thermal: qcom: tsens: Add a skeletal TSENS drivers

TSENS is Qualcomms' thermal temperature sensor device. It
supports reading temperatures from multiple thermal sensors
present on various QCOM SoCs.
Calibration data is generally read from a non-volatile memory
(eeprom) device.

Add a skeleton driver with all the necessary abstractions so
a variety of qcom device families which support TSENS can
add driver extensions.

Also add the required device tree bindings which can be used
to describe the TSENS device in DT.
Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Lina Iyer <lina.iyer@linaro.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

Documentation/devicetree/bindings/thermal/qcom-tsens.txt

+* QCOM SoC Temperature Sensor (TSENS)
+
+Required properties:
+- compatible :
+ - "qcom,msm8916-tsens" : For 8916 Family of SoCs
+ - "qcom,msm8974-tsens" : For 8974 Family of SoCs
+ - "qcom,msm8996-tsens" : For 8996 Family of SoCs
+
+- reg: Address range of the thermal registers
+- #thermal-sensor-cells : Should be 1. See ./thermal.txt for a description.
+- Refer to Documentation/devicetree/bindings/nvmem/nvmem.txt to know how to specify
+nvmem cells
+
+Example:
+tsens: thermal-sensor@900000 {
+		compatible = "qcom,msm8916-tsens";
+		reg = <0x4a8000 0x2000>;
+		nvmem-cells = <&tsens_caldata>, <&tsens_calsel>;
+		nvmem-cell-names = "caldata", "calsel";
+		#thermal-sensor-cells = <1>;
+	};

drivers/thermal/Kconfig

@@ -399,4 +399,9 @@ config GENERIC_ADC_THERMAL
 	  to this driver. This driver reports the temperature by reading ADC
 	  channel and converts it to temperature based on lookup table.
 
+menu "Qualcomm thermal drivers"
+depends on (ARCH_QCOM && OF) || COMPILE_TEST
+source "drivers/thermal/qcom/Kconfig"
+endmenu
+
 endif

drivers/thermal/Makefile

@@ -47,6 +47,7 @@ obj-$(CONFIG_TI_SOC_THERMAL)	+= ti-soc-thermal/
 obj-$(CONFIG_INT340X_THERMAL)  += int340x_thermal/
 obj-$(CONFIG_INTEL_PCH_THERMAL)	+= intel_pch_thermal.o
 obj-$(CONFIG_ST_THERMAL)	+= st/
+obj-$(CONFIG_QCOM_TSENS)	+= qcom/
 obj-$(CONFIG_TEGRA_SOCTHERM)	+= tegra/
 obj-$(CONFIG_HISI_THERMAL)     += hisi_thermal.o
 obj-$(CONFIG_MTK_THERMAL)	+= mtk_thermal.o

drivers/thermal/qcom/Kconfig

+config QCOM_TSENS
+	tristate "Qualcomm TSENS Temperature Alarm"
+	depends on THERMAL
+	depends on QCOM_QFPROM
+	depends on ARCH_QCOM || COMPILE_TEST
+	help
+	  This enables the thermal sysfs driver for the TSENS device. It shows
+	  up in Sysfs as a thermal zone with multiple trip points. Disabling the
+	  thermal zone device via the mode file results in disabling the sensor.
+	  Also able to set threshold temperature for both hot and cold and update
+	  when a threshold is reached.

