drivers/thermal/imx_thermal.c - maze/linux - Git at Google

 /*
  * 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/clk.h>
 #include <linux/cpu_cooling.h>
 #include <linux/cpufreq.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/init.h>
 #include <linux/interrupt.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_ALARM_VALUE_SHIFT	20
 #define TEMPSENSE0_ALARM_VALUE_MASK	(0xfff << TEMPSENSE0_ALARM_VALUE_SHIFT)
 #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

 #define FACTOR0				10000000
 #define FACTOR1				15976
 #define FACTOR2				4297157

 struct imx_thermal_data {
 	struct thermal_zone_device *tz;
 	struct thermal_cooling_device *cdev;
 	enum thermal_device_mode mode;
 	struct regmap *tempmon;
 	u32 c1, c2; /* See formula in imx_get_sensor_data() */
 	unsigned long temp_passive;
 	unsigned long temp_critical;
 	unsigned long alarm_temp;
 	unsigned long last_temp;
 	bool irq_enabled;
 	int irq;
 	struct clk *thermal_clk;
 };

 static void imx_set_alarm_temp(struct imx_thermal_data *data,
 			       signed long alarm_temp)
 {
 	struct regmap *map = data->tempmon;
 	int alarm_value;

 	data->alarm_temp = alarm_temp;
 	alarm_value = (data->c2 - alarm_temp) / data->c1;
 	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_ALARM_VALUE_MASK);
 	regmap_write(map, TEMPSENSE0 + REG_SET, alarm_value <<
 			TEMPSENSE0_ALARM_VALUE_SHIFT);
 }

 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;
 	unsigned int n_meas;
 	bool wait;
 	u32 val;

 	if (data->mode == THERMAL_DEVICE_ENABLED) {
 		/* Check if a measurement is currently in progress */
 		regmap_read(map, TEMPSENSE0, &val);
 		wait = !(val & TEMPSENSE0_FINISHED);
 	} else {
 		/*
 		 * 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);

 		wait = true;
 	}

 	/*
 	 * According to the temp sensor designers, it may require up to ~17us
 	 * to complete a measurement.
 	 */
 	if (wait)
 		usleep_range(20, 50);

 	regmap_read(map, TEMPSENSE0, &val);

 	if (data->mode != THERMAL_DEVICE_ENABLED) {
 		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 - n_meas * data->c1;

 	/* Update alarm value to next higher trip point */
 	if (data->alarm_temp == data->temp_passive && *temp >= data->temp_passive)
 		imx_set_alarm_temp(data, data->temp_critical);
 	if (data->alarm_temp == data->temp_critical && *temp < data->temp_passive) {
 		imx_set_alarm_temp(data, data->temp_passive);
 		dev_dbg(&tz->device, "thermal alarm off: T < %lu\n",
 			data->alarm_temp / 1000);
 	}

 	if (*temp != data->last_temp) {
 		dev_dbg(&tz->device, "millicelsius: %ld\n", *temp);
 		data->last_temp = *temp;
 	}

 	/* Reenable alarm IRQ if temperature below alarm temperature */
 	if (!data->irq_enabled && *temp < data->alarm_temp) {
 		data->irq_enabled = true;
 		enable_irq(data->irq);
 	}

 	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;
 	struct regmap *map = data->tempmon;

 	if (mode == THERMAL_DEVICE_ENABLED) {
 		tz->polling_delay = IMX_POLLING_DELAY;
 		tz->passive_delay = IMX_PASSIVE_DELAY;

 		regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
 		regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);

 		if (!data->irq_enabled) {
 			data->irq_enabled = true;
 			enable_irq(data->irq);
 		}
 	} else {
 		regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
 		regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);

 		tz->polling_delay = 0;
 		tz->passive_delay = 0;

 		if (data->irq_enabled) {
 			disable_irq(data->irq);
 			data->irq_enabled = false;
 		}
 	}

 	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;

 	imx_set_alarm_temp(data, 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 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;
 	u64 temp64;

 	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
 	 * Use universal formula now and only need sensor value @ 25C
 	 * slope = 0.4297157 - (0.0015976 * 25C fuse)
 	 */
 	n1 = val >> 20;
 	n2 = (val & 0xfff00) >> 8;
 	t2 = val & 0xff;
 	t1 = 25; /* t1 always 25C */

