[PATCH] Hwmon for Taco

[Sean MacLennan <smaclennan@pikatech.com>]

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The taco has an fpga that controls the fan. It must be feed the current 
temperature from an ad7414 chip. This patch adds a patched ad7414 temp 
sensor from the ppc arch and adds a small driver (taco-dtm) to read the 
temperature and feed it to the fpga.

Without this driver, the taco will just run the fan at high speed all 
the time. I don't even know if this is a problem since cases for the 
taco are very rare and I don't have one. I have never actually heard the 
fan running in a case. Although I did see an early version of the fan 
spin up and spin down.

Cheers,
   Sean

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diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index a0445be..2fda94d 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -57,6 +57,16 @@ config SENSORS_ABITUGURU3
 	  This driver can also be built as a module.  If so, the module
 	  will be called abituguru3.
 
+config SENSORS_AD7414
+	tristate "Analog Devices AD7414"
+	depends on I2C && EXPERIMENTAL
+	help
+	  If you say yes here you get support for the Analog Devices
+	  AD7414 temperature monitoring chip.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called ad7414.
+
 config SENSORS_AD7418
 	tristate "Analog Devices AD7416, AD7417 and AD7418"
 	depends on I2C && EXPERIMENTAL
@@ -763,4 +773,13 @@ config HWMON_DEBUG_CHIP
 	  a problem with I2C support and want to see more of what is going
 	  on.
 
+config TACO_DTM
+	tristate "PIKA DTM (Dynamic Thermal Management)"
+	depends on HWMON && TACO
+	select SENSORS_AD7414
+	default y
+	help
+	  Say Y here if you have a PIKA Taco board. This driver is
+	  required for the DTM to work properly.
+
 endif # HWMON
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 55595f6..f993c5a 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_SENSORS_W83791D)	+= w83791d.o
 
 obj-$(CONFIG_SENSORS_ABITUGURU)	+= abituguru.o
 obj-$(CONFIG_SENSORS_ABITUGURU3)+= abituguru3.o
+obj-$(CONFIG_SENSORS_AD7414)	+= ad7414.o
 obj-$(CONFIG_SENSORS_AD7418)	+= ad7418.o
 obj-$(CONFIG_SENSORS_ADM1021)	+= adm1021.o
 obj-$(CONFIG_SENSORS_ADM1025)	+= adm1025.o
@@ -69,6 +70,8 @@ obj-$(CONFIG_SENSORS_VT8231)	+= vt8231.o
 obj-$(CONFIG_SENSORS_W83627EHF)	+= w83627ehf.o
 obj-$(CONFIG_SENSORS_W83L785TS)	+= w83l785ts.o
 
