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>
Tue, 24 Jul 2018 12:56:12 +0000 (14:56 +0200)
commit2b16fd63059ab9a46d473620749672dc342e1d21
tree79df77bec181d92ef8b194bbd42bd2e51cda06cb
parent9f9e3e0d4dd3338b3f3dde080789f71901e1e4ff
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>
Cc: stable@kernel.org
drivers/i2c/busses/i2c-rcar.c