drivers/thermal/qcom/Makefile

+obj-$(CONFIG_QCOM_TSENS)	+= qcom_tsens.o
+qcom_tsens-y			+= tsens.o tsens-common.o

drivers/thermal/qcom/tsens-common.c

+/*
+ * Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include "tsens.h"
+
+#define S0_ST_ADDR		0x1030
+#define SN_ADDR_OFFSET		0x4
+#define SN_ST_TEMP_MASK		0x3ff
+#define CAL_DEGC_PT1		30
+#define CAL_DEGC_PT2		120
+#define SLOPE_FACTOR		1000
+#define SLOPE_DEFAULT		3200
+
+char *qfprom_read(struct device *dev, const char *cname)
+{
+	struct nvmem_cell *cell;
+	ssize_t data;
+	char *ret;
+
+	cell = nvmem_cell_get(dev, cname);
+	if (IS_ERR(cell))
+		return ERR_CAST(cell);
+
+	ret = nvmem_cell_read(cell, &data);
+	nvmem_cell_put(cell);
+
+	return ret;
+}
+
+/*
+ * Use this function on devices where slope and offset calculations
+ * depend on calibration data read from qfprom. On others the slope
+ * and offset values are derived from tz->tzp->slope and tz->tzp->offset
+ * resp.
+ */
+void compute_intercept_slope(struct tsens_device *tmdev, u32 *p1,
+			     u32 *p2, u32 mode)
+{
+	int i;
+	int num, den;
+
+	for (i = 0; i < tmdev->num_sensors; i++) {
+		dev_dbg(tmdev->dev,
+			"sensor%d - data_point1:%#x data_point2:%#x\n",
+			i, p1[i], p2[i]);
+
+		tmdev->sensor[i].slope = SLOPE_DEFAULT;
+		if (mode == TWO_PT_CALIB) {
+			/*
+			 * slope (m) = adc_code2 - adc_code1 (y2 - y1)/
+			 *	temp_120_degc - temp_30_degc (x2 - x1)
+			 */
+			num = p2[i] - p1[i];
+			num *= SLOPE_FACTOR;
+			den = CAL_DEGC_PT2 - CAL_DEGC_PT1;
+			tmdev->sensor[i].slope = num / den;
+		}
+
+		tmdev->sensor[i].offset = (p1[i] * SLOPE_FACTOR) -
+				(CAL_DEGC_PT1 *
+				tmdev->sensor[i].slope);
+		dev_dbg(tmdev->dev, "offset:%d\n", tmdev->sensor[i].offset);
+	}
+}
+
+static inline int code_to_degc(u32 adc_code, const struct tsens_sensor *s)
+{
+	int degc, num, den;
+
+	num = (adc_code * SLOPE_FACTOR) - s->offset;
+	den = s->slope;
+
+	if (num > 0)
+		degc = num + (den / 2);
+	else if (num < 0)
+		degc = num - (den / 2);
+	else
+		degc = num;
+
+	degc /= den;
+
+	return degc;
+}
+
+int get_temp_common(struct tsens_device *tmdev, int id, int *temp)
+{
+	struct tsens_sensor *s = &tmdev->sensor[id];
+	u32 code;
+	unsigned int sensor_addr;
+	int last_temp = 0, ret;
+
+	sensor_addr = S0_ST_ADDR + s->hw_id * SN_ADDR_OFFSET;
+	ret = regmap_read(tmdev->map, sensor_addr, &code);
+	if (ret)
+		return ret;
+	last_temp = code & SN_ST_TEMP_MASK;
+
+	*temp = code_to_degc(last_temp, s) * 1000;
+
+	return 0;
+}
+
+static const struct regmap_config tsens_config = {
+	.reg_bits	= 32,
+	.val_bits	= 32,
+	.reg_stride	= 4,
+};
+
+int __init init_common(struct tsens_device *tmdev)
+{
+	void __iomem *base;
+
+	base = of_iomap(tmdev->dev->of_node, 0);
+	if (IS_ERR(base))
+		return -EINVAL;
+
+	tmdev->map = devm_regmap_init_mmio(tmdev->dev, base, &tsens_config);
+	if (!tmdev->map) {
+		iounmap(base);
+		return -ENODEV;
+	}
+
+	return 0;
+}

