thermal: add Renesas R-Car thermal sensor support

This patch add basic Renesas R-Car thermal sensor support.
It was tested on R-Car H1 Marzen board.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

drivers/thermal/Kconfig

@@ -27,3 +27,11 @@ config SPEAR_THERMAL
 	help
 	  Enable this to plug the SPEAr thermal sensor driver into the Linux
 	  thermal framework
+
+config RCAR_THERMAL
+	tristate "Renesas R-Car thermal driver"
+	depends on THERMAL
+	depends on ARCH_SHMOBILE
+	help
+	  Enable this to plug the R-Car thermal sensor driver into the Linux
+	  thermal framework

drivers/thermal/Makefile

@@ -3,4 +3,5 @@
 #
 
 obj-$(CONFIG_THERMAL)		+= thermal_sys.o
-obj-$(CONFIG_SPEAR_THERMAL)		+= spear_thermal.o
+obj-$(CONFIG_SPEAR_THERMAL)		+= spear_thermal.o
+obj-$(CONFIG_RCAR_THERMAL)	+= rcar_thermal.o

drivers/thermal/rcar_thermal.c

@@ -0,0 +1,260 @@
+/*
+ *  R-Car THS/TSC thermal sensor driver
+ *
+ * Copyright (C) 2012 Renesas Solutions Corp.
+ * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; version 2 of the License.
+ *
+ *  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.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/thermal.h>
+
+#define THSCR	0x2c
+#define THSSR	0x30
+
+/* THSCR */
+#define CPTAP	0xf
+
+/* THSSR */
+#define CTEMP	0x3f
+
+
+struct rcar_thermal_priv {
+	void __iomem *base;
+	struct device *dev;
+	spinlock_t lock;
+	u32 comp;
+};
+
+/*
+ *		basic functions
+ */
+static u32 rcar_thermal_read(struct rcar_thermal_priv *priv, u32 reg)
+{
+	unsigned long flags;
+	u32 ret;
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	ret = ioread32(priv->base + reg);
+
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return ret;
+}
+
+#if 0 /* no user at this point */
+static void rcar_thermal_write(struct rcar_thermal_priv *priv,
+			       u32 reg, u32 data)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	iowrite32(data, priv->base + reg);
+
+	spin_unlock_irqrestore(&priv->lock, flags);
+}
+#endif
+
+static void rcar_thermal_bset(struct rcar_thermal_priv *priv, u32 reg,
+			      u32 mask, u32 data)
+{
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	val = ioread32(priv->base + reg);
+	val &= ~mask;
+	val |= (data & mask);
+	iowrite32(val, priv->base + reg);
+
+	spin_unlock_irqrestore(&priv->lock, flags);
+}
+
+/*
+ *		zone device functions
+ */
+static int rcar_thermal_get_temp(struct thermal_zone_device *zone,
+			   unsigned long *temp)
+{
+	struct rcar_thermal_priv *priv = zone->devdata;
+	int val, min, max, tmp;
+
+	tmp = -200; /* default */
+	while (1) {
+		if (priv->comp < 1 || priv->comp > 12) {
+			dev_err(priv->dev,
+				"THSSR invalid data (%d)\n", priv->comp);
+			priv->comp = 4; /* for next thermal */
+			return -EINVAL;
+		}
+
+		/*
+		 * THS comparator offset and the reference temperature
+		 *
+		 * Comparator	| reference	| Temperature field
+		 * offset	| temperature	| measurement
+		 *		| (degrees C)	| (degrees C)
+		 * -------------+---------------+-------------------
+		 *  1		|  -45		|  -45 to  -30
+		 *  2		|  -30		|  -30 to  -15
+		 *  3		|  -15		|  -15 to    0
+		 *  4		|    0		|    0 to  +15
+		 *  5		|  +15		|  +15 to  +30
+		 *  6		|  +30		|  +30 to  +45
