From a40fe217d19fdb9804fdc88342ce4bb0a0440c84 Mon Sep 17 00:00:00 2001 From: Lukasz Majewski Date: Thu, 4 Apr 2019 12:35:34 +0200 Subject: 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 --- include/i2c.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/i2c.h') 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 @@ 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; }; /* -- cgit v1.1