target/linux/octeontx/patches-5.4/0003-can-mcp251x-convert-to-half-duplex-SPI.patch

   1 From 6edfb172ff1dd3cfc84c19790c245a4005474bb7 Mon Sep 17 00:00:00 2001
   2 From: Tim Harvey <tharvey@gateworks.com>
   3 Date: Tue, 25 Feb 2020 12:01:36 -0800
   4 Subject: [PATCH 03/12] can: mcp251x: convert to half-duplex SPI
   5
   6 Some SPI host controllers such as the Cavium Thunder do not support
   7 full-duplex SPI. Using half-duplex transfers allows the driver to work
   8 with those host controllers.
   9
  10 Signed-off-by: Tim Harvey <tharvey@gateworks.com>
  11 ---
  12  drivers/net/can/spi/mcp251x.c | 10 +++++-----
  13  1 file changed, 5 insertions(+), 5 deletions(-)
  14
  15 diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
  16 index 0b0dd3f0..c655b29 100644
  17 --- a/drivers/net/can/spi/mcp251x.c
  18 +++ b/drivers/net/can/spi/mcp251x.c
  19 @@ -345,8 +345,7 @@ static u8 mcp251x_read_reg(struct spi_device *spi, uint8_t reg)
  20         priv->spi_tx_buf[0] = INSTRUCTION_READ;
  21         priv->spi_tx_buf[1] = reg;
  22
  23 -       mcp251x_spi_trans(spi, 3);
  24 -       val = priv->spi_rx_buf[2];
  25 +       spi_write_then_read(spi, priv->spi_tx_buf, 2, &val, 1);
  26
  27         return val;
  28  }
  29 @@ -354,15 +353,16 @@ static u8 mcp251x_read_reg(struct spi_device *spi, uint8_t reg)
  30  static void mcp251x_read_2regs(struct spi_device *spi, uint8_t reg,
  31                 uint8_t *v1, uint8_t *v2)
  32  {
  33 +       u8 val[4] = {0};
  34         struct mcp251x_priv *priv = spi_get_drvdata(spi);
  35
  36         priv->spi_tx_buf[0] = INSTRUCTION_READ;
  37         priv->spi_tx_buf[1] = reg;
  38
  39 -       mcp251x_spi_trans(spi, 4);
  40 +       spi_write_then_read(spi, priv->spi_tx_buf, 2, val, 2);
  41
  42 -       *v1 = priv->spi_rx_buf[2];
  43 -       *v2 = priv->spi_rx_buf[3];
  44 +       *v1 = val[0];
  45 +       *v2 = val[1];
  46  }
  47
  48  static void mcp251x_write_reg(struct spi_device *spi, u8 reg, uint8_t val)
  49 --
  50 2.7.4
  51