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From 6edfb172ff1dd3cfc84c19790c245a4005474bb7 Mon Sep 17 00:00:00 2001
From: Tim Harvey <tharvey@gateworks.com>
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 <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 0b0dd3f0..c655b29 100644
--- a/drivers/net/can/spi/mcp251x.c
+++ b/drivers/net/can/spi/mcp251x.c
@@ -345,8 +345,7 @@ static u8 mcp251x_read_reg(struct spi_device *spi, uint8_t 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;
}
@@ -354,15 +353,16 @@ static u8 mcp251x_read_reg(struct spi_device *spi, uint8_t reg)
static void mcp251x_read_2regs(struct spi_device *spi, uint8_t reg,
uint8_t *v1, uint8_t *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, uint8_t val)
--
2.7.4
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