linux/drivers/thermal/imx_thermal.c

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/*
* Copyright 2013 Freescale Semiconductor, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/cpu_cooling.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/thermal.h>
#include <linux/types.h>
#define REG_SET 0x4
#define REG_CLR 0x8
#define REG_TOG 0xc
#define MISC0 0x0150
#define MISC0_REFTOP_SELBIASOFF (1 << 3)
#define TEMPSENSE0 0x0180
#define TEMPSENSE0_TEMP_CNT_SHIFT 8
#define TEMPSENSE0_TEMP_CNT_MASK (0xfff << TEMPSENSE0_TEMP_CNT_SHIFT)
#define TEMPSENSE0_FINISHED (1 << 2)
#define TEMPSENSE0_MEASURE_TEMP (1 << 1)
#define TEMPSENSE0_POWER_DOWN (1 << 0)
#define TEMPSENSE1 0x0190
#define TEMPSENSE1_MEASURE_FREQ 0xffff
#define OCOTP_ANA1 0x04e0
/* The driver supports 1 passive trip point and 1 critical trip point */
enum imx_thermal_trip {
IMX_TRIP_PASSIVE,
IMX_TRIP_CRITICAL,
IMX_TRIP_NUM,
};
/*
* It defines the temperature in millicelsius for passive trip point
* that will trigger cooling action when crossed.
*/
#define IMX_TEMP_PASSIVE 85000
#define IMX_POLLING_DELAY 2000 /* millisecond */
#define IMX_PASSIVE_DELAY 1000
struct imx_thermal_data {
struct thermal_zone_device *tz;
struct thermal_cooling_device *cdev;
enum thermal_device_mode mode;
struct regmap *tempmon;
int c1, c2; /* See formula in imx_get_sensor_data() */
unsigned long temp_passive;
unsigned long temp_critical;
};
static int imx_get_temp(struct thermal_zone_device *tz, unsigned long *temp)
{
struct imx_thermal_data *data = tz->devdata;
struct regmap *map = data->tempmon;
static unsigned long last_temp;
unsigned int n_meas;
u32 val;
/*
* Every time we measure the temperature, we will power on the
* temperature sensor, enable measurements, take a reading,
* disable measurements, power off the temperature sensor.
*/
regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);
/*
* According to the temp sensor designers, it may require up to ~17us
* to complete a measurement.
*/
usleep_range(20, 50);
regmap_read(map, TEMPSENSE0, &val);
regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
if ((val & TEMPSENSE0_FINISHED) == 0) {
dev_dbg(&tz->device, "temp measurement never finished\n");
return -EAGAIN;
}
n_meas = (val & TEMPSENSE0_TEMP_CNT_MASK) >> TEMPSENSE0_TEMP_CNT_SHIFT;
/* See imx_get_sensor_data() for formula derivation */
*temp = data->c2 + data->c1 * n_meas;
if (*temp != last_temp) {
dev_dbg(&tz->device, "millicelsius: %ld\n", *temp);
last_temp = *temp;
}
return 0;
}
static int imx_get_mode(struct thermal_zone_device *tz,
enum thermal_device_mode *mode)
{
struct imx_thermal_data *data = tz->devdata;
*mode = data->mode;
return 0;
}
static int imx_set_mode(struct thermal_zone_device *tz,
enum thermal_device_mode mode)
{
struct imx_thermal_data *data = tz->devdata;
if (mode == THERMAL_DEVICE_ENABLED) {
tz->polling_delay = IMX_POLLING_DELAY;
tz->passive_delay = IMX_PASSIVE_DELAY;
} else {
tz->polling_delay = 0;
tz->passive_delay = 0;
}
data->mode = mode;
thermal_zone_device_update(tz);
return 0;
}
static int imx_get_trip_type(struct thermal_zone_device *tz, int trip,
enum thermal_trip_type *type)
{
*type = (trip == IMX_TRIP_PASSIVE) ? THERMAL_TRIP_PASSIVE :
THERMAL_TRIP_CRITICAL;
return 0;
}