+obj-$(CONFIG_TACO_DTM)		+= taco-dtm.o
+
 ifeq ($(CONFIG_HWMON_DEBUG_CHIP),y)
 EXTRA_CFLAGS += -DDEBUG
 endif
--- /dev/null	2005-11-20 22:22:37.000000000 -0500
+++ drivers/hwmon/ad7414.c	2008-01-04 15:26:08.000000000 -0500
@@ -0,0 +1,311 @@
+/*
+ * An hwmon driver for the Analog Devices AD7414
+ *
+ * Copyright 2006 Stefan Roese <sr@denx.de>, DENX Software Engineering
+ *
+ * Based on ad7418.c
+ * Copyright 2006 Tower Technologies, Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * 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>
+#include <linux/delay.h>
+
+
+#define DRV_VERSION "0.2" // upped version for Pika mods
+
+/* straight from the datasheet */
+#define AD7414_TEMP_MIN (-55000)
+#define AD7414_TEMP_MAX 125000
+
+/* Addresses to scan */
+static unsigned short normal_i2c[] = { 0x48, 0x4a, I2C_CLIENT_END };
+
+/* Insmod parameters */
+I2C_CLIENT_INSMOD;
+
+/* AD7414 registers */
+#define AD7414_REG_TEMP		0x00
+#define AD7414_REG_CONF		0x01
+#define AD7414_REG_T_HIGH	0x02
+#define AD7414_REG_T_LOW	0x03
+
+struct ad7414_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 */
+	u8			temp_max;
+	u8			temp_min;
+	u8			temp_alert;
+	u8			temp_max_flag;
+	u8			temp_min_flag;
+};
+
+static int ad7414_attach_adapter(struct i2c_adapter *adapter);
+static int ad7414_detect(struct i2c_adapter *adapter, int address, int kind);
+static int ad7414_detach_client(struct i2c_client *client);
+
+static struct i2c_driver ad7414_driver = {
+	.driver = {
+		.name	= "ad7414",
+	},
+	.attach_adapter	= ad7414_attach_adapter,
+	.detach_client	= ad7414_detach_client,
+};
+
+/*
+ * TEMP: 0.001C/bit (-55C to +125C)
+ * REG: (0.5C/bit, two's complement) << 7
+ */
+static inline int AD7414_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.
+ * AD7414 uses a high-byte first convention, which is exactly opposite to
+ * the usual practice.
+ */
+static int ad7414_read(struct i2c_client *client, u8 reg)
+{
+	if (reg == AD7414_REG_TEMP)
+		return swab16(i2c_smbus_read_word_data(client, reg));
+	else
+		return i2c_smbus_read_byte_data(client, reg);
+}
+
+static int ad7414_write(struct i2c_client *client, u8 reg, u16 value)
+{
+	return i2c_smbus_write_byte_data(client, reg, value);
+}
+
+/* PIKA Taco - we need to access the temperature in kernel mode. As a
+ * hack we store the device here. This works because we only have one
+ * ad7414 chip.
+ */
+static struct device *ad7414_dev;
+
+static void ad7414_init_client(struct i2c_client *client)
+{
+	/* TODO: anything to do here??? */
+	ad7414_dev = &client->dev;
+}
+
+static struct ad7414_data *ad7414_update_device(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ad7414_data *data = i2c_get_clientdata(client);
+
+	mutex_lock(&data->lock);
+
+	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
+		|| !data->valid) {
+		dev_dbg(&client->dev, "starting ad7414 update\n");
+
+		/* This is the difference - set one-shot.
+		 *
+		 * After fairly extensive testing it looks like the config
+		 * always returns 0x40. So since I was told to write 0x44, I
+		 * am not only following orders but save a read. The udelay is
+		 * required for the one shot.
+		 *
+		 * Turning this on doesn't seem to make a difference and it
+		 * will only be called every second so it looks like a
+		 * relatively harmless change.
+		 */
+		ad7414_write(client, AD7414_REG_CONF, 0x44);
+		udelay(29);
+		/* */
+
+		data->temp_input = ad7414_read(client, AD7414_REG_TEMP);
+		data->temp_alert = (data->temp_input >> 5) & 0x01;
+		data->temp_max_flag = (data->temp_input >> 4) & 0x01;
+		data->temp_min_flag = (data->temp_input >> 3) & 0x01;
+		data->temp_max = ad7414_read(client, AD7414_REG_T_HIGH);
+		data->temp_min = ad7414_read(client, AD7414_REG_T_LOW);
+
+		data->last_updated = jiffies;
+		data->valid = 1;
+	}
+
+	mutex_unlock(&data->lock);
+
+	return data;
+}
+
+int ad7414_get_temp(void)
+{
+	if(ad7414_dev) {
+		struct ad7414_data *data = ad7414_update_device(ad7414_dev);
+		return data->temp_input;
+	} else
+		return 0x1f4; // +125
+}
+EXPORT_SYMBOL(ad7414_get_temp);
+
+#define show(value) \
+static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf)		\
+{									\
+	struct ad7414_data *data = ad7414_update_device(dev);		\
+	return sprintf(buf, "%d\n", AD7414_TEMP_FROM_REG(data->value));	\
+}
+show(temp_input);
+
+#define show_8(value)	\
+static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf)		\
+{								\
+	struct ad7414_data *data = ad7414_update_device(dev);	\
+	return sprintf(buf, "%d\n", data->value);		\
+}
+show_8(temp_max);
+show_8(temp_min);
+show_8(temp_alert);
