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From:   Dmitry Osipenko <digetx@gmail.com>
To:     Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Zhang Rui <rui.zhang@intel.com>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Amit Kucheria <amitk@kernel.org>,
        Andreas Westman Dorcsak <hedmoo@yahoo.com>,
        Maxim Schwalm <maxim.schwalm@gmail.com>,
        Svyatoslav Ryhel <clamor95@gmail.com>,
        Ihor Didenko <tailormoon@rambler.ru>,
        Ion Agorria <ion@agorria.com>,
        Matt Merhar <mattmerhar@protonmail.com>,
        Peter Geis <pgwipeout@gmail.com>
Cc:     devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-tegra@vger.kernel.org, linux-pm@vger.kernel.org
Subject: [PATCH v3 4/7] thermal/drivers/tegra: Add driver for Tegra30 thermal sensor
Date:   Sat, 29 May 2021 20:09:52 +0300
Message-Id: <20210529170955.32574-5-digetx@gmail.com>
In-Reply-To: <20210529170955.32574-1-digetx@gmail.com>
References: <20210529170955.32574-1-digetx@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

All NVIDIA Tegra30 SoCs have a two-channel on-chip sensor unit which
monitors temperature and voltage of the SoC. Sensors control CPU frequency
throttling, which is activated by hardware once preprogrammed temperature
level is breached, they also send signal to Power Management controller to
perform emergency shutdown on a critical overheat of the SoC die. Add
driver for the Tegra30 TSENSOR module, exposing it as a thermal sensor
and a cooling device.

Tested-by: Andreas Westman Dorcsak <hedmoo@yahoo.com> # Asus TF700T
Tested-by: Maxim Schwalm <maxim.schwalm@gmail.com> # Asus TF700T
Tested-by: Svyatoslav Ryhel <clamor95@gmail.com> # Asus TF201T
Tested-by: Ihor Didenko <tailormoon@rambler.ru> # Asus TF300T
Tested-by: Ion Agorria <ion@agorria.com> # Asus TF201T
Tested-by: Matt Merhar <mattmerhar@protonmail.com> # Ouya
Tested-by: Peter Geis <pgwipeout@gmail.com> # Ouya
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/thermal/tegra/Kconfig           |   7 +
 drivers/thermal/tegra/Makefile          |   1 +
 drivers/thermal/tegra/tegra30-tsensor.c | 736 ++++++++++++++++++++++++
 3 files changed, 744 insertions(+)
 create mode 100644 drivers/thermal/tegra/tegra30-tsensor.c

diff --git a/drivers/thermal/tegra/Kconfig b/drivers/thermal/tegra/Kconfig
index 46c2215867cd..019e3a2eb69e 100644
--- a/drivers/thermal/tegra/Kconfig
+++ b/drivers/thermal/tegra/Kconfig
@@ -18,4 +18,11 @@ config TEGRA_BPMP_THERMAL
 	  Enable this option for support for sensing system temperature of NVIDIA
 	  Tegra systems-on-chip with the BPMP coprocessor (Tegra186).
 
+config TEGRA30_TSENSOR
+	tristate "Tegra30 Thermal Sensor"
+	depends on ARCH_TEGRA_3x_SOC || COMPILE_TEST
+	help
+	  Enable this option to support thermal management of NVIDIA Tegra30
+	  system-on-chip.
+
 endmenu
diff --git a/drivers/thermal/tegra/Makefile b/drivers/thermal/tegra/Makefile
index 0f2b66edf0d2..eb27d194c583 100644
--- a/drivers/thermal/tegra/Makefile
+++ b/drivers/thermal/tegra/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_TEGRA_SOCTHERM)		+= tegra-soctherm.o
 obj-$(CONFIG_TEGRA_BPMP_THERMAL)	+= tegra-bpmp-thermal.o
+obj-$(CONFIG_TEGRA30_TSENSOR)		+= tegra30-tsensor.o
 
 tegra-soctherm-y				:= soctherm.o soctherm-fuse.o
 tegra-soctherm-$(CONFIG_ARCH_TEGRA_124_SOC)	+= tegra124-soctherm.o
diff --git a/drivers/thermal/tegra/tegra30-tsensor.c b/drivers/thermal/tegra/tegra30-tsensor.c
new file mode 100644
index 000000000000..f7562eac01d6
--- /dev/null
+++ b/drivers/thermal/tegra/tegra30-tsensor.c
@@ -0,0 +1,736 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Tegra30 SoC Thermal Sensor driver
+ *
+ * Based on downstream HWMON driver from NVIDIA.
