Messages in this thread | | | From | Eric Miao <> | Date | Wed, 9 Nov 2011 20:33:27 +0800 | Subject | Re: [lm-sensors] [PATCH] hwmon: (max1111) change sysfs interface to in[0-3]_input in millivolts |
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On Wed, Nov 9, 2011 at 8:22 PM, Jean Delvare <khali@linux-fr.org> 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@linux-fr.org> >> Signed-off-by: Eric Miao <eric.y.miao@gmail.com> >> --- >> 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?
>> } >> >> #define MAX1111_ADC_ATTR(_id) \ >> - SENSOR_DEVICE_ATTR(adc##_id##_in, S_IRUGO, show_adc, NULL, _id) >> + SENSOR_DEVICE_ATTR(in##_id##_input, S_IRUGO, show_adc, NULL, _id) >> >> static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); >> static MAX1111_ADC_ATTR(0); >> @@ -120,10 +121,10 @@ static MAX1111_ADC_ATTR(3); >> >> static struct attribute *max1111_attributes[] = { >> &dev_attr_name.attr, >> - &sensor_dev_attr_adc0_in.dev_attr.attr, >> - &sensor_dev_attr_adc1_in.dev_attr.attr, >> - &sensor_dev_attr_adc2_in.dev_attr.attr, >> - &sensor_dev_attr_adc3_in.dev_attr.attr, >> + &sensor_dev_attr_in0_input.dev_attr.attr, >> + &sensor_dev_attr_in1_input.dev_attr.attr, >> + &sensor_dev_attr_in2_input.dev_attr.attr, >> + &sensor_dev_attr_in3_input.dev_attr.attr, >> NULL, >> }; >> > > The rest of the changes look good. > > -- > Jean Delvare > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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