[PATCH 14/14] spi: rspi: Add support for Quad and Dual SPI Transfers on QSPI

From: Geert Uytterhoeven
Date: Fri Jan 24 2014 - 03:47:48 EST

From: Geert Uytterhoeven <geert+renesas@xxxxxxxxxxxxxx>

Add support for Quad and Dual SPI Transfers on the Renesas Quad Serial
Peripheral Interface, as found in R-Car Gen2 SoCs like R-Car H2 (r8a7790)
and R-Car M2 (r8a7791):
- Add unidirectional transfer methods for Quad/Dual SPI Transfers.
- Program the sequencer to handle SPI messages with multiple transfer
modes when Quad or Dual transfers are enabled for an SPI slave.
Up to 4 transfer modes per SPI message are supported by the hardware.
- Advertise the availability of Quad and Dual SPI modes on QSPI.

Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxxxxxxx>
---
drivers/spi/spi-rspi.c | 162 +++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 148 insertions(+), 14 deletions(-)

diff --git a/drivers/spi/spi-rspi.c b/drivers/spi/spi-rspi.c
index e56fcb5f7f99..34ad4bca8a41 100644
--- a/drivers/spi/spi-rspi.c
+++ b/drivers/spi/spi-rspi.c
@@ -2,6 +2,7 @@
* SH RSPI driver
*
* Copyright (C) 2012, 2013 Renesas Solutions Corp.
+ * Copyright (C) 2014 Glider bvba
*
* Based on spi-sh.c:
* Copyright (C) 2011 Renesas Solutions Corp.
@@ -57,6 +58,10 @@
#define RSPI_SPCMD5 0x1a /* Command Register 5 */
#define RSPI_SPCMD6 0x1c /* Command Register 6 */
#define RSPI_SPCMD7 0x1e /* Command Register 7 */
+#define RSPI_SPCMD(i) (RSPI_SPCMD0 + (i) * 2)
+#define RSPI_NUM_SPCMD 8
+#define RSPI_RZ_NUM_SPCMD 4
+#define QSPI_NUM_SPCMD 4

/* RSPI on RZ only */
#define RSPI_SPBFCR 0x20 /* Buffer Control Register */
@@ -69,6 +74,7 @@
#define QSPI_SPBMUL1 0x20 /* Transfer Data Length Multiplier Setting Register 1 */
#define QSPI_SPBMUL2 0x24 /* Transfer Data Length Multiplier Setting Register 2 */
#define QSPI_SPBMUL3 0x28 /* Transfer Data Length Multiplier Setting Register 3 */
+#define QSPI_SPBMUL(i) (QSPI_SPBMUL0 + (i) * 4)

/* SPCR - Control Register */
#define SPCR_SPRIE 0x80 /* Receive Interrupt Enable */
@@ -152,7 +158,7 @@
#define SPCMD_LSBF 0x1000 /* LSB First */
#define SPCMD_SPB_MASK 0x0f00 /* Data Length Setting */
#define SPCMD_SPB_8_TO_16(bit) (((bit - 1) << 8) & SPCMD_SPB_MASK)
-#define SPCMD_SPB_8BIT 0x0000 /* qspi only */
+#define SPCMD_SPB_8BIT 0x0000 /* QSPI only */
#define SPCMD_SPB_16BIT 0x0100
#define SPCMD_SPB_20BIT 0x0000
#define SPCMD_SPB_24BIT 0x0100
@@ -245,6 +251,7 @@ struct spi_ops {
int (*set_config_register)(struct rspi_data *rspi, int access_size);
int (*transfer_one)(struct spi_master *master, struct spi_device *spi,
struct spi_transfer *xfer);
+ u16 mode_bits;
};

/*
@@ -274,8 +281,8 @@ static int rspi_set_config_register(struct rspi_data *rspi, int access_size)
rspi_write8(rspi, 0x00, RSPI_SPCR2);

/* Sets SPCMD */
- rspi_write16(rspi, SPCMD_SPB_8_TO_16(access_size) | rspi->spcmd,
- RSPI_SPCMD0);
+ rspi->spcmd |= SPCMD_SPB_8_TO_16(access_size);
+ rspi_write16(rspi, rspi->spcmd, RSPI_SPCMD0);