+ * Copyright (C) 2011 NVIDIA Corporation
+ *
+ * Author: Dmitry Osipenko <digetx@gmail.com>
+ * Copyright (C) 2021 GRATE-DRIVER project
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/math.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+#include <linux/types.h>
+
+#include <soc/tegra/fuse.h>
+
+#include "../thermal_core.h"
+#include "../thermal_hwmon.h"
+
+#define TSENSOR_SENSOR0_CONFIG0				0x0
+#define TSENSOR_SENSOR0_CONFIG0_SENSOR_STOP		BIT(0)
+#define TSENSOR_SENSOR0_CONFIG0_HW_FREQ_DIV_EN		BIT(1)
+#define TSENSOR_SENSOR0_CONFIG0_THERMAL_RST_EN		BIT(2)
+#define TSENSOR_SENSOR0_CONFIG0_DVFS_EN			BIT(3)
+#define TSENSOR_SENSOR0_CONFIG0_INTR_OVERFLOW_EN	BIT(4)
+#define TSENSOR_SENSOR0_CONFIG0_INTR_HW_FREQ_DIV_EN	BIT(5)
+#define TSENSOR_SENSOR0_CONFIG0_INTR_THERMAL_RST_EN	BIT(6)
+#define TSENSOR_SENSOR0_CONFIG0_M			GENMASK(23,  8)
+#define TSENSOR_SENSOR0_CONFIG0_N			GENMASK(31, 24)
+
+#define TSENSOR_SENSOR0_CONFIG1				0x8
+#define TSENSOR_SENSOR0_CONFIG1_TH1			GENMASK(15,  0)
+#define TSENSOR_SENSOR0_CONFIG1_TH2			GENMASK(31, 16)
+
+#define TSENSOR_SENSOR0_CONFIG2				0xc
+#define TSENSOR_SENSOR0_CONFIG2_TH3			GENMASK(15,  0)
+
+#define TSENSOR_SENSOR0_STATUS0				0x18
+#define TSENSOR_SENSOR0_STATUS0_STATE			GENMASK(2, 0)
+#define TSENSOR_SENSOR0_STATUS0_INTR			BIT(8)
+#define TSENSOR_SENSOR0_STATUS0_CURRENT_VALID		BIT(9)
+
+#define TSENSOR_SENSOR0_TS_STATUS1			0x1c
+#define TSENSOR_SENSOR0_TS_STATUS1_CURRENT_COUNT	GENMASK(31, 16)
+
+#define TEGRA30_FUSE_TEST_PROG_VER			0x28
+
+#define TEGRA30_FUSE_TSENSOR_CALIB			0x98
+#define TEGRA30_FUSE_TSENSOR_CALIB_LOW			GENMASK(15,  0)
+#define TEGRA30_FUSE_TSENSOR_CALIB_HIGH			GENMASK(31, 16)
+
+#define TEGRA30_FUSE_SPARE_BIT				0x144
+
+struct tegra_tsensor;
+
+struct tegra_tsensor_calibration_data {
+	int a, b, m, n, p, r;
+};
+
+struct tegra_tsensor_channel {
+	void __iomem *regs;
+	unsigned int id;
+	struct tegra_tsensor *ts;
+	struct thermal_zone_device *tzd;
+};
+
+struct tegra_tsensor {
+	void __iomem *regs;
+	bool swap_channels;
+	struct clk *clk;
+	struct device *dev;
+	struct reset_control *rst;
+	struct tegra_tsensor_channel ch[2];
+	struct thermal_cooling_device *cdev;
+	struct tegra_tsensor_calibration_data calib;
+};
+
+static int tegra_tsensor_hw_enable(const struct tegra_tsensor *ts)
+{
+	u32 val;
+	int err;
+
+	err = reset_control_assert(ts->rst);
+	if (err) {
+		dev_err(ts->dev, "failed to assert hardware reset: %d\n", err);
+		return err;
+	}
+
+	err = clk_prepare_enable(ts->clk);
+	if (err) {
+		dev_err(ts->dev, "failed to enable clock: %d\n", err);
+		return err;
+	}
+
+	fsleep(1000);
+
+	err = reset_control_deassert(ts->rst);
+	if (err) {
+		dev_err(ts->dev, "failed to deassert hardware reset: %d\n", err);
+		goto disable_clk;
+	}
+
+	/*
+	 * Sensors are enabled after reset by default, but not gauging
+	 * until clock counter is programmed.
