On Sat, Jan 10, 2015 at 1:23 AM, Dmitry Torokhov
<dmitry.torokhov@xxxxxxxxx> wrote:
> On Fri, Jan 09, 2015 at 06:17:48PM +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.
>>
>> This also adds a comment stating that we do not know the actual formula
>> for calculating the temperature.
>>
>> Signed-off-by: Chen-Yu Tsai <wens@xxxxxxxx>
>> ---
>
>
> CC [M] drivers/input/touchscreen/sun4i-ts.o
> drivers/input/touchscreen/sun4i-ts.c:208:15: error: variable
> ‘sun4i_ts_tz_ops’ has initializer but incomplete type
> static struct thermal_zone_of_device_ops sun4i_ts_tz_ops = {
> ^
> drivers/input/touchscreen/sun4i-ts.c:209:2: error: unknown field
> ‘get_temp’ specified in initializer
> .get_temp = get_temp,
> ^
> drivers/input/touchscreen/sun4i-ts.c:209:2: warning: excess elements in
> struct initializer [enabled by default]
> drivers/input/touchscreen/sun4i-ts.c:209:2: warning: (near
> initialization for ‘sun4i_ts_tz_ops’) [enabled by default]
> drivers/input/touchscreen/sun4i-ts.c: In function ‘sun4i_ts_probe’:
> drivers/input/touchscreen/sun4i-ts.c:331:8: warning: passing argument 4
> of ‘thermal_zone_of_sensor_register’ from incompatible pointer type
> [enabled by default]
> &sun4i_ts_tz_ops);
> ^
> In file included from drivers/input/touchscreen/sun4i-ts.c:37:0:
> include/linux/thermal.h:302:1: note: expected ‘int (*)(void *, long int
> *)’ but argument is of type ‘struct thermal_zone_of_device_ops *’
> thermal_zone_of_sensor_register(struct device *dev, int id,
> ^
> drivers/input/touchscreen/sun4i-ts.c:331:8: error: too few arguments to
> function ‘thermal_zone_of_sensor_register’
> &sun4i_ts_tz_ops);
> ^
> In file included from drivers/input/touchscreen/sun4i-ts.c:37:0:
> include/linux/thermal.h:302:1: note: declared here
> thermal_zone_of_sensor_register(struct device *dev, int id,
> ^
> make[1]: *** [drivers/input/touchscreen/sun4i-ts.o] Error 1
> make: *** [drivers/input/touchscreen/sun4i-ts.o] Error 2
>
struct thermal_zone_of_device_ops was introduced in 3.19-rc1 in
184a4bf623fa thermal: of: Extend current of-thermal.c code to
allow setting emulated temp
>>
>> changes since v1:
>>
>> - clean up thermal zone sensor when input device register fails
>> - unconditionally unregister thermal zone sensor on removal.
>> the unregister function checks the pointers passed in.
>> - add comment explaining the lack of documents for the temperature
>> calculation formula
>>
>> ---
>> .../bindings/input/touchscreen/sun4i.txt | 2 +
>> drivers/input/touchscreen/sun4i-ts.c | 47 ++++++++++++++++++++++
>> 2 files changed, 49 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt b/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt
>> index aef57791f40b..a8405bab6c00 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
>>
>> Optional properties:
>> - allwinner,ts-attached: boolean indicating that an actual touchscreen is
>> @@ -17,4 +18,5 @@ Example:
>> reg = <0x01c25000 0x100>;
>> interrupts = <29>;
>> allwinner,ts-attached;
>> + #thermal-sensor-cells = <0>;
>> };
>> diff --git a/drivers/input/touchscreen/sun4i-ts.c b/drivers/input/touchscreen/sun4i-ts.c
>> index 28a06749ae42..aac49db0b09d 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 +182,33 @@ 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;
>> +
>> + /*
>> + * The user manuals do not contain the formula for calculating
>> + * the temperature. The formula used here is from the AXP209,
>> + * which is designed by X-Powers, an affiliate of Allwinner:
>> + *
>> + * temperature = -144.7 + (value * 0.1)
>> + *
>> + * This should be replaced with the correct one if such information
>> + * becomes available.
>> + */
>> + *temp = (ts->temp_data - 1447) * 100;
>> +
>> + 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)
>> {
>> @@ -189,6 +218,16 @@ static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
>> if (ts->temp_data == -1)
>> return -EAGAIN;
>>
>> + /*
>> + * The user manuals do not contain the formula for calculating
>> + * the temperature. The formula used here is from the AXP209,
>> + * which is designed by X-Powers, an affiliate of Allwinner:
>> + *
>> + * temperature = -144.7 + (value * 0.1)
>> + *
>> + * This should be replaced with the correct one if such information
>> + * becomes available.
>> + */
>> return sprintf(buf, "%d\n", (ts->temp_data - 1447) * 100);
>
> Why duplicate it here, instead of doing:
>
> static int sun4i_get_temp(struct sun4i_ts_data *ts, int *temp)
> {
> if (ts->temp_data == -1)
> return -EAGAIN;
>
> /* comment */
> *temp = (ts->temp_data - 1447) * 100);
>
> return 0;
> }
>
> static int sun4i_tz_get_temp(void *data, long *temp)
> {
> return sun4i_get_temp(data, temp);
> }
>
> static ssize_t sun4i_show_temp(...)
> {
> error = sun4i_get_temp(ts, &temp);
> if (error)
> return error;
>
> return sprintf(buf, "%d\n", temp);
> }
I suppose that would be better, especially after I added the large comment.
> Also, thermal core seems to allow creating hwmon devices for thermal
> zones, can we use this feature?
For thermal sensors that also have hwmon devices registered, that step is
skipped.
I sort of like having separate hwmon bits, just for a nicer, more informative
label. But I am not opposed to removing the bits from the driver and having
it go through the thermal core. We could also remove the build dependency
on HWMON as a result.
If you prefer this, I will do so in v3.
Thanks
ChenYu
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