Re: [PATCH] i2c: i2c-stm32f7: fix first byte to send in slave mode

From: Pierre Yves MORDRET
Date: Tue Oct 01 2019 - 03:10:46 EST


Hi,

Reviewed-by: Pierre-Yves MORDRET <pierre-yves.mordret@xxxxxx>

Thx

On 9/30/19 5:28 PM, Fabrice Gasnier wrote:
> 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.
>
> Fixes: 60d609f30de2 ("i2c: i2c-stm32f7: Add slave support")
>
> [1] https://www.kernel.org/doc/Documentation/i2c/slave-interface
>
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
> ---
> 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 266d1c2..0af9219 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);
>