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@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.
>
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