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 --- a/drivers/net/can/spi/mcp251x.c
  16 +++ b/drivers/net/can/spi/mcp251x.c
  17 @@ -291,23 +291,23 @@ static u8 mcp251x_read_reg(struct spi_de
  18         priv->spi_tx_buf[0] = INSTRUCTION_READ;
  19         priv->spi_tx_buf[1] = reg;
  20
  21 -       mcp251x_spi_trans(spi, 3);
  22 -       val = priv->spi_rx_buf[2];
  23 +       spi_write_then_read(spi, priv->spi_tx_buf, 2, &val, 1);
  24
  25         return val;
  26  }
  27
  28  static void mcp251x_read_2regs(struct spi_device *spi, u8 reg, u8 *v1, u8 *v2)
  29  {
  30 +       u8 val[4] = {0};
  31         struct mcp251x_priv *priv = spi_get_drvdata(spi);
  32
  33         priv->spi_tx_buf[0] = INSTRUCTION_READ;
  34         priv->spi_tx_buf[1] = reg;
  35
  36 -       mcp251x_spi_trans(spi, 4);
  37 +       spi_write_then_read(spi, priv->spi_tx_buf, 2, val, 2);
  38
  39 -       *v1 = priv->spi_rx_buf[2];
  40 -       *v2 = priv->spi_rx_buf[3];
  41 +       *v1 = val[0];
  42 +       *v2 = val[1];
  43  }
  44
  45  static void mcp251x_write_reg(struct spi_device *spi, u8 reg, u8 val)