path: root/drivers
diff options
authorWolfram Sang <wsa+renesas@sang-engineering.com>2017-12-04 09:16:18 +0100
committerWolfram Sang <wsa@the-dreams.de>2017-12-31 00:16:37 +0100
commit3e5f06bed72fe72166a6778f630241a893f67799 (patch)
treeecfdc707cf42d7e687ba406bc8042ba502c65bb4 /drivers
parente53537653791b4aaa9ec88a9eb5fd187d44ff6ac (diff)
i2c: algo-bit: init the bus to a known state
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>
Diffstat (limited to 'drivers')
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c
index 1147bddb8b2c..3df0efd69ae3 100644
--- a/drivers/i2c/algos/i2c-algo-bit.c
+++ b/drivers/i2c/algos/i2c-algo-bit.c
@@ -649,6 +649,11 @@ static int __i2c_bit_add_bus(struct i2c_adapter *adap,
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;

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