static int imx_get_crit_temp(struct thermal_zone_device *tz,
unsigned long *temp)
{
struct imx_thermal_data *data = tz->devdata;
*temp = data->temp_critical;
return 0;
}
static int imx_get_trip_temp(struct thermal_zone_device *tz, int trip,
unsigned long *temp)
{
struct imx_thermal_data *data = tz->devdata;
*temp = (trip == IMX_TRIP_PASSIVE) ? data->temp_passive :
data->temp_critical;
return 0;
}
static int imx_set_trip_temp(struct thermal_zone_device *tz, int trip,
unsigned long temp)
{
struct imx_thermal_data *data = tz->devdata;
if (trip == IMX_TRIP_CRITICAL)
return -EPERM;
if (temp > IMX_TEMP_PASSIVE)
return -EINVAL;
data->temp_passive = temp;
return 0;
}
static int imx_bind(struct thermal_zone_device *tz,
struct thermal_cooling_device *cdev)
{
int ret;
ret = thermal_zone_bind_cooling_device(tz, IMX_TRIP_PASSIVE, cdev,
THERMAL_NO_LIMIT,
THERMAL_NO_LIMIT);
if (ret) {
dev_err(&tz->device,
"binding zone %s with cdev %s failed:%d\n",
tz->type, cdev->type, ret);
return ret;
}
return 0;
}
static int imx_unbind(struct thermal_zone_device *tz,
struct thermal_cooling_device *cdev)
{
int ret;
ret = thermal_zone_unbind_cooling_device(tz, IMX_TRIP_PASSIVE, cdev);
if (ret) {
dev_err(&tz->device,
"unbinding zone %s with cdev %s failed:%d\n",
tz->type, cdev->type, ret);
return ret;
}
return 0;
}
static const struct thermal_zone_device_ops imx_tz_ops = {
.bind = imx_bind,
.unbind = imx_unbind,
.get_temp = imx_get_temp,
.get_mode = imx_get_mode,
.set_mode = imx_set_mode,
.get_trip_type = imx_get_trip_type,
.get_trip_temp = imx_get_trip_temp,
.get_crit_temp = imx_get_crit_temp,
.set_trip_temp = imx_set_trip_temp,
};
static int imx_get_sensor_data(struct platform_device *pdev)
{
struct imx_thermal_data *data = platform_get_drvdata(pdev);
struct regmap *map;
int t1, t2, n1, n2;
int ret;
u32 val;
map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
"fsl,tempmon-data");
if (IS_ERR(map)) {
ret = PTR_ERR(map);
dev_err(&pdev->dev, "failed to get sensor regmap: %d\n", ret);
return ret;
}
ret = regmap_read(map, OCOTP_ANA1, &val);
if (ret) {
dev_err(&pdev->dev, "failed to read sensor data: %d\n", ret);
return ret;
}
if (val == 0 || val == ~0) {
dev_err(&pdev->dev, "invalid sensor calibration data\n");
return -EINVAL;
}
/*
* Sensor data layout:
* [31:20] - sensor value @ 25C
* [19:8] - sensor value of hot
* [7:0] - hot temperature value
*/
n1 = val >> 20;
n2 = (val & 0xfff00) >> 8;
t2 = val & 0xff;
t1 = 25; /* t1 always 25C */
/*
* Derived from linear interpolation,
* Tmeas = T2 + (Nmeas - N2) * (T1 - T2) / (N1 - N2)
* We want to reduce this down to the minimum computation necessary
* for each temperature read. Also, we want Tmeas in millicelsius
* and we don't want to lose precision from integer division. So...
* milli_Tmeas = 1000 * T2 + 1000 * (Nmeas - N2) * (T1 - T2) / (N1 - N2)
* Let constant c1 = 1000 * (T1 - T2) / (N1 - N2)
* milli_Tmeas = (1000 * T2) + c1 * (Nmeas - N2)
* milli_Tmeas = (1000 * T2) + (c1 * Nmeas) - (c1 * N2)
* Let constant c2 = (1000 * T2) - (c1 * N2)
* milli_Tmeas = c2 + (c1 * Nmeas)
*/
data->c1 = 1000 * (t1 - t2) / (n1 - n2);
data->c2 = 1000 * t2 - data->c1 * n2;
/*
* Set the default passive cooling trip point to 20 °C below the
* maximum die temperature. Can be changed from userspace.
