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Subject[PATCH V3 3/4] spi: lpspi: Let watermark change with send data length
Date
Configure watermark to change with the length of the sent data.
Support LPSPI sending message shorter than tx/rxfifosize.

Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>
---
Change log:
V2/V3:
- No change.
---
drivers/spi/spi-fsl-lpspi.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-fsl-lpspi.c b/drivers/spi/spi-fsl-lpspi.c
index cbf165e7bd17..08dcc3c22e88 100644
--- a/drivers/spi/spi-fsl-lpspi.c
+++ b/drivers/spi/spi-fsl-lpspi.c
@@ -89,6 +89,7 @@ struct fsl_lpspi_data {
void (*rx)(struct fsl_lpspi_data *);

u32 remain;
+ u8 watermark;
u8 txfifosize;
u8 rxfifosize;

@@ -235,7 +236,7 @@ static void fsl_lpspi_set_watermark(struct fsl_lpspi_data *fsl_lpspi)
{
u32 temp;

- temp = fsl_lpspi->txfifosize >> 1 | (fsl_lpspi->rxfifosize >> 1) << 16;
+ temp = fsl_lpspi->watermark >> 1 | (fsl_lpspi->watermark >> 1) << 16;

writel(temp, fsl_lpspi->base + IMX7ULP_FCR);

@@ -261,7 +262,8 @@ static int fsl_lpspi_set_bitrate(struct fsl_lpspi_data *fsl_lpspi)
if (prescale == 8 && scldiv >= 256)
return -EINVAL;

- writel(scldiv, fsl_lpspi->base + IMX7ULP_CCR);
+ writel(scldiv | (scldiv << 8) | ((scldiv >> 1) << 16),
+ fsl_lpspi->base + IMX7ULP_CCR);

dev_dbg(fsl_lpspi->dev, "perclk=%d, speed=%d, prescale =%d, scldiv=%d\n",
perclk_rate, config.speed_hz, prescale, scldiv);
@@ -329,6 +331,11 @@ static void fsl_lpspi_setup_transfer(struct spi_device *spi,
fsl_lpspi->tx = fsl_lpspi_buf_tx_u32;
}

+ if (t->len <= fsl_lpspi->txfifosize)
+ fsl_lpspi->watermark = t->len;
+ else
+ fsl_lpspi->watermark = fsl_lpspi->txfifosize;
+
fsl_lpspi_config(fsl_lpspi);
}

--
2.17.1
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