+	 *
+	 * M: number of reference clock pulses after which every
+	 *    temperature / voltage measurement is made
+	 *
+	 * N: number of reference clock counts for which the counter runs
+	 */
+	val  = FIELD_PREP(TSENSOR_SENSOR0_CONFIG0_M, 12500);
+	val |= FIELD_PREP(TSENSOR_SENSOR0_CONFIG0_N, 255);
+
+	/* apply the same configuration to both channels */
+	writel_relaxed(val, ts->regs + 0x40 + TSENSOR_SENSOR0_CONFIG0);
+	writel_relaxed(val, ts->regs + 0x80 + TSENSOR_SENSOR0_CONFIG0);
+
+	return 0;
+
+disable_clk:
+	clk_disable_unprepare(ts->clk);
+
+	return err;
+}
+
+static int tegra_tsensor_hw_disable(const struct tegra_tsensor *ts)
+{
+	int err;
+
+	err = reset_control_assert(ts->rst);
+	if (err) {
+		dev_err(ts->dev, "failed to assert hardware reset: %d\n", err);
+		return err;
+	}
+
+	clk_disable_unprepare(ts->clk);
+
+	return 0;
+}
+
+static void devm_tegra_tsensor_hw_disable(void *data)
+{
+	const struct tegra_tsensor *ts = data;
+
+	tegra_tsensor_hw_disable(ts);
+}
+
+static int tegra_tsensor_get_temp(void *data, int *temp)
+{
+	const struct tegra_tsensor_channel *tsc = data;
+	const struct tegra_tsensor *ts = tsc->ts;
+	int err, c1, c2, c3, c4, counter;
+	u32 val;
+
+	/*
+	 * Counter will be invalid if hardware is misprogrammed or not enough
+	 * time passed since the time when sensor was enabled.
+	 */
+	err = readl_relaxed_poll_timeout(tsc->regs + TSENSOR_SENSOR0_STATUS0, val,
+					 val & TSENSOR_SENSOR0_STATUS0_CURRENT_VALID,
+					 21 * USEC_PER_MSEC,
+					 21 * USEC_PER_MSEC * 50);
+	if (err) {
+		dev_err_once(ts->dev, "ch%u: counter invalid\n", tsc->id);
+		return err;
+	}
+
+	val = readl_relaxed(tsc->regs + TSENSOR_SENSOR0_TS_STATUS1);
+	counter = FIELD_GET(TSENSOR_SENSOR0_TS_STATUS1_CURRENT_COUNT, val);
+
+	/*
+	 * This shouldn't happen with a valid counter status, nevertheless
+	 * lets verify the value since it's in a separate (from status)
+	 * register.
+	 */
+	if (counter == 0xffff) {
+		dev_err_once(ts->dev, "ch%u: counter overflow\n", tsc->id);
+		return -EINVAL;
+	}
+
+	/*
+	 * temperature = a * counter + b
+	 * temperature = m * (temperature ^ 2) + n * temperature + p
+	 */
+	c1 = DIV_ROUND_CLOSEST(ts->calib.a * counter + ts->calib.b, 1000000);
+	c1 = c1 ?: 1;
+	c2 = DIV_ROUND_CLOSEST(ts->calib.p, c1);
+	c3 = c1 * ts->calib.m;
+	c4 = ts->calib.n;
+
+	*temp = DIV_ROUND_CLOSEST(c1 * (c2 + c3 + c4), 1000);
+
+	return 0;
+}
+
+static int tegra_tsensor_temp_to_counter(const struct tegra_tsensor *ts, int temp)
+{
+	int c1, c2;
+
+	c1 = DIV_ROUND_CLOSEST(ts->calib.p - temp * 1000, ts->calib.m);
+	c2 = -ts->calib.r - int_sqrt(ts->calib.r * ts->calib.r - c1);
+
+	return DIV_ROUND_CLOSEST(c2 * 1000000 - ts->calib.b, ts->calib.a);
+}
+
+static int tegra_tsensor_set_trips(void *data, int low, int high)
+{
+	const struct tegra_tsensor_channel *tsc = data;
+	const struct tegra_tsensor *ts = tsc->ts;
+	u32 val;
+
+	/*
+	 * TSENSOR doesn't trigger interrupt on the "low" temperature breach,
+	 * hence bail out if high temperature is unspecified.