*/
data->temp_passive = 1000 * (t2 - 20);
/*
* The maximum die temperature is t2, let's give 5 °C cushion
* for noise and possible temperature rise between measurements.
*/
data->temp_critical = 1000 * (t2 - 5);
return 0;
}
static int imx_thermal_probe(struct platform_device *pdev)
{
struct imx_thermal_data *data;
struct cpumask clip_cpus;
struct regmap *map;
int ret;
data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "fsl,tempmon");
if (IS_ERR(map)) {
ret = PTR_ERR(map);
dev_err(&pdev->dev, "failed to get tempmon regmap: %d\n", ret);
return ret;
}
data->tempmon = map;
platform_set_drvdata(pdev, data);
ret = imx_get_sensor_data(pdev);
if (ret) {
dev_err(&pdev->dev, "failed to get sensor data\n");
return ret;
}
/* Make sure sensor is in known good state for measurements */
regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
regmap_write(map, TEMPSENSE1 + REG_CLR, TEMPSENSE1_MEASURE_FREQ);
regmap_write(map, MISC0 + REG_SET, MISC0_REFTOP_SELBIASOFF);
regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
cpumask_set_cpu(0, &clip_cpus);
data->cdev = cpufreq_cooling_register(&clip_cpus);
if (IS_ERR(data->cdev)) {
ret = PTR_ERR(data->cdev);
dev_err(&pdev->dev,
"failed to register cpufreq cooling device: %d\n", ret);
return ret;
}
data->tz = thermal_zone_device_register("imx_thermal_zone",
IMX_TRIP_NUM,
BIT(IMX_TRIP_PASSIVE), data,
&imx_tz_ops, NULL,
IMX_PASSIVE_DELAY,
IMX_POLLING_DELAY);
if (IS_ERR(data->tz)) {
ret = PTR_ERR(data->tz);
dev_err(&pdev->dev,
"failed to register thermal zone device %d\n", ret);
cpufreq_cooling_unregister(data->cdev);
return ret;
}
data->mode = THERMAL_DEVICE_ENABLED;
return 0;
}
static int imx_thermal_remove(struct platform_device *pdev)
{
struct imx_thermal_data *data = platform_get_drvdata(pdev);
thermal_zone_device_unregister(data->tz);
cpufreq_cooling_unregister(data->cdev);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int imx_thermal_suspend(struct device *dev)
{
struct imx_thermal_data *data = dev_get_drvdata(dev);
struct regmap *map = data->tempmon;
u32 val;
regmap_read(map, TEMPSENSE0, &val);
if ((val & TEMPSENSE0_POWER_DOWN) == 0) {
/*
* If a measurement is taking place, wait for a long enough
* time for it to finish, and then check again. If it still
* does not finish, something must go wrong.
*/
udelay(50);
regmap_read(map, TEMPSENSE0, &val);
if ((val & TEMPSENSE0_POWER_DOWN) == 0)
return -ETIMEDOUT;
}
return 0;
}
static int imx_thermal_resume(struct device *dev)
{
/* Nothing to do for now */
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(imx_thermal_pm_ops,
imx_thermal_suspend, imx_thermal_resume);
static const struct of_device_id of_imx_thermal_match[] = {
{ .compatible = "fsl,imx6q-tempmon", },
{ /* end */ }
};
static struct platform_driver imx_thermal = {
.driver = {
.name = "imx_thermal",
.owner = THIS_MODULE,
.pm = &imx_thermal_pm_ops,
.of_match_table = of_imx_thermal_match,
},
.probe = imx_thermal_probe,
.remove = imx_thermal_remove,
};
module_platform_driver(imx_thermal);
MODULE_AUTHOR("Freescale Semiconductor, Inc.");
MODULE_DESCRIPTION("Thermal driver for Freescale i.MX SoCs");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:imx-thermal");