[PATCH] i2c #1/3: listify i2c core

This is the first of tree patches for i2c.  Trying to get the i2c
cleanups finshed before 2.6.x, so we (hopefully) don't have a
ever-changing i2c subsystem in 2.7.x again (which is very annonying for
driver maintainance).

Changes:

 * listify i2c-core, i.e. make it use <linux/list.h> instead of
   statically-sized arrays, removed lots of ugly code :)
 * added i2c_(get|put)_adapter, changed i2c-dev.c to use these
   functions instead maintaining is own adapter list.
 * killed the I2C_DF_DUMMY flag which had the strange semantics to
   make the i2c subsystem call driver->attach_adapter on detaches.
   Added a detach_adapter() callback instead.
 * some other minor cleanups along the way ...

drivers/i2c/i2c-dev.c

@@ -58,6 +58,7 @@ static int i2cdev_open (struct inode *inode, struct file *file);
 static int i2cdev_release (struct inode *inode, struct file *file);
 
 static int i2cdev_attach_adapter(struct i2c_adapter *adap);
+static int i2cdev_detach_adapter(struct i2c_adapter *adap);
 static int i2cdev_detach_client(struct i2c_client *client);
 static int i2cdev_command(struct i2c_client *client, unsigned int cmd,
                            void *arg);
@@ -72,15 +73,13 @@ static struct file_operations i2cdev_fops = {
 	.release	= i2cdev_release,
 };
 
-#define I2CDEV_ADAPS_MAX I2C_ADAP_MAX
-static struct i2c_adapter *i2cdev_adaps[I2CDEV_ADAPS_MAX];
-
 static struct i2c_driver i2cdev_driver = {
 	.owner		= THIS_MODULE,
 	.name		= "dev driver",
 	.id		= I2C_DRIVERID_I2CDEV,
-	.flags		= I2C_DF_DUMMY,
+	.flags		= I2C_DF_NOTIFY,
 	.attach_adapter	= i2cdev_attach_adapter,
+	.detach_adapter	= i2cdev_detach_adapter,
 	.detach_client	= i2cdev_detach_client,
 	.command	= i2cdev_command,
 };
@@ -340,35 +339,31 @@ static int i2cdev_open(struct inode *inode, struct file *file)
 {
 	unsigned int minor = minor(inode->i_rdev);
 	struct i2c_client *client;
+	struct i2c_adapter *adap;
 
-	if ((minor >= I2CDEV_ADAPS_MAX) || !(i2cdev_adaps[minor]))
+	adap = i2c_get_adapter(minor);
+	if (NULL == adap)
 		return -ENODEV;
 
 	client = kmalloc(sizeof(*client), GFP_KERNEL);
-	if (!client)
+	if (!client) {
+		i2c_put_adapter(adap);
 		return -ENOMEM;
+	}
 	memcpy(client, &i2cdev_client_template, sizeof(*client));
 
 	/* registered with adapter, passed as client to user */
-	client->adapter = i2cdev_adaps[minor];
+	client->adapter = adap;
 	file->private_data = client;
 
-	/* use adapter module, i2c-dev handled with fops */
-	if (!try_module_get(client->adapter->owner))
-		goto out_kfree;
-
 	return 0;
-
-out_kfree:
-	kfree(client);
-	return -ENODEV;
 }
 
 static int i2cdev_release(struct inode *inode, struct file *file)
 {
 	struct i2c_client *client = file->private_data;
 
-	module_put(client->adapter->owner);
+	i2c_put_adapter(client->adapter);
 	kfree(client);
 	file->private_data = NULL;
 
@@ -377,33 +372,28 @@ static int i2cdev_release(struct inode *inode, struct file *file)
 
 int i2cdev_attach_adapter(struct i2c_adapter *adap)
 {
-	int i;
 	char name[12];
+	int i;
 
-	if ((i = i2c_adapter_id(adap)) < 0) {
-		dev_dbg(&adap->dev, "Unknown adapter ?!?\n");
-		return -ENODEV;
-	}
-	if (i >= I2CDEV_ADAPS_MAX) {
-		dev_dbg(&adap->dev, "Adapter number too large?!? (%d)\n",i);
-		return -ENODEV;
-	}
-
+	i = i2c_adapter_id(adap);
 	sprintf (name, "i2c/%d", i);
-	if (! i2cdev_adaps[i]) {
-		i2cdev_adaps[i] = adap;
-		devfs_register (NULL, name,
+
+	devfs_register (NULL, name,
 			DEVFS_FL_DEFAULT, I2C_MAJOR, i,
 			S_IFCHR | S_IRUSR | S_IWUSR,
 			&i2cdev_fops, NULL);
-		dev_dbg(&adap->dev, "Registered as minor %d\n", i);
-	} else {
-		/* This is actually a detach_adapter call! */
-		devfs_remove("i2c/%d", i);
-		i2cdev_adaps[i] = NULL;
-		dev_dbg(&adap->dev, "Adapter unregistered\n");
-	}
+	dev_dbg(&adap->dev, "Registered as minor %d\n", i);
+	return 0;
+}
+
+int i2cdev_detach_adapter(struct i2c_adapter *adap)
+{
+	int i;
+
+	i = i2c_adapter_id(adap);
 
