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From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
To: Lars-Peter Clausen <lars@metafoo.de>
Cc: Guenter Roeck <linux@roeck-us.net>,
	Maxime Ripard <maxime.ripard@free-electrons.com>,
	Shawn Guo <shawn.guo@linaro.org>,
	Jean Delvare <khali@linux-fr.org>,
	jimwall@q.com, brian@crystalfontz.com,
	Grant Likely <grant.likely@linaro.org>,
	Rob Herring <rob.herring@calxeda.com>,
	Rob Landley <rob@landley.net>,
	Russell King <linux@arm.linux.org.uk>,
	devicetree-discuss@lists.ozlabs.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, lm-sensors@lm-sensors.org,
	linux-arm-kernel@lists.infradead.org, linux-iio@vger.kernel.org
Subject: Re: [PATCH 3/4] hwmon: Add a simple driver to read the MXS SoC temperature
Date: Fri, 28 Jun 2013 16:50:39 +0200	[thread overview]
Message-ID: <51CDA2BF.5050501@free-electrons.com> (raw)
In-Reply-To: <51CD9B19.90407@metafoo.de>

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,

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com


WARNING: multiple messages have this Message-ID (diff)
From: alexandre.belloni@free-electrons.com (Alexandre Belloni)
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 16:50:39 +0200	[thread overview]
Message-ID: <51CDA2BF.5050501@free-electrons.com> (raw)
In-Reply-To: <51CD9B19.90407@metafoo.de>

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,

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

WARNING: multiple messages have this Message-ID (diff)
From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
To: Lars-Peter Clausen <lars@metafoo.de>
Cc: Guenter Roeck <linux@roeck-us.net>,
	Maxime Ripard <maxime.ripard@free-electrons.com>,
	Shawn Guo <shawn.guo@linaro.org>,
	Jean Delvare <khali@linux-fr.org>,
	jimwall@q.com, brian@crystalfontz.com,
	Grant Likely <grant.likely@linaro.org>,
	Rob Herring <rob.herring@calxeda.com>,
	Rob Landley <rob@landley.net>,
	Russell King <linux@arm.linux.org.uk>,
	devicetree-discuss@lists.ozlabs.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, lm-sensors@lm-sensors.org,
	linux-arm-kernel@lists.infradead.org, linux-iio@vger.kernel.org
Subject: Re: [lm-sensors] [PATCH 3/4] hwmon: Add a simple driver to read the MXS SoC temperature
Date: Fri, 28 Jun 2013 14:50:39 +0000	[thread overview]
Message-ID: <51CDA2BF.5050501@free-electrons.com> (raw)
In-Reply-To: <51CD9B19.90407@metafoo.de>

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,

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com


_______________________________________________
lm-sensors mailing list
lm-sensors@lm-sensors.org
http://lists.lm-sensors.org/mailman/listinfo/lm-sensors

  reply	other threads:[~2013-06-28 14:50 UTC|newest]

Thread overview: 42+ 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 ` [lm-sensors] " Alexandre Belloni
2013-06-26  8:51 ` 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   ` [lm-sensors] " Alexandre Belloni
2013-06-26  8:51   ` Alexandre Belloni
2013-06-26  8:51 ` [PATCH 2/4] arm: mxs: add lradc to cfa10036 Alexandre Belloni
2013-06-26  8:51   ` [lm-sensors] " Alexandre Belloni
2013-06-26  8:51   ` 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  8:51   ` [lm-sensors] " Alexandre Belloni
2013-06-26  8:51   ` Alexandre Belloni
2013-06-26 14:39   ` Guenter Roeck
2013-06-26 14:39     ` [lm-sensors] " Guenter Roeck
2013-06-26 14:39     ` Guenter Roeck
2013-06-27  9:17     ` Maxime Ripard
2013-06-27  9:17       ` [lm-sensors] " Maxime Ripard
2013-06-27  9:17       ` Maxime Ripard
2013-06-27  9:17       ` Maxime Ripard
2013-06-27 14:27       ` Guenter Roeck
2013-06-27 14:27         ` [lm-sensors] " Guenter Roeck
2013-06-27 14:27         ` Guenter Roeck
2013-06-27 19:26         ` Alexandre Belloni
2013-06-27 19:26           ` [lm-sensors] " Alexandre Belloni
2013-06-27 19:26           ` Alexandre Belloni
2013-06-27 19:26           ` Alexandre Belloni
2013-06-28 14:18           ` Lars-Peter Clausen
2013-06-28 14:18             ` [lm-sensors] " Lars-Peter Clausen
2013-06-28 14:18             ` Lars-Peter Clausen
2013-06-28 14:50             ` Alexandre Belloni [this message]
2013-06-28 14:50               ` [lm-sensors] " Alexandre Belloni
2013-06-28 14:50               ` Alexandre Belloni
2013-06-28 15:24               ` Lars-Peter Clausen
2013-06-28 15:24                 ` [lm-sensors] " Lars-Peter Clausen
2013-06-28 15:24                 ` Lars-Peter Clausen
2013-06-28 15:24                 ` Lars-Peter Clausen
2013-06-28 16:35                 ` Guenter Roeck
2013-06-28 16:35                   ` [lm-sensors] " Guenter Roeck
2013-06-28 16:35                   ` Guenter Roeck
2013-06-26  8:51 ` [PATCH 4/4] arm: mxs: Add mxs internal temp sensor to cfa-10036 Alexandre Belloni
2013-06-26  8:51   ` [lm-sensors] " Alexandre Belloni
2013-06-26  8:51   ` Alexandre Belloni

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