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@xxxxxxxx>
> ---
> .../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@01c25000 {
compatible = "allwinner,sun4i-a10-ts";
reg = <0x01c25000 0x100>;
interrupts = <29>;
allwinner,ts-attached;
#thermal-sensor-cells = <0>;
};
> 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?
> + 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);
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
>
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