Hi, On 27/06/2013 16:27, Guenter Roeck wrote: > On Thu, Jun 27, 2013 at 11:17:32AM +0200, Maxime Ripard wrote: >> On Wed, Jun 26, 2013 at 07:39:27AM -0700, Guenter Roeck wrote: >>> On Wed, Jun 26, 2013 at 10:51:12AM +0200, Alexandre Belloni wrote: >>>> The low resolution ADC of the mxs is able to read an internal temperature >>>> sensor, expose that using hwmon. >>>> >>>> Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx> >>>> --- >>> Wouldn't it make more sense to use iio-hwmon and improve it if necessary ? >> Actually, I wonder if we should not just put the hwmon driver >> capabilities directly into the mxs-lradc driver, just like it's already >> been done in this driver for the touchscreen support. >> >> The probing of this hwmon driver doesn't really belong to the DT, it's >> not really realistic to probe it from the machine definition, and it >> really is the IP that is wired that way. >> > Merging iio-hwmon functionality into an adc driver seems just as bad > (or even worse) as copying it into a new driver. > > If the lradc driver knows that the ADC channels are temperature sensors, it > should register them with the iio subsystem as IIO_TEMP type. Then you should > be able to use iio_hwmon as is. They are already registered as IIO_TEMP but only implement read_raw. Also, iio_hwmon_read_val() is using iio_read_channel_processed() and that will basically only read one of the 2 channels. As I documented, you actually need to read both channel 8 and channel 9 and then compute the value in Kelvins. I'm not sure how you want me to do that in the current framework. Regards, -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
