[PATCH v7 1/5] spi: dw: Add 32 bpw support to SPI DW DMA driver

Joy Chakraborty
2023-04-18T05:29:23Z

Add Support for AxSize = 4 bytes configuration from dw dma driver if
n_bytes i.e. number of bytes per write to fifo is 4.

Number of bytes written to fifo per write is depended on the bits/word
configuration being used which the DW core driver translates to n_bytes.
Hence, for bits per word values between 17 and 32 n_bytes should be
equal to 4.

Signed-off-by: Joy Chakraborty <joychakr@google.com>
---
drivers/spi/spi-dw-dma.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-dw-dma.c b/drivers/spi/spi-dw-dma.c
index ababb910b391..c1b42cb59965 100644
--- a/drivers/spi/spi-dw-dma.c
+++ b/drivers/spi/spi-dw-dma.c
@@ -208,12 +208,16 @@ static bool dw_spi_can_dma(struct spi_controller *master,

static enum dma_slave_buswidth dw_spi_dma_convert_width(u8 n_bytes)
{
- if (n_bytes == 1)
+ switch (n_bytes) {
+ case 1:
return DMA_SLAVE_BUSWIDTH_1_BYTE;
- else if (n_bytes == 2)
+ case 2:
return DMA_SLAVE_BUSWIDTH_2_BYTES;
-
- return DMA_SLAVE_BUSWIDTH_UNDEFINED;
+ case 4:
+ return DMA_SLAVE_BUSWIDTH_4_BYTES;
+ default:
+ return DMA_SLAVE_BUSWIDTH_UNDEFINED;
+ }
}

static int dw_spi_dma_wait(struct dw_spi *dws, unsigned int len, u32 speed)
--
2.40.0.634.g4ca3ef3211-goog