There are slave devices that understand I2C but have read-only SDA and SCL. Examples are FD650 7-segment LED controller and its derivatives. Typical board designs don't even have a pull-up for both pins. This patch makes i2c-gpio usable with such devices, based on new DT property i2c-gpio,sda-output-only. v2: - improve commit message for patch 1 v3: - patch 2: check for adap->getsda in readbytes() - patch 2: align warning message level for info on missing getscl/getsda - patch 3: improve description of attribute sda_is_output_only Heiner Kallweit (3): dt-bindings: i2c-gpio: Add property i2c-gpio,sda-output-only i2c: algo: bit: allow getsda to be NULL i2c: gpio: support write-only sda .../devicetree/bindings/i2c/i2c-gpio.yaml | 4 ++++ drivers/i2c/algos/i2c-algo-bit.c | 16 ++++++++++++++-- drivers/i2c/busses/i2c-gpio.c | 14 +++++++++++--- include/linux/platform_data/i2c-gpio.h | 3 +++ 4 files changed, 32 insertions(+), 5 deletions(-) -- 2.39.0