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spi: lpspi: Let watermark change with send data length

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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>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Clark Wang 2018-12-07 02:50:38 +00:00 committed by Mark Brown
parent bcd87317aa
commit cf86874bb9
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 9 additions and 2 deletions
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11
drivers/spi/spi-fsl-lpspi.c
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@ -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);
}