/* Sets RSPI mode */
rspi_write8(rspi, SPCR_MSTR, RSPI_SPCR);
@@ -321,7 +328,6 @@ static int rspi_rz_set_config_register(struct rspi_data *rspi, int access_size)
*/
static int qspi_set_config_register(struct rspi_data *rspi, int access_size)
{
- u16 spcmd;
int spbr;

/* Sets output mode, MOSI signal, and (optionally) loopback */
@@ -342,13 +348,13 @@ static int qspi_set_config_register(struct rspi_data *rspi, int access_size)

/* Data Length Setting */
if (access_size == 8)
- spcmd = SPCMD_SPB_8BIT;
+ rspi->spcmd |= SPCMD_SPB_8BIT;
else if (access_size == 16)
- spcmd = SPCMD_SPB_16BIT;
+ rspi->spcmd |= SPCMD_SPB_16BIT;
else
- spcmd = SPCMD_SPB_32BIT;
+ rspi->spcmd |= SPCMD_SPB_32BIT;

- spcmd |= SPCMD_SCKDEN | SPCMD_SLNDEN | rspi->spcmd | SPCMD_SPNDEN;
+ rspi->spcmd |= SPCMD_SCKDEN | SPCMD_SLNDEN | SPCMD_SPNDEN;

/* Resets transfer data length */
rspi_write32(rspi, 0, QSPI_SPBMUL0);
@@ -359,9 +365,9 @@ static int qspi_set_config_register(struct rspi_data *rspi, int access_size)
rspi_write8(rspi, 0x00, QSPI_SPBFCR);

/* Sets SPCMD */
- rspi_write16(rspi, spcmd, RSPI_SPCMD0);
+ rspi_write16(rspi, rspi->spcmd, RSPI_SPCMD0);

- /* Enables SPI function in a master mode */
+ /* Enables SPI function in master mode */
rspi_write8(rspi, SPCR_SPE | SPCR_MSTR, RSPI_SPCR);

return 0;
@@ -811,12 +817,55 @@ static int qspi_transfer_out_in(struct rspi_data *rspi,
return 0;
}

+static int qspi_transfer_out(struct rspi_data *rspi, struct spi_transfer *xfer)
+{
+ const u8 *buf = xfer->tx_buf;
+ unsigned int i;
+ int ret;
+
+ for (i = 0; i < xfer->len; i++) {
+ ret = rspi_data_out(rspi, *buf++);
+ if (ret < 0)
+ return ret;
+ }
+
+ /* Wait for the last transmission */
+ rspi_wait_for_interrupt(rspi, SPSR_SPTEF, SPCR_SPTIE);
+
+ return 0;
+}
+
+static int qspi_transfer_in(struct rspi_data *rspi, struct spi_transfer *xfer)
+{
+ u8 *buf = xfer->rx_buf;
+ unsigned int i;
+ int ret;
+
+ for (i = 0; i < xfer->len; i++) {
+ ret = rspi_data_in(rspi);
+ if (ret < 0)
+ return ret;
+ *buf++ = ret;
+ }
+
+ return 0;
+}
+
static int qspi_transfer_one(struct spi_master *master, struct spi_device *spi,
struct spi_transfer *xfer)
{
struct rspi_data *rspi = spi_master_get_devdata(master);

- return qspi_transfer_out_in(rspi, xfer);
+ if (xfer->tx_buf && xfer->tx_nbits > SPI_NBITS_SINGLE) {
+ /* Quad or Dual SPI Write */
+ return qspi_transfer_out(rspi, xfer);
+ } else if (xfer->rx_buf && xfer->rx_nbits > SPI_NBITS_SINGLE) {
+ /* Quad or Dual SPI Read */
+ return qspi_transfer_in(rspi, xfer);
+ } else {
+ /* Single SPI Transfer */
+ return qspi_transfer_out_in(rspi, xfer);
+ }
}

static int rspi_setup(struct spi_device *spi)
@@ -845,21 +894,101 @@ static void rspi_cleanup(struct spi_device *spi)
{
}

