/*
- i2c-isa.c - Part of lm_sensors, Linux kernel modules for hardware
- monitoring
+ i2c-isa.c - an i2c-core-like thing for ISA hardware monitoring chips
+ Copyright (C) 2005 Jean Delvare <khali@linux-fr.org>
+
+ Based on the i2c-isa pseudo-adapter from the lm_sensors project
Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl>
This program is free software; you can redistribute it and/or modify
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
-/* This implements an i2c algorithm/adapter for ISA bus. Not that this is
- on first sight very useful; almost no functionality is preserved.
- Except that it makes writing drivers for chips which can be on both
- the SMBus and the ISA bus very much easier. See lm78.c for an example
- of this. */
+/* This implements an i2c-core-like thing for ISA hardware monitoring
+ chips. Such chips are linked to the i2c subsystem for historical
+ reasons (because the early ISA hardware monitoring chips such as the
+ LM78 had both an I2C and an ISA interface). They used to be
+ registered with the main i2c-core, but as a first step in the
+ direction of a clean separation between I2C and ISA chip drivers,
+ we now have this separate core for ISA ones. It is significantly
+ more simple than the real one, of course, because we don't have to
+ handle multiple busses: there is only one (fake) ISA adapter.
+ It is worth noting that we still rely on i2c-core for some things
+ at the moment - but hopefully this won't last. */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/i2c.h>
+#include <linux/i2c-isa.h>
+#include <linux/platform_device.h>
static u32 isa_func(struct i2c_adapter *adapter);
/* This is the actual algorithm we define */
static struct i2c_algorithm isa_algorithm = {
- .name = "ISA bus algorithm",
- .id = I2C_ALGO_ISA,
.functionality = isa_func,
};
/* There can only be one... */
static struct i2c_adapter isa_adapter = {
.owner = THIS_MODULE,
+ .id = I2C_HW_ISA,
.class = I2C_CLASS_HWMON,
.algo = &isa_algorithm,
.name = "ISA main adapter",
return 0;
}
+
+/* Copied from i2c-core */
+static ssize_t show_adapter_name(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct i2c_adapter *adap = dev_to_i2c_adapter(dev);
+ return sprintf(buf, "%s\n", adap->name);
+}
+static DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
+
+static int i2c_isa_device_probe(struct device *dev)
+{
+ return -ENODEV;
+}
+
+static int i2c_isa_device_remove(struct device *dev)
+{
+ return 0;
+}
+
+
+/* We implement an interface which resembles i2c_{add,del}_driver,
+ but for i2c-isa drivers. We don't have to remember and handle lists
+ of drivers and adapters so this is much more simple, of course. */
+
+int i2c_isa_add_driver(struct i2c_driver *driver)
+{
+ int res;
+
+ /* Add the driver to the list of i2c drivers in the driver core */
+ driver->driver.name = driver->name;
+ driver->driver.owner = driver->owner;
+ driver->driver.bus = &i2c_bus_type;
+ driver->driver.probe = i2c_isa_device_probe;
+ driver->driver.remove = i2c_isa_device_remove;
+ res = driver_register(&driver->driver);
+ if (res)
+ return res;
+ dev_dbg(&isa_adapter.dev, "Driver %s registered\n", driver->name);
+
+ /* Now look for clients */
+ driver->attach_adapter(&isa_adapter);
+
+ return 0;
+}
+
+int i2c_isa_del_driver(struct i2c_driver *driver)
+{
+ struct list_head *item, *_n;
+ struct i2c_client *client;
+ int res;
+
+ /* Detach all clients belonging to this one driver */
+ list_for_each_safe(item, _n, &isa_adapter.clients) {
+ client = list_entry(item, struct i2c_client, list);
+ if (client->driver != driver)
+ continue;
+ dev_dbg(&isa_adapter.dev, "Detaching client %s at 0x%x\n",
+ client->name, client->addr);
+ if ((res = driver->detach_client(client))) {
+ dev_err(&isa_adapter.dev, "Failed, driver "
+ "%s not unregistered!\n",
+ driver->name);
+ return res;
+ }
+ }
+
+ /* Get the driver off the core list */
+ driver_unregister(&driver->driver);
+ dev_dbg(&isa_adapter.dev, "Driver %s unregistered\n", driver->name);
+
+ return 0;
+}
+
+
static int __init i2c_isa_init(void)
{
- return i2c_add_adapter(&isa_adapter);
+ init_MUTEX(&isa_adapter.clist_lock);
+ INIT_LIST_HEAD(&isa_adapter.clients);
+
+ isa_adapter.nr = ANY_I2C_ISA_BUS;
+ isa_adapter.dev.parent = &platform_bus;
+ sprintf(isa_adapter.dev.bus_id, "i2c-%d", isa_adapter.nr);
+ isa_adapter.dev.driver = &i2c_adapter_driver;
+ isa_adapter.dev.release = &i2c_adapter_dev_release;
+ device_register(&isa_adapter.dev);
+ device_create_file(&isa_adapter.dev, &dev_attr_name);
+
+ /* Add this adapter to the i2c_adapter class */
+ memset(&isa_adapter.class_dev, 0x00, sizeof(struct class_device));
+ isa_adapter.class_dev.dev = &isa_adapter.dev;
+ isa_adapter.class_dev.class = &i2c_adapter_class;
+ strlcpy(isa_adapter.class_dev.class_id, isa_adapter.dev.bus_id,
+ BUS_ID_SIZE);
+ class_device_register(&isa_adapter.class_dev);
+
+ dev_dbg(&isa_adapter.dev, "%s registered\n", isa_adapter.name);
+
+ return 0;
}
static void __exit i2c_isa_exit(void)
{
- i2c_del_adapter(&isa_adapter);
+#ifdef DEBUG
+ struct list_head *item, *_n;
+ struct i2c_client *client = NULL;
+#endif
+
+ /* There should be no more active client */
+#ifdef DEBUG
+ dev_dbg(&isa_adapter.dev, "Looking for clients\n");
+ list_for_each_safe(item, _n, &isa_adapter.clients) {
+ client = list_entry(item, struct i2c_client, list);
+ dev_err(&isa_adapter.dev, "Driver %s still has an active "
+ "ISA client at 0x%x\n", client->driver->name,
+ client->addr);
+ }
+ if (client != NULL)
+ return;
+#endif
+
+ /* Clean up the sysfs representation */
+ dev_dbg(&isa_adapter.dev, "Unregistering from sysfs\n");
+ init_completion(&isa_adapter.dev_released);
+ init_completion(&isa_adapter.class_dev_released);
+ class_device_unregister(&isa_adapter.class_dev);
+ device_remove_file(&isa_adapter.dev, &dev_attr_name);
+ device_unregister(&isa_adapter.dev);
+
+ /* Wait for sysfs to drop all references */
+ dev_dbg(&isa_adapter.dev, "Waiting for sysfs completion\n");
+ wait_for_completion(&isa_adapter.dev_released);
+ wait_for_completion(&isa_adapter.class_dev_released);
+
+ dev_dbg(&isa_adapter.dev, "%s unregistered\n", isa_adapter.name);
}
-MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
+EXPORT_SYMBOL(i2c_isa_add_driver);
+EXPORT_SYMBOL(i2c_isa_del_driver);
+
+MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
MODULE_DESCRIPTION("ISA bus access through i2c");
MODULE_LICENSE("GPL");
projects / karo-tx-linux.git / blobdiff