+		 *  7		|  +45		|  +45 to  +60
+		 *  8		|  +60		|  +60 to  +75
+		 *  9		|  +75		|  +75 to  +90
+		 * 10		|  +90		|  +90 to +105
+		 * 11		| +105		| +105 to +120
+		 * 12		| +120		| +120 to +135
+		 */
+
+		/* calculate thermal limitation */
+		min = (priv->comp * 15) - 60;
+		max = min + 15;
+
+		/*
+		 * we need to wait 300us after changing comparator offset
+		 * to get stable temperature.
+		 * see "Usage Notes" on datasheet
+		 */
+		rcar_thermal_bset(priv, THSCR, CPTAP, priv->comp);
+		udelay(300);
+
+		/* calculate current temperature */
+		val = rcar_thermal_read(priv, THSSR) & CTEMP;
+		val = (val * 5) - 65;
+
+		dev_dbg(priv->dev, "comp/min/max/val = %d/%d/%d/%d\n",
+			priv->comp, min, max, val);
+
+		/*
+		 * If val is same as min/max, then,
+		 * it should try again on next comparator.
+		 * But the val might be correct temperature.
+		 * Keep it on "tmp" and compare with next val.
+		 */
+		if (tmp == val)
+			break;
+
+		if (val <= min) {
+			tmp = min;
+			priv->comp--; /* try again */
+		} else if (val >= max) {
+			tmp = max;
+			priv->comp++; /* try again */
+		} else {
+			tmp = val;
+			break;
+		}
+	}
+
+	*temp = tmp;
+	return 0;
+}
+
+static struct thermal_zone_device_ops rcar_thermal_zone_ops = {
+	.get_temp = rcar_thermal_get_temp,
+};
+
+/*
+ *		platform functions
+ */
+static int rcar_thermal_probe(struct platform_device *pdev)
+{
+	struct thermal_zone_device *zone;
+	struct rcar_thermal_priv *priv;
+	struct resource *res;
+	int ret;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "Could not get platform resource\n");
+		return -ENODEV;
+	}
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv) {
+		dev_err(&pdev->dev, "Could not allocate priv\n");
+		return -ENOMEM;
+	}
+
+	priv->comp = 4; /* basic setup */
+	priv->dev = &pdev->dev;
+	spin_lock_init(&priv->lock);
+	priv->base = devm_ioremap_nocache(&pdev->dev,
+					  res->start, resource_size(res));
+	if (!priv->base) {
+		dev_err(&pdev->dev, "Unable to ioremap thermal register\n");
+		ret = -ENOMEM;
+		goto error_free_priv;
+	}
+
+	zone = thermal_zone_device_register("rcar_thermal", 0, priv,
+					    &rcar_thermal_zone_ops, 0, 0);
+	if (IS_ERR(zone)) {
+		dev_err(&pdev->dev, "thermal zone device is NULL\n");
+		ret = PTR_ERR(zone);
+		goto error_iounmap;
+	}
+
+	platform_set_drvdata(pdev, zone);
+
+	dev_info(&pdev->dev, "proved\n");
+
+	return 0;
+
+error_iounmap:
+	devm_iounmap(&pdev->dev, priv->base);
+error_free_priv:
+	devm_kfree(&pdev->dev, priv);
+
+	return ret;
+}
+
+static int rcar_thermal_remove(struct platform_device *pdev)
+{
+	struct thermal_zone_device *zone = platform_get_drvdata(pdev);
+	struct rcar_thermal_priv *priv = zone->devdata;
+
+	thermal_zone_device_unregister(zone);
+	platform_set_drvdata(pdev, NULL);
+
+	devm_iounmap(&pdev->dev, priv->base);
+	devm_kfree(&pdev->dev, priv);
+
+	return 0;
+}
+
+static struct platform_driver rcar_thermal_driver = {
+	.driver	= {
+		.name	= "rcar_thermal",
+	},
+	.probe		= rcar_thermal_probe,
+	.remove		= rcar_thermal_remove,
+};
+module_platform_driver(rcar_thermal_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("R-Car THS/TSC thermal sensor driver");
+MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");