Changeset 3417

Timestamp:

12/08/99 21:33:58 (9 years ago)

Author:

frodo

Message:

Previously announced i2c_check_addr function added

Changes in i2c-core.c:

i2c_check_addr(adapter,addr) checks all registered clients of this adapter
to see whether addr is already claimed. If so, it returns -EBUSY; if not,
it returns 0.

i2c_attach_client returns -EBUSY if you try to register a client whose
address is already in use. Note that you can cheat by using a client
without registering it; there is no check for this (I can imagine
situations in which this is useful).

i2c_probe will skip already used addresses.

Changes in i2c-dev.c:

Ioctl I2C_SLAVE (which sets the address to read from/write to) fails
if you try to set it to an already used address. A new ioctl called
I2C_SLAVE_FORCE overrides this, allowing you to access already
claimed addresses. This is the old behaviour, AND MAY BE DANGEROUS!

Files:

• i2c/trunk/doc/writing-clients (modified) (1 diff)
• i2c/trunk/kernel/i2c-core.c (modified) (4 diffs)
• i2c/trunk/kernel/i2c-dev.c (modified) (1 diff)
• i2c/trunk/kernel/i2c.h (modified) (2 diffs)

i2c/trunk/doc/writing-clients

@@ -357 +357 @@
-The i2c_probe or sensors_detect function will call the foo_detect_client
-function only for those i2c addresses that actually have a device on
-
+
+
-
-

i2c/trunk/kernel/i2c-core.c

@@ -452 +452 @@
-}
-
+int i2c_check_addr (struct i2c_adapter *adapter, int addr)
+{
+  int i;
+  for (i = 0; i < I2C_CLIENT_MAX ; i++) 
+    if (adapter->clients[i] && (adapter->clients[i]->addr == addr))
+      return -EBUSY;
+  return 0;
+}
-
-int i2c_attach_client(struct i2c_client *client)
@@ -457 +465 @@
-        struct i2c_adapter *adapter = client->adapter;
-        int i;
+
+        if (i2c_check_addr(client->adapter,client->addr))
+          return -EBUSY;
-
-        for (i = 0; i < I2C_CLIENT_MAX; i++)
@@ -855 +866 @@
-       addr <= 0x7f;
-       addr++) {
+
+    /* Skip if already in use */
+    if (i2c_check_addr(adapter,addr))
+      continue;
-
-    /* If it is in one of the force entries, we don't do any detection
@@ -1312 +1327 @@
-EXPORT_SYMBOL(i2c_inc_use_client);
-EXPORT_SYMBOL(i2c_dec_use_client);
+EXPORT_SYMBOL(i2c_check_addr);
-
-

i2c/trunk/kernel/i2c-dev.c

@@ -278 +278 @@
-  switch ( cmd ) {
-    case I2C_SLAVE:
+    case I2C_SLAVE_FORCE:
-      if ((arg > 0x3ff) || (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
-        return -EINVAL;
+      if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg))
+        return -EBUSY;
-      client->addr = arg;
-      return 0;

i2c/trunk/kernel/i2c.h

@@ -325 +325 @@
-extern void i2c_dec_use_client(struct i2c_client *);
-
+/* returns -EBUSY if address has been taken, 0 if not. Note that the only
+   other place at which this is called is within i2c_attach_client; so
+   you can cheat by simply not registering. Not recommended, of course! */
+extern int i2c_check_addr (struct i2c_adapter *adapter, int addr);
-
-/* Detect function. It itterates over all possible addresses itself.
@@ -428 +432 @@
-#define I2C_SLAVE       0x0703  /* Change slave address                 */
-                                /* Attn.: Slave address is 7 or 10 bits */
+#define I2C_SLAVE_FORCE 0x0706  /* Change slave address                 */
+                                /* Attn.: Slave address is 7 or 10 bits */
+                                /* This changes the address, even if it */
+                                /* is already taken!                    */
-#define I2C_TENBIT      0x0704  /* 0 for 7 bit addrs, != 0 for 10 bit   */
-