drivers/thermal/qcom/tsens.c

+/*
+ * Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+#include "tsens.h"
+
+static int tsens_get_temp(void *data, int *temp)
+{
+	const struct tsens_sensor *s = data;
+	struct tsens_device *tmdev = s->tmdev;
+
+	return tmdev->ops->get_temp(tmdev, s->id, temp);
+}
+
+static int tsens_get_trend(void *data, long *temp)
+{
+	const struct tsens_sensor *s = data;
+	struct tsens_device *tmdev = s->tmdev;
+
+	if (tmdev->ops->get_trend)
+		return tmdev->ops->get_trend(tmdev, s->id, temp);
+
+	return -ENOTSUPP;
+}
+
+static int tsens_suspend(struct device *dev)
+{
+	struct tsens_device *tmdev = dev_get_drvdata(dev);
+
+	if (tmdev->ops && tmdev->ops->suspend)
+		return tmdev->ops->suspend(tmdev);
+
+	return 0;
+}
+
+static int tsens_resume(struct device *dev)
+{
+	struct tsens_device *tmdev = dev_get_drvdata(dev);
+
+	if (tmdev->ops && tmdev->ops->resume)
+		return tmdev->ops->resume(tmdev);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(tsens_pm_ops, tsens_suspend, tsens_resume);
+
+static const struct of_device_id tsens_table[] = {
+	{
+		.compatible = "qcom,msm8916-tsens",
+	}, {
+		.compatible = "qcom,msm8974-tsens",
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(of, tsens_table);
+
+static const struct thermal_zone_of_device_ops tsens_of_ops = {
+	.get_temp = tsens_get_temp,
+	.get_trend = tsens_get_trend,
+};
+
+static int tsens_register(struct tsens_device *tmdev)
+{
+	int i;
+	struct thermal_zone_device *tzd;
+	u32 *hw_id, n = tmdev->num_sensors;
+
+	hw_id = devm_kcalloc(tmdev->dev, n, sizeof(u32), GFP_KERNEL);
+	if (!hw_id)
+		return -ENOMEM;
+
+	for (i = 0;  i < tmdev->num_sensors; i++) {
+		tmdev->sensor[i].tmdev = tmdev;
+		tmdev->sensor[i].id = i;
+		tzd = devm_thermal_zone_of_sensor_register(tmdev->dev, i,
+							   &tmdev->sensor[i],
+							   &tsens_of_ops);
+		if (IS_ERR(tzd))
+			continue;
+		tmdev->sensor[i].tzd = tzd;
+		if (tmdev->ops->enable)
+			tmdev->ops->enable(tmdev, i);
+	}
+	return 0;
+}
+
+static int tsens_probe(struct platform_device *pdev)
+{
+	int ret, i;
+	struct device *dev;
+	struct device_node *np;
+	struct tsens_sensor *s;
+	struct tsens_device *tmdev;
+	const struct tsens_data *data;
+	const struct of_device_id *id;
+
+	if (pdev->dev.of_node)
+		dev = &pdev->dev;
+	else
+		dev = pdev->dev.parent;
+
+	np = dev->of_node;
+
+	id = of_match_node(tsens_table, np);
+	if (!id)
+		return -EINVAL;
+
+	data = id->data;
+
+	if (data->num_sensors <= 0) {
+		dev_err(dev, "invalid number of sensors\n");
+		return -EINVAL;
+	}
+
+	tmdev = devm_kzalloc(dev, sizeof(*tmdev) +
+			     data->num_sensors * sizeof(*s), GFP_KERNEL);
+	if (!tmdev)
+		return -ENOMEM;
+
+	tmdev->dev = dev;
+	tmdev->num_sensors = data->num_sensors;
+	tmdev->ops = data->ops;
+	for (i = 0;  i < tmdev->num_sensors; i++) {
+		if (data->hw_ids)
+			tmdev->sensor[i].hw_id = data->hw_ids[i];
+		else
+			tmdev->sensor[i].hw_id = i;
+	}
+
+	if (!tmdev->ops || !tmdev->ops->init || !tmdev->ops->get_temp)
+		return -EINVAL;
+
+	ret = tmdev->ops->init(tmdev);
+	if (ret < 0) {
+		dev_err(dev, "tsens init failed\n");
+		return ret;
+	}
+
+	if (tmdev->ops->calibrate) {
+		ret = tmdev->ops->calibrate(tmdev);
+		if (ret < 0) {
+			dev_err(dev, "tsens calibration failed\n");
+			return ret;
+		}
+	}
+
+	ret = tsens_register(tmdev);
+
+	platform_set_drvdata(pdev, tmdev);
+
+	return ret;
+}
+
+static int tsens_remove(struct platform_device *pdev)
+{
+	struct tsens_device *tmdev = platform_get_drvdata(pdev);
+
+	if (tmdev->ops->disable)
+		tmdev->ops->disable(tmdev);
+
+	return 0;
+}
+
+static struct platform_driver tsens_driver = {
+	.probe = tsens_probe,
+	.remove = tsens_remove,
+	.driver = {
+		.name = "qcom-tsens",
+		.pm	= &tsens_pm_ops,
+		.of_match_table = tsens_table,
+	},
+};
+module_platform_driver(tsens_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("QCOM Temperature Sensor driver");
+MODULE_ALIAS("platform:qcom-tsens");

