[PATCH v4 1/2] spi: microchip-core: Refactor FIFO read and write handlers

Andy Shevchenko
2025-11-28T18:55:25Z

Make both handlers to be shorter and easier to understand.
While at it, unify their style.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Prajna Rajendra Kumar <prajna.rajendrakumar@microchip.com>
---
drivers/spi/spi-microchip-core-spi.c | 31 +++++++++++-----------------
1 file changed, 12 insertions(+), 19 deletions(-)

diff --git a/drivers/spi/spi-microchip-core-spi.c b/drivers/spi/spi-microchip-core-spi.c
index 892f066f0074..98bf0e6cd00e 100644
--- a/drivers/spi/spi-microchip-core-spi.c
+++ b/drivers/spi/spi-microchip-core-spi.c
@@ -97,15 +97,12 @@ static inline void mchp_corespi_read_fifo(struct mchp_corespi *spi, u32 fifo_max
MCHP_CORESPI_STATUS_RXFIFO_EMPTY)
;

+ /* On TX-only transfers always perform a dummy read */
data = readb(spi->regs + MCHP_CORESPI_REG_RXDATA);
+ if (spi->rx_buf)
+ *spi->rx_buf++ = data;

spi->rx_len--;
- if (!spi->rx_buf)
- continue;
-
- *spi->rx_buf = data;
-
- spi->rx_buf++;
}
}

@@ -127,23 +124,19 @@ static void mchp_corespi_disable_ints(struct mchp_corespi *spi)

static inline void mchp_corespi_write_fifo(struct mchp_corespi *spi, u32 fifo_max)
{
- int i = 0;
-
- while ((i < fifo_max) &&
- !(readb(spi->regs + MCHP_CORESPI_REG_STAT) &
- MCHP_CORESPI_STATUS_TXFIFO_FULL)) {
- u32 word;
-
- word = spi->tx_buf ? *spi->tx_buf : 0xaa;
- writeb(word, spi->regs + MCHP_CORESPI_REG_TXDATA);
+ for (int i = 0; i < fifo_max; i++) {
+ if (readb(spi->regs + MCHP_CORESPI_REG_STAT) &
+ MCHP_CORESPI_STATUS_TXFIFO_FULL)
+ break;

+ /* On RX-only transfers always perform a dummy write */
if (spi->tx_buf)
- spi->tx_buf++;
+ writeb(*spi->tx_buf++, spi->regs + MCHP_CORESPI_REG_TXDATA);
+ else
+ writeb(0xaa, spi->regs + MCHP_CORESPI_REG_TXDATA);

- i++;
+ spi->tx_len--;
}
-
- spi->tx_len -= i;
}

static void mchp_corespi_set_cs(struct spi_device *spi, bool disable)
--
2.50.1