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-rw-r--r--Documentation/i2c/i2c-stub16
1 files changed, 11 insertions, 5 deletions
diff --git a/Documentation/i2c/i2c-stub b/Documentation/i2c/i2c-stub
index 0d8be1c20c16..fa4b669c166b 100644
--- a/Documentation/i2c/i2c-stub
+++ b/Documentation/i2c/i2c-stub
@@ -2,9 +2,9 @@ MODULE: i2c-stub
DESCRIPTION:
-This module is a very simple fake I2C/SMBus driver. It implements four
-types of SMBus commands: write quick, (r/w) byte, (r/w) byte data, and
-(r/w) word data.
+This module is a very simple fake I2C/SMBus driver. It implements five
+types of SMBus commands: write quick, (r/w) byte, (r/w) byte data, (r/w)
+word data, and (r/w) I2C block data.
You need to provide chip addresses as a module parameter when loading this
driver, which will then only react to SMBus commands to these addresses.
@@ -21,8 +21,8 @@ EEPROMs, among others.
The typical use-case is like this:
1. load this module
- 2. use i2cset (from lm_sensors project) to pre-load some data
- 3. load the target sensors chip driver module
+ 2. use i2cset (from the i2c-tools project) to pre-load some data
+ 3. load the target chip driver module
4. observe its behavior in the kernel log
There's a script named i2c-stub-from-dump in the i2c-tools package which
@@ -33,6 +33,12 @@ PARAMETERS:
int chip_addr[10]:
The SMBus addresses to emulate chips at.
+unsigned long functionality:
+ Functionality override, to disable some commands. See I2C_FUNC_*
+ constants in <linux/i2c.h> for the suitable values. For example,
+ value 0x1f0000 would only enable the quick, byte and byte data
+ commands.
+
CAVEATS:
If your target driver polls some byte or word waiting for it to change, the