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

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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: e0e25001d0 ("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: Tim Harvey <tharvey@gateworks.com>
Reported-by: Gerhard Bertelsmann <info@gerhard-bertelsmann.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Marc Kleine-Budde 2021-03-30 11:46:07 +02:00
parent 08c27f3322
commit 617085fca6
1 changed files with 18 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
drivers/net/can/spi/mcp251x.c
View File

@ -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;