From: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/i2c/slave-interface | 9 ++++++---
Documentation/i2c/ten-bit-addresses | 4 ++++
drivers/i2c/i2c-core.c | 12 +++++++++++-
3 files changed, 21 insertions(+), 4 deletions(-)
diff --git a/Documentation/i2c/slave-interface b/Documentation/i2c/slave-interface
index 2dee4e2d62df19..61ed05cd95317f 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 cdfe13901b99cb..7b2d11e53a49f1 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 24c96dd0a5bee4..4c1f31f039964b 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1156,6 +1156,16 @@ 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;
@@ -1207,7 +1217,7 @@ 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);
--
2.1.4
--
To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