 	/*
 	 * Derived from linear interpolation:
 	 * slope = 0.4297157 - (0.0015976 * 25C fuse)
 	 * slope = (FACTOR2 - FACTOR1 * n1) / FACTOR0
 	 * (Nmeas - n1) / (Tmeas - t1) = slope
 	 * 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...
 	 * Tmeas = (Nmeas - n1) / slope + t1
 	 * milli_Tmeas = 1000 * (Nmeas - n1) / slope + 1000 * t1
 	 * milli_Tmeas = -1000 * (n1 - Nmeas) / slope + 1000 * t1
 	 * Let constant c1 = (-1000 / slope)
 	 * milli_Tmeas = (n1 - Nmeas) * c1 + 1000 * t1
 	 * Let constant c2 = n1 *c1 + 1000 * t1
 	 * milli_Tmeas = c2 - Nmeas * c1
 	 */
 	temp64 = FACTOR0;
 	temp64 *= 1000;
 	do_div(temp64, FACTOR1 * n1 - FACTOR2);
 	data->c1 = temp64;
 	data->c2 = n1 * data->c1 + 1000 * t1;

 	/*
 	 * 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 irqreturn_t imx_thermal_alarm_irq(int irq, void *dev)
 {
 	struct imx_thermal_data *data = dev;

 	disable_irq_nosync(irq);
 	data->irq_enabled = false;

 	return IRQ_WAKE_THREAD;
 }

 static irqreturn_t imx_thermal_alarm_irq_thread(int irq, void *dev)
 {
 	struct imx_thermal_data *data = dev;

 	dev_dbg(&data->tz->device, "THERMAL ALARM: T > %lu\n",
 		data->alarm_temp / 1000);

 	thermal_zone_device_update(data->tz);

 	return IRQ_HANDLED;
 }

 static int imx_thermal_probe(struct platform_device *pdev)
 {
 	struct imx_thermal_data *data;
 	struct cpumask clip_cpus;
 	struct regmap *map;
 	int measure_freq;
 	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;

 	data->irq = platform_get_irq(pdev, 0);
 	if (data->irq < 0)
 		return data->irq;

 	ret = devm_request_threaded_irq(&pdev->dev, data->irq,
 			imx_thermal_alarm_irq, imx_thermal_alarm_irq_thread,
 			0, "imx_thermal", data);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to request alarm irq: %d\n", ret);
 		return ret;
 	}

 	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->thermal_clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(data->thermal_clk)) {
 		dev_warn(&pdev->dev, "failed to get thermal clk!\n");
 	} else {
 		/*
 		 * Thermal sensor needs clk on to get correct value, normally
 		 * we should enable its clk before taking measurement and disable
 		 * clk after measurement is done, but if alarm function is enabled,
 		 * hardware will auto measure the temperature periodically, so we
 		 * need to keep the clk always on for alarm function.
 		 */
 		ret = clk_prepare_enable(data->thermal_clk);
 		if (ret)
 			dev_warn(&pdev->dev, "failed to enable thermal clk: %d\n", ret);
 	}

 	/* Enable measurements at ~ 10 Hz */
 	regmap_write(map, TEMPSENSE1 + REG_CLR, TEMPSENSE1_MEASURE_FREQ);
 	measure_freq = DIV_ROUND_UP(32768, 10); /* 10 Hz */
 	regmap_write(map, TEMPSENSE1 + REG_SET, measure_freq);
 	imx_set_alarm_temp(data, data->temp_passive);
 	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
 	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);

 	data->irq_enabled = true;
 	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);
 	struct regmap *map = data->tempmon;

 	/* Disable measurements */
 	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
 	if (!IS_ERR(data->thermal_clk))
 		clk_disable_unprepare(data->thermal_clk);

 	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;

 	/*
 	 * Need to disable thermal sensor, otherwise, when thermal core
 	 * try to get temperature before thermal sensor resume, a wrong
 	 * temperature will be read as the thermal sensor is powered
 	 * down.
 	 */
 	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
 	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
 	data->mode = THERMAL_DEVICE_DISABLED;

 	return 0;
 }

 static int imx_thermal_resume(struct device *dev)
 {
 	struct imx_thermal_data *data = dev_get_drvdata(dev);
 	struct regmap *map = data->tempmon;

