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>
diff --git a/include/i2c.h b/include/i2c.h
index ccffc19..a5c760c 100644
--- a/include/i2c.h
+++ b/include/i2c.h
@@ -68,9 +68,11 @@
* 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;
};
/*