2012-01-13 09:09:25.000000000 +0100
> +++ linux-3.3-rc0/Documentation/hwmon/lm63	2012-01-13 09:54:38.000000000 +0100
> @@ -54,7 +54,9 @@ value for measuring the speed of the fan
>  Note that the pin used for fan monitoring is shared with an alert out
>  function. Depending on how the board designer wanted to use the chip, fan
>  speed monitoring will or will not be possible. The proper chip configuration
> -is left to the BIOS, and the driver will blindly trust it.
> +is left to the BIOS, and the driver will blindly trust it. Only the original
> +LM63 suffers from this limitation, the LM64 and LM96163 have separate pins
> +for fan monitoring and alert out.
>  
>  A PWM output can be used to control the speed of the fan. The LM63 has two
>  PWM modes: manual and automatic. Automatic mode is not fully implemented yet
> --- linux-3.3-rc0.orig/drivers/hwmon/lm63.c	2012-01-13 09:33:23.000000000 +0100
> +++ linux-3.3-rc0/drivers/hwmon/lm63.c	2012-01-13 09:53:19.000000000 +0100
> @@ -745,7 +745,8 @@ static int lm63_probe(struct i2c_client
>  	err = sysfs_create_group(&new_client->dev.kobj, &lm63_group);
>  	if (err)
>  		goto exit_free;
> -	if (data->config & 0x04) { /* tachometer enabled */
> +	if (data->kind == lm64 ||	/* tachometer has dedicated pin */
> +	    (data->config & 0x04)) {	/* tachometer enabled */
>  		err = sysfs_create_group(&new_client->dev.kobj,
>  					 &lm63_group_fan1);
>  		if (err)
> 
Just realized: In lm63_update_device(), the code checks for data->config & 0x04 again
and never reads the fan registers if it is 0. Since the bit is reserved on LM64, fan status
will never be read for it.

Guenter