target/linux/ar71xx/patches-3.8/005-spi-ath79-avoid-multiple-initialization-of-the-SPI-c.patch

   1 From d731c08cf1d264fd6113b9a97790c5a3a86ea520 Mon Sep 17 00:00:00 2001
   2 From: Gabor Juhos <juhosg@openwrt.org>
   3 Date: Thu, 27 Dec 2012 10:42:28 +0100
   4 Subject: [PATCH] spi/ath79: avoid multiple initialization of the SPI
   5  controller
   6
   7 commit c4a31f43005512b366e8bfc346e7f14c1a7a1ba7 upstream.
   8
   9 Currently we are initializing the SPI controller in
  10 the chip select line function, and that function is
  11 called once for each SPI device on the bus. If a
  12 board has multiple SPI devices, the controller will
  13 be initialized multiple times.
  14
  15 Introduce ath79_spi_{en,dis}able helper functions,
  16 and call those from probe/response in order to avoid
  17 the mutliple initialization of the controller.
  18
  19 Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
  20 Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
  21 ---
  22  drivers/spi/spi-ath79.c |   41 ++++++++++++++++++++++++-----------------
  23  1 file changed, 24 insertions(+), 17 deletions(-)
  24
  25 --- a/drivers/spi/spi-ath79.c
  26 +++ b/drivers/spi/spi-ath79.c
  27 @@ -96,16 +96,8 @@ static void ath79_spi_chipselect(struct
  28
  29  }
  30
  31 -static int ath79_spi_setup_cs(struct spi_device *spi)
  32 +static void ath79_spi_enable(struct ath79_spi *sp)
  33  {
  34 -       struct ath79_spi *sp = ath79_spidev_to_sp(spi);
  35 -       struct ath79_spi_controller_data *cdata;
  36 -       int status;
  37 -
  38 -       cdata = spi->controller_data;
  39 -       if (spi->chip_select && !cdata)
  40 -               return -EINVAL;
  41 -
  42         /* enable GPIO mode */
  43         ath79_spi_wr(sp, AR71XX_SPI_REG_FS, AR71XX_SPI_FS_GPIO);
  44
  45 @@ -115,6 +107,24 @@ static int ath79_spi_setup_cs(struct spi
  46
  47         /* TODO: setup speed? */
  48         ath79_spi_wr(sp, AR71XX_SPI_REG_CTRL, 0x43);
  49 +}
  50 +
  51 +static void ath79_spi_disable(struct ath79_spi *sp)
  52 +{
  53 +       /* restore CTRL register */
  54 +       ath79_spi_wr(sp, AR71XX_SPI_REG_CTRL, sp->reg_ctrl);
  55 +       /* disable GPIO mode */
  56 +       ath79_spi_wr(sp, AR71XX_SPI_REG_FS, 0);
  57 +}
  58 +
  59 +static int ath79_spi_setup_cs(struct spi_device *spi)
  60 +{
  61 +       struct ath79_spi_controller_data *cdata;
  62 +       int status;
  63 +
  64 +       cdata = spi->controller_data;
  65 +       if (spi->chip_select && !cdata)
  66 +               return -EINVAL;
  67
  68         status = 0;
  69         if (spi->chip_select) {
  70 @@ -135,17 +145,10 @@ static int ath79_spi_setup_cs(struct spi
  71
  72  static void ath79_spi_cleanup_cs(struct spi_device *spi)
  73  {
  74 -       struct ath79_spi *sp = ath79_spidev_to_sp(spi);
  75 -
  76         if (spi->chip_select) {
  77                 struct ath79_spi_controller_data *cdata = spi->controller_data;
  78                 gpio_free(cdata->gpio);
  79         }
  80 -
  81 -       /* restore CTRL register */
  82 -       ath79_spi_wr(sp, AR71XX_SPI_REG_CTRL, sp->reg_ctrl);
  83 -       /* disable GPIO mode */
  84 -       ath79_spi_wr(sp, AR71XX_SPI_REG_FS, 0);
  85  }
  86
  87  static int ath79_spi_setup(struct spi_device *spi)
  88 @@ -268,12 +271,15 @@ static int ath79_spi_probe(struct platfo
  89         dev_dbg(&pdev->dev, "register read/write delay is %u nsecs\n",
  90                 sp->rrw_delay);
  91
  92 +       ath79_spi_enable(sp);
  93         ret = spi_bitbang_start(&sp->bitbang);
  94         if (ret)
  95 -               goto err_clk_disable;
  96 +               goto err_disable;
  97
  98         return 0;
  99
 100 +err_disable:
 101 +       ath79_spi_disable(sp);
 102  err_clk_disable:
 103         clk_disable(sp->clk);
 104  err_clk_put:
 105 @@ -292,6 +298,7 @@ static int ath79_spi_remove(struct platf
 106         struct ath79_spi *sp = platform_get_drvdata(pdev);
 107
 108         spi_bitbang_stop(&sp->bitbang);
 109 +       ath79_spi_disable(sp);
 110         clk_disable(sp->clk);
 111         clk_put(sp->clk);
 112         iounmap(sp->base);