+	 */
+	if (high == INT_MAX)
+		return 0;
+
+	val = readl_relaxed(tsc->regs + TSENSOR_SENSOR0_CONFIG1);
+	val &= ~TSENSOR_SENSOR0_CONFIG1_TH1;
+
+	high = tegra_tsensor_temp_to_counter(ts, high);
+	val |= FIELD_PREP(TSENSOR_SENSOR0_CONFIG1_TH1, high);
+	writel_relaxed(val, tsc->regs + TSENSOR_SENSOR0_CONFIG1);
+
+	return 0;
+}
+
+static const struct thermal_zone_of_device_ops ops = {
+	.get_temp = tegra_tsensor_get_temp,
+	.set_trips = tegra_tsensor_set_trips,
+};
+
+static int tegra_tsensor_get_max_state(struct thermal_cooling_device *cdev,
+				       unsigned long *state)
+{
+	*state = 1;
+
+	return 0;
+}
+
+static bool tegra_tsensor_channel_div2_active(const struct tegra_tsensor *ts,
+					      unsigned int id)
+{
+	u32 val;
+
+	val = readl_relaxed(ts->ch[id].regs + TSENSOR_SENSOR0_CONFIG0);
+	if (!FIELD_GET(TSENSOR_SENSOR0_CONFIG0_HW_FREQ_DIV_EN, val))
+		return false;
+
+	val = readl_relaxed(ts->ch[id].regs + TSENSOR_SENSOR0_STATUS0);
+
+	/* CPU frequency is halved when LEVEL2 is breached */
+	return FIELD_GET(TSENSOR_SENSOR0_STATUS0_STATE, val) > 2;
+}
+
+static int tegra_tsensor_get_cur_state(struct thermal_cooling_device *cdev,
+				       unsigned long *state)
+{
+	const struct tegra_tsensor *ts = cdev->devdata;
+	unsigned int i, div2_state = 0;
+
+	for (i = 0; i < ARRAY_SIZE(ts->ch); i++)
+		div2_state |= tegra_tsensor_channel_div2_active(ts, i);
+
+	*state = div2_state;
+
+	return 0;
+}
+
+static int tegra_tsensor_set_cur_state(struct thermal_cooling_device *cdev,
+				       unsigned long state)
+{
+	/* state is controlled by hardware and can't be changed by software */
+	return -EOPNOTSUPP;
+}
+
+static const struct thermal_cooling_device_ops tegra_tsensor_cpu_cooling_ops = {
+	.get_max_state = tegra_tsensor_get_max_state,
+	.get_cur_state = tegra_tsensor_get_cur_state,
+	.set_cur_state = tegra_tsensor_set_cur_state,
+};
+
+static bool
+tegra_tsensor_handle_channel_interrupt(const struct tegra_tsensor *ts,
+				       unsigned int id)
+{
+	const struct tegra_tsensor_channel *tsc = &ts->ch[id];
+	u32 val;
+
+	val = readl_relaxed(tsc->regs + TSENSOR_SENSOR0_STATUS0);
+	writel_relaxed(val, tsc->regs + TSENSOR_SENSOR0_STATUS0);
+
+	if (FIELD_GET(TSENSOR_SENSOR0_STATUS0_STATE, val) == 5)
+		dev_err_ratelimited(ts->dev, "ch%u: counter overflowed\n", id);
+
