The Synopsys I2C Controller has a bus clock, but typically SoCs hide this away. However, on some SoCs you need to explicity enable the bus clock in order to access the registers. Phil Edworthy (2): dt: snps,designware-i2c: Add clock bindings documentation i2c: designware: Add support for a bus clock Documentation/devicetree/bindings/i2c/i2c-designware.txt | 9 +++++++-- drivers/i2c/busses/i2c-designware-common.c | 14 +++++++++++++- drivers/i2c/busses/i2c-designware-core.h | 1 + drivers/i2c/busses/i2c-designware-platdrv.c | 2 ++ 4 files changed, 23 insertions(+), 3 deletions(-) -- 2.7.4