From f284504b771b8741222ac54fd2d773d88e53de39 Mon Sep 17 00:00:00 2001 From: Tim Harvey Date: Thu, 30 Aug 2018 15:16:08 -0700 Subject: [PATCH] can: mcp251x: convert driver to half-duplex SPI Some SPI host controllers such as the Cavium Thunder TX do not support full-duplex SPI. Using half-duplex transfers allows the driver to work with those host controllers. Signed-off-by: Tim Harvey --- drivers/net/can/spi/mcp251x.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c index bb20a9b75cc6..dc0574a1df53 100644 --- a/drivers/net/can/spi/mcp251x.c +++ b/drivers/net/can/spi/mcp251x.c @@ -291,23 +291,23 @@ static u8 mcp251x_read_reg(struct spi_device *spi, u8 reg) priv->spi_tx_buf[0] = INSTRUCTION_READ; priv->spi_tx_buf[1] = reg; - mcp251x_spi_trans(spi, 3); - val = priv->spi_rx_buf[2]; + spi_write_then_read(spi, priv->spi_tx_buf, 2, &val, 1); return val; } static void mcp251x_read_2regs(struct spi_device *spi, u8 reg, u8 *v1, u8 *v2) { + u8 val[4] = {0}; struct mcp251x_priv *priv = spi_get_drvdata(spi); priv->spi_tx_buf[0] = INSTRUCTION_READ; priv->spi_tx_buf[1] = reg; - mcp251x_spi_trans(spi, 4); + spi_write_then_read(spi, priv->spi_tx_buf, 2, val, 2); - *v1 = priv->spi_rx_buf[2]; - *v2 = priv->spi_rx_buf[3]; + *v1 = val[0]; + *v2 = val[1]; } static void mcp251x_write_reg(struct spi_device *spi, u8 reg, u8 val) @@ -398,8 +398,9 @@ static void mcp251x_hw_rx_frame(struct spi_device *spi, u8 *buf, buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i); } else { priv->spi_tx_buf[RXBCTRL_OFF] = INSTRUCTION_READ_RXB(buf_idx); - mcp251x_spi_trans(spi, SPI_TRANSFER_BUF_LEN); - memcpy(buf, priv->spi_rx_buf, SPI_TRANSFER_BUF_LEN); + spi_write_then_read(spi, priv->spi_tx_buf, 1, priv->spi_rx_buf, + SPI_TRANSFER_BUF_LEN); + memcpy(buf + 1, priv->spi_rx_buf, SPI_TRANSFER_BUF_LEN - 1); } }