This series adds a callback function pointer to be executed after the adapter performs a transfer. The purpose of such a callback is for a client to execute some code while "owning" the bus entirely. Holding the adapter lock is insufficient in the case where the client is behind a mux, as the mux driver could perform mux selection operations on the bus while locked. The only use case for now is the SI7020 driver. While the SI7020 is starting up after power on or reset, any I2C commands on the bus can potentially upset the startup sequence. Since the SI7020 may be behind a mux, the driver needs to use the new transfer callback to sleep while the chip starts up. Eddie James (2): i2c: core: Add adapter transfer callback iio: humidity: si7020: Use core transfer callback to sleep after reset drivers/i2c/i2c-core-base.c | 3 +++ drivers/iio/humidity/si7020.c | 12 ++++++++++-- include/linux/i2c.h | 25 +++++++++++++++++++++++++ 3 files changed, 38 insertions(+), 2 deletions(-) -- 2.27.0
