thermal: Add support for the thermal sensor on Kirkwood SoCs

* Kirkwood Thermal

This version is for Kirkwood 88F8262 & 88F6283 SoCs. Other kirkwoods

don't contain a thermal sensor.

Required properties:

- compatible : "marvell,kirkwood-thermal"

- reg : Address range of the thermal registers

Example:

	thermal@10078 {

		compatible = "marvell,kirkwood-thermal";

		reg = <0x10078 0x4>;

	};

	  Enable this to plug the R-Car thermal sensor driver into the Linux

	  thermal framework

config KIRKWOOD_THERMAL

	tristate "Temperature sensor on Marvell Kirkwood SoCs"

	depends on ARCH_KIRKWOOD

	depends on OF

	help

	  Support for the Kirkwood thermal sensor driver into the Linux thermal

	  framework. Only kirkwood 88F6282 and 88F6283 have this sensor.

config EXYNOS_THERMAL

	tristate "Temperature sensor on Samsung EXYNOS"

	depends on (ARCH_EXYNOS4 || ARCH_EXYNOS5)

# platform thermal drivers

obj-$(CONFIG_SPEAR_THERMAL)	+= spear_thermal.o

obj-$(CONFIG_RCAR_THERMAL)	+= rcar_thermal.o

obj-$(CONFIG_KIRKWOOD_THERMAL)  += kirkwood_thermal.o

obj-$(CONFIG_EXYNOS_THERMAL)	+= exynos_thermal.o

obj-$(CONFIG_DB8500_THERMAL)	+= db8500_thermal.o

obj-$(CONFIG_DB8500_CPUFREQ_COOLING)	+= db8500_cpufreq_cooling.o

/*

 * Kirkwood thermal sensor driver

 *

 * Copyright (C) 2012 Nobuhiro Iwamatsu <iwamatsu@nigauri.org>

 *

 * 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.

 *

 */

#include <linux/device.h>

#include <linux/err.h>

#include <linux/io.h>

#include <linux/kernel.h>

#include <linux/of.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/thermal.h>

#define KIRKWOOD_THERMAL_VALID_OFFSET	9

#define KIRKWOOD_THERMAL_VALID_MASK	0x1

#define KIRKWOOD_THERMAL_TEMP_OFFSET	10

#define KIRKWOOD_THERMAL_TEMP_MASK	0x1FF

/* Kirkwood Thermal Sensor Dev Structure */

struct kirkwood_thermal_priv {

	void __iomem *sensor;

};

static int kirkwood_get_temp(struct thermal_zone_device *thermal,

			  unsigned long *temp)

{

	unsigned long reg;

	struct kirkwood_thermal_priv *priv = thermal->devdata;

	reg = readl_relaxed(priv->sensor);

	/* Valid check */

	if (!(reg >> KIRKWOOD_THERMAL_VALID_OFFSET) &

	    KIRKWOOD_THERMAL_VALID_MASK) {

		dev_err(&thermal->device,

			"Temperature sensor reading not valid\n");

		return -EIO;

	}

	/*

	 * Calculate temperature. See Section 8.10.1 of the 88AP510,

	 * datasheet, which has the same sensor.

	 * Documentation/arm/Marvell/README

	 */

	reg = (reg >> KIRKWOOD_THERMAL_TEMP_OFFSET) &

		KIRKWOOD_THERMAL_TEMP_MASK;

	*temp = ((2281638UL - (7298*reg)) / 10);

	return 0;

}

static struct thermal_zone_device_ops ops = {

	.get_temp = kirkwood_get_temp,

};

static const struct of_device_id kirkwood_thermal_id_table[] = {

	{ .compatible = "marvell,kirkwood-thermal" },

	{}

};

static int kirkwood_thermal_probe(struct platform_device *pdev)

{

	struct thermal_zone_device *thermal = NULL;

	struct kirkwood_thermal_priv *priv;

	struct resource *res;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	if (!res) {

		dev_err(&pdev->dev, "Failed to get platform resource\n");

		return -ENODEV;

	}

	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);

	if (!priv)

		return -ENOMEM;

	priv->sensor = devm_request_and_ioremap(&pdev->dev, res);

	if (!priv->sensor) {

		dev_err(&pdev->dev, "Failed to request_ioremap memory\n");

		return -EADDRNOTAVAIL;

	}

	thermal = thermal_zone_device_register("kirkwood_thermal", 0, 0,

					       priv, &ops, NULL, 0, 0);

	if (IS_ERR(thermal)) {

		dev_err(&pdev->dev,

			"Failed to register thermal zone device\n");

		return PTR_ERR(thermal);

	}

	platform_set_drvdata(pdev, thermal);

	return 0;

}

static int kirkwood_thermal_exit(struct platform_device *pdev)

{

	struct thermal_zone_device *kirkwood_thermal =

		platform_get_drvdata(pdev);

	thermal_zone_device_unregister(kirkwood_thermal);

	platform_set_drvdata(pdev, NULL);

	return 0;

}

MODULE_DEVICE_TABLE(of, kirkwood_thermal_id_table);

static struct platform_driver kirkwood_thermal_driver = {

	.probe = kirkwood_thermal_probe,

	.remove = kirkwood_thermal_exit,

	.driver = {

		.name = "kirkwood_thermal",

		.owner = THIS_MODULE,

		.of_match_table = of_match_ptr(kirkwood_thermal_id_table),

	},

};

module_platform_driver(kirkwood_thermal_driver);

MODULE_AUTHOR("Nobuhiro Iwamatsu <iwamatsu@nigauri.org>");

MODULE_DESCRIPTION("kirkwood thermal driver");

MODULE_LICENSE("GPL");