powerpc/windfarm: Add lm87 sensor

For use by the upcoming windfarm_rm31
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

drivers/macintosh/windfarm_lm87_sensor.c

+/*
+ * Windfarm PowerMac thermal control. LM87 sensor
+ *
+ * Copyright 2012 Benjamin Herrenschmidt, IBM Corp.
+ *
+ * Released under the term of the GNU GPL v2.
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/wait.h>
+#include <linux/i2c.h>
+#include <asm/prom.h>
+#include <asm/machdep.h>
+#include <asm/io.h>
+#include <asm/sections.h>
+#include <asm/pmac_low_i2c.h>
+
+#include "windfarm.h"
+
+#define VERSION "1.0"
+
+#undef DEBUG
+
+#ifdef DEBUG
+#define DBG(args...)	printk(args)
+#else
+#define DBG(args...)	do { } while(0)
+#endif
+
+struct wf_lm87_sensor {
+	struct i2c_client	*i2c;
+	struct wf_sensor	sens;
+};
+#define wf_to_lm87(c) container_of(c, struct wf_lm87_sensor, sens)
+
+
+static int wf_lm87_read_reg(struct i2c_client *chip, int reg)
+{
+	int rc, tries = 0;
+	u8 buf;
+
+	for (;;) {
+		/* Set address */
+		buf = (u8)reg;
+		rc = i2c_master_send(chip, &buf, 1);
+		if (rc <= 0)
+			goto error;
+		rc = i2c_master_recv(chip, &buf, 1);
+		if (rc <= 0)
+			goto error;
+		return (int)buf;
+	error:
+		DBG("wf_lm87: Error reading LM87, retrying...\n");
+		if (++tries > 10) {
+			printk(KERN_ERR "wf_lm87: Error reading LM87 !\n");
+			return -EIO;
+		}
+		msleep(10);
+	}
+}
+
+static int wf_lm87_get(struct wf_sensor *sr, s32 *value)
+{
+	struct wf_lm87_sensor *lm = sr->priv;
+	s32 temp;
+
+	if (lm->i2c == NULL)
+		return -ENODEV;
+
+#define LM87_INT_TEMP		0x27
+
+	/* Read temperature register */
+	temp = wf_lm87_read_reg(lm->i2c, LM87_INT_TEMP);
+	if (temp < 0)
+		return temp;
+	*value = temp << 16;
+
+	return 0;
+}
+
+static void wf_lm87_release(struct wf_sensor *sr)
+{
+	struct wf_lm87_sensor *lm = wf_to_lm87(sr);
+
+	kfree(lm);
+}
+
+static struct wf_sensor_ops wf_lm87_ops = {
+	.get_value	= wf_lm87_get,
+	.release	= wf_lm87_release,
+	.owner		= THIS_MODULE,
+};
+
+static int wf_lm87_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{	
+	struct wf_lm87_sensor *lm;
+	const char *name = NULL, *loc;
+	struct device_node *np = NULL;
+	int rc;
+
+	/*
+	 * The lm87 contains a whole pile of sensors, additionally,
+	 * the Xserve G5 has several lm87's. However, for now we only
+	 * care about the internal temperature sensor
+	 */
+	while ((np = of_get_next_child(client->dev.of_node, np)) != NULL) {
+		if (strcmp(np->name, "int-temp"))
+			continue;
+		loc = of_get_property(np, "location", NULL);
+		if (!loc)
+			continue;
+		if (strstr(loc, "DIMM"))
+			name = "dimms-temp";
+		else if (strstr(loc, "Processors"))
+			name = "between-cpus-temp";
+		if (name) {
+			of_node_put(np);
+			break;
+		}
+	}
+	if (!name) {
+		pr_warning("wf_lm87: Unsupported sensor %s\n",
+			   client->dev.of_node->full_name);
+		return -ENODEV;
+	}
+
+	lm = kzalloc(sizeof(struct wf_lm87_sensor), GFP_KERNEL);
+	if (lm == NULL)
+		return -ENODEV;
+
+	lm->i2c = client;
+	lm->sens.name = name;
+	lm->sens.ops = &wf_lm87_ops;
+	lm->sens.priv = lm;
+	i2c_set_clientdata(client, lm);
+
+	rc = wf_register_sensor(&lm->sens);
+	if (rc)
+		kfree(lm);
+	return rc;
+}
+
+static int wf_lm87_remove(struct i2c_client *client)
+{
+	struct wf_lm87_sensor *lm = i2c_get_clientdata(client);
+
+	DBG("wf_lm87: i2c detatch called for %s\n", lm->sens.name);
+
+	/* Mark client detached */
+	lm->i2c = NULL;
+
+	/* release sensor */
+	wf_unregister_sensor(&lm->sens);
+
+	return 0;
+}
+
+static const struct i2c_device_id wf_lm87_id[] = {
+	{ "MAC,lm87cimt", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, wf_lm87_id);
+
+static struct i2c_driver wf_lm87_driver = {
+	.driver = {
+		.name	= "wf_lm87",
+	},
+	.probe		= wf_lm87_probe,
+	.remove		= wf_lm87_remove,
+	.id_table	= wf_lm87_id,
+};
+
+static int __init wf_lm87_sensor_init(void)
+{
+	/* We only support this on the Xserve */
+	if (!of_machine_is_compatible("RackMac3,1"))
+		return -ENODEV;
+
+	return i2c_add_driver(&wf_lm87_driver);
+}
+
+static void __exit wf_lm87_sensor_exit(void)
+{
+	i2c_del_driver(&wf_lm87_driver);
+}
+
+
+module_init(wf_lm87_sensor_init);
+module_exit(wf_lm87_sensor_exit);
+
+MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
+MODULE_DESCRIPTION("LM87 sensor objects for PowerMacs thermal control");
+MODULE_LICENSE("GPL");
+