+	if (!FIELD_GET(TSENSOR_SENSOR0_STATUS0_INTR, val))
+		return false;
+
+	thermal_zone_device_update(tsc->tzd, THERMAL_EVENT_UNSPECIFIED);
+
+	return true;
+}
+
+static irqreturn_t tegra_tsensor_isr(int irq, void *data)
+{
+	const struct tegra_tsensor *ts = data;
+	bool div2_state = false;
+	bool handled = false;
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(ts->ch); i++) {
+		div2_state |= tegra_tsensor_channel_div2_active(ts, i);
+		handled    |= tegra_tsensor_handle_channel_interrupt(ts, i);
+	}
+
+	thermal_cooling_device_stats_update(ts->cdev, div2_state);
+
+	return handled ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static int tegra_tsensor_disable_hw_channel(const struct tegra_tsensor *ts,
+					    unsigned int id)
+{
+	const struct tegra_tsensor_channel *tsc = &ts->ch[id];
+	struct thermal_zone_device *tzd = tsc->tzd;
+	u32 val;
+	int err;
+
+	if (!tzd)
+		goto stop_channel;
+
+	err = thermal_zone_device_disable(tzd);
+	if (err) {
+		dev_err(ts->dev, "ch%u: failed to disable zone: %d\n", id, err);
+		return err;
+	}
+
+stop_channel:
+	/* stop channel gracefully */
+	val = readl_relaxed(tsc->regs + TSENSOR_SENSOR0_CONFIG0);
+	val |= FIELD_PREP(TSENSOR_SENSOR0_CONFIG0_SENSOR_STOP, 1);
+	writel_relaxed(val, tsc->regs + TSENSOR_SENSOR0_CONFIG0);
+
+	return 0;
+}
+
+static void tegra_tsensor_get_hw_channel_trips(struct thermal_zone_device *tzd,
+					       int *hot_trip, int *crit_trip)
+{
+	unsigned int i;
+
+	/*
+	 * 90C is the maximal critical temperature of all Tegra30 SoC variants,
+	 * use it for the default trip if unspecified in a device-tree.
+	 */
+	*hot_trip  = 85000;
+	*crit_trip = 90000;
+
+	for (i = 0; i < tzd->trips; i++) {
+		enum thermal_trip_type type;
+		int trip_temp;
+
+		tzd->ops->get_trip_temp(tzd, i, &trip_temp);
+		tzd->ops->get_trip_type(tzd, i, &type);
+
+		if (type == THERMAL_TRIP_HOT)
+			*hot_trip = trip_temp;
+
+		if (type == THERMAL_TRIP_CRITICAL)
+			*crit_trip = trip_temp;
+	}
+
+	/* clamp hardware trips to the calibration limits */
+	*hot_trip = clamp(*hot_trip, 25000, 90000);
+
+	/*
+	 * Kernel will perform a normal system shut down if it will
+	 * see that critical temperature is breached, hence set the
+	 * hardware limit by 5C higher in order to allow system to
+	 * shut down gracefully before sending signal to the Power
+	 * Management controller.
