On Mon, Jan 12, 2015 at 12:34:01PM +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 protected]>
Acked-by: Eduardo Valentin <[email protected]> > --- > > changes since v2: > > - Use common function for temperature calculation > > 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 | 54 > ++++++++++++++++++++-- > 2 files changed, 52 insertions(+), 4 deletions(-) > > 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..5851aa0bd78b 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; > @@ -180,16 +182,48 @@ static void sun4i_ts_close(struct input_dev *dev) > writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC); > } > > +static int get_temp(const struct sun4i_ts_data *ts, long *temp) > +{ > + /* 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 int get_tz_temp(void *data, long *temp) > +{ > + return get_temp(data, temp); > +} > + > +static struct thermal_zone_of_device_ops sun4i_ts_tz_ops = { > + .get_temp = get_tz_temp, > +}; > + > static ssize_t show_temp(struct device *dev, struct device_attribute > *devattr, > char *buf) > { > struct sun4i_ts_data *ts = dev_get_drvdata(dev); > + long temp; > + int ret; > > - /* No temp_data until the first irq */ > - if (ts->temp_data == -1) > - return -EAGAIN; > + ret = get_temp(ts, &temp); > + if (ret) > + return ret; > > - return sprintf(buf, "%d\n", (ts->temp_data - 1447) * 100); > + return sprintf(buf, "%ld\n", temp); > } > > static ssize_t show_temp_label(struct device *dev, > @@ -283,17 +317,27 @@ static int sun4i_ts_probe(struct platform_device *pdev) > writel(STYLUS_UP_DEBOUN(5) | STYLUS_UP_DEBOUN_EN(1) | TP_MODE_EN(1), > ts->base + TP_CTRL1); > > + /* > + * The thermal core does not register hwmon devices for DT-based > + * thermal zone sensors, such as this one. > + */ > hwmon = devm_hwmon_device_register_with_groups(ts->dev, "sun4i_ts", > ts, sun4i_ts_groups); > 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) { > error = input_register_device(ts->input); > if (error) { > writel(0, ts->base + TP_INT_FIFOC); > + thermal_zone_of_sensor_unregister(ts->dev, ts->tz); > return error; > } > } > @@ -310,6 +354,8 @@ static int sun4i_ts_remove(struct platform_device *pdev) > if (ts->input) > input_unregister_device(ts->input); > > + 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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