Hi Guenter, On Sun, 29 Mar 2015 23:33:41 -0700, Guenter Roeck wrote: > On chips with newer pwm control, the pwm frequency divider is 256 > instead of 128. Since the base pwm frequency remained the same, the actual > pwm frequency is half of what it used to be with the older pwm control > mechanism. > > Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx> > --- > drivers/hwmon/it87.c | 34 +++++++++++++++++++++++++--------- > 1 file changed, 25 insertions(+), 9 deletions(-) > > diff --git a/drivers/hwmon/it87.c b/drivers/hwmon/it87.c > index ab12dc2eb896..7ab5bd026e91 100644 > --- a/drivers/hwmon/it87.c > +++ b/drivers/hwmon/it87.c > @@ -502,15 +502,25 @@ static int DIV_TO_REG(int val) > } > #define DIV_FROM_REG(val) (1 << (val)) > > +/* > + * pwm base frequencies. The frequency has to be divided by either 128 or 256, > + * depending on the chip type, to calculate the actual pwm frequency. > + * > + * Some of the chip datasheets suggest a base frequency of 51kHz instead > + * of 750kHz for the slowest base frequency, resulting in a pwm frequency > + * of 200Hz. Sometimes both pwm frequency select registers are affected, > + * sometimes just one. It is unknown if this is a datasheet error or real, > + * so this is ignored for now. Leaving a space between the number and kHz or Hz makes it easier to read IMHO. I would also capitalize PWM everywhere. Other than these minor suggestions, this looks good, good catch! I never noticed this difference between the various chips. Jean -- Jean Delvare SUSE L3 Support _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
