On Wed, Nov 9, 2011 at 8:51 PM, Jean Delvare <khali@xxxxxxxxxxxx> wrote: > On Wed, 9 Nov 2011 20:33:27 +0800, Eric Miao wrote: >> On Wed, Nov 9, 2011 at 8:22 PM, Jean Delvare <khali@xxxxxxxxxxxx> wrote: >> > Hi Eric, >> > >> > On Wed, 9 Nov 2011 19:15:03 +0800, Eric Miao wrote: >> >> This patch fixed the inconsistent max1111 sysfs interface as pointed >> >> out by Jean Delvare: >> >> >> >> It was pointed to me that the max1111 driver doesn't implement the >> >> standard sysfs interface for hwmon drivers (as described in >> >> Documentation/hwmon/sysfs-interface). It exports files adc[0-3]_in, >> >> which >> >> aren't part of the standard interface. Presumably these should be >> >> renamed to in[0-3]_input. Renaming them is probably not sufficient >> >> though, as I see no scaling done in the driver. As the MAX1111 chip has >> >> a documented full scale of 2.048V, I take it that the LSB of the ADC >> >> has a weight of 8 mV. Exporting raw register values to user-space is >> >> not OK. >> >> >> >> Reported-by: Jean Delvare <khali@xxxxxxxxxxxx> >> >> Signed-off-by: Eric Miao <eric.y.miao@xxxxxxxxx> >> >> --- >> >> drivers/hwmon/max1111.c | 13 +++++++------ >> >> 1 files changed, 7 insertions(+), 6 deletions(-) >> >> >> >> diff --git a/drivers/hwmon/max1111.c b/drivers/hwmon/max1111.c >> >> index c97b78e..0e9fcfd 100644 >> >> --- a/drivers/hwmon/max1111.c >> >> +++ b/drivers/hwmon/max1111.c >> >> @@ -106,11 +106,12 @@ static ssize_t show_adc(struct device *dev, >> >> if (ret < 0) >> >> return ret; >> >> >> >> - return sprintf(buf, "%d\n", ret); >> >> + /* assume the reference voltage to be 2.048V */ >> >> + return sprintf(buf, "%d\n", 2048 * 256 / ret); >> > >> > I bet you did not actually test your changes? ret == 0 would obviously >> > crash the driver. The formula looks wrong anyway, should be 2048 * >> > ret / 256. Or in short ret * 8, i.e. LSB weight of the ADC is 8 mV. >> > >> >> Oops, shame to death. >> >> How about simply '2048 * ret / 256' to make it clear and leave it to >> the compiler to optimize? > > I find the concept of LSB weight clear enough, but ultimately that's up > to you, as long as the compiler actually optimizes it. Sounds good, updated and resubmitted. _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