+static u16 qspi_transfer_mode(const struct spi_transfer *xfer)
+{
+ if (xfer->tx_buf)
+ switch (xfer->tx_nbits) {
+ case SPI_NBITS_QUAD:
+ return SPCMD_SPIMOD_QUAD;
+ case SPI_NBITS_DUAL:
+ return SPCMD_SPIMOD_DUAL;
+ default:
+ return 0;
+ }
+ if (xfer->rx_buf)
+ switch (xfer->rx_nbits) {
+ case SPI_NBITS_QUAD:
+ return SPCMD_SPIMOD_QUAD | SPCMD_SPRW;
+ case SPI_NBITS_DUAL:
+ return SPCMD_SPIMOD_DUAL | SPCMD_SPRW;
+ default:
+ return 0;
+ }
+
+ return 0;
+}
+
+static int qspi_setup_sequencer(struct rspi_data *rspi,
+ const struct spi_message *msg)
+{
+ const struct spi_transfer *xfer;
+ unsigned int i = 0, len = 0;
+ u16 current_mode = 0xffff, mode;
+
+ list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+ mode = qspi_transfer_mode(xfer);
+ if (mode == current_mode) {
+ len += xfer->len;
+ continue;
+ }
+
+ /* Transfer mode change */
+ if (i) {
+ /* Set transfer data length of previous transfer */
+ rspi_write32(rspi, len, QSPI_SPBMUL(i - 1));
+ }
+
+ if (i >= QSPI_NUM_SPCMD) {
+ dev_err(&msg->spi->dev,
+ "Too many different transfer modes");
+ return -EINVAL;
+ }
+
+ /* Program transfer mode for this transfer */
+ rspi_write16(rspi, rspi->spcmd | mode, RSPI_SPCMD(i));
+ current_mode = mode;
+ len = xfer->len;
+ i++;
+ }
+ if (i) {
+ /* Set final transfer data length and sequence length */
+ rspi_write32(rspi, len, QSPI_SPBMUL(i - 1));
+ rspi_write8(rspi, i - 1, RSPI_SPSCR);
+ }
+
+ return 0;
+}
+
static int rspi_prepare_message(struct spi_master *master,
- struct spi_message *message)
+ struct spi_message *msg)
{
struct rspi_data *rspi = spi_master_get_devdata(master);
+ int ret;

+ if (msg->spi->mode &
+ (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)) {
+ /* Setup sequencer for messages with multiple transfer modes */
+ ret = qspi_setup_sequencer(rspi, msg);
+ if (ret < 0)
+ return ret;
+ }
+
+ /* Enable SPI function in master mode */
rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) | SPCR_SPE, RSPI_SPCR);
return 0;
}

static int rspi_unprepare_message(struct spi_master *master,
- struct spi_message *message)
+ struct spi_message *msg)
{
struct rspi_data *rspi = spi_master_get_devdata(master);

+ /* Disable SPI function */
rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) & ~SPCR_SPE, RSPI_SPCR);
+
+ /* Reset sequencer for Single SPI Transfers */
+ rspi_write16(rspi, rspi->spcmd, RSPI_SPCMD0);
+ rspi_write8(rspi, 0, RSPI_SPSCR);
return 0;
}

@@ -989,16 +1118,21 @@ static int rspi_remove(struct platform_device *pdev)
static const struct spi_ops rspi_ops = {
.set_config_register = rspi_set_config_register,
.transfer_one = rspi_transfer_one,
+ .mode_bits = SPI_CPHA | SPI_CPOL | SPI_LOOP,
};

static const struct spi_ops rspi_rz_ops = {
.set_config_register = rspi_rz_set_config_register,
.transfer_one = rspi_rz_transfer_one,
+ .mode_bits = SPI_CPHA | SPI_CPOL | SPI_LOOP,
};

static const struct spi_ops qspi_ops = {
.set_config_register = qspi_set_config_register,
.transfer_one = qspi_transfer_one,
+ .mode_bits = SPI_CPHA | SPI_CPOL | SPI_LOOP |
+ SPI_TX_DUAL | SPI_TX_QUAD |
+ SPI_RX_DUAL | SPI_RX_QUAD,
};

#ifdef CONFIG_OF
@@ -1120,7 +1254,7 @@ static int rspi_probe(struct platform_device *pdev)
master->cleanup = rspi_cleanup;
master->prepare_message = rspi_prepare_message;
master->unprepare_message = rspi_unprepare_message;
- master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_LOOP;
+ master->mode_bits = ops->mode_bits;
master->dev.of_node = pdev->dev.of_node;

ret = platform_get_irq_byname(pdev, "rx");
--
1.7.9.5

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