+	devfs_remove("i2c/%d", i);
+	dev_dbg(&adap->dev, "Adapter unregistered\n");
 	return 0;
 }
 

drivers/media/video/dpc7146.c

@@ -96,7 +96,8 @@ struct dpc
 static int dpc_probe(struct saa7146_dev* dev)
 {
 	struct dpc* dpc = 0;	
-	int i = 0;
+	struct i2c_client *client;
+	struct list_head *item;
 
 	dpc = (struct dpc*)kmalloc(sizeof(struct dpc), GFP_KERNEL);
 	if( NULL == dpc ) {
@@ -117,12 +118,10 @@ static int dpc_probe(struct saa7146_dev* dev)
 	}
 
 	/* loop through all i2c-devices on the bus and look who is there */
-	for(i = 0; i < I2C_CLIENT_MAX; i++) {
-		if( NULL == dpc->i2c_adapter.clients[i] ) {
-			continue;
-		}
-		if( I2C_SAA7111A == dpc->i2c_adapter.clients[i]->addr ) 
-			dpc->saa7111a = dpc->i2c_adapter.clients[i];
+	list_for_each(item,&dpc->i2c_adapter.clients) {
+		client = list_entry(item, struct i2c_client, list);
+		if( I2C_SAA7111A == client->addr ) 
+			dpc->saa7111a = client;
 	}
 
 	/* check if all devices are present */

drivers/media/video/mxb.c

@@ -208,7 +208,8 @@ static int mxb_vbi_bypass(struct saa7146_dev* dev)
 static int mxb_probe(struct saa7146_dev* dev)
 {
 	struct mxb* mxb = 0;
-	int i = 0;	
+	struct i2c_client *client;
+	struct list_head *item;
 
 	request_module("tuner");
 	request_module("tea6420");
@@ -235,22 +236,20 @@ static int mxb_probe(struct saa7146_dev* dev)
 	}
 
 	/* loop through all i2c-devices on the bus and look who is there */
-	for(i = 0; i < I2C_CLIENT_MAX; i++) {
-		if( NULL == mxb->i2c_adapter.clients[i] ) {
-			continue;
-		}
-		if( I2C_TEA6420_1 == mxb->i2c_adapter.clients[i]->addr )
-			mxb->tea6420_1 = mxb->i2c_adapter.clients[i];
-		if( I2C_TEA6420_2 == mxb->i2c_adapter.clients[i]->addr ) 
-			mxb->tea6420_2 = mxb->i2c_adapter.clients[i];
-		if( I2C_TEA6415C_2 == mxb->i2c_adapter.clients[i]->addr ) 
-			mxb->tea6415c = mxb->i2c_adapter.clients[i];
-		if( I2C_TDA9840 == mxb->i2c_adapter.clients[i]->addr ) 
-			mxb->tda9840 = mxb->i2c_adapter.clients[i];
-		if( I2C_SAA7111A == mxb->i2c_adapter.clients[i]->addr ) 
-			mxb->saa7111a = mxb->i2c_adapter.clients[i];
-		if( 0x60 == mxb->i2c_adapter.clients[i]->addr ) 
-			mxb->tuner = mxb->i2c_adapter.clients[i];
+	list_for_each(item,&mxb->i2c_adapter.clients) {
+		client = list_entry(item, struct i2c_client, list);
+		if( I2C_TEA6420_1 == client->addr )
+			mxb->tea6420_1 = client;
+		if( I2C_TEA6420_2 == client->addr ) 
+			mxb->tea6420_2 = client;
+		if( I2C_TEA6415C_2 == client->addr ) 
+			mxb->tea6415c = client;
+		if( I2C_TDA9840 == client->addr ) 
+			mxb->tda9840 = client;
+		if( I2C_SAA7111A == client->addr ) 
+			mxb->saa7111a = client;
+		if( 0x60 == client->addr ) 
+			mxb->tuner = client;
 	}
 
