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octeontx: fix mcp251x can controller

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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>
This commit is contained in:
Tim Harvey 2020-05-28 07:58:49 -07:00 committed by Petr Štetiar
parent 3fd8e86079
commit 0cf101d6b3
1 changed files with 24 additions and 7 deletions
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31
target/linux/octeontx/patches-5.4/0003-can-mcp251x-convert-to-half-duplex-SPI.patch
View File

@ -1,20 +1,22 @@
From 6edfb172ff1dd3cfc84c19790c245a4005474bb7 Mon Sep 17 00:00:00 2001
From 097cc81ee5c15913ad330baffff2e3dea09bdad0 Mon Sep 17 00:00:00 2001
From: Tim Harvey <tharvey@gateworks.com>
Date: Tue, 25 Feb 2020 12:01:36 -0800
Subject: [PATCH 03/12] can: mcp251x: convert to half-duplex SPI
Date: Thu, 30 Aug 2018 15:16:08 -0700
Subject: [PATCH] can: mcp251x: convert driver to half-duplex SPI
Some SPI host controllers such as the Cavium Thunder do not support
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.
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
---
drivers/net/can/spi/mcp251x.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
drivers/net/can/spi/mcp251x.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
index bb20a9b..dc0574a 100644
--- a/drivers/net/can/spi/mcp251x.c
+++ b/drivers/net/can/spi/mcp251x.c
@@ -291,23 +291,23 @@ static u8 mcp251x_read_reg(struct spi_de
@@ -291,23 +291,23 @@ static u8 mcp251x_read_reg(struct spi_device *spi, u8 reg)
priv->spi_tx_buf[0] = INSTRUCTION_READ;
priv->spi_tx_buf[1] = reg;
@ -43,3 +45,18 @@ Signed-off-by: Tim Harvey <tharvey@gateworks.com>
}
static void mcp251x_write_reg(struct spi_device *spi, u8 reg, u8 val)
@@ -398,8 +398,9 @@ static void mcp251x_hw_rx_frame(struct spi_device *spi, u8 *buf,
buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i);
} else {
priv->spi_tx_buf[RXBCTRL_OFF] = INSTRUCTION_READ_RXB(buf_idx);
- mcp251x_spi_trans(spi, SPI_TRANSFER_BUF_LEN);
- memcpy(buf, priv->spi_rx_buf, SPI_TRANSFER_BUF_LEN);
+ spi_write_then_read(spi, priv->spi_tx_buf, 1, priv->spi_rx_buf,
+ SPI_TRANSFER_BUF_LEN);
+ memcpy(buf + 1, priv->spi_rx_buf, SPI_TRANSFER_BUF_LEN - 1);
}
}
--
2.7.4