[lm-sensors] [PATCH 4/5] hwmon/lm85: Clean up the handling of additional resolution bits

[Juerg Haefliger]

> The way the lm85 driver currently handles the additional resolution
> bits some chips have for the voltage and temperature measurements is
> quite complex. This is my attempt to make it simpler.
>
> Signed-off-by: Jean Delvare <khali at linux-fr.org>
> ---
>  drivers/hwmon/lm85.c |   32 ++++++++++++--------------------
>  1 file changed, 12 insertions(+), 20 deletions(-)
>
> --- linux-2.6.22-rc6.orig/drivers/hwmon/lm85.c	2007-07-01 14:12:18.000000000 +0200
> +++ linux-2.6.22-rc6/drivers/hwmon/lm85.c	2007-07-01 17:26:43.000000000 +0200
> @@ -139,10 +139,10 @@ static int lm85_scaling[] = {  /* .001 V
>  #define INS_TO_REG(n,val)	\
>  		SENSORS_LIMIT(SCALE(val,lm85_scaling[n],192),0,255)
>
> -#define INSEXT_FROM_REG(n,val,ext,scale)	\
> -		SCALE((val)*(scale) + (ext),192*(scale),lm85_scaling[n])
> +#define INSEXT_FROM_REG(n,val,ext)	\
> +		SCALE(((val) << 4) + (ext), 192 << 4, lm85_scaling[n])
>
> -#define INS_FROM_REG(n,val)   INSEXT_FROM_REG(n,val,0,1)
> +#define INS_FROM_REG(n,val)	SCALE((val), 192, lm85_scaling[n])
>
>  /* FAN speed is measured using 90kHz clock */
>  #define FAN_TO_REG(val)		(SENSORS_LIMIT( (val)<=0?0: 5400000/(val),0,65534))
> @@ -151,10 +151,9 @@ static int lm85_scaling[] = {  /* .001 V
>  /* Temperature is reported in .001 degC increments */
>  #define TEMP_TO_REG(val)	\
>  		SENSORS_LIMIT(SCALE(val,1000,1),-127,127)
> -#define TEMPEXT_FROM_REG(val,ext,scale)	\
> -		SCALE((val)*scale + (ext),scale,1000)
> -#define TEMP_FROM_REG(val)	\
> -		TEMPEXT_FROM_REG(val,0,1)
> +#define TEMPEXT_FROM_REG(val,ext)	\
> +		SCALE(((val) << 4) + (ext), 16, 1000)
> +#define TEMP_FROM_REG(val)	((val) * 1000)
>
>  #define PWM_TO_REG(val)			(SENSORS_LIMIT(val,0,255))
>  #define PWM_FROM_REG(val)		(val)
> @@ -334,7 +333,6 @@ struct lm85_data {
>  	u8 tach_mode;		/* Register encoding, combined */
>  	u8 temp_ext[3];		/* Decoded values */
>  	u8 in_ext[8];		/* Decoded values */
> -	u8 adc_scale;		/* ADC Extended bits scaling factor */
>  	u8 fan_ppr;		/* Register value */
>  	u8 smooth[3];		/* Register encoding */
>  	u8 vid;			/* Register value */
> @@ -541,8 +539,7 @@ static ssize_t show_in(struct device *de
>  	struct lm85_data *data = lm85_update_device(dev);
>  	return sprintf(	buf, "%d\n", INSEXT_FROM_REG(nr,
>  						     data->in[nr],
> -						     data->in_ext[nr],
> -						     data->adc_scale) );
> +						     data->in_ext[nr]));
>  }
>
>  static ssize_t show_in_min(struct device *dev,  struct device_attribute *attr,
> @@ -616,8 +613,7 @@ static ssize_t show_temp(struct device *
>  	int nr = to_sensor_dev_attr(attr)->index;
>  	struct lm85_data *data = lm85_update_device(dev);
>  	return sprintf(buf,"%d\n", TEMPEXT_FROM_REG(data->temp[nr],
> -						    data->temp_ext[nr],
> -						    data->adc_scale) );
> +						    data->temp_ext[nr]));
>  }
>
>  static ssize_t show_temp_min(struct device *dev, struct device_attribute *attr,
> @@ -1394,6 +1390,8 @@ static struct lm85_data *lm85_update_dev
>  		
>  		/* Have to read extended bits first to "freeze" the
>  		 * more significant bits that are read later.
> +		 * There are 2 additional resolution bits per channel and we
> +		 * have room for 4, so we shift them to the left.
>  		 */
>  		if ( (data->type == adm1027) || (data->type == adt7463) ) {
>  			int ext1 = lm85_read_value(client,
> @@ -1403,18 +1401,12 @@ static struct lm85_data *lm85_update_dev
>  			int val = (ext1 << 8) + ext2;
>
>  			for(i = 0; i <= 4; i++)
> -				data->in_ext[i] = (val>>(i * 2))&0x03;
> +				data->in_ext[i] = ((val>>(i * 2))&0x03) << 2;
>
>  			for(i = 0; i <= 2; i++)
> -				data->temp_ext[i] = (val>>((i + 5) * 2))&0x03;
> +				data->temp_ext[i] = (val>>((i + 4) * 2))&0x0c;
>  		}
>
> -		/* adc_scale is 2^(number of LSBs). There are 4 extra bits in
> -		   the emc6d102 and 2 in the adt7463 and adm1027. In all
> -		   other chips ext is always 0 and the value of scale is
> -		   irrelevant. So it is left in 4*/
> -		data->adc_scale = (data->type == emc6d102 ) ? 16 : 4;
> -
>  		data->vid = lm85_read_value(client, LM85_REG_VID);
>
>  		for (i = 0; i <= 3; ++i) {
>

Looks good.

Acked-by: Juerg Haefliger <juergh at gmail.com>