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Subject[PATCH 01/12] spi: spi-fsl-dspi: Simplify bytes_per_word gymnastics
Date
From: Vladimir Oltean <vladimir.oltean@nxp.com>

Reduce the if-then-else-if-then-else sequence to:
- a simple division in the case of bytes_per_word calculation
- a memcpy command with a variable size. The semantics of larger-than-8
xfer->bits_per_word is that those words are to be interpreted and
transmitted in CPU native endianness.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
drivers/spi/spi-fsl-dspi.c | 21 +++------------------
1 file changed, 3 insertions(+), 18 deletions(-)

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index c357c3247232..896d7a0f45b0 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -252,12 +252,7 @@ static u32 dspi_pop_tx(struct fsl_dspi *dspi)
u32 txdata = 0;

if (dspi->tx) {
- if (dspi->bytes_per_word == 1)
- txdata = *(u8 *)dspi->tx;
- else if (dspi->bytes_per_word == 2)
- txdata = *(u16 *)dspi->tx;
- else /* dspi->bytes_per_word == 4 */
- txdata = *(u32 *)dspi->tx;
+ memcpy(&txdata, dspi->tx, dspi->bytes_per_word);
dspi->tx += dspi->bytes_per_word;
}
dspi->len -= dspi->bytes_per_word;
@@ -284,12 +279,7 @@ static void dspi_push_rx(struct fsl_dspi *dspi, u32 rxdata)
/* Mask off undefined bits */
rxdata &= (1 << dspi->bits_per_word) - 1;

- if (dspi->bytes_per_word == 1)
- *(u8 *)dspi->rx = rxdata;
- else if (dspi->bytes_per_word == 2)
- *(u16 *)dspi->rx = rxdata;
- else /* dspi->bytes_per_word == 4 */
- *(u32 *)dspi->rx = rxdata;
+ memcpy(dspi->rx, &rxdata, dspi->bytes_per_word);
dspi->rx += dspi->bytes_per_word;
}

@@ -814,12 +804,7 @@ static int dspi_transfer_one_message(struct spi_controller *ctlr,
dspi->progress = 0;
/* Validated transfer specific frame size (defaults applied) */
dspi->bits_per_word = transfer->bits_per_word;
- if (transfer->bits_per_word <= 8)
- dspi->bytes_per_word = 1;
- else if (transfer->bits_per_word <= 16)
- dspi->bytes_per_word = 2;
- else
- dspi->bytes_per_word = 4;
+ dspi->bytes_per_word = DIV_ROUND_UP(dspi->bits_per_word, 8);

regmap_update_bits(dspi->regmap, SPI_MCR,
SPI_MCR_CLR_TXF | SPI_MCR_CLR_RXF,
--
2.17.1
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