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Input: sun4i-ts - add thermal zone sensor support

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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@csie.org>
Acked-by: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Chen-Yu Tsai 2015-01-15 10:26:32 -08:00 committed by Dmitry Torokhov
parent 0c49cd295d
commit 2236971079
2 changed files with 53 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/devicetree/bindings/input/touchscreen/sun4i.txt
View File

@ -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>;
};

56
drivers/input/touchscreen/sun4i-ts.c
View File

@ -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 ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
char *buf)
static int sun4i_get_temp(const struct sun4i_ts_data *ts, long *temp)
{
struct sun4i_ts_data *ts = dev_get_drvdata(dev);
/* No temp_data until the first irq */
if (ts->temp_data == -1)
return -EAGAIN;
return sprintf(buf, "%d\n", (ts->temp_data - 1447) * 100);
/*
* 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 sun4i_get_tz_temp(void *data, long *temp)
{
return sun4i_get_temp(data, temp);
}
static struct thermal_zone_of_device_ops sun4i_ts_tz_ops = {
.get_temp = sun4i_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 error;
error = sun4i_get_temp(ts, &temp);
if (error)
return error;
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);