From: Fabrice Gasnier <fabrice.gasnier@xxxxxx> [ Upstream commit 02e64276c6dbcc4c5f39844f33d18180832a58f3 ] The slave-interface documentation [1] states "the bus driver should transmit the first byte" upon I2C_SLAVE_READ_REQUESTED slave event: - 'val': backend returns first byte to be sent The driver currently ignores the 1st byte to send on this event. [1] https://www.kernel.org/doc/Documentation/i2c/slave-interface Fixes: 60d609f30de2 ("i2c: i2c-stm32f7: Add slave support") Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx> Reviewed-by: Pierre-Yves MORDRET <pierre-yves.mordret@xxxxxx> Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/i2c/busses/i2c-stm32f7.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c index 266d1c269b835..0af9219e45f79 100644 --- a/drivers/i2c/busses/i2c-stm32f7.c +++ b/drivers/i2c/busses/i2c-stm32f7.c @@ -1192,6 +1192,8 @@ static void stm32f7_i2c_slave_start(struct stm32f7_i2c_dev *i2c_dev) STM32F7_I2C_CR1_TXIE; stm32f7_i2c_set_bits(base + STM32F7_I2C_CR1, mask); + /* Write 1st data byte */ + writel_relaxed(value, base + STM32F7_I2C_TXDR); } else { /* Notify i2c slave that new write transfer is starting */ i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value); -- 2.20.1
