i8k: Integrate with the hwmon subsystem

Let i8k create an hwmon class device so that libsensors will expose
the CPU temperature and fan speeds to monitoring applications.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Massimo Dal Zotto <dz@debian.org>

arch/x86/Kconfig

@@ -917,6 +917,7 @@ config TOSHIBA
 
 config I8K
 	tristate "Dell laptop support"
+	select HWMON
 	---help---
 	  This adds a driver to safely access the System Management Mode
 	  of the CPU on the Dell Inspiron 8000. The System Management Mode

drivers/char/i8k.c

@@ -5,6 +5,9 @@
  *
  * Copyright (C) 2001  Massimo Dal Zotto <dz@debian.org>
  *
+ * Hwmon integration:
+ * Copyright (C) 2011  Jean Delvare <khali@linux-fr.org>
+ *
  * 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, or (at your option) any
@@ -24,6 +27,8 @@
 #include <linux/dmi.h>
 #include <linux/capability.h>
 #include <linux/mutex.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
 #include <asm/uaccess.h>
 #include <asm/io.h>
 
@@ -58,6 +63,7 @@
 
 static DEFINE_MUTEX(i8k_mutex);
 static char bios_version[4];
+static struct device *i8k_hwmon_dev;
 
 MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
 MODULE_DESCRIPTION("Driver for accessing SMM BIOS on Dell laptops");
@@ -455,6 +461,152 @@ static int i8k_open_fs(struct inode *inode, struct file *file)
 	return single_open(file, i8k_proc_show, NULL);
 }
 
