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Message-Id: <1582655734-20890-1-git-send-email-tharvey@gateworks.com>
Date: Tue, 25 Feb 2020 10:35:34 -0800
From: Tim Harvey <tharvey@...eworks.com>
To: linux-kernel@...r.kernel.org, linux-can@...r.kernel.org,
Wolfgang Grandegger <wg@...ndegger.com>,
Marc Kleine-Budde <mkl@...gutronix.de>
Cc: Timo Schlüßler <schluessler@...use.de>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Tim Harvey <tharvey@...eworks.com>
Subject: [PATCH] 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@...eworks.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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