[PATCH 03/17] Input: sun4i-ts: Add thermal zone sensor support

[Chen-Yu Tsai]

Hi,

On Tue, Jan 6, 2015 at 11:24 PM, Eduardo Valentin <edubezval at gmail.com> wrote:
> Hello Chen-Yu,
>
>
> On Tue, Jan 06, 2015 at 10:35:13AM +0800, Chen-Yu Tsai wrote:
>> The touchscreen controller has a temperature sensor embedded in the SoC,
>> which already has hwmon support in the driver.
>>
>> Add DT thermal zone support so we can use it with cpufreq for thermal
>> throttling.
>>
>> Signed-off-by: Chen-Yu Tsai <wens at csie.org>
>> ---
>>  .../bindings/input/touchscreen/sun4i.txt           |  1 +
>>  drivers/input/touchscreen/sun4i-ts.c               | 27 ++++++++++++++++++++++
>>  2 files changed, 28 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt b/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt
>> index aef57791f40b..7f1110adbd24 100644
>> --- a/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt
>> +++ b/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt
>> @@ -5,6 +5,7 @@ Required properties:
>>   - compatible: "allwinner,sun4i-a10-ts"
>>   - reg: mmio address range of the chip
>>   - interrupts: interrupt to which the chip is connected
>> + - #thermal-sensor-cells: shall be 0
>>
>
> You may want to update your Example section too, below.
> Example:
>
>         rtp: rtp at 01c25000 {
>                 compatible = "allwinner,sun4i-a10-ts";
>                 reg = <0x01c25000 0x100>;
>                 interrupts = <29>;
>                 allwinner,ts-attached;
>                 #thermal-sensor-cells = <0>;
>         };

Ok.

>
>
>>  Optional properties:
>>   - allwinner,ts-attached: boolean indicating that an actual touchscreen is
>> diff --git a/drivers/input/touchscreen/sun4i-ts.c b/drivers/input/touchscreen/sun4i-ts.c
>> index 28a06749ae42..b6e9043446d6 100644
>> --- a/drivers/input/touchscreen/sun4i-ts.c
>> +++ b/drivers/input/touchscreen/sun4i-ts.c
>> @@ -34,6 +34,7 @@
>>
>>  #include <linux/err.h>
>>  #include <linux/hwmon.h>
>> +#include <linux/thermal.h>
>>  #include <linux/init.h>
>>  #include <linux/input.h>
>>  #include <linux/interrupt.h>
>> @@ -107,6 +108,7 @@
>>  struct sun4i_ts_data {
>>       struct device *dev;
>>       struct input_dev *input;
>> +     struct thermal_zone_device *tz;
>>       void __iomem *base;
>>       unsigned int irq;
>>       bool ignore_fifo_data;
>> @@ -180,6 +182,23 @@ static void sun4i_ts_close(struct input_dev *dev)
>>       writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
>>  }
>>
>> +static int get_temp(void *data, long *temp)
>> +{
>> +     struct sun4i_ts_data *ts = data;
>> +
>> +     /* No temp_data until the first irq */
>> +     if (ts->temp_data == -1)
>> +             return -EAGAIN;
>> +
>> +     *temp = (ts->temp_data - 1447) * 100;
>> +
>
> Care to explain the formula in a simple comment?

This was just copied from the hwmon section. AFAIK there is no documentation
for the formula. It was probably copied from Allwinner's SDK code.

Hans? Do you remember where you got this?

>> +     return 0;
>> +}
>> +
>> +static struct thermal_zone_of_device_ops sun4i_ts_tz_ops = {
>> +     .get_temp = get_temp,
>> +};
>> +
>>  static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
>>                        char *buf)
>>  {
>> @@ -288,6 +307,11 @@ static int sun4i_ts_probe(struct platform_device *pdev)
>>       if (IS_ERR(hwmon))
>>               return PTR_ERR(hwmon);
>>
>> +     ts->tz = thermal_zone_of_sensor_register(ts->dev, 0, ts,
>> +                                              &sun4i_ts_tz_ops);
>> +     if (IS_ERR(ts->tz))
>> +             ts->tz = NULL;
>> +
>>       writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
>>
>>       if (ts_attached) {
>
> here.. if input_register_device fails, you will keep an orphan thermal zone
> registered in your system:
>
>                 error = input_register_device(ts->input);
>                 if (error) {
>                         writel(0, ts->base + TP_INT_FIFOC);

Will add an unregister call here.


Thanks for the review.

ChenYu

>                         return error;
>                 }
>                 ...
>
>
>> @@ -310,6 +334,9 @@ static int sun4i_ts_remove(struct platform_device *pdev)
>>       if (ts->input)
>>               input_unregister_device(ts->input);
>>
>> +     if (ts->tz)
>> +             thermal_zone_of_sensor_unregister(ts->dev, ts->tz);
>> +
>>       /* Deactivate all IRQs */
>>       writel(0, ts->base + TP_INT_FIFOC);
>>
>> --
>> 2.1.4
>>