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.
> }
>
> #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
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