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From: wni@nvidia.com (Wei Ni)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH 5/9] Thermal: Support using dt node to get sensor
Date: Wed, 20 Feb 2013 18:36:00 +0800	[thread overview]
Message-ID: <5124A710.1050205@nvidia.com> (raw)
In-Reply-To: <512406F0.4080708@wwwdotorg.org>

On 02/20/2013 07:12 AM, Stephen Warren wrote:
> On 02/18/2013 04:30 AM, Wei Ni wrote:
>> Add functions to support using dt node with args to get sensor.
> 
> You need to write a device tree binding document to explain this.
> 
>> diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
> 
>> +struct thermal_sensor *get_sensor_by_node(struct node_args *np_args)
>> +{
>> +	struct thermal_sensor *pos;
> 
> "pos" isn't a great variable name. Why not use "sensor", or just the
> "ts" variable you have right below?

Oh, yes, it can just use "ts" simply. I didn't consider it, thanks.

> 
>> +	struct thermal_sensor *ts = NULL;
>> +	struct node_args *args;
>> +
>> +	mutex_lock(&sensor_list_lock);
>> +	for_each_thermal_sensor(pos) {
>> +		args = &pos->np_args;
>> +		if (args->np) {
>> +			if ((args->np == np_args->np) &&
>> +			   (args->index == np_args->index)) {
>> +				ts = pos;
>> +				break;
> 
> Replace those 2 lines with "goto out;".
> 
>> +			}
>> +		}
>> +	}
> 
> here, add:
> 
> 	ts = NULL;
> out:
> 
> That way, you can use "ts" as the loop iteration variable.
> 
> This whole patch rather assumes that all DT nodes can identify their
> exposed thermal sensors using an index in a single DT cell. That's not
> very flexible. All other DT bindings work like this:
> 
> Provider of a service indicates how many DT cells are in the object
> (GPIO, IRQ, thermal sensors) specifier:
> 
> sensor1: lm90 at 1c {
> 	...
> 	#thermal-sensor-cells = <1>;
> };
> 
> Each consumer of a service imports it by referencing it:
> 
> thermal-zone {
> 	...
> 	sensors = <&sensor1 0>;
> };
> 
> The driver for LM90 provides an "of_xlate" function which receives a
> struct of_phandle_args and outputs/returns whatever Linux-internal
> identification/representation of the object is required. For example, see:
> 
>> include/linux/pwm.h:161:	struct pwm_device *	(*of_xlate)(struct pwm_chip *pc,
> 
> This allows each providing object's DT binding to define its own value
> of #thermal-sensor-cells, as suited for its own requirements, and allows
> each driver to implement the mapping from DT to internal ID in whatever
> way is necessary.
> 
> Now, many bindings/drivers might just end up using a common simple
> implementation. That's why functions such as of_pwm_simple_xlate() or
> of_gpio_simple_xlate() exist.

It looks like the "of_xlate" can handle the sensor identification.
I'm not familiar with this function, I will look into it and try to use.
Thanks for your comments.

Wei.

> 

  reply	other threads:[~2013-02-20 10:36 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-18 11:30 [RFC PATCH 0/9] Support for tegra30 thermal Wei Ni
2013-02-18 11:30 ` [RFC PATCH 1/9] ARM: dt: t30 cardhu: add dt entry for lm90 Wei Ni
2013-02-19  3:28   ` Alex Courbot
2013-02-19  9:52     ` Wei Ni
2013-02-19 22:48     ` Stephen Warren
2013-02-18 11:30 ` [RFC PATCH 2/9] hwmon: (lm90) split set&show temp as common codes Wei Ni
2013-02-18 22:29   ` Matthew Longnecker
2013-02-19  9:48     ` Wei Ni
2013-02-19  3:31   ` [lm-sensors] " Guenter Roeck
2013-02-19 10:00     ` Wei Ni
2013-02-19 22:56   ` Stephen Warren
2013-02-20 12:31     ` Wei Ni
2013-02-18 11:30 ` [RFC PATCH 3/9] hwmon: (lm90) add support to handle irq Wei Ni
2013-02-19  3:34   ` [lm-sensors] " Guenter Roeck
2013-02-19 10:43     ` Wei Ni
2013-02-19 23:00   ` Stephen Warren
2013-02-20  3:27     ` Alex Courbot
2013-02-20 10:27       ` Wei Ni
2013-02-18 11:30 ` [RFC PATCH 4/9] hwmon: (lm90) use macros for the indexes of temp8 and temp11 Wei Ni
2013-02-19  5:39   ` Alex Courbot
2013-02-19  9:58     ` Wei Ni
2013-02-19 23:02   ` Stephen Warren
2013-02-20 10:29     ` Wei Ni
2013-02-18 11:30 ` [RFC PATCH 5/9] Thermal: Support using dt node to get sensor Wei Ni
2013-02-19 23:12   ` Stephen Warren
2013-02-20 10:36     ` Wei Ni [this message]
2013-02-18 11:30 ` [RFC PATCH 6/9] hwmon: (lm90) Register to the thermal framework Wei Ni
2013-02-19  3:42   ` [lm-sensors] " Guenter Roeck
2013-02-19 10:47     ` Wei Ni
2013-02-19  5:22   ` Alex Courbot
2013-02-19 10:58     ` Wei Ni
2013-02-19 23:18   ` Stephen Warren
2013-02-20 10:40     ` Wei Ni
2013-02-18 11:30 ` [RFC PATCH 7/9] thermal: tegra30: add tegra30 thermal driver Wei Ni
2013-02-19 23:48   ` Stephen Warren
2013-02-20 12:23     ` Wei Ni
2013-02-19 23:56   ` Russell King - ARM Linux
2013-02-20 12:29     ` Wei Ni
2013-02-18 11:30 ` [RFC PATCH 8/9] ARM: dt: t30 cardhu: add dt entry for " Wei Ni
2013-02-19  3:42   ` Alex Courbot
2013-02-19  9:56     ` Wei Ni
2013-02-19 23:28   ` Stephen Warren
2013-02-20 11:53     ` Wei Ni
2013-02-20 17:18       ` Stephen Warren
2013-02-18 11:30 ` [RFC PATCH 9/9] ARM: tegra: defconfig: enable thermal framework Wei Ni

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