[lm-sensors] [PATCH] ad7418 driver

[azummo-lists@towertech.it (Alessandro Zummo)]

 This patch add support for AD7417 and AD7418 chips.

 Signed-off-by: Alessandro Zummo <a.zummo at towertech.it>

---
 drivers/hwmon/Kconfig  |   10 +
 drivers/hwmon/Makefile |    1 
 drivers/hwmon/ad7418.c |  353 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 364 insertions(+)

--- linux-ixp4xx.orig/drivers/hwmon/Makefile	2006-10-19 13:40:47.000000000 +0200
+++ linux-ixp4xx/drivers/hwmon/Makefile	2006-10-19 13:44:08.000000000 +0200
@@ -50,6 +50,7 @@ obj-$(CONFIG_SENSORS_VT1211)	+= vt1211.o
 obj-$(CONFIG_SENSORS_VT8231)	+= vt8231.o
 obj-$(CONFIG_SENSORS_W83627EHF)	+= w83627ehf.o
 obj-$(CONFIG_SENSORS_W83L785TS)	+= w83l785ts.o
+obj-$(CONFIG_SENSORS_AD7418)	+= ad7418.o
 
 ifeq ($(CONFIG_HWMON_DEBUG_CHIP),y)
 EXTRA_CFLAGS += -DDEBUG
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-ixp4xx/drivers/hwmon/ad7418.c	2006-10-19 13:55:17.000000000 +0200
@@ -0,0 +1,353 @@
+/*
+ * An hwmon driver for the Analog Devices AD7417/18
+ * Copyright 2006 Tower Technologies
+ *
+ * Author: Alessandro Zummo <a.zummo at towertech.it>
+ *
+ * Based on lm75.c
+ * Copyright 1998-99 Frodo Looijaard <frodol at dds.nl>
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/jiffies.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+
+#define DRV_VERSION "0.2"
+
+/* straight from the datasheet */
+#define AD7418_TEMP_MIN (-55000)
+#define AD7418_TEMP_MAX 125000
+
+/* Addresses to scan */
+static unsigned short normal_i2c[] = { 0x28, 0x29, 0x2A, 0x2B, 0x2C,
+					0x2D, 0x2E, 0x2F, I2C_CLIENT_END };
+
+/* Insmod parameters */
+I2C_CLIENT_INSMOD;
+
+/* AD7418 registers */
+#define AD7418_REG_TEMP		0x00
+#define AD7418_REG_CONF		0x01
+#define AD7418_REG_TEMP_HYST	0x02
+#define AD7418_REG_TEMP_OS	0x03
+#define AD7418_REG_ADC		0x04
+#define AD7418_REG_CONF2	0x05
+
+#define AD7418_REG_ADC_CH(x)	(x << 5)
+
+#define AD7418_CH_TEMP		AD7418_REG_ADC_CH(0)
+#define AD7418_CH_AIN1		AD7418_REG_ADC_CH(1)
+#define AD7418_CH_AIN2		AD7418_REG_ADC_CH(2)
+#define AD7418_CH_AIN3		AD7418_REG_ADC_CH(3)
+#define AD7418_CH_AIN4		AD7418_REG_ADC_CH(4)
+
+struct ad7418_data {
+	struct i2c_client	client;
+	struct class_device	*class_dev;
+	struct mutex		lock;
+	char			valid;		/* !=0 if following fields are valid */
+	unsigned long		last_updated;	/* In jiffies */
+	u16			temp_input;	/* Register values */
+	u16			temp_max;
+	u16			temp_hyst;
+	u16			in1;
+	u16			in2;
+	u16			in3;
+	u16			in4;
+};
+
+static int ad7418_attach_adapter(struct i2c_adapter *adapter);
+static int ad7418_detect(struct i2c_adapter *adapter, int address, int kind);
+static int ad7418_detach_client(struct i2c_client *client);
+
+static struct i2c_driver ad7418_driver = {
+	.driver = {
+		.name	= "ad7418",
+	},
+	.attach_adapter	= ad7418_attach_adapter,
+	.detach_client	= ad7418_detach_client,
+};
+
+/* TEMP: 0.001C/bit (-55C to +125C)
+ * REG: (0.5C/bit, two's complement) << 7
+ */
+static inline u16 AD7418_TEMP_TO_REG(int temp)
+{
+	int ntemp = SENSORS_LIMIT(temp, AD7418_TEMP_MIN, AD7418_TEMP_MAX);
+	ntemp += (ntemp < 0 ? -250 : 250);
+	return (u16)((ntemp / 500) << 7);
+}
+
+static inline int AD7418_TEMP_FROM_REG(u16 reg)
+{
+	/* use integer division instead of equivalent right shift to
+	 * guarantee arithmetic shift and preserve the sign
+	 */
+	return ((s16)reg / 128) * 500;
+}
+
+/* All registers are word-sized, except for the configuration registers.
+ * AD7418 uses a high-byte first convention, which is exactly opposite to
+ * the usual practice.
+ */
+static int ad7418_read(struct i2c_client *client, u8 reg)
+{
+	if (reg = AD7418_REG_CONF || reg = AD7418_REG_CONF2)
+		return i2c_smbus_read_byte_data(client, reg);
