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Subject[PATCH 3/3] spi: bcm-qspi: add support for 3-wire mode for half duplex transfer
Date
From: Kamal Dasu <kdasu@broadcom.com>

This change configures the MSPI controller to use 3-wire interface when
a slave device devictree nodes indicates this via the optional property.

Signed-off-by: Kamal Dasu <kdasu@broadcom.com>
---
drivers/spi/spi-bcm-qspi.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-bcm-qspi.c b/drivers/spi/spi-bcm-qspi.c
index c7c467f15e63..6cb2019cc8fc 100644
--- a/drivers/spi/spi-bcm-qspi.c
+++ b/drivers/spi/spi-bcm-qspi.c
@@ -103,6 +103,7 @@
#define MSPI_MASTER_BIT BIT(7)

#define MSPI_NUM_CDRAM 16
+#define MSPI_CDRAM_OUTP BIT(8)
#define MSPI_CDRAM_CONT_BIT BIT(7)
#define MSPI_CDRAM_BITSE_BIT BIT(6)
#define MSPI_CDRAM_DT_BIT BIT(5)
@@ -122,6 +123,8 @@
#define MSPI_SPCR3_DAM_8BYTE 0
#define MSPI_SPCR3_DAM_16BYTE (BIT(2) | BIT(4))
#define MSPI_SPCR3_DAM_32BYTE (BIT(3) | BIT(5))
+#define MSPI_SPCR3_HALFDUPLEX BIT(6)
+#define MSPI_SPCR3_HDOUTTYPE BIT(7)
#define MSPI_SPCR3_DATA_REG_SZ BIT(8)
#define MSPI_SPCR3_CPHARX BIT(9)

@@ -613,6 +616,9 @@ static void bcm_qspi_hw_set_parms(struct bcm_qspi *qspi,
/* enable fastbr */
spcr |= MSPI_SPCR3_FASTBR;

+ if (xp->mode & SPI_3WIRE)
+ spcr |= MSPI_SPCR3_HALFDUPLEX | MSPI_SPCR3_HDOUTTYPE;
+
if (bcm_qspi_has_sysclk_108(qspi)) {
/* SYSCLK_108 */
spcr |= MSPI_SPCR3_SYSCLKSEL_108;
@@ -940,6 +946,10 @@ static int write_to_hw(struct bcm_qspi *qspi, struct spi_device *spi)
mspi_cdram |= ((tp.trans->bits_per_word <= 8) ? 0 :
MSPI_CDRAM_BITSE_BIT);

+ /* set 3wrire halfduplex mode data from master to slave */
+ if ((spi->mode & SPI_3WIRE) && tp.trans->tx_buf)
+ mspi_cdram |= MSPI_CDRAM_OUTP;
+
if (has_bspi(qspi))
mspi_cdram &= ~1;
else
@@ -1480,7 +1490,8 @@ int bcm_qspi_probe(struct platform_device *pdev,
qspi->master = master;

master->bus_num = -1;
- master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_RX_DUAL | SPI_RX_QUAD;
+ master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_RX_DUAL | SPI_RX_QUAD |
+ SPI_3WIRE;
master->setup = bcm_qspi_setup;
master->transfer_one = bcm_qspi_transfer_one;
master->mem_ops = &bcm_qspi_mem_ops;
--
2.17.1
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