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spi: spi-fsl-dspi: Fix MCR register handling 

The MCR register is not changed, so initialize it in dspi_init().

The exception is the CLR_TXF and CLR_RXF bits, which should be written to
before each transfer to make sure we start with empty FIFOs.  With MCR
register now configured as volatile, the regmap_update_bits will do a real
read-modify-write cycle.

Signed-off-by: Esben Haabendal <eha@deif.com>
Acked-by: Martin Hundebøll <martin@geanix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Esben Haabendal 2018-06-20 09:34:37 +02:00 committed by Mark Brown
parent dadcf4abd6
commit d87e08f142
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GPG Key ID: 24D68B725D5487D0
1 changed files with 3 additions and 7 deletions
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10
drivers/spi/spi-fsl-dspi.c
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@ -120,7 +120,6 @@
#define DMA_COMPLETION_TIMEOUT msecs_to_jiffies(3000)
struct chip_data {
u32 mcr_val;
u32 ctar_val;
u16 void_write_data;
};
@ -644,10 +643,9 @@ static int dspi_transfer_one_message(struct spi_master *master,
else
dspi->bytes_per_word = 2;
regmap_write(dspi->regmap, SPI_MCR, dspi->cur_chip->mcr_val);
regmap_update_bits(dspi->regmap, SPI_MCR,
SPI_MCR_CLR_TXF | SPI_MCR_CLR_RXF,
SPI_MCR_CLR_TXF | SPI_MCR_CLR_RXF);
SPI_MCR_CLR_TXF | SPI_MCR_CLR_RXF,
SPI_MCR_CLR_TXF | SPI_MCR_CLR_RXF);
regmap_write(dspi->regmap, SPI_CTAR(0),
dspi->cur_chip->ctar_val |
SPI_FRAME_BITS(transfer->bits_per_word));
@ -725,9 +723,6 @@ static int dspi_setup(struct spi_device *spi)
sck_cs_delay = pdata->sck_cs_delay;
}
chip->mcr_val = SPI_MCR_MASTER | SPI_MCR_PCSIS |
SPI_MCR_CLR_TXF | SPI_MCR_CLR_RXF;
chip->void_write_data = 0;
clkrate = clk_get_rate(dspi->clk);
@ -871,6 +866,7 @@ static const struct regmap_config dspi_regmap_config = {
static void dspi_init(struct fsl_dspi *dspi)
{
regmap_write(dspi->regmap, SPI_MCR, SPI_MCR_MASTER | SPI_MCR_PCSIS);
regmap_write(dspi->regmap, SPI_SR, SPI_SR_CLEAR);
}