diff options
| author | Simon Glass <sjg@chromium.org> | 2012-06-26 14:19:54 -0700 |
|---|---|---|
| committer | Gerrit <chrome-bot@google.com> | 2012-06-29 10:46:22 -0700 |
| commit | 7bcf881bd60537cd3eefa1d391ad13f7c838b23c (patch) | |
| tree | 611b1445195dd4e831141cc7a9931a5a03c9817d /include/i2c.h | |
| parent | 7e50e844a3bf1888f5abfa57cc82a6f94b87cbe2 (diff) | |
| download | chrome-ec-7bcf881bd60537cd3eefa1d391ad13f7c838b23c.tar.gz | |
Implement board-level I2C arbitration
Add a way for boards to permit or deny access to the I2C port. This
works in a board-specific manner.
All I2C master traffic requires that board_i2c_claim() be called
first. A dummy function is provided for boards which do not require
this.
BUG=chrome-os-partner:10888
TEST=manual:
build for all boards
boot on snow (cannot test i2c as it is broken)
Change-Id: I786d4ae17f1d798faf13b303b5389679fb6720cb
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/26141
Diffstat (limited to 'include/i2c.h')
| -rw-r--r-- | include/i2c.h | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/include/i2c.h b/include/i2c.h index 726ebb641a..dbf933e102 100644 --- a/include/i2c.h +++ b/include/i2c.h @@ -48,4 +48,32 @@ int i2c_write8(int port, int slave_addr, int offset, int data); int i2c_read_string(int port, int slave_addr, int offset, uint8_t *data, int len); +/** + * Claim an I2C port for use in master mode + * + * If this function succeed, then you must later call board_i2c_release() + * to release the claim. + * + * This function may optionally be implemented by a board file. If provided + * then it should check the port number and arbitrate as needed. + * + * This function will not be called to claim an already-claimed port. + * + * @param port Port to claim (0 for first, 1 for second, etc.) + * @return 0 if claimed successfully, -1 if it is in use + */ +int board_i2c_claim(int port); + +/** + * Release an I2C port (after previously being claimed) + * + * This function may optionally be implemented by a board file. If provided + * then it should check the port number and arbitrate as needed. + * + * This function will not be called to release an already-released port. + * + * @param port Port to claim (0 for first, 1 for second, etc.) + */ +void board_i2c_release(int port); + #endif /* __CROS_EC_I2C_H */ |