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 <w...@csie.org>
> ---
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
>
> 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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