+	 */
+	*crit_trip = clamp(*crit_trip + 5000, 25000, 90000);
+}
+
+static int tegra_tsensor_enable_hw_channel(const struct tegra_tsensor *ts,
+					   unsigned int id)
+{
+	const struct tegra_tsensor_channel *tsc = &ts->ch[id];
+	struct thermal_zone_device *tzd = tsc->tzd;
+	int err, hot_trip = 0, crit_trip = 0;
+	u32 val;
+
+	if (!tzd) {
+		val = readl_relaxed(tsc->regs + TSENSOR_SENSOR0_CONFIG0);
+		val &= ~TSENSOR_SENSOR0_CONFIG0_SENSOR_STOP;
+		writel_relaxed(val, tsc->regs + TSENSOR_SENSOR0_CONFIG0);
+
+		return 0;
+	}
+
+	tegra_tsensor_get_hw_channel_trips(tzd, &hot_trip, &crit_trip);
+
+	/* prevent potential racing with tegra_tsensor_set_trips() */
+	mutex_lock(&tzd->lock);
+
+	dev_info_once(ts->dev, "ch%u: CPU freq div2 throttle trip set to %dC\n",
+		      id, DIV_ROUND_CLOSEST(hot_trip, 1000));
+
+	dev_info_once(ts->dev, "ch%u: PMC emergency shutdown trip set to %dC\n",
+		      id, DIV_ROUND_CLOSEST(crit_trip, 1000));
+
+	hot_trip  = tegra_tsensor_temp_to_counter(ts, hot_trip);
+	crit_trip = tegra_tsensor_temp_to_counter(ts, crit_trip);
+
+	/* program LEVEL2 counter threshold */
+	val = readl_relaxed(tsc->regs + TSENSOR_SENSOR0_CONFIG1);
+	val &= ~TSENSOR_SENSOR0_CONFIG1_TH2;
+	val |= FIELD_PREP(TSENSOR_SENSOR0_CONFIG1_TH2, hot_trip);
+	writel_relaxed(val, tsc->regs + TSENSOR_SENSOR0_CONFIG1);
+
+	/* program LEVEL3 counter threshold */
+	val = readl_relaxed(tsc->regs + TSENSOR_SENSOR0_CONFIG2);
+	val &= ~TSENSOR_SENSOR0_CONFIG2_TH3;
+	val |= FIELD_PREP(TSENSOR_SENSOR0_CONFIG2_TH3, crit_trip);
+	writel_relaxed(val, tsc->regs + TSENSOR_SENSOR0_CONFIG2);
+
+	/*
+	 * Enable sensor, DIV2 throttle, emergency shutdown, interrupts
+	 * for level 1/2/3 breaches and counter overflow condition.
+	 *
+	 * Thermal levels supported by hardware:
+	 *
+	 *     Level 0 = cold
+	 *     Level 1 = passive cooling (cpufreq DVFS)
+	 *     Level 2 = passive cooling assisted by hardware (DIV2)
+	 *     Level 3 = emergency shutdown assisted by hardware (PMC)
+	 */
+	val = readl_relaxed(tsc->regs + TSENSOR_SENSOR0_CONFIG0);
+	val &= ~TSENSOR_SENSOR0_CONFIG0_SENSOR_STOP;
+	val |= FIELD_PREP(TSENSOR_SENSOR0_CONFIG0_DVFS_EN, 1);
+	val |= FIELD_PREP(TSENSOR_SENSOR0_CONFIG0_HW_FREQ_DIV_EN, 1);
+	val |= FIELD_PREP(TSENSOR_SENSOR0_CONFIG0_THERMAL_RST_EN, 1);
+	val |= FIELD_PREP(TSENSOR_SENSOR0_CONFIG0_INTR_OVERFLOW_EN, 1);
+	val |= FIELD_PREP(TSENSOR_SENSOR0_CONFIG0_INTR_HW_FREQ_DIV_EN, 1);
+	val |= FIELD_PREP(TSENSOR_SENSOR0_CONFIG0_INTR_THERMAL_RST_EN, 1);
+	writel_relaxed(val, tsc->regs + TSENSOR_SENSOR0_CONFIG0);
+
+	mutex_unlock(&tzd->lock);
+
+	err = thermal_zone_device_enable(tzd);
+	if (err) {
+		dev_err(ts->dev, "ch%u: failed to enable zone: %d\n", id, err);
+		return err;
+	}
+
+	return 0;
+}
+
+static bool tegra_tsensor_fuse_read_spare(unsigned int spare)
+{
+	u32 val = 0;
+
+	tegra_fuse_readl(TEGRA30_FUSE_SPARE_BIT + spare * 4, &val);
+
+	return !!val;
+}
+
+static int tegra_tsensor_nvmem_setup(struct tegra_tsensor *ts)
+{
+	u32 i, ate_ver = 0, cal = 0, t1_25C = 0, t2_90C = 0;
+	int err, c1_25C, c2_90C;
+
+	err = tegra_fuse_readl(TEGRA30_FUSE_TEST_PROG_VER, &ate_ver);
+	if (err) {
+		dev_err_probe(ts->dev, err, "failed to get ATE version\n");
+		return err;
+	}
+
+	if (ate_ver < 8) {
+		dev_info(ts->dev, "unsupported ATE version: %u\n", ate_ver);
+		return -ENODEV;
+	}
+
+	/*
+	 * We have two TSENSOR channels in a two different spots on SoC.
