Commit 617085fc authored by Marc Kleine-Budde's avatar Marc Kleine-Budde
Browse files

can: mcp251x: fix support for half duplex SPI host controllers 

Some SPI host controllers do not support full-duplex SPI transfers.

The function mcp251x_spi_trans() does a full duplex transfer. It is
used in several places in the driver, where a TX half duplex transfer
is sufficient.

To fix support for half duplex SPI host controllers, this patch
introduces a new function mcp251x_spi_write() and changes all callers
that do a TX half duplex transfer to use mcp251x_spi_write().

Fixes: e0e25001 ("can: mcp251x: add support for half duplex controllers")
Link: https://lore.kernel.org/r/20210330100246.1074375-1-mkl@pengutronix.de


Cc: Tim Harvey <tharvey@gateworks.com>
Tested-By: default avatarTim Harvey <tharvey@gateworks.com>
Reported-by: default avatarGerhard Bertelsmann <info@gerhard-bertelsmann.de>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 08c27f33

drivers/net/can/spi/mcp251x.c

+18 −6
Original line number Diff line number Diff line
@@ -314,6 +314,18 @@ static int mcp251x_spi_trans(struct spi_device *spi, int len) 
	return ret;

}



static int mcp251x_spi_write(struct spi_device *spi, int len)

{

	struct mcp251x_priv *priv = spi_get_drvdata(spi);

	int ret;



	ret = spi_write(spi, priv->spi_tx_buf, len);

	if (ret)

		dev_err(&spi->dev, "spi write failed: ret = %d\n", ret);



	return ret;

}



static u8 mcp251x_read_reg(struct spi_device *spi, u8 reg)

{

	struct mcp251x_priv *priv = spi_get_drvdata(spi);
@@ -361,7 +373,7 @@ static void mcp251x_write_reg(struct spi_device *spi, u8 reg, u8 val) 
	priv->spi_tx_buf[1] = reg;

	priv->spi_tx_buf[2] = val;



	mcp251x_spi_trans(spi, 3);

	mcp251x_spi_write(spi, 3);

}



static void mcp251x_write_2regs(struct spi_device *spi, u8 reg, u8 v1, u8 v2)
@@ -373,7 +385,7 @@ static void mcp251x_write_2regs(struct spi_device *spi, u8 reg, u8 v1, u8 v2) 
	priv->spi_tx_buf[2] = v1;

	priv->spi_tx_buf[3] = v2;



	mcp251x_spi_trans(spi, 4);

	mcp251x_spi_write(spi, 4);

}



static void mcp251x_write_bits(struct spi_device *spi, u8 reg,
@@ -386,7 +398,7 @@ static void mcp251x_write_bits(struct spi_device *spi, u8 reg, 
	priv->spi_tx_buf[2] = mask;

	priv->spi_tx_buf[3] = val;



	mcp251x_spi_trans(spi, 4);

	mcp251x_spi_write(spi, 4);

}



static u8 mcp251x_read_stat(struct spi_device *spi)
@@ -618,7 +630,7 @@ static void mcp251x_hw_tx_frame(struct spi_device *spi, u8 *buf, 
					  buf[i]);

	} else {

		memcpy(priv->spi_tx_buf, buf, TXBDAT_OFF + len);

		mcp251x_spi_trans(spi, TXBDAT_OFF + len);

		mcp251x_spi_write(spi, TXBDAT_OFF + len);

	}

}
@@ -650,7 +662,7 @@ static void mcp251x_hw_tx(struct spi_device *spi, struct can_frame *frame, 


	/* use INSTRUCTION_RTS, to avoid "repeated frame problem" */

	priv->spi_tx_buf[0] = INSTRUCTION_RTS(1 << tx_buf_idx);

	mcp251x_spi_trans(priv->spi, 1);

	mcp251x_spi_write(priv->spi, 1);

}



static void mcp251x_hw_rx_frame(struct spi_device *spi, u8 *buf,
@@ -888,7 +900,7 @@ static int mcp251x_hw_reset(struct spi_device *spi) 
	mdelay(MCP251X_OST_DELAY_MS);



	priv->spi_tx_buf[0] = INSTRUCTION_RESET;

	ret = mcp251x_spi_trans(spi, 1);

	ret = mcp251x_spi_write(spi, 1);

	if (ret)

		return ret;