kernel/git/stable/linux.git/drivers/i2c/algos/i2c-algo-bit.c, branch master

i2c: algo: bit: Allow to skip bit test

2026-07-29T18:51:16+00:00

An I2C bus can make use of shared resources. E.g. two GPIO based buses that share a single SCL line. To synchronize access to the bus the driver might use locking with the help of i2c_lock_operations(). While this works for normal transfers it is not available during initialization. Especially if i2c-algo-bit module is loaded with parameter bit_test it will issue some basic sanity checks that will access the bus without locking. This might interfere badly with concurrent transfers. Even if these are well synchronized via locks. Allow the consumer of an algorithm to override if the bit_test is allowed or not. For this add a new boolean attribute named skip_bit_test to i2c_algo_bit_data. If set the test is not run. Signed-off-by: Markus Stockhausen Reviewed-by: Bartosz Golaszewski Reviewed-by: Wolfram Sang Tested-by: Wolfram Sang Signed-off-by: Andi Shyti Link: https://lore.kernel.org/r/20260714162915.3018703-2-markus.stockhausen@gmx.de

i2c: algo: bit: use str_plural helper in bit_xfer

2026-06-16T21:58:35+00:00

Replace the manual ternary "s" pluralizations with str_plural() to simplify the code. Signed-off-by: Thorsten Blum Signed-off-by: Andi Shyti Link: https://lore.kernel.org/r/20260511104911.183606-3-thorsten.blum@linux.dev

i2c: use inclusive callbacks in struct i2c_algorithm

2025-06-12T08:05:31+00:00

Convert the I2C subsystem to drop using the 'master_'-prefixed callbacks in favor of the simplified ones. Fix alignment of '=' while here. Signed-off-by: Wolfram Sang

i2c: algo: bit: allow getsda to be NULL

2023-01-23T22:15:49+00:00

This is in preparation of supporting write-only SDA in i2c-gpio. Signed-off-by: Heiner Kallweit Signed-off-by: Wolfram Sang

i2c: algo: bit: use new macro to specifiy capabilities

2021-01-22T08:59:21+00:00

Let's use the new macro for emulating SMBus with RECV_LEN support. Signed-off-by: Wolfram Sang Signed-off-by: Wolfram Sang

i2c: algo: bit: add flag to whitelist atomic transfers

2019-04-16T11:08:16+00:00

Use the new xfer_atomic callback to check a newly introduced flag to whitelist atomic transfers. This will report configurations which worked accidently. Signed-off-by: Wolfram Sang Signed-off-by: Wolfram Sang

i2c: algo-bit: convert to SPDX header

2019-02-05T13:05:03+00:00

And use kernel style for the remaining comments in the header. Signed-off-by: Wolfram Sang Reviewed-by: Simon Horman Signed-off-by: Wolfram Sang

i2c: algos: bit: make the error messages grepable

2018-08-30T21:11:42+00:00

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 Signed-off-by: Wolfram Sang

i2c: algos: bit: mention our experience about initial states

2018-06-29T06:19:51+00:00

So, if somebody wants to re-implement this in the future, we pinpoint to a problem case. Signed-off-by: Wolfram Sang Acked-by: Alex Deucher Signed-off-by: Wolfram Sang

Revert "i2c: algo-bit: init the bus to a known state"

2018-06-29T06:19:41+00:00

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 Fixes: 3e5f06bed72f ("i2c: algo-bit: init the bus to a known state") Signed-off-by: Wolfram Sang Acked-by: Alex Deucher Tested-by: Sergey Larin Signed-off-by: Wolfram Sang Cc: stable@kernel.org