On Tue, 2024-06-04 at 19:42 -0300, Marcelo Schmitt wrote:
> Some SPI peripherals may require strict MOSI line state when the controller
> is not clocking out data.
> Implement support for MOSI idle state configuration (low or high) by
> setting the data output line level on controller setup and after transfers.
> Bitbang operations now call controller specific set_mosi_idle() call back
> to set MOSI to its idle state.
> The MOSI line is kept at its idle state if no tx buffer is provided.
>
> Signed-off-by: Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx>
> ---
Some minor nit below in case a re-spin is needed. Anyways,
Acked-by: Nuno Sa <nuno.sa@xxxxxxxxxx>
> drivers/spi/spi-bitbang.c | 24 ++++++++++++++++++++++++
> include/linux/spi/spi_bitbang.h | 1 +
> 2 files changed, 25 insertions(+)
>
> diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c
> index ca5cc67555c5..3dee085d3570 100644
> --- a/drivers/spi/spi-bitbang.c
> +++ b/drivers/spi/spi-bitbang.c
> @@ -63,21 +63,28 @@ static unsigned bitbang_txrx_8(
> unsigned flags
> )
> {
> + struct spi_bitbang *bitbang;
> unsigned bits = t->bits_per_word;
> unsigned count = t->len;
> const u8 *tx = t->tx_buf;
> u8 *rx = t->rx_buf;
>
> + bitbang = spi_controller_get_devdata(spi->controller);
> while (likely(count > 0)) {
> u8 word = 0;
>
> if (tx)
> word = *tx++;
> + else
> + word = (spi->mode & SPI_MOSI_IDLE_HIGH) ? 0xFF : 0;
no need for ()
> word = txrx_word(spi, ns, word, bits, flags);
> if (rx)
> *rx++ = word;
> count -= 1;
> }
> + if (bitbang->set_mosi_idle)
> + bitbang->set_mosi_idle(spi);
> +
> return t->len - count;
> }
>
> @@ -92,21 +99,28 @@ static unsigned bitbang_txrx_16(
> unsigned flags
> )
> {
> + struct spi_bitbang *bitbang;
> unsigned bits = t->bits_per_word;
> unsigned count = t->len;
> const u16 *tx = t->tx_buf;
> u16 *rx = t->rx_buf;
>
> + bitbang = spi_controller_get_devdata(spi->controller);
> while (likely(count > 1)) {
> u16 word = 0;
>
> if (tx)
> word = *tx++;
> + else
> + word = (spi->mode & SPI_MOSI_IDLE_HIGH) ? 0xFFFF : 0;
ditto (and for the txrx8 function)
- Nuno Sá
