powerpc/windfarm: Add ad7417 sensor

For user by the upcoming windfarm_pm72 and windfarm_rm31
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

drivers/macintosh/windfarm_ad7417_sensor.c

+/*
+ * Windfarm PowerMac thermal control. AD7417 sensors
+ *
+ * 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 "windfarm.h"
+#include "windfarm_mpu.h"
+
+#define VERSION "1.0"
+
+struct wf_ad7417_priv {
+	struct kref		ref;
+	struct i2c_client	*i2c;
+	u8			config;
+	u8			cpu;
+	const struct mpu_data	*mpu;
+	struct wf_sensor	sensors[5];
+	struct mutex		lock;
+};
+
+static int wf_ad7417_temp_get(struct wf_sensor *sr, s32 *value)
+{
+	struct wf_ad7417_priv *pv = sr->priv;
+	u8 buf[2];
+	s16 raw;
+	int rc;
+
+	*value = 0;
+	mutex_lock(&pv->lock);
+
+	/* Read temp register */
+	buf[0] = 0;
+	rc = i2c_master_send(pv->i2c, buf, 1);
+	if (rc < 0)
+		goto error;
+	rc = i2c_master_recv(pv->i2c, buf, 2);
+	if (rc < 0)
+		goto error;
+
+	/* Read a a 16-bit signed value */
+	raw = be16_to_cpup((__le16 *)buf);
+
+	/* Convert 8.8-bit to 16.16 fixed point */
+	*value = ((s32)raw) << 8;
+
+	mutex_unlock(&pv->lock);
+	return 0;
+
+error:
+	mutex_unlock(&pv->lock);
+	return -1;
+}
+
+/*
+ * Scaling factors for the AD7417 ADC converters (except
+ * for the CPU diode which is obtained from the EEPROM).
+ * Those values are obtained from the property list of
+ * the darwin driver
+ */
+#define ADC_12V_CURRENT_SCALE	0x0320	/* _AD2 */
+#define ADC_CPU_VOLTAGE_SCALE	0x00a0	/* _AD3 */
+#define ADC_CPU_CURRENT_SCALE	0x1f40	/* _AD4 */
+
+static void wf_ad7417_adc_convert(struct wf_ad7417_priv *pv,
+				  int chan, s32 raw, s32 *value)
+{
+	switch(chan) {
+	case 1: /* Diode */
+		*value = (raw * (s32)pv->mpu->mdiode +
+			((s32)pv->mpu->bdiode << 12)) >> 2;
+		break;
+	case 2: /* 12v current */
+		*value = raw * ADC_12V_CURRENT_SCALE;
+		break;
+	case 3: /* core voltage */
+		*value = raw * ADC_CPU_VOLTAGE_SCALE;
+		break;
+	case 4: /* core current */
+		*value = raw * ADC_CPU_CURRENT_SCALE;
+		break;
+	}
+}
+
+static int wf_ad7417_adc_get(struct wf_sensor *sr, s32 *value)
+{
+	struct wf_ad7417_priv *pv = sr->priv;
+	int chan = sr - pv->sensors;
+	int i, rc;
+	u8 buf[2];
+	u16 raw;
+
+	*value = 0;
+	mutex_lock(&pv->lock);
+	for (i = 0; i < 10; i++) {
+		/* Set channel */
+		buf[0] = 1;
+		buf[1] = (pv->config & 0x1f) | (chan << 5);
+		rc = i2c_master_send(pv->i2c, buf, 2);
+		if (rc < 0)
+			goto error;
+
+		/* Wait for conversion */
+		msleep(1);
+
+		/* Switch to data register */
+		buf[0] = 4;
+		rc = i2c_master_send(pv->i2c, buf, 1);
+		if (rc < 0)
+			goto error;
+
+		/* Read result */
+		rc = i2c_master_recv(pv->i2c, buf, 2);
+		if (rc < 0)
+			goto error;
+
+		/* Read a a 16-bit signed value */
+		raw = be16_to_cpup((__le16 *)buf) >> 6;
+		wf_ad7417_adc_convert(pv, chan, raw, value);
+
+		dev_vdbg(&pv->i2c->dev, "ADC chan %d [%s]"
+			 " raw value: 0x%x, conv to: 0x%08x\n",
+			 chan, sr->name, raw, *value);
+
+		mutex_unlock(&pv->lock);
+		return 0;
+
+	error:
+		dev_dbg(&pv->i2c->dev,
+			  "Error reading ADC, try %d...\n", i);
+		if (i < 9)
+			msleep(10);
+	}
+	mutex_unlock(&pv->lock);
+	return -1;
+}
+
+static void wf_ad7417_release(struct kref *ref)
+{
+	struct wf_ad7417_priv *pv = container_of(ref,
+						 struct wf_ad7417_priv, ref);
+	kfree(pv);
+}
+
+static void wf_ad7417_sensor_release(struct wf_sensor *sr)
+{
+	struct wf_ad7417_priv *pv = sr->priv;
+
+	kfree(sr->name);
+	kref_put(&pv->ref, wf_ad7417_release);
+}
+
+static const struct wf_sensor_ops wf_ad7417_temp_ops = {
+	.get_value	= wf_ad7417_temp_get,
+	.release	= wf_ad7417_sensor_release,
+	.owner		= THIS_MODULE,
+};
+
+static const struct wf_sensor_ops wf_ad7417_adc_ops = {
+	.get_value	= wf_ad7417_adc_get,
+	.release	= wf_ad7417_sensor_release,
+	.owner		= THIS_MODULE,
+};
+
+static void __devinit wf_ad7417_add_sensor(struct wf_ad7417_priv *pv,
+					   int index, const char *name,
+					   const struct wf_sensor_ops *ops)
+{
+	pv->sensors[index].name = kasprintf(GFP_KERNEL, "%s-%d", name, pv->cpu);