+	 * Second channel provides more accurate data on older SoC versions,
+	 * use it as a primary channel.
+	 */
+	if (ate_ver <= 21) {
+		dev_info_once(ts->dev,
+			      "older ATE version detected, channels remapped\n");
+		ts->swap_channels = true;
+	}
+
+	err = tegra_fuse_readl(TEGRA30_FUSE_TSENSOR_CALIB, &cal);
+	if (err) {
+		dev_err(ts->dev, "failed to get calibration data: %d\n", err);
+		return err;
+	}
+
+	/* get calibrated counter values for 25C/90C thresholds */
+	c1_25C = FIELD_GET(TEGRA30_FUSE_TSENSOR_CALIB_LOW, cal);
+	c2_90C = FIELD_GET(TEGRA30_FUSE_TSENSOR_CALIB_HIGH, cal);
+
+	/* and calibrated temperatures corresponding to the counter values */
+	for (i = 0; i < 7; i++) {
+		t1_25C |= tegra_tsensor_fuse_read_spare(14 + i) << i;
+		t1_25C |= tegra_tsensor_fuse_read_spare(21 + i) << i;
+
+		t2_90C |= tegra_tsensor_fuse_read_spare(0 + i) << i;
+		t2_90C |= tegra_tsensor_fuse_read_spare(7 + i) << i;
+	}
+
+	if (c2_90C - c1_25C <= t2_90C - t1_25C) {
+		dev_err(ts->dev, "invalid calibration data: %d %d %u %u\n",
+			c2_90C, c1_25C, t2_90C, t1_25C);
+		return -EINVAL;
+	}
+
+	/* all calibration coefficients are premultiplied by 1000000 */
+
+	ts->calib.a = DIV_ROUND_CLOSEST((t2_90C - t1_25C) * 1000000,
+					(c2_90C - c1_25C));
+
+	ts->calib.b = t1_25C * 1000000 - ts->calib.a * c1_25C;
+
+	if (tegra_sku_info.revision == TEGRA_REVISION_A01) {
+		ts->calib.m =     -2775;
+		ts->calib.n =   1338811;
+		ts->calib.p =  -7300000;
+	} else {
+		ts->calib.m =     -3512;
+		ts->calib.n =   1528943;
+		ts->calib.p = -11100000;
+	}
+
+	/* except the coefficient of a reduced quadratic equation */
+	ts->calib.r = DIV_ROUND_CLOSEST(ts->calib.n, ts->calib.m * 2);
+
+	dev_info_once(ts->dev,
+		      "calibration: %d %d %u %u ATE ver: %u SoC rev: %u\n",
+		      c2_90C, c1_25C, t2_90C, t1_25C, ate_ver,
+		      tegra_sku_info.revision);
+
+	return 0;
+}
+
+static int tegra_tsensor_register_channel(struct tegra_tsensor *ts,
+					  unsigned int id)
+{
+	struct tegra_tsensor_channel *tsc = &ts->ch[id];
+	unsigned int hw_id = ts->swap_channels ? !id : id;
+
+	tsc->ts = ts;
+	tsc->id = id;
+	tsc->regs = ts->regs + 0x40 * (hw_id + 1);
+
+	tsc->tzd = devm_thermal_zone_of_sensor_register(ts->dev, id, tsc, &ops);
+	if (IS_ERR(tsc->tzd)) {
+		if (PTR_ERR(tsc->tzd) != -ENODEV)
+			return dev_err_probe(ts->dev, PTR_ERR(tsc->tzd),
+					     "failed to register thermal zone\n");
+
+		/*
+		 * It's okay if sensor isn't assigned to any thermal zone
+		 * in a device-tree.
