target/linux/brcm2708/patches-4.4/0139-FIXUP-i2c_bcm2708-Don-t-change-module-baudrate-param.patch

   1 From 68f3ff91c01ecdd6be1738429f586095427cecd7 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Tue, 19 Jan 2016 16:28:05 +0000
   4 Subject: [PATCH] FIXUP i2c_bcm2708: Don't change module baudrate parameter
   5
   6 Overwriting the baudrate module parameter creates an apparent
   7 forced baudrate for i2c busses after the first. Not only does this
   8 override the baudrate from DT it also prevents the bus ID from
   9 being initialised.
  10
  11 Also fix whitespace errors.
  12 ---
  13  drivers/i2c/busses/i2c-bcm2708.c | 48 +++++++++++++++++++++-------------------
  14  1 file changed, 25 insertions(+), 23 deletions(-)
  15
  16 --- a/drivers/i2c/busses/i2c-bcm2708.c
  17 +++ b/drivers/i2c/busses/i2c-bcm2708.c
  18 @@ -71,7 +71,6 @@
  19
  20  #define DRV_NAME               "bcm2708_i2c"
  21
  22 -static unsigned int baudrate_default = CONFIG_I2C_BCM2708_BAUDRATE;
  23  static unsigned int baudrate;
  24  module_param(baudrate, uint, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
  25  MODULE_PARM_DESC(baudrate, "The I2C baudrate");
  26 @@ -317,25 +316,28 @@ static int bcm2708_i2c_probe(struct plat
  27         struct i2c_adapter *adap;
  28         unsigned long bus_hz;
  29         u32 cdiv, clk_tout;
  30 -
  31 -       if (!baudrate) {
  32 -               baudrate = baudrate_default;
  33 -               if (pdev->dev.of_node) {
  34 -                       u32 bus_clk_rate;
  35 -                       pdev->id = of_alias_get_id(pdev->dev.of_node, "i2c");
  36 -                       if (pdev->id < 0) {
  37 -                               dev_err(&pdev->dev, "alias is missing\n");
  38 -                               return -EINVAL;
  39 -                       }
  40 -                       if (!of_property_read_u32(pdev->dev.of_node,
  41 -                                               "clock-frequency", &bus_clk_rate))
  42 -                               baudrate = bus_clk_rate;
  43 -                       else
  44 -                               dev_warn(&pdev->dev,
  45 -                                       "Could not read clock-frequency property\n");
  46 +       u32 baud;
  47 +
  48 +       baud = CONFIG_I2C_BCM2708_BAUDRATE;
  49 +
  50 +       if (pdev->dev.of_node) {
  51 +               u32 bus_clk_rate;
  52 +               pdev->id = of_alias_get_id(pdev->dev.of_node, "i2c");
  53 +               if (pdev->id < 0) {
  54 +                       dev_err(&pdev->dev, "alias is missing\n");
  55 +                       return -EINVAL;
  56                 }
  57 +               if (!of_property_read_u32(pdev->dev.of_node,
  58 +                                       "clock-frequency", &bus_clk_rate))
  59 +                       baud = bus_clk_rate;
  60 +               else
  61 +                       dev_warn(&pdev->dev,
  62 +                               "Could not read clock-frequency property\n");
  63         }
  64
  65 +       if (baudrate)
  66 +               baud = baudrate;
  67 +
  68         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  69         if (!regs) {
  70                 dev_err(&pdev->dev, "could not get IO memory\n");
  71 @@ -419,21 +421,21 @@ static int bcm2708_i2c_probe(struct plat
  72         }
  73
  74         bus_hz = clk_get_rate(bi->clk);
  75 -       cdiv = bus_hz / baudrate;
  76 +       cdiv = bus_hz / baud;
  77         if (cdiv > 0xffff) {
  78                 cdiv = 0xffff;
  79 -               baudrate = bus_hz / cdiv;
  80 +               baud = bus_hz / cdiv;
  81         }
  82 -
  83 -       clk_tout = 35/1000*baudrate; //35ms timeout as per SMBus specs.
  84 -       if (clk_tout > 0xffff)
  85 +
  86 +       clk_tout = 35/1000*baud; //35ms timeout as per SMBus specs.
  87 +       if (clk_tout > 0xffff)
  88                 clk_tout = 0xffff;
  89
  90         bi->cdiv = cdiv;
  91         bi->clk_tout = clk_tout;
  92
  93         dev_info(&pdev->dev, "BSC%d Controller at 0x%08lx (irq %d) (baudrate %d)\n",
  94 -               pdev->id, (unsigned long)regs->start, irq, baudrate);
  95 +               pdev->id, (unsigned long)regs->start, irq, baud);
  96
  97         return 0;
  98