[ Upstream commit 0a355aeb24081e4538d4d424cd189f16c0bbd983 ]

If something goes wrong (such as the SCL being stuck low) then we need
to reset the PCA chip. The issue with this is that on reset we lose all
config settings and the chip ends up in a disabled state which results
in a lock up/high CPU usage. We need to re-apply any configuration that
had previously been set and re-enable the chip.

Signed-off-by: Evan Nimmo <evan.nimmo@alliedtelesis.co.nz>
Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit cd217f2300793a106b49c7dfcbfb26e348bc7593 ]

The PCA9665 datasheet says that I2CSTA = 78h indicates that SCL is stuck
low, this differs to the PCA9564 which uses 90h for this indication.
Treat either 0x78 or 0x90 as an indication that the SCL line is stuck.

Based on looking through the PCA9564 and PCA9665 datasheets this should
be safe for both chips. The PCA9564 should not return 0x78 for any valid
state and the PCA9665 should not return 0x90.

Fixes: eff9ec95efaa ("i2c-algo-pca: Add PCA9665 support")
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Yep, I went looking for one of these, and I wasn't able to find it
easily.  That's worse than a line which is 82-chars long, IMHO.

Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

So, if somebody wants to re-implement this in the future, we pinpoint to
a problem case.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

This reverts commit 3e5f06bed72fe72166a6778f630241a893f67799. As per
bugzilla #200045, this caused a regression. I don't really see a way to
fix it without having the hardware. So, revert the patch and I will fix
the issue I was seeing originally in the i2c-gpio driver itself. I
couldn't find new users of this algorithm since, so there should be no
one depending on the new behaviour.

Reported-by: Sergey Larin <cerg2010cerg2010@mail.ru>
Fixes: 3e5f06bed72f ("i2c: algo-bit: init the bus to a known state")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Tested-by: Sergey Larin <cerg2010cerg2010@mail.ru>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org

Because it looks neater.

Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Ensure the bus is free when we register the adapter. Before the SCL/SDA
wires were in an unknown state. It used to work because sending a byte
has a retry mechanism which was triggered if the bus was initially in a
non-free state. But the graceful way to do it is to initialize
correctly.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Support for enforced STOPs will allow us to use SCCB compatible devices.

Based on a preliminary patch by Wolfram Sang.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c_bit_quirk_no_clk_stretch is used in i2c-algo-bit.c only, so
declare it as static.

Signed-off-by: Michele Curti <michele.curti@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Add I2C_AQ_NO_CLK_STRETCH to drivers/i2c/algos/i2c-algo-bit.c when getscl
is not available.

Signed-off-by: Nicola Corna <nicola@corna.info>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>