+		 */
+		tsc->tzd = NULL;
+		return 0;
+	}
+
+	if (devm_thermal_add_hwmon_sysfs(tsc->tzd))
+		dev_warn(ts->dev, "failed to add hwmon sysfs attributes\n");
+
+	return 0;
+}
+
+static int tegra_tsensor_probe(struct platform_device *pdev)
+{
+	struct tegra_tsensor *ts;
+	unsigned int i;
+	int err, irq;
+
+	ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
+	if (!ts)
+		return -ENOMEM;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	ts->dev = &pdev->dev;
+	platform_set_drvdata(pdev, ts);
+
+	ts->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(ts->regs))
+		return PTR_ERR(ts->regs);
+
+	ts->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(ts->clk))
+		return dev_err_probe(&pdev->dev, PTR_ERR(ts->clk),
+				     "failed to get clock\n");
+
+	ts->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+	if (IS_ERR(ts->rst))
+		return dev_err_probe(&pdev->dev, PTR_ERR(ts->rst),
+				     "failed to get reset control\n");
+
+	err = tegra_tsensor_nvmem_setup(ts);
+	if (err)
+		return err;
+
+	err = tegra_tsensor_hw_enable(ts);
+	if (err)
+		return err;
+
+	err = devm_add_action_or_reset(&pdev->dev,
+				       devm_tegra_tsensor_hw_disable,
+				       ts);
+	if (err)
+		return err;
+
+	for (i = 0; i < ARRAY_SIZE(ts->ch); i++) {
+		err = tegra_tsensor_register_channel(ts, i);
+		if (err)
+			return err;
+	}
+
+	ts->cdev = devm_thermal_of_cooling_device_register(&pdev->dev,
+				pdev->dev.of_node, "tegra-cpu-div2-throttle",
+				ts, &tegra_tsensor_cpu_cooling_ops);
+	if (IS_ERR(ts->cdev))
+		return dev_err_probe(&pdev->dev, PTR_ERR(ts->cdev),
+				     "failed to register cooling device\n");
+
+	err = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+					tegra_tsensor_isr, IRQF_ONESHOT,
+					"tegra_tsensor", ts);
+	if (err)
+		return dev_err_probe(&pdev->dev, err,
+				     "failed to request interrupt\n");
+
+	for (i = 0; i < ARRAY_SIZE(ts->ch); i++) {
+		err = tegra_tsensor_enable_hw_channel(ts, i);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int __maybe_unused tegra_tsensor_suspend(struct device *dev)
+{
+	struct tegra_tsensor *ts = dev_get_drvdata(dev);
+	unsigned int i;
+	int err;
+
+	for (i = 0; i < ARRAY_SIZE(ts->ch); i++) {
+		err = tegra_tsensor_disable_hw_channel(ts, i);
+		if (err)
+			goto enable_channel;
+	}
+
+	err = tegra_tsensor_hw_disable(ts);
+	if (err)
+		goto enable_channel;
+
+	return 0;
+
+enable_channel:
+	while (i--)
+		tegra_tsensor_enable_hw_channel(ts, i);
+
+	return err;
+}
+
+static int __maybe_unused tegra_tsensor_resume(struct device *dev)
+{
+	struct tegra_tsensor *ts = dev_get_drvdata(dev);
+	unsigned int i;
+	int err;
+
+	err = tegra_tsensor_hw_enable(ts);
+	if (err)
+		return err;
+
+	for (i = 0; i < ARRAY_SIZE(ts->ch); i++) {
+		err = tegra_tsensor_enable_hw_channel(ts, i);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static const struct dev_pm_ops tegra_tsensor_pm_ops = {
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(tegra_tsensor_suspend,
+				      tegra_tsensor_resume)
+};
+
+static const struct of_device_id tegra_tsensor_of_match[] = {
+	{ .compatible = "nvidia,tegra30-tsensor", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, tegra_tsensor_of_match);
+
+static struct platform_driver tegra_tsensor_driver = {
+	.probe = tegra_tsensor_probe,
+	.driver = {
+		.name = "tegra30-tsensor",
+		.of_match_table = tegra_tsensor_of_match,
+		.pm = &tegra_tsensor_pm_ops,
+	},
+};
+module_platform_driver(tegra_tsensor_driver);
+
+MODULE_DESCRIPTION("NVIDIA Tegra30 Thermal Sensor driver");
+MODULE_AUTHOR("Dmitry Osipenko <digetx@gmail.com>");
+MODULE_LICENSE("GPL");
-- 
2.30.2