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: e0e25001d088 ("can: mcp251x: add support for half duplex controllers")
Link: https://lore.kernel.org/r/20210330100246.1074375-1-mkl@xxxxxxxxxxxxxx
Cc: Tim Harvey <tharvey@xxxxxxxxxxxxx>
Tested-By: Tim Harvey <tharvey@xxxxxxxxxxxxx>
Reported-by: Gerhard Bertelsmann <info@xxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
---
drivers/net/can/spi/mcp251x.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
index f69fb4238a65..a57da43680d8 100644
--- a/drivers/net/can/spi/mcp251x.c
+++ b/drivers/net/can/spi/mcp251x.c
@@ -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;
base-commit: 08c27f3322fec11950b8f1384aa0f3b11d028528
--
2.30.2
