Subject: [PATCH v2 1/9] Input: sun4i-ts: Add thermal zone sensor support

From: [email-masked] (Eduardo Valentin)
Date: Fri, 9 Jan 2015 14:33:15 -0400

Dmitry,

On Fri, Jan 09, 2015 at 09:23:18AM -0800, Dmitry Torokhov 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 <[email-masked]>
> > ---
> 
> 
>   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
> 

What kernel version are you using?

It looks like you are missing the of thermal ops commit.

> > 
> > 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);
> }
> 
> Also, thermal core seems to allow creating hwmon devices for thermal
> zones, can we use this feature?
> 
> Thanks.
> 
> -- 
> Dmitry
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