thermal: Add support for the thermal sensor on Kirkwood SoCs

This patch adds support for Kirkwood 88F6282 and 88F6283 thermal sensor.

Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

3 files changed, 143 insertions, 0 deletions

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index e4cf7fbc3a59..5070fbee24ef 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -101,6 +101,14 @@ config RCAR_THERMAL
           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)
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 574f5f505b9f..b32c35de67e7 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_CPU_THERMAL)	+= cpu_cooling.o
 # platform thermal drivers
 obj-$(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
diff --git a/drivers/thermal/kirkwood_thermal.c b/drivers/thermal/kirkwood_thermal.c
new file mode 100644
index 000000000000..65cb4f09e8f6
--- /dev/null
+++ b/drivers/thermal/kirkwood_thermal.c
@@ -0,0 +1,134 @@
+/*
+ * 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");