+show_8(temp_max_flag);
+show_8(temp_min_flag);
+
+#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 ad7414_data *data = i2c_get_clientdata(client);	\
+	int temp = simple_strtoul(buf, NULL, 10);		\
+								\
+	mutex_lock(&data->lock);				\
+	data->value = temp;					\
+	ad7414_write(client, reg, data->value);			\
+	mutex_unlock(&data->lock);				\
+	return count;						\
+}
+set(temp_max, AD7414_REG_T_HIGH);
+set(temp_min, AD7414_REG_T_LOW);
+
+static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max, set_temp_max);
+static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp_min, set_temp_min);
+static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL);
+static DEVICE_ATTR(temp1_alert, S_IRUGO, show_temp_alert, NULL);
+static DEVICE_ATTR(temp1_max_flag, S_IRUGO, show_temp_max_flag, NULL);
+static DEVICE_ATTR(temp1_min_flag, S_IRUGO, show_temp_min_flag, NULL);
+
+static int ad7414_attach_adapter(struct i2c_adapter *adapter)
+{
+	if (!(adapter->class & I2C_CLASS_HWMON))
+		return 0;
+	return i2c_probe(adapter, &addr_data, ad7414_detect);
+}
+
+static struct attribute *ad7414_attributes[] = {
+	&dev_attr_temp1_input.attr,
+	&dev_attr_temp1_max.attr,
+	&dev_attr_temp1_min.attr,
+	&dev_attr_temp1_alert.attr,
+	&dev_attr_temp1_max_flag.attr,
+	&dev_attr_temp1_min_flag.attr,
+	NULL
+};
+
+static const struct attribute_group ad7414_group = {
+	.attrs = ad7414_attributes,
+};
+
+static int ad7414_detect(struct i2c_adapter *adapter, int address, int kind)
+{
+	struct i2c_client *client;
+	struct ad7414_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 ad7414_data), GFP_KERNEL))) {
+		err = -ENOMEM;
+		goto exit;
+	}
+
+	client = &data->client;
+	client->addr = address;
+	client->adapter = adapter;
+	client->driver = &ad7414_driver;
+	client->flags = 0;
+
+	i2c_set_clientdata(client, data);
+
+	mutex_init(&data->lock);
+
+	/* TODO: not testing for AD7414 done yet... */
+
+	strlcpy(client->name, ad7414_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 AD7414 chip */
+	ad7414_init_client(client);
+
+	/* Register sysfs hooks */
+	if ((err = sysfs_create_group(&client->dev.kobj, &ad7414_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, &ad7414_group);
+exit_detach:
+	i2c_detach_client(client);
+exit_free:
+	kfree(data);
+exit:
+	return err;
+}
+
+static int ad7414_detach_client(struct i2c_client *client)
+{
+	struct ad7414_data *data = i2c_get_clientdata(client);
+	ad7414_dev = NULL;
+	hwmon_device_unregister(data->class_dev);
+	sysfs_remove_group(&client->dev.kobj, &ad7414_group);
+	i2c_detach_client(client);
+	kfree(data);
+	return 0;
+}
+
+static int __init ad7414_init(void)
+{
+	return i2c_add_driver(&ad7414_driver);
+}
+
+static void __exit ad7414_exit(void)
+{
+	i2c_del_driver(&ad7414_driver);
+}
+
+MODULE_AUTHOR("Stefan Roese <sr@denx.de>");
+MODULE_DESCRIPTION("AD7414 driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+
+module_init(ad7414_init);
+module_exit(ad7414_exit);
--- /dev/null	2005-11-20 22:22:37.000000000 -0500
+++ drivers/hwmon/taco-dtm.c	2008-01-05 00:06:21.000000000 -0500
@@ -0,0 +1,78 @@
+/*
+ *  drivers/hwmon/taco-dtm.c
+ *
+ *  Overview: On the Taco, the fpga controls the fan. This provides
+ *  the temperature to the fpga.
+ *
+ *  Copyright (c) 2008 PIKA Technologies
+ *    Sean MacLennan <smaclennan@pikatech.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;  either version 2 of the	License, or (at your
+ *  option) any later version.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/io.h>
+
+
+#define TACO_FPGA_BASE 0x80000000
+
+
+extern int ad7414_get_temp(void);
+
+static unsigned __iomem *dtm_fpga;
+static struct task_struct *dtm_thread;
+
+
+static int taco_dtm_thread(void *arg)
+{
+	while(!kthread_should_stop()) {
+		int temp = ad7414_get_temp();
+
+		// Write to FPGA
+		out_be32(dtm_fpga, temp);
+
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule_timeout(HZ);
+	}
+
+	return 0;
+}
+
+
+int __init taco_dtm_init_module(void)
+{
+	if((dtm_fpga = ioremap(TACO_FPGA_BASE + 0x20, 4)) == 0) {
+		printk("FPGA ioremap failed\n");
+		return -ENODEV;
+	}
+
+	dtm_thread = kthread_run(taco_dtm_thread, NULL, "taco-dtm");
+
+	if(IS_ERR(dtm_thread)) {
+		iounmap(dtm_fpga);
+		printk("Unable to start Taco DTM thread\n");
+		return PTR_ERR(dtm_thread);
+	}
+
+	return 0;
+}
+
+
+void __exit taco_dtm_exit_module(void)
+{
+	kthread_stop(dtm_thread);
+	iounmap(dtm_fpga);
+}
+
+
+module_init(taco_dtm_init_module);
+module_exit(taco_dtm_exit_module);
+
+MODULE_DESCRIPTION("PIKA DTM driver");
+MODULE_AUTHOR("Sean MacLennan");
+MODULE_LICENSE("GPL");