From: linux@roeck-us•net (Guenter Roeck)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 3/4] hwmon: Add a simple driver to read the MXS SoC temperature
Date: Fri, 28 Jun 2013 09:35:40 -0700 [thread overview]
Message-ID: <20130628163540.GA26547@roeck-us.net> (raw)
In-Reply-To: <51CDAABB.4020505@metafoo.de>
On Fri, Jun 28, 2013 at 05:24:43PM +0200, Lars-Peter Clausen wrote:
> On 06/28/2013 04:50 PM, Alexandre Belloni wrote:
> > On 28/06/2013 16:18, Lars-Peter Clausen wrote:
> >> On 06/27/2013 09:26 PM, Alexandre Belloni wrote:
> >>>
> >>> 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.
> >> What are these two channels actually measuring? Is the value of a single
> >> channel meaningful on it's own? If not it might make sense to update the IIO
> >> driver to just have one temperature channel.
> >
> > It's not actually meaningful on its own. So, what you would do is expose
> > one iio channel for two ADC channels and do the computation in read_raw
> > ? or read_processed ? Then using iio-hwon to export it. ?
> >
> > Regards,
> >
>
> Yes, return channel9 - channel8 as the raw value for the temperature channel
> and provide proper scale and offset values, so that
> iio_read_channel_processed() will return the correct value.
>
Agreed.
Guenter
next prev parent reply other threads:[~2013-06-28 16:35 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-26 8:51 [PATCH 0/4] Add an hwmon driver for the mxs soc internal sensor Alexandre Belloni
2013-06-26 8:51 ` [PATCH 1/4] arm: mxs: Add #io-channel-cells property to lradc Alexandre Belloni
2013-06-26 8:51 ` [PATCH 2/4] arm: mxs: add lradc to cfa10036 Alexandre Belloni
2013-06-26 8:51 ` [PATCH 3/4] hwmon: Add a simple driver to read the MXS SoC temperature Alexandre Belloni
2013-06-26 14:39 ` Guenter Roeck
2013-06-27 9:17 ` Maxime Ripard
2013-06-27 14:27 ` Guenter Roeck
2013-06-27 19:26 ` Alexandre Belloni
2013-06-28 14:18 ` Lars-Peter Clausen
2013-06-28 14:50 ` Alexandre Belloni
2013-06-28 15:24 ` Lars-Peter Clausen
2013-06-28 16:35 ` Guenter Roeck [this message]
2013-06-26 8:51 ` [PATCH 4/4] arm: mxs: Add mxs internal temp sensor to cfa-10036 Alexandre Belloni
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