smaeul-u-boot/doc/device-tree-bindings
Lukasz Majewski a40fe217d1 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>
2019-04-11 15:21:33 +02:00
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2018-12-10 10:04:44 +01:00

Device Tree Bindings Staging Area
=================================

This directory contains device tree bindings for U-Boot.

These follow along with Linux kernel bindings, with a few additions. By
adding the files here, U-Boot patches can clearly show thees additions.
This makes it easier for device tree people to review these additions in
patches sent to the U-Boot mailing list.

The intent IS to commit these files to U-Boot. Hopefully at some point
the files will be stored in another repo (shared with Linux) which is
brought in as needed. Changes here are intended to mirror changes in the
Linux Documentation/devicetree/bindings/ directory.

sjg@chromium.org
17-Jan-12