]> git.ipfire.org Git - thirdparty/kernel/stable.git/commit
Revert "i2c: cadence: Fix the hold bit setting"
authorRaviteja Narayanam <raviteja.narayanam@xilinx.com>
Fri, 3 Jul 2020 13:55:49 +0000 (19:25 +0530)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 21 Aug 2020 08:52:54 +0000 (10:52 +0200)
commit3a8336f976a553288bd9ee44409546e45da58d03
treedb6705d2f263c9c6094fcfd69f637b031401201d
parentee07ec61b03ebcd9a4ad458851265bc41fb66561
Revert "i2c: cadence: Fix the hold bit setting"

[ Upstream commit 0db9254d6b896b587759e2c844c277fb1a6da5b9 ]

This reverts commit d358def706880defa4c9e87381c5bf086a97d5f9.

There are two issues with "i2c: cadence: Fix the hold bit setting" commit.

1. In case of combined message request from user space, when the HOLD
bit is cleared in cdns_i2c_mrecv function, a STOP condition is sent
on the bus even before the last message is started. This is because when
the HOLD bit is cleared, the FIFOS are empty and there is no pending
transfer. The STOP condition should occur only after the last message
is completed.

2. The code added by the commit is redundant. Driver is handling the
setting/clearing of HOLD bit in right way before the commit.

The setting of HOLD bit based on 'bus_hold_flag' is taken care in
cdns_i2c_master_xfer function even before cdns_i2c_msend/cdns_i2c_recv
functions.

The clearing of HOLD bit is taken care at the end of cdns_i2c_msend and
cdns_i2c_recv functions based on bus_hold_flag and byte count.
Since clearing of HOLD bit is done after the slave address is written to
the register (writing to address register triggers the message transfer),
it is ensured that STOP condition occurs at the right time after
completion of the pending transfer (last message).

Signed-off-by: Raviteja Narayanam <raviteja.narayanam@xilinx.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/i2c/busses/i2c-cadence.c