From 6edfb172ff1dd3cfc84c19790c245a4005474bb7 Mon Sep 17 00:00:00 2001 From: Tim Harvey Date: Tue, 25 Feb 2020 12:01:36 -0800 Subject: [PATCH 03/12] can: mcp251x: convert to half-duplex SPI Some SPI host controllers such as the Cavium Thunder 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 | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- 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_de 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)