 	/* Enabled thermal sensor after resume */
 	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
 	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);
 	data->mode = THERMAL_DEVICE_ENABLED;

 	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 */ }
 };
 MODULE_DEVICE_TABLE(of, of_imx_thermal_match);

 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");
	/*
	* 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/clk.h>
	#include <linux/cpu_cooling.h>
	#include <linux/cpufreq.h>
	#include <linux/delay.h>
	#include <linux/device.h>
	#include <linux/init.h>
	#include <linux/interrupt.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_ALARM_VALUE_SHIFT 20
	#define TEMPSENSE0_ALARM_VALUE_MASK (0xfff << TEMPSENSE0_ALARM_VALUE_SHIFT)
	#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

	#define FACTOR0 10000000
	#define FACTOR1 15976
	#define FACTOR2 4297157

	struct imx_thermal_data {
	struct thermal_zone_device *tz;
	struct thermal_cooling_device *cdev;
	enum thermal_device_mode mode;
	struct regmap *tempmon;
	u32 c1, c2; /* See formula in imx_get_sensor_data() */
	unsigned long temp_passive;
	unsigned long temp_critical;
	unsigned long alarm_temp;
	unsigned long last_temp;
	bool irq_enabled;
	int irq;
	struct clk *thermal_clk;
	};

	static void imx_set_alarm_temp(struct imx_thermal_data *data,
	signed long alarm_temp)
	{
	struct regmap *map = data->tempmon;
	int alarm_value;

	data->alarm_temp = alarm_temp;
	alarm_value = (data->c2 - alarm_temp) / data->c1;
	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_ALARM_VALUE_MASK);
	regmap_write(map, TEMPSENSE0 + REG_SET, alarm_value <<
	TEMPSENSE0_ALARM_VALUE_SHIFT);
	}

	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;
	unsigned int n_meas;
	bool wait;
	u32 val;

	if (data->mode == THERMAL_DEVICE_ENABLED) {
	/* Check if a measurement is currently in progress */
	regmap_read(map, TEMPSENSE0, &val);
	wait = !(val & TEMPSENSE0_FINISHED);
	} else {
	/*
	* 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);

	wait = true;
	}

	/*
	* According to the temp sensor designers, it may require up to ~17us
	* to complete a measurement.
	*/
	if (wait)
	usleep_range(20, 50);

	regmap_read(map, TEMPSENSE0, &val);

	if (data->mode != THERMAL_DEVICE_ENABLED) {
	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 - n_meas data->c1;

	/* Update alarm value to next higher trip point */
	if (data->alarm_temp == data->temp_passive && *temp >= data->temp_passive)
	imx_set_alarm_temp(data, data->temp_critical);
	if (data->alarm_temp == data->temp_critical && *temp < data->temp_passive) {
	imx_set_alarm_temp(data, data->temp_passive);
	dev_dbg(&tz->device, "thermal alarm off: T < %lu\n",
	data->alarm_temp / 1000);
	}

	if (*temp != data->last_temp) {
	dev_dbg(&tz->device, "millicelsius: %ld\n", *temp);
	data->last_temp = *temp;
	}

	/* Reenable alarm IRQ if temperature below alarm temperature */
	if (!data->irq_enabled && *temp < data->alarm_temp) {
	data->irq_enabled = true;
	enable_irq(data->irq);
	}

	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;
	struct regmap *map = data->tempmon;

	if (mode == THERMAL_DEVICE_ENABLED) {
	tz->polling_delay = IMX_POLLING_DELAY;
	tz->passive_delay = IMX_PASSIVE_DELAY;

	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);

	if (!data->irq_enabled) {
	data->irq_enabled = true;
	enable_irq(data->irq);
	}
	} else {
	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);

	tz->polling_delay = 0;
	tz->passive_delay = 0;

	if (data->irq_enabled) {
	disable_irq(data->irq);
	data->irq_enabled = false;
	}
	}

	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;

	imx_set_alarm_temp(data, 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 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;
	u64 temp64;

	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
	* Use universal formula now and only need sensor value @ 25C
	* slope = 0.4297157 - (0.0015976 * 25C fuse)
	*/
	n1 = val >> 20;
	n2 = (val & 0xfff00) >> 8;
	t2 = val & 0xff;
	t1 = 25; /* t1 always 25C */

