i2c: rcar: handle RXDMA HW behaviour on Gen3
authorWolfram Sang <wsa+renesas@sang-engineering.com>
Thu, 28 Jun 2018 20:45:38 +0000 (22:45 +0200)
committerWolfram Sang <wsa@the-dreams.de>
Mon, 23 Jul 2018 18:10:56 +0000 (20:10 +0200)
commit3b770017b03a4cdfde0b61a49b4801dc8cca9f69
tree9c0acfd899adff2fd0dc3acc688fe15401d0ae46
parent263fe5d45dcd0c610e41d1662f83cdd43b881cc5
i2c: rcar: handle RXDMA HW behaviour on Gen3

On Gen3, we can only do RXDMA once per transfer reliably. For that, we
must reset the device, then we can have RXDMA once. This patch
implements this. When there is no reset controller or the reset fails,
RXDMA will be blocked completely. Otherwise, it will be disabled after
the first RXDMA transfer. Based on a commit from the BSP by Hiromitsu
Yamasaki, yet completely refactored to handle multiple read messages
within one transfer.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
drivers/i2c/busses/i2c-rcar.c