[PATCH 4.17 206/220] Revert "i2c: algo-bit: init the bus to a known state"

From: Greg Kroah-Hartman
Date: Sun Jul 01 2018 - 12:46:18 EST

4.17-stable review patch. If anyone has any objections, please let me know.


From: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>

commit 2a2c8ee2d72c4f1ba0f7fbb02dc74f971df0f934 upstream.

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@xxxxxxx>
Fixes: 3e5f06bed72f ("i2c: algo-bit: init the bus to a known state")
Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Acked-by: Alex Deucher <alexander.deucher@xxxxxxx>
Tested-by: Sergey Larin <cerg2010cerg2010@xxxxxxx>
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/i2c/algos/i2c-algo-bit.c | 5 -----
1 file changed, 5 deletions(-)

--- a/drivers/i2c/algos/i2c-algo-bit.c
+++ b/drivers/i2c/algos/i2c-algo-bit.c
@@ -649,11 +649,6 @@ static int __i2c_bit_add_bus(struct i2c_
if (bit_adap->getscl == NULL)
adap->quirks = &i2c_bit_quirk_no_clk_stretch;

- /* Bring bus to a known state. Looks like STOP if bus is not free yet */
- setscl(bit_adap, 1);
- udelay(bit_adap->udelay);
- setsda(bit_adap, 1);
ret = add_adapter(adap);
if (ret < 0)
return ret;