	/*
	* Derived from linear interpolation:
	* slope = 0.4297157 - (0.0015976 * 25C fuse)
	* slope = (FACTOR2 - FACTOR1 * n1) / FACTOR0
	* (Nmeas - n1) / (Tmeas - t1) = slope
	* 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...
	* Tmeas = (Nmeas - n1) / slope + t1
	* milli_Tmeas = 1000 * (Nmeas - n1) / slope + 1000 * t1
	* milli_Tmeas = -1000 * (n1 - Nmeas) / slope + 1000 * t1
	* Let constant c1 = (-1000 / slope)
	* milli_Tmeas = (n1 - Nmeas) * c1 + 1000 * t1
	* Let constant c2 = n1 c1 + 1000 t1
	* milli_Tmeas = c2 - Nmeas * c1
	*/
	temp64 = FACTOR0;
	temp64 *= 1000;
	do_div(temp64, FACTOR1 * n1 - FACTOR2);
	data->c1 = temp64;
	data->c2 = n1 * data->c1 + 1000 * t1;

	/*
	* 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 irqreturn_t imx_thermal_alarm_irq(int irq, void *dev)
	{
	struct imx_thermal_data *data = dev;

	disable_irq_nosync(irq);
	data->irq_enabled = false;

	return IRQ_WAKE_THREAD;
	}

	static irqreturn_t imx_thermal_alarm_irq_thread(int irq, void *dev)
	{
	struct imx_thermal_data *data = dev;

	dev_dbg(&data->tz->device, "THERMAL ALARM: T > %lu\n",
	data->alarm_temp / 1000);

	thermal_zone_device_update(data->tz);

	return IRQ_HANDLED;
	}

	static int imx_thermal_probe(struct platform_device *pdev)
	{
	struct imx_thermal_data *data;
	struct cpumask clip_cpus;
	struct regmap *map;
	int measure_freq;
	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;

	data->irq = platform_get_irq(pdev, 0);
	if (data->irq < 0)
	return data->irq;

	ret = devm_request_threaded_irq(&pdev->dev, data->irq,
	imx_thermal_alarm_irq, imx_thermal_alarm_irq_thread,
	0, "imx_thermal", data);
	if (ret < 0) {
	dev_err(&pdev->dev, "failed to request alarm irq: %d\n", ret);
	return ret;
	}

	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->thermal_clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(data->thermal_clk)) {
	dev_warn(&pdev->dev, "failed to get thermal clk!\n");
	} else {
	/*
	* Thermal sensor needs clk on to get correct value, normally
	* we should enable its clk before taking measurement and disable
	* clk after measurement is done, but if alarm function is enabled,
	* hardware will auto measure the temperature periodically, so we
	* need to keep the clk always on for alarm function.
	*/
	ret = clk_prepare_enable(data->thermal_clk);
	if (ret)
	dev_warn(&pdev->dev, "failed to enable thermal clk: %d\n", ret);
	}

	/* Enable measurements at ~ 10 Hz */
	regmap_write(map, TEMPSENSE1 + REG_CLR, TEMPSENSE1_MEASURE_FREQ);
	measure_freq = DIV_ROUND_UP(32768, 10); /* 10 Hz */
	regmap_write(map, TEMPSENSE1 + REG_SET, measure_freq);
	imx_set_alarm_temp(data, data->temp_passive);
	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);

	data->irq_enabled = true;
	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);
	struct regmap *map = data->tempmon;

	/* Disable measurements */
	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
	if (!IS_ERR(data->thermal_clk))
	clk_disable_unprepare(data->thermal_clk);

	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;

	/*
	* Need to disable thermal sensor, otherwise, when thermal core
	* try to get temperature before thermal sensor resume, a wrong
	* temperature will be read as the thermal sensor is powered
	* down.
	*/
	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
	data->mode = THERMAL_DEVICE_DISABLED;

	return 0;
	}

	static int imx_thermal_resume(struct device *dev)
	{
	struct imx_thermal_data *data = dev_get_drvdata(dev);
	struct regmap *map = data->tempmon;

	/* Enabled thermal sensor after resume */
	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);
	data->mode = THERMAL_DEVICE_ENABLED;

	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 */ }
	};
	MODULE_DEVICE_TABLE(of, of_imx_thermal_match);

	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");