+	else
+		return swab16(i2c_smbus_read_word_data(client, reg));
+}
+
+static int ad7418_write(struct i2c_client *client, u8 reg, u16 value)
+{
+	if (reg = AD7418_REG_CONF || reg = AD7418_REG_CONF2)
+		return i2c_smbus_write_byte_data(client, reg, value);
+	else
+		return i2c_smbus_write_word_data(client, reg, swab16(value));
+}
+
+static void ad7418_init_client(struct i2c_client *client)
+{
+	/* Enable if in shutdown mode */
+	int reg = ad7418_read(client, AD7418_REG_CONF);
+	if (reg >= 0 && (reg & 0x01))
+		ad7418_write(client, AD7418_REG_CONF, reg & 0xfe);
+}
+
+static struct ad7418_data *ad7418_update_device(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ad7418_data *data = i2c_get_clientdata(client);
+
+	mutex_lock(&data->lock);
+
+	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
+		|| !data->valid) {
+		u8 cfg;
+		dev_dbg(&client->dev, "starting ad7418 update\n");
+
+		data->temp_input = ad7418_read(client, AD7418_REG_TEMP);
+		data->temp_max = ad7418_read(client, AD7418_REG_TEMP_OS);
+		data->temp_hyst = ad7418_read(client, AD7418_REG_TEMP_HYST);
+
+		/* read config register and clear channel bits */
+		cfg = ad7418_read(client, AD7418_REG_CONF);
+		cfg &= 0x1F;
+
+		ad7418_write(client, AD7418_REG_CONF, cfg | AD7418_CH_AIN1);
+		data->in1 = ad7418_read(client, AD7418_REG_ADC);
+
+		ad7418_write(client, AD7418_REG_CONF, cfg | AD7418_CH_AIN2);
+		data->in2 = ad7418_read(client, AD7418_REG_ADC);
+
+		ad7418_write(client, AD7418_REG_CONF, cfg | AD7418_CH_AIN3);
+		data->in3 = ad7418_read(client, AD7418_REG_ADC);
+
+		ad7418_write(client, AD7418_REG_CONF, cfg | AD7418_CH_AIN4);
+		data->in4 = ad7418_read(client, AD7418_REG_ADC);
+
+		/* restore old configuration value */
+		ad7418_write(client, AD7418_REG_CONF, cfg);
+
+		data->last_updated = jiffies;
+		data->valid = 1;
+	}
+
+	mutex_unlock(&data->lock);
+
+	return data;
+}
+
+#define show(value) \
+static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf)		\
+{									\
+	struct ad7418_data *data = ad7418_update_device(dev);		\
+	return sprintf(buf, "%d\n", AD7418_TEMP_FROM_REG(data->value));	\
+}
+show(temp_max);
+show(temp_hyst);
+show(temp_input);
+
+#define show_adc(value)	\
+static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf)		\
+{								\
+	struct ad7418_data *data = ad7418_update_device(dev);	\
+	return sprintf(buf, "%d\n", data->value >> 6);		\
+}
+
+show_adc(in1);
+show_adc(in2);
+show_adc(in3);
+show_adc(in4);
+
+#define set(value, reg)	\
+static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)	\
+{								\
+	struct i2c_client *client = to_i2c_client(dev);		\
+	struct ad7418_data *data = i2c_get_clientdata(client);	\
+	int temp = simple_strtoul(buf, NULL, 10);		\
+								\
+	mutex_lock(&data->lock);				\
+	data->value = AD7418_TEMP_TO_REG(temp);			\
+	ad7418_write(client, reg, data->value);		\
+	mutex_unlock(&data->lock);					\
+	return count;						\
+}
+set(temp_max, AD7418_REG_TEMP_OS);
+set(temp_hyst, AD7418_REG_TEMP_HYST);
+
+static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max, set_temp_max);
+static DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, show_temp_hyst, set_temp_hyst);
+static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL);
+
+static DEVICE_ATTR(in1, S_IRUGO, show_in1, NULL);
+static DEVICE_ATTR(in2, S_IRUGO, show_in2, NULL);
+static DEVICE_ATTR(in3, S_IRUGO, show_in3, NULL);
+static DEVICE_ATTR(in4, S_IRUGO, show_in4, NULL);
+
+static int ad7418_attach_adapter(struct i2c_adapter *adapter)
+{
+	if (!(adapter->class & I2C_CLASS_HWMON))
+		return 0;
+	return i2c_probe(adapter, &addr_data, ad7418_detect);
+}
+
+static struct attribute *ad7418_attributes[] = {
+	&dev_attr_temp1_max.attr,
