diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-isa.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-isa.c | 161 |
1 files changed, 149 insertions, 12 deletions
diff --git a/drivers/i2c/busses/i2c-isa.c b/drivers/i2c/busses/i2c-isa.c index 00e7f7157b7..bdc6806dafa 100644 --- a/drivers/i2c/busses/i2c-isa.c +++ b/drivers/i2c/busses/i2c-isa.c @@ -1,6 +1,8 @@ /* - 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 @@ -18,30 +20,36 @@ 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> 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", @@ -53,17 +61,146 @@ static u32 isa_func(struct i2c_adapter *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.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"); |