diff options
| -rw-r--r-- | Documentation/i2c/slave-interface | 9 | ||||
| -rw-r--r-- | Documentation/i2c/ten-bit-addresses | 4 | ||||
| -rw-r--r-- | 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 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); |