2 files changed, 177 insertions, 10 deletions

diff --git a/drivers/i2c/busses/i2c-isa.c b/drivers/i2c/busses/i2c-isa.c
index 00e7f7157b75..a60f4801757e 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
@@ -18,17 +20,24 @@
     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);
 
@@ -53,17 +62,146 @@ 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");
 
diff --git a/include/linux/i2c-isa.h b/include/linux/i2c-isa.h
new file mode 100644
index 000000000000..b5727d7702e1
--- /dev/null
+++ b/include/linux/i2c-isa.h
@@ -0,0 +1,29 @@
+/*
+ * i2c-isa.h - definitions for the i2c-isa pseudo-i2c-adapter interface
+ *
+ * Copyright (C) 2005 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 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef _LINUX_I2C_ISA_H
+#define _LINUX_I2C_ISA_H
+
+#include <linux/i2c.h>
+
+extern int i2c_isa_add_driver(struct i2c_driver *driver);
+extern int i2c_isa_del_driver(struct i2c_driver *driver);
+
+#endif /* _LINUX_I2C_ISA_H */