i2c: support 10 bit and slave addresses in sysfs 'new_device'

We now have seperate address spaces for 10 bit and we-are-slave clients.
Update the sysfs device instantiation method to support these types by
accepting the address offsets that are assigned to the extra address
spaces. Update the documentation, too.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

3 files changed, 21 insertions, 4 deletions

diff --git a/Documentation/i2c/slave-interface b/Documentation/i2c/slave-interface
index 2dee4e2d62df..61ed05cd9531 100644
--- a/Documentation/i2c/slave-interface
+++ b/Documentation/i2c/slave-interface
@@ -31,10 +31,13 @@ User manual
 ===========
 
 I2C slave backends behave like standard I2C clients. So, you can instantiate
-them as described in the document 'instantiating-devices'. A quick example for
-instantiating the slave-eeprom driver from userspace at address 0x64 on bus 1:
+them as described in the document 'instantiating-devices'. The only difference
+is that i2c slave backends have their own address space. So, you have to add
+0x1000 to the address you would originally request. An example for
+instantiating the slave-eeprom driver from userspace at the 7 bit address 0x64
+on bus 1:
 
-  # echo slave-24c02 0x64 > /sys/bus/i2c/devices/i2c-1/new_device
+  # echo slave-24c02 0x1064 > /sys/bus/i2c/devices/i2c-1/new_device
 
 Each backend should come with separate documentation to describe its specific
 behaviour and setup.
diff --git a/Documentation/i2c/ten-bit-addresses b/Documentation/i2c/ten-bit-addresses
index cdfe13901b99..7b2d11e53a49 100644
--- a/Documentation/i2c/ten-bit-addresses
+++ b/Documentation/i2c/ten-bit-addresses
@@ -2,6 +2,10 @@ The I2C protocol knows about two kinds of device addresses: normal 7 bit
 addresses, and an extended set of 10 bit addresses. The sets of addresses
 do not intersect: the 7 bit address 0x10 is not the same as the 10 bit
 address 0x10 (though a single device could respond to both of them).
+To avoid ambiguity, the user sees 10 bit addresses mapped to a different
+address space, namely 0xa000-0xa3ff. The leading 0xa (= 10) represents the
+10 bit mode. This is used for creating device names in sysfs. It is also
+needed when instantiating 10 bit devices via the new_device file in sysfs.
 
 I2C messages to and from 10-bit address devices have a different format.
 See the I2C specification for the details.
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index fc6d89316144..039817eaecb5 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1158,6 +1158,16 @@ i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
                 return -EINVAL;
         }
 
+        if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
+                info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
+                info.flags |= I2C_CLIENT_TEN;
+        }
+
+        if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
+                info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
+                info.flags |= I2C_CLIENT_SLAVE;
+        }
+
         client = i2c_new_device(adap, &info);
         if (!client)
                 return -EINVAL;
@@ -1209,7 +1219,7 @@ i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
                           i2c_adapter_depth(adap));
         list_for_each_entry_safe(client, next, &adap->userspace_clients,
                                  detected) {
-                if (client->addr == addr) {
+                if (i2c_encode_flags_to_addr(client) == addr) {
                         dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
                                  "delete_device", client->name, client->addr);