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spi: spi-fsl-dspi: Fix per transfer cs_change handling
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As of 92dc20d, transfer->cs_change has
been supported for non-last transfers, but not for last transfer.

This change brings handling of cs_change in line with the specification in
spi.h, implementing handling of transfer->cs_change for all transfers.

The value for CMD FIFO is precalculated with transfer->cs_change field
taken into account, allowing for CS de-activate between transfers and
keeping CS activated after last transfer.

Signed-off-by: Esben Haabendal <eha@deif.com>
Acked-by: Martin Hundebøll <martin@geanix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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Esben Haabendal authored and Mark Brown committed Jun 20, 2018
1 parent 4779f23 commit 9e1dc9b
Showing 1 changed file with 40 additions and 28 deletions.
68 changes: 40 additions & 28 deletions drivers/spi/spi-fsl-dspi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -84,11 +84,16 @@
#define SPI_RSER_TCFQE 0x80000000

#define SPI_PUSHR 0x34
#define SPI_PUSHR_CONT (1 << 31)
#define SPI_PUSHR_CTAS(x) (((x) & 0x00000003) << 28)
#define SPI_PUSHR_EOQ (1 << 27)
#define SPI_PUSHR_CTCNT (1 << 26)
#define SPI_PUSHR_PCS(x) (((1 << x) & 0x0000003f) << 16)
#define SPI_PUSHR_CMD_CONT (1 << 15)
#define SPI_PUSHR_CONT (SPI_PUSHR_CMD_CONT << 16)
#define SPI_PUSHR_CMD_CTAS(x) (((x) & 0x0003) << 12)
#define SPI_PUSHR_CTAS(x) (SPI_PUSHR_CMD_CTAS(x) << 16)
#define SPI_PUSHR_CMD_EOQ (1 << 11)
#define SPI_PUSHR_EOQ (SPI_PUSHR_CMD_EOQ << 16)
#define SPI_PUSHR_CMD_CTCNT (1 << 10)
#define SPI_PUSHR_CTCNT (SPI_PUSHR_CMD_CTCNT << 16)
#define SPI_PUSHR_CMD_PCS(x) ((1 << x) & 0x003f)
#define SPI_PUSHR_PCS(x) (SPI_PUSHR_CMD_PCS(x) << 16)
#define SPI_PUSHR_TXDATA(x) ((x) & 0x0000ffff)

#define SPI_PUSHR_SLAVE 0x34
Expand Down Expand Up @@ -189,9 +194,8 @@ struct fsl_dspi {
void *rx;
void *rx_end;
char dataflags;
u8 cs;
u16 void_write_data;
u32 cs_change;
u16 tx_cmd;
const struct fsl_dspi_devtype_data *devtype_data;

wait_queue_head_t waitq;
Expand Down Expand Up @@ -254,8 +258,6 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)

for (i = 0; i < dma->curr_xfer_len; i++) {
dspi->dma->tx_dma_buf[i] = dspi_data_to_pushr(dspi, tx_word);
if ((dspi->cs_change) && (!dspi->len))
dspi->dma->tx_dma_buf[i] &= ~SPI_PUSHR_CONT;
}

dma->tx_desc = dmaengine_prep_slave_single(dma->chan_tx,
Expand Down Expand Up @@ -534,21 +536,22 @@ static void ns_delay_scale(char *psc, char *sc, int delay_ns,

static u32 dspi_data_to_pushr(struct fsl_dspi *dspi, int tx_word)
{
u16 d16;
u16 data, cmd;

if (dspi->tx) {
d16 = tx_word ? *(u16 *)dspi->tx : *(u8 *)dspi->tx;
data = tx_word ? *(u16 *)dspi->tx : *(u8 *)dspi->tx;
dspi->tx += tx_word + 1;
} else {
d16 = dspi->void_write_data;
data = dspi->void_write_data;
}

dspi->len -= tx_word + 1;

return SPI_PUSHR_TXDATA(d16) |
SPI_PUSHR_PCS(dspi->cs) |
SPI_PUSHR_CTAS(0) |
SPI_PUSHR_CONT;
cmd = dspi->tx_cmd;
if (dspi->len > 0)
cmd |= SPI_PUSHR_CMD_CONT;

return (cmd << 16) | SPI_PUSHR_TXDATA(data);
}

static void dspi_data_from_popr(struct fsl_dspi *dspi, int rx_word)
Expand Down Expand Up @@ -587,12 +590,9 @@ static int dspi_eoq_write(struct fsl_dspi *dspi)

dspi_pushr = dspi_data_to_pushr(dspi, tx_word);

if (dspi->len == 0 || tx_count == DSPI_FIFO_SIZE - 1) {
/* last transfer in the transfer */
if (dspi->len == 0 || tx_count == DSPI_FIFO_SIZE - 1)
/* request EOQ flag for last transfer in queue */
dspi_pushr |= SPI_PUSHR_EOQ;
if ((dspi->cs_change) && (!dspi->len))
dspi_pushr &= ~SPI_PUSHR_CONT;
}

regmap_write(dspi->regmap, SPI_PUSHR, dspi_pushr);

Expand Down Expand Up @@ -635,9 +635,6 @@ static int dspi_tcfq_write(struct fsl_dspi *dspi)

dspi_pushr = dspi_data_to_pushr(dspi, tx_word);

if ((dspi->cs_change) && (!dspi->len))
dspi_pushr &= ~SPI_PUSHR_CONT;

regmap_write(dspi->regmap, SPI_PUSHR, dspi_pushr);

return tx_word + 1;
Expand Down Expand Up @@ -672,11 +669,26 @@ static int dspi_transfer_one_message(struct spi_master *master,
dspi->cur_transfer = transfer;
dspi->cur_msg = message;
dspi->cur_chip = spi_get_ctldata(spi);
dspi->cs = spi->chip_select;
dspi->cs_change = 0;
/* Prepare command word for CMD FIFO */
dspi->tx_cmd = SPI_PUSHR_CMD_CTAS(0) |
SPI_PUSHR_CMD_PCS(spi->chip_select);
if (list_is_last(&dspi->cur_transfer->transfer_list,
&dspi->cur_msg->transfers) || transfer->cs_change)
dspi->cs_change = 1;
&dspi->cur_msg->transfers)) {
/* Leave PCS activated after last transfer when
* cs_change is set.
*/
if (transfer->cs_change)
dspi->tx_cmd |= SPI_PUSHR_CMD_CONT;
} else {
/* Keep PCS active between transfers in same message
* when cs_change is not set, and de-activate PCS
* between transfers in the same message when
* cs_change is set.
*/
if (!transfer->cs_change)
dspi->tx_cmd |= SPI_PUSHR_CMD_CONT;
}

dspi->void_write_data = dspi->cur_chip->void_write_data;

dspi->dataflags = 0;
Expand Down

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