+	pv->sensors[index].priv = pv;
+	pv->sensors[index].ops = ops;
+	if (!wf_register_sensor(&pv->sensors[index]))
+		kref_get(&pv->ref);
+}
+
+static void __devinit wf_ad7417_init_chip(struct wf_ad7417_priv *pv)
+{
+	int rc;
+	u8 buf[2];
+	u8 config = 0;
+
+	/*
+	 * Read ADC the configuration register and cache it. We
+	 * also make sure Config2 contains proper values, I've seen
+	 * cases where we got stale grabage in there, thus preventing
+	 * proper reading of conv. values
+	 */
+
+	/* Clear Config2 */
+	buf[0] = 5;
+	buf[1] = 0;
+	i2c_master_send(pv->i2c, buf, 2);
+
+	/* Read & cache Config1 */
+	buf[0] = 1;
+	rc = i2c_master_send(pv->i2c, buf, 1);
+	if (rc > 0) {
+		rc = i2c_master_recv(pv->i2c, buf, 1);
+		if (rc > 0) {
+			config = buf[0];
+
+			dev_dbg(&pv->i2c->dev, "ADC config reg: %02x\n",
+				config);
+
+			/* Disable shutdown mode */
+			config &= 0xfe;
+			buf[0] = 1;
+			buf[1] = config;
+			rc = i2c_master_send(pv->i2c, buf, 2);
+		}
+	}
+	if (rc <= 0)
+		dev_err(&pv->i2c->dev, "Error reading ADC config\n");
+
+	pv->config = config;
+}
+
+static int __devinit wf_ad7417_probe(struct i2c_client *client,
+				     const struct i2c_device_id *id)
+{
+	struct wf_ad7417_priv *pv;
+	const struct mpu_data *mpu;
+	const char *loc;
+	int cpu_nr;
+
+	loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL);
+	if (!loc) {
+		dev_warn(&client->dev, "Missing hwsensor-location property!\n");
+		return -ENXIO;
+	}
+
+	/*
+	 * Identify which CPU we belong to by looking at the first entry
+	 * in the hwsensor-location list
+	 */
+	if (!strncmp(loc, "CPU A", 5))
+		cpu_nr = 0;
+	else if (!strncmp(loc, "CPU B", 5))
+		cpu_nr = 1;
+	else {
+		pr_err("wf_ad7417: Can't identify location %s\n", loc);
+		return -ENXIO;
+	}
+	mpu = wf_get_mpu(cpu_nr);
+	if (!mpu) {
+		dev_err(&client->dev, "Failed to retrieve MPU data\n");
+		return -ENXIO;
+	}
+
+	pv = kzalloc(sizeof(struct wf_ad7417_priv), GFP_KERNEL);
+	if (pv == NULL)
+		return -ENODEV;
+
+	kref_init(&pv->ref);
+	mutex_init(&pv->lock);
+	pv->i2c = client;
+	pv->cpu = cpu_nr;
+	pv->mpu = mpu;
+	dev_set_drvdata(&client->dev, pv);
+
+	/* Initialize the chip */
+	wf_ad7417_init_chip(pv);
+
+	/*
+	 * We cannot rely on Apple device-tree giving us child
+	 * node with the names of the individual sensors so we
+	 * just hard code what we know about them
+	 */
+	wf_ad7417_add_sensor(pv, 0, "cpu-amb-temp", &wf_ad7417_temp_ops);
+	wf_ad7417_add_sensor(pv, 1, "cpu-diode-temp", &wf_ad7417_adc_ops);
+	wf_ad7417_add_sensor(pv, 2, "cpu-12v-current", &wf_ad7417_adc_ops);
+	wf_ad7417_add_sensor(pv, 3, "cpu-voltage", &wf_ad7417_adc_ops);
+	wf_ad7417_add_sensor(pv, 4, "cpu-current", &wf_ad7417_adc_ops);
+
+	return 0;
+}
+
+static int __devexit wf_ad7417_remove(struct i2c_client *client)
+{
+	struct wf_ad7417_priv *pv = dev_get_drvdata(&client->dev);
+	int i;
+
+	/* Mark client detached */
+	pv->i2c = NULL;
+
+	/* Release sensor */
+	for (i = 0; i < 5; i++)
+		wf_unregister_sensor(&pv->sensors[i]);
+
+	kref_put(&pv->ref, wf_ad7417_release);
+
+	return 0;
+}
+
+static const struct i2c_device_id wf_ad7417_id[] = {
+	{ "MAC,ad7417", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, wf_ad7417_id);
+
+static struct i2c_driver wf_ad7417_driver = {
+	.driver = {
+		.name	= "wf_ad7417",
+	},
+	.probe		= wf_ad7417_probe,
+	.remove		= wf_ad7417_remove,
+	.id_table	= wf_ad7417_id,
+};
+
+static int __devinit wf_ad7417_init(void)
+{
+	/* This is only supported on these machines */
+	if (!of_machine_is_compatible("PowerMac7,2") &&
+	    !of_machine_is_compatible("PowerMac7,3") &&
+	    !of_machine_is_compatible("RackMac3,1"))
+		return -ENODEV;
+
+	return i2c_add_driver(&wf_ad7417_driver);
+}
+
+static void __devexit wf_ad7417_exit(void)
+{
+	i2c_del_driver(&wf_ad7417_driver);
+}
+
+module_init(wf_ad7417_init);
+module_exit(wf_ad7417_exit);
+
+MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
+MODULE_DESCRIPTION("ad7417 sensor driver for PowerMacs");
+MODULE_LICENSE("GPL");
+