1 From 097cc81ee5c15913ad330baffff2e3dea09bdad0 Mon Sep 17 00:00:00 2001
2 From: Tim Harvey <tharvey@gateworks.com>
3 Date: Thu, 30 Aug 2018 15:16:08 -0700
4 Subject: [PATCH] can: mcp251x: convert driver to half-duplex SPI
6 Some SPI host controllers such as the Cavium Thunder TX do not support
7 full-duplex SPI. Using half-duplex transfers allows the driver to work
8 with those host controllers.
10 Signed-off-by: Tim Harvey <tharvey@gateworks.com>
12 drivers/net/can/spi/mcp251x.c | 15 ++++++++-------
13 1 file changed, 8 insertions(+), 7 deletions(-)
15 --- a/drivers/net/can/spi/mcp251x.c
16 +++ b/drivers/net/can/spi/mcp251x.c
17 @@ -291,23 +291,23 @@ static u8 mcp251x_read_reg(struct spi_de
18 priv->spi_tx_buf[0] = INSTRUCTION_READ;
19 priv->spi_tx_buf[1] = reg;
21 - mcp251x_spi_trans(spi, 3);
22 - val = priv->spi_rx_buf[2];
23 + spi_write_then_read(spi, priv->spi_tx_buf, 2, &val, 1);
28 static void mcp251x_read_2regs(struct spi_device *spi, u8 reg, u8 *v1, u8 *v2)
31 struct mcp251x_priv *priv = spi_get_drvdata(spi);
33 priv->spi_tx_buf[0] = INSTRUCTION_READ;
34 priv->spi_tx_buf[1] = reg;
36 - mcp251x_spi_trans(spi, 4);
37 + spi_write_then_read(spi, priv->spi_tx_buf, 2, val, 2);
39 - *v1 = priv->spi_rx_buf[2];
40 - *v2 = priv->spi_rx_buf[3];
45 static void mcp251x_write_reg(struct spi_device *spi, u8 reg, u8 val)
46 @@ -398,8 +398,9 @@ static void mcp251x_hw_rx_frame(struct s
47 buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i);
49 priv->spi_tx_buf[RXBCTRL_OFF] = INSTRUCTION_READ_RXB(buf_idx);
50 - mcp251x_spi_trans(spi, SPI_TRANSFER_BUF_LEN);
51 - memcpy(buf, priv->spi_rx_buf, SPI_TRANSFER_BUF_LEN);
52 + spi_write_then_read(spi, priv->spi_tx_buf, 1, priv->spi_rx_buf,
53 + SPI_TRANSFER_BUF_LEN);
54 + memcpy(buf + 1, priv->spi_rx_buf, SPI_TRANSFER_BUF_LEN - 1);