The .probe_chip function is supposed to probe an i2c device on the bus to
determine whether a device is answering to a particular address.
at91_i2c_probe_chip() did not do anything resembling this and always
returned 0.

It looks as though at91_i2c_probe_chip() was intended to be a .probe
function for the controller, as it was copied-and-pasted to become
at91_i2c_probe() in 0bc8f640a4d7ed.

Removing the at91_i2c_probe_chip() function makes the higher layer
(i2c_probe_chip()) try a zero-length read transfer to test for the
presence of a device instead, which does work.

Signed-off-by: Alan Ott <alan@softiron.com>
Acked-by: Wenyou Yang <wenyou.yang@microchip.com>
Reviewed-by: Heiko Schocher <hs@denx.de>

The driver must wait for TXRDY after each byte is pushed into
the i2c FIFO before pushing the next byte. Previously this was
not done for the first byte, causing a race condition with zeros
sometimes being sent for the next byte (which is typically the
first actual data byte).

Signed-off-by: Alan Ott <alan@softiron.com>
Reviewed-by: Heiko Schocher <hs@denx.de>

Add some comment describing the purpose of struct members and
functions.

Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>

Change meson_i2c_xfer_msg() to return -EREMOTEIO in case of NACK, as
done by other drivers. Also, don't change the return error in
meson_i2c_xfer().

Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>

The datasheet doesn't specify a suggested timeout and 500ms seems very
long: reduce it to 100ms.

Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>

Expand the Kconfig description with hardware features.

Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>

Add driver for the RCar IIC or DVFS I2C controller. This driver is based
on the SH I2C driver, but supports DM and DT probing as well as modern
I2C framework API.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>

Signed-off-by: Tom Rini <trini@konsulko.com>

Add a driver for the I2C controller available on Amlogic Meson SoCs.

Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>

Tweak the i2c transfer to work for devices that want to read data
without addressing a register.

Signed-off-by: Nandor Han <nandor.han@ge.com>
Signed-off-by: Martyn Welch <martyn.welch@collabora.co.uk>
Acked-by: Heiko Schocher <hs@denx.de>
Cc: Heiko Schocher <hs@denx.de>
Cc: Stefano Babic <sbabic@denx.de>