 	/* check if all devices are present */

drivers/media/video/tvmixer.c

@@ -217,8 +217,9 @@ static struct i2c_driver driver = {
 	.owner           = THIS_MODULE,
 	.name            = "tv card mixer driver",
         .id              = I2C_DRIVERID_TVMIXER,
-	.flags           = I2C_DF_DUMMY,
+	.flags           = I2C_DF_NOTIFY,
         .attach_adapter  = tvmixer_adapters,
+        .detach_adapter  = tvmixer_adapters,
         .detach_client   = tvmixer_clients,
 };
 
@@ -234,14 +235,15 @@ static struct file_operations tvmixer_fops = {
 
 static int tvmixer_adapters(struct i2c_adapter *adap)
 {
-	int i;
+	struct list_head  *item;
+	struct i2c_client *client;
 
 	if (debug)
 		printk("tvmixer: adapter %s\n",adap->dev.name);
-	for (i=0; i<I2C_CLIENT_MAX; i++) {
-		if (!adap->clients[i])
-			continue;
-		tvmixer_clients(adap->clients[i]);
+
+	list_for_each(item,&adap->clients) {
+		client = list_entry(item, struct i2c_client, list);
+		tvmixer_clients(client);
 	}
 	return 0;
 }
@@ -264,7 +266,8 @@ static int tvmixer_clients(struct i2c_client *client)
 			       client->adapter->dev.name);
 		return -1;
 	}
-	printk("tvmixer: debug: %s\n",client->dev.name);
+	if (debug)
+		printk("tvmixer: debug: %s\n",client->dev.name);
 
 	/* unregister ?? */
 	for (i = 0; i < DEV_MAX; i++) {

include/linux/i2c.h

@@ -39,12 +39,6 @@
 
 /* --- General options ------------------------------------------------	*/
 
-#define I2C_ALGO_MAX	4		/* control memory consumption	*/
-#define I2C_ADAP_MAX	16
-#define I2C_DRIVER_MAX	16
-#define I2C_CLIENT_MAX	32
-#define I2C_DUMMY_MAX 4
-
 struct i2c_msg;
 struct i2c_algorithm;
 struct i2c_adapter;
@@ -131,6 +125,7 @@ struct i2c_driver {
 	 * i2c_attach_client.
 	 */
 	int (*attach_adapter)(struct i2c_adapter *);
+	int (*detach_adapter)(struct i2c_adapter *);
 
 	/* tells the driver that a client is about to be deleted & gives it 
 	 * the chance to remove its private data. Also, if the client struct
@@ -145,6 +140,7 @@ struct i2c_driver {
 	int (*command)(struct i2c_client *client,unsigned int cmd, void *arg);
 
 	struct device_driver driver;
+	struct list_head list;
 };
 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
 
@@ -169,6 +165,7 @@ struct i2c_client {
 	int usage_count;		/* How many accesses currently  */
 					/* to the client		*/
 	struct device dev;		/* the device structure		*/
+	struct list_head list;
 };
 #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
 
@@ -236,12 +233,10 @@ struct i2c_adapter {
 	int (*client_unregister)(struct i2c_client *);
 
 	/* data fields that are valid for all devices	*/
-	struct semaphore bus;
-	struct semaphore list;  
+	struct semaphore bus_lock;
+	struct semaphore clist_lock;
 	unsigned int flags;/* flags specifying div. data		*/
 
-	struct i2c_client *clients[I2C_CLIENT_MAX];
-
 	int timeout;
 	int retries;
 	struct device dev;	/* the adapter device */
@@ -250,6 +245,10 @@ struct i2c_adapter {
 	/* No need to set this when you initialize the adapter          */
 	int inode;
 #endif /* def CONFIG_PROC_FS */
+
+	int nr;
+	struct list_head clients;
+	struct list_head list;
 };
 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
 
@@ -265,7 +264,11 @@ static inline void i2c_set_adapdata (struct i2c_adapter *dev, void *data)
 
 /*flags for the driver struct: */
 #define I2C_DF_NOTIFY	0x01		/* notify on bus (de/a)ttaches 	*/
-#define I2C_DF_DUMMY	0x02		/* do not connect any clients */
+#if 0
+/* this flag is gone -- there is a (optional) driver->detach_adapter
+ * callback now which can be used instead */
+# define I2C_DF_DUMMY	0x02
+#endif
 
 /*flags for the client struct: */
 #define I2C_CLIENT_ALLOW_USE		0x01	/* Client allows access */
@@ -352,7 +355,8 @@ extern int i2c_control(struct i2c_client *,unsigned int, unsigned long);
  * or -1 if the adapter was not registered. 
  */
 extern int i2c_adapter_id(struct i2c_adapter *adap);
-
+extern struct i2c_adapter* i2c_get_adapter(int id);
+extern void i2c_put_adapter(struct i2c_adapter *adap);
 
 
 /* Return the functionality mask */