drivers/thermal/qcom/tsens.h

+/*
+ * Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#ifndef __QCOM_TSENS_H__
+#define __QCOM_TSENS_H__
+
+#define ONE_PT_CALIB		0x1
+#define ONE_PT_CALIB2		0x2
+#define TWO_PT_CALIB		0x3
+
+struct tsens_device;
+
+struct tsens_sensor {
+	struct tsens_device		*tmdev;
+	struct thermal_zone_device	*tzd;
+	int				offset;
+	int				id;
+	int				hw_id;
+	int				slope;
+	u32				status;
+};
+
+/**
+ * struct tsens_ops - operations as supported by the tsens device
+ * @init: Function to initialize the tsens device
+ * @calibrate: Function to calibrate the tsens device
+ * @get_temp: Function which returns the temp in millidegC
+ * @enable: Function to enable (clocks/power) tsens device
+ * @disable: Function to disable the tsens device
+ * @suspend: Function to suspend the tsens device
+ * @resume: Function to resume the tsens device
+ * @get_trend: Function to get the thermal/temp trend
+ */
+struct tsens_ops {
+	/* mandatory callbacks */
+	int (*init)(struct tsens_device *);
+	int (*calibrate)(struct tsens_device *);
+	int (*get_temp)(struct tsens_device *, int, int *);
+	/* optional callbacks */
+	int (*enable)(struct tsens_device *, int);
+	void (*disable)(struct tsens_device *);
+	int (*suspend)(struct tsens_device *);
+	int (*resume)(struct tsens_device *);
+	int (*get_trend)(struct tsens_device *, int, long *);
+};
+
+/**
+ * struct tsens_data - tsens instance specific data
+ * @num_sensors: Max number of sensors supported by platform
+ * @ops: operations the tsens instance supports
+ * @hw_ids: Subset of sensors ids supported by platform, if not the first n
+ */
+struct tsens_data {
+	const u32		num_sensors;
+	const struct tsens_ops	*ops;
+	unsigned int		*hw_ids;
+};
+
+/* Registers to be saved/restored across a context loss */
+struct tsens_context {
+	int	threshold;
+	int	control;
+};
+
+struct tsens_device {
+	struct device			*dev;
+	u32				num_sensors;
+	struct regmap			*map;
+	struct regmap_field		*status_field;
+	struct tsens_context		ctx;
+	bool				trdy;
+	const struct tsens_ops		*ops;
+	struct tsens_sensor		sensor[0];
+};
+
+char *qfprom_read(struct device *, const char *);
+void compute_intercept_slope(struct tsens_device *, u32 *, u32 *, u32);
+int init_common(struct tsens_device *);
+int get_temp_common(struct tsens_device *, int, int *);
+
+#endif /* __QCOM_TSENS_H__ */