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Subject[PATCH] can: mcp251x: convert to half-duplex SPI
Date
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 <tharvey@gateworks.com>
---
drivers/net/can/spi/mcp251x.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
index 5009ff2..840c31c 100644
--- a/drivers/net/can/spi/mcp251x.c
+++ b/drivers/net/can/spi/mcp251x.c
@@ -290,23 +290,23 @@ 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)
--
2.7.4
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