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0cf101d6b3
Update the can-mcp251x-convert-to-half-duplex-SPI patch to fix reception 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. This patch fixes the fact that mcp251x_hw_rx_frame was still relying on a full-duplex transfer where bits were being shifted on MOSI at the same time as MISO. After splitting the transaction into a spi_write_then_read() care must be taken to ignore the first byte. Signed-off-by: Tim Harvey <tharvey@gateworks.com>
63 lines
2.0 KiB
Diff
63 lines
2.0 KiB
Diff
From 097cc81ee5c15913ad330baffff2e3dea09bdad0 Mon Sep 17 00:00:00 2001
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From: Tim Harvey <tharvey@gateworks.com>
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Date: Thu, 30 Aug 2018 15:16:08 -0700
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Subject: [PATCH] can: mcp251x: convert driver to half-duplex SPI
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Some SPI host controllers such as the Cavium Thunder TX do not support
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full-duplex SPI. Using half-duplex transfers allows the driver to work
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with those host controllers.
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Signed-off-by: Tim Harvey <tharvey@gateworks.com>
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---
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drivers/net/can/spi/mcp251x.c | 15 ++++++++-------
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1 file changed, 8 insertions(+), 7 deletions(-)
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diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
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index bb20a9b..dc0574a 100644
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--- a/drivers/net/can/spi/mcp251x.c
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+++ b/drivers/net/can/spi/mcp251x.c
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@@ -291,23 +291,23 @@ static u8 mcp251x_read_reg(struct spi_device *spi, u8 reg)
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priv->spi_tx_buf[0] = INSTRUCTION_READ;
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priv->spi_tx_buf[1] = reg;
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- mcp251x_spi_trans(spi, 3);
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- val = priv->spi_rx_buf[2];
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+ spi_write_then_read(spi, priv->spi_tx_buf, 2, &val, 1);
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return val;
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}
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static void mcp251x_read_2regs(struct spi_device *spi, u8 reg, u8 *v1, u8 *v2)
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{
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+ u8 val[4] = {0};
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struct mcp251x_priv *priv = spi_get_drvdata(spi);
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priv->spi_tx_buf[0] = INSTRUCTION_READ;
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priv->spi_tx_buf[1] = reg;
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- mcp251x_spi_trans(spi, 4);
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+ spi_write_then_read(spi, priv->spi_tx_buf, 2, val, 2);
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- *v1 = priv->spi_rx_buf[2];
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- *v2 = priv->spi_rx_buf[3];
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+ *v1 = val[0];
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+ *v2 = val[1];
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}
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static void mcp251x_write_reg(struct spi_device *spi, u8 reg, u8 val)
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@@ -398,8 +398,9 @@ static void mcp251x_hw_rx_frame(struct spi_device *spi, u8 *buf,
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buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i);
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} else {
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priv->spi_tx_buf[RXBCTRL_OFF] = INSTRUCTION_READ_RXB(buf_idx);
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- mcp251x_spi_trans(spi, SPI_TRANSFER_BUF_LEN);
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- memcpy(buf, priv->spi_rx_buf, SPI_TRANSFER_BUF_LEN);
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+ spi_write_then_read(spi, priv->spi_tx_buf, 1, priv->spi_rx_buf,
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+ SPI_TRANSFER_BUF_LEN);
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+ memcpy(buf + 1, priv->spi_rx_buf, SPI_TRANSFER_BUF_LEN - 1);
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}
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}
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--
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2.7.4
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