Re: [lm-sensors] [PATCH 3/4] hwmon: (w83791d) add pwm_enable support

[Hans de Goede <j.w.r.degoede@hhs.nl>]

Marc Hulsman wrote:
> These patches add support for pwm_enable. I did allow for setting fan speed 
> cruise mode although I will only implement further support for thermal cruise 
> mode (next patch), as the bios could initialize the chip with this mode. 
> 
> Marc
> 
> ---
> Add support for pwm_enable.
> 
> Signed-off-by: Marc Hulsman <m.hulsman@tudelft.nl> 
> 
> ---
>  Documentation/hwmon/w83791d |   13 ++++++-
>  drivers/hwmon/w83791d.c     |   79 
> ++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 91 insertions(+), 1 deletion(-)
> 
> ---
> Index: linux-2.6.27-rc1/Documentation/hwmon/w83791d
> =================================> --- linux-2.6.27-rc1.orig/Documentation/hwmon/w83791d
> +++ linux-2.6.27-rc1/Documentation/hwmon/w83791d
> @@ -108,6 +108,17 @@ going forward.
>  The driver reads the hardware chip values at most once every three seconds.
>  User mode code requesting values more often will receive cached values.
>  
> +/sys files
> +----------
> +The sysfs-interface is documented in the 'sysfs-interface' file. Only
> +chip-specific options are documented here.
> +
> +pwm[1-3]_enable - 	this file controls mode of fan/temperature control for
> +		  	fan 1-3. Fan/PWM 4-5 only support manual mode.
> +		            * 1 Manual mode
> +		            * 2 Thermal Cruise mode   (no further support)
> +		            * 3 Fan Speed Cruise mode (no further support)
> +
>  Alarms bitmap vs. beep_mask bitmask
>  ------------------------------------
>  For legacy code using the alarms and beep_mask files:
> @@ -138,4 +149,4 @@ global_enable:  alarms: -------- beep_ma
>  
>  W83791D TODO:
>  ---------------
> -Provide a patch for smart-fan control (still need appropriate 
> motherboard/fans)
> +Provide a patch for Thermal Cruise registers.
> Index: linux-2.6.27-rc1/drivers/hwmon/w83791d.c
> =================================> --- linux-2.6.27-rc1.orig/drivers/hwmon/w83791d.c
> +++ linux-2.6.27-rc1/drivers/hwmon/w83791d.c
> @@ -287,6 +287,8 @@ struct w83791d_data {
>  
>  	/* PWMs */
>  	u8 pwm[5];		/* pwm duty cycle */
> +	u8 pwm_enable[3];	/* pwm enable status for fan 1-3
> +					(fan 4-5 only support manual mode) */
>  
>  	/* Misc */
>  	u32 alarms;		/* realtime status register encoding,combined */
> @@ -707,6 +709,71 @@ static struct sensor_device_attribute sd
>  			show_pwm, store_pwm, 4),
>  };
>  
> +static ssize_t show_pwmenable(struct device *dev, struct device_attribute 
> *attr,
> +				char *buf)
> +{
> +	struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
> +	int nr = sensor_attr->index;
> +	struct w83791d_data *data = w83791d_update_device(dev);
> +	return sprintf(buf, "%u\n", data->pwm_enable[nr]);
> +}

You show data->pwm_enable "as is", but ...

> +
> +static ssize_t store_pwmenable(struct device *dev,
> +		struct device_attribute *attr, const char *buf, size_t count)
> +{
> +	struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct w83791d_data *data = i2c_get_clientdata(client);
> +	int nr = sensor_attr->index;
> +	unsigned long val;
> +	u8 reg_cfg_tmp;
> +	u8 reg_idx = 0;
> +	u8 val_shift = 0;
> +	u8 keep_mask = 0;
> +
> +	int ret = strict_strtoul(buf, 10, &val);
> +
> +	if (ret || val < 1 || val > 3)
> +		return -EINVAL;
> +
> +	mutex_lock(&data->update_lock);
> +	data->pwm_enable[nr] = val - 1;

Here you store "val - 1", continued ...

> +	switch (nr) {
> +	case 0:
> +		reg_idx = 0;
> +		val_shift = 2;
> +		keep_mask = 0xf3;
> +		break;

<snip>

> @@ -1324,6 +1394,15 @@ static struct w83791d_data *w83791d_upda
>  						W83791D_REG_PWM[i]);
>  		}
>  
> +		/* Update PWM enable status */
> +		for (i = 0; i < 2; i++) {
> +			reg_array_tmp[i] = w83791d_read(client,
> +						W83791D_REG_FAN_CFG[i]);
> +		}
> +		data->pwm_enable[0] = ((reg_array_tmp[0] >> 2) & 0x03) + 1;
> +		data->pwm_enable[1] = ((reg_array_tmp[0] >> 4) & 0x03) + 1;
> +		data->pwm_enable[2] = ((reg_array_tmp[1] >> 2) & 0x03) + 1;
> +
>  		/* Update the first temperature sensor */
>  		for (i = 0; i < 3; i++) {
>  			data->temp1[i] = w83791d_read(client,

And here you store the register val + 1 again, making show_pwmenable actually 
show the less value, unless pwm#_enable is read very quickly after a write, in 
which case w83791d_update won't do anything and the shown pwm_enable value will 
be one to small.

I think it would be best to consistently store the val as seen by userspace - 1 
(iow the actual reg val) in pwm_enable (as you do in store_pwmenable) and then 
add the + 1 when showing it.

Regards,

Hans

_______________________________________________
lm-sensors mailing list
lm-sensors@lm-sensors.org
http://lists.lm-sensors.org/mailman/listinfo/lm-sensors