+
+/*
+ * Hwmon interface
+ */
+
+static ssize_t i8k_hwmon_show_temp(struct device *dev,
+				   struct device_attribute *devattr,
+				   char *buf)
+{
+	int cpu_temp;
+
+	cpu_temp = i8k_get_temp(0);
+	if (cpu_temp < 0)
+		return cpu_temp;
+	return sprintf(buf, "%d\n", cpu_temp * 1000);
+}
+
+static ssize_t i8k_hwmon_show_fan(struct device *dev,
+				  struct device_attribute *devattr,
+				  char *buf)
+{
+	int index = to_sensor_dev_attr(devattr)->index;
+	int fan_speed;
+
+	fan_speed = i8k_get_fan_speed(index);
+	if (fan_speed < 0)
+		return fan_speed;
+	return sprintf(buf, "%d\n", fan_speed);
+}
+
+static ssize_t i8k_hwmon_show_label(struct device *dev,
+				    struct device_attribute *devattr,
+				    char *buf)
+{
+	static const char *labels[4] = {
+		"i8k",
+		"CPU",
+		"Left Fan",
+		"Right Fan",
+	};
+	int index = to_sensor_dev_attr(devattr)->index;
+
+	return sprintf(buf, "%s\n", labels[index]);
+}
+
+static DEVICE_ATTR(temp1_input, S_IRUGO, i8k_hwmon_show_temp, NULL);
+static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, i8k_hwmon_show_fan, NULL,
+			  I8K_FAN_LEFT);
+static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, i8k_hwmon_show_fan, NULL,
+			  I8K_FAN_RIGHT);
+static SENSOR_DEVICE_ATTR(name, S_IRUGO, i8k_hwmon_show_label, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, i8k_hwmon_show_label, NULL, 1);
+static SENSOR_DEVICE_ATTR(fan1_label, S_IRUGO, i8k_hwmon_show_label, NULL, 2);
+static SENSOR_DEVICE_ATTR(fan2_label, S_IRUGO, i8k_hwmon_show_label, NULL, 3);
+
+static void i8k_hwmon_remove_files(struct device *dev)
+{
+	device_remove_file(dev, &dev_attr_temp1_input);
+	device_remove_file(dev, &sensor_dev_attr_fan1_input.dev_attr);
+	device_remove_file(dev, &sensor_dev_attr_fan2_input.dev_attr);
+	device_remove_file(dev, &sensor_dev_attr_temp1_label.dev_attr);
+	device_remove_file(dev, &sensor_dev_attr_fan1_label.dev_attr);
+	device_remove_file(dev, &sensor_dev_attr_fan2_label.dev_attr);
+	device_remove_file(dev, &sensor_dev_attr_name.dev_attr);
+}
+
+static int __init i8k_init_hwmon(void)
+{
+	int err;
+
+	i8k_hwmon_dev = hwmon_device_register(NULL);
+	if (IS_ERR(i8k_hwmon_dev)) {
+		err = PTR_ERR(i8k_hwmon_dev);
+		i8k_hwmon_dev = NULL;
+		printk(KERN_ERR "i8k: hwmon registration failed (%d)\n", err);
+		return err;
+	}
+
+	/* Required name attribute */
+	err = device_create_file(i8k_hwmon_dev,
+				 &sensor_dev_attr_name.dev_attr);
+	if (err)
+		goto exit_unregister;
+
+	/* CPU temperature attributes, if temperature reading is OK */
+	err = i8k_get_temp(0);
+	if (err < 0) {
+		dev_dbg(i8k_hwmon_dev,
+			"Not creating temperature attributes (%d)\n", err);
+	} else {
+		err = device_create_file(i8k_hwmon_dev, &dev_attr_temp1_input);
+		if (err)
+			goto exit_remove_files;
+		err = device_create_file(i8k_hwmon_dev,
+					 &sensor_dev_attr_temp1_label.dev_attr);
+		if (err)
+			goto exit_remove_files;
+	}
+
+	/* Left fan attributes, if left fan is present */
+	err = i8k_get_fan_status(I8K_FAN_LEFT);
+	if (err < 0) {
+		dev_dbg(i8k_hwmon_dev,
+			"Not creating %s fan attributes (%d)\n", "left", err);
+	} else {
+		err = device_create_file(i8k_hwmon_dev,
+					 &sensor_dev_attr_fan1_input.dev_attr);
+		if (err)
+			goto exit_remove_files;
+		err = device_create_file(i8k_hwmon_dev,
+					 &sensor_dev_attr_fan1_label.dev_attr);
+		if (err)
+			goto exit_remove_files;
+	}
+
+	/* Right fan attributes, if right fan is present */
+	err = i8k_get_fan_status(I8K_FAN_RIGHT);
+	if (err < 0) {
+		dev_dbg(i8k_hwmon_dev,
+			"Not creating %s fan attributes (%d)\n", "right", err);
+	} else {
+		err = device_create_file(i8k_hwmon_dev,
+					 &sensor_dev_attr_fan2_input.dev_attr);
+		if (err)
+			goto exit_remove_files;
+		err = device_create_file(i8k_hwmon_dev,
+					 &sensor_dev_attr_fan2_label.dev_attr);
+		if (err)
+			goto exit_remove_files;
+	}
+
+	return 0;
+
+ exit_remove_files:
+	i8k_hwmon_remove_files(i8k_hwmon_dev);
+ exit_unregister:
+	hwmon_device_unregister(i8k_hwmon_dev);
+	return err;
+}
+
+static void __exit i8k_exit_hwmon(void)
+{
+	i8k_hwmon_remove_files(i8k_hwmon_dev);
+	hwmon_device_unregister(i8k_hwmon_dev);
+}
+
 static struct dmi_system_id __initdata i8k_dmi_table[] = {
 	{
 		.ident = "Dell Inspiron",
@@ -580,6 +732,7 @@ static int __init i8k_probe(void)
 static int __init i8k_init(void)
 {
 	struct proc_dir_entry *proc_i8k;
+	int err;
 
 	/* Are we running on an supported laptop? */
 	if (i8k_probe())
@@ -590,15 +743,24 @@ static int __init i8k_init(void)
 	if (!proc_i8k)
 		return -ENOENT;
 
+	err = i8k_init_hwmon();
+	if (err)
+		goto exit_remove_proc;
+
 	printk(KERN_INFO
 	       "Dell laptop SMM driver v%s Massimo Dal Zotto (dz@debian.org)\n",
 	       I8K_VERSION);
 
 	return 0;
+
+ exit_remove_proc:
+	remove_proc_entry("i8k", NULL);
+	return err;
 }
 
 static void __exit i8k_exit(void)
 {
+	i8k_exit_hwmon();
 	remove_proc_entry("i8k", NULL);
 }