diff options
| author | Lukasz Majewski <lukma@denx.de> | 2019-04-04 12:35:34 +0200 |
|---|---|---|
| committer | Heiko Schocher <hs@denx.de> | 2019-04-11 15:21:33 +0200 |
| commit | a40fe217d19fdb9804fdc88342ce4bb0a0440c84 (patch) | |
| tree | 07fc2927d51569ad0614579c3e22f947e3eb8851 /include/i2c.h | |
| parent | 3c99166441bf3ea325af2da83cfe65430b49c066 (diff) | |
DM: I2C: Introduce 'u-boot, i2c-transaction-bytes' property
The 'u-boot,i2c-transaction-bytes' device tree property provides
information regarding number of bytes transferred by a device in a
single transaction.
This change is necessary to avoid hanging devices after soft reset.
One notable example is communication with MC34708 device:
1. Reset when communicating with MC34708 via I2C.
2. The u-boot (after reboot -f) tries to setup the I2C and then calls
force_idle_bus. In the same time MC34708 still has some data to be sent
(as it transfers data in 24 bits chunks).
3. The force_idle_bus() is not able to make the bus idle as 8 SCL
clocks may be not enough to have the full transmission.
4. We end up with I2C inconsistency with MC34708.
This PMIC device requires 24+ SCL cycles to make finish any pending I2C
transmission.
Signed-off-by: Lukasz Majewski <lukma@denx.de>
Diffstat (limited to 'include/i2c.h')
| -rw-r--r-- | include/i2c.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/i2c.h b/include/i2c.h index ccffc19552..a5c760c711 100644 --- a/include/i2c.h +++ b/include/i2c.h @@ -68,9 +68,11 @@ struct dm_i2c_chip { * I2C bus udevice. * * @speed_hz: Bus speed in hertz (typically 100000) + * @max_transaction_bytes: Maximal size of single I2C transfer */ struct dm_i2c_bus { int speed_hz; + int max_transaction_bytes; }; /* |