+	&dev_attr_temp1_max_hyst.attr,
+	&dev_attr_temp1_input.attr,
+	&dev_attr_in1.attr,
+	&dev_attr_in2.attr,
+	&dev_attr_in3.attr,
+	&dev_attr_in4.attr,
+	NULL
+};
+
+static const struct attribute_group ad7418_group = {
+	.attrs = ad7418_attributes,
+};
+
+static int ad7418_detect(struct i2c_adapter *adapter, int address, int kind)
+{
+	struct i2c_client *client;
+	struct ad7418_data *data;
+	int err = 0;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
+					I2C_FUNC_SMBUS_WORD_DATA))
+		goto exit;
+
+	if (!(data = kzalloc(sizeof(struct ad7418_data), GFP_KERNEL))) {
+		err = -ENOMEM;
+		goto exit;
+	}
+
+	client = &data->client;
+	client->addr = address;
+	client->adapter = adapter;
+	client->driver = &ad7418_driver;
+	client->flags = 0;
+
+	i2c_set_clientdata(client, data);
+
+	mutex_init(&data->lock);
+
+	/* AD7418 has a curious behaviour on registers 6 and 7. They
+	 * both always read 0xC071 and are not documented on the datasheet.
+	 * We use them to detect the chip.
+	 */
+	if (kind < 0) {
+		int reg;
+
+		reg = i2c_smbus_read_word_data(client, 0x06);
+		if (reg != 0xC071) {
+			dev_dbg(&adapter->dev, "failed detection at %d: %x\n", 6, reg);
+			err = -ENODEV;
+			goto exit_free;
+		}
+
+		reg = i2c_smbus_read_word_data(client, 0x07);
+		if (reg != 0xC071) {
+			dev_dbg(&adapter->dev, "failed detection at %d: %x\n", 7, reg);
+			err = -ENODEV;
+			goto exit_free;
+		}
+
+		reg = i2c_smbus_read_byte_data(client, AD7418_REG_CONF2);
+
+		/* bits 0-5 must be at 0 */
+		if (reg & 0x3F) {
+			dev_dbg(&adapter->dev, "failed detection at %d: %x\n",
+				AD7418_REG_CONF2, reg);
+			err = -ENODEV;
+		 	goto exit_free;
+		}
+	}
+
+	strlcpy(client->name, ad7418_driver.driver.name, I2C_NAME_SIZE);
+
+	if ((err = i2c_attach_client(client)))
+		goto exit_free;
+
+	dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
+
+	/* Initialize the AD7418 chip */
+	ad7418_init_client(client);
+
+	/* Register sysfs hooks */
+	if ((err = sysfs_create_group(&client->dev.kobj, &ad7418_group)))
+		goto exit_detach;
+
+	data->class_dev = hwmon_device_register(&client->dev);
+	if (IS_ERR(data->class_dev)) {
+		err = PTR_ERR(data->class_dev);
+		goto exit_remove;
+	}
+
+	return 0;
+
+exit_remove:
+	sysfs_remove_group(&client->dev.kobj, &ad7418_group);
+exit_detach:
+	i2c_detach_client(client);
+exit_free:
+	kfree(data);
+exit:
+	return err;
+}
+
+static int ad7418_detach_client(struct i2c_client *client)
+{
+	struct ad7418_data *data = i2c_get_clientdata(client);
+	hwmon_device_unregister(data->class_dev);
+	sysfs_remove_group(&client->dev.kobj, &ad7418_group);
+	i2c_detach_client(client);
+	kfree(data);
+	return 0;
+}
+
+static int __init ad7418_init(void)
+{
+	return i2c_add_driver(&ad7418_driver);
+}
+
+static void __exit ad7418_exit(void)
+{
+	i2c_del_driver(&ad7418_driver);
+}
+
+MODULE_AUTHOR("Alessandro Zummo <a.zummo at towertech.it>");
+MODULE_DESCRIPTION("AD7417/8 driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+
+module_init(ad7418_init);
+module_exit(ad7418_exit);
--- linux-ixp4xx.orig/drivers/hwmon/Kconfig	2006-10-19 13:40:47.000000000 +0200
+++ linux-ixp4xx/drivers/hwmon/Kconfig	2006-10-19 13:44:08.000000000 +0200
@@ -512,6 +512,16 @@ config SENSORS_W83627EHF
 	  This driver can also be built as a module.  If so, the module
 	  will be called w83627ehf.
 
+config SENSORS_AD7418
+	tristate "Analog Devices AD7417/18"
+	depends on HWMON && I2C && EXPERIMENTAL
+	help
+	  If you say yes here you get support for the Analog Devices AD7417
+	  and AD7418 chips.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called ad7418.
+
 config SENSORS_HDAPS
 	tristate "IBM Hard Drive Active Protection System (hdaps)"
 	depends on HWMON && INPUT && X86