target/linux/brcm2708/patches-3.18/0103-w1-gpio-Sort-out-the-pullup-parasitic-power-tangle.patch

   1 From 8ceb69e8548f27305e37866ec3b81a79e1402b1a Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Wed, 4 Feb 2015 12:59:36 +0000
   4 Subject: [PATCH 103/114] w1-gpio: Sort out the pullup/parasitic power tangle
   5
   6 ---
   7  arch/arm/boot/dts/w1-gpio-overlay.dts        |  4 +++-
   8  arch/arm/boot/dts/w1-gpio-pullup-overlay.dts |  6 +++--
   9  drivers/w1/masters/w1-gpio.c                 | 36 ++++++++++++++++++----------
  10  include/linux/w1-gpio.h                      |  1 +
  11  4 files changed, 32 insertions(+), 15 deletions(-)
  12
  13 diff --git a/arch/arm/boot/dts/w1-gpio-overlay.dts b/arch/arm/boot/dts/w1-gpio-overlay.dts
  14 index b2c5ee2..29a3b48 100644
  15 --- a/arch/arm/boot/dts/w1-gpio-overlay.dts
  16 +++ b/arch/arm/boot/dts/w1-gpio-overlay.dts
  17 @@ -1,4 +1,4 @@
  18 -// Definitions for lirc-rpi module
  19 +// Definitions for w1-gpio module (without external pullup)
  20  /dts-v1/;
  21  /plugin/;
  22
  23 @@ -14,6 +14,7 @@
  24                                 pinctrl-names = "default";
  25                                 pinctrl-0 = <&w1_pins>;
  26                                 gpios = <&gpio 4 0>;
  27 +                               rpi,parasitic-power = <0>;
  28                                 status = "okay";
  29                         };
  30                 };
  31 @@ -33,5 +34,6 @@
  32         __overrides__ {
  33                 gpiopin =       <&w1>,"gpios:4",
  34                                 <&w1_pins>,"brcm,pins:0";
  35 +               pullup =        <&w1>,"rpi,parasitic-power:0";
  36         };
  37  };
  38 diff --git a/arch/arm/boot/dts/w1-gpio-pullup-overlay.dts b/arch/arm/boot/dts/w1-gpio-pullup-overlay.dts
  39 index b3e97c2..66a98f6 100644
  40 --- a/arch/arm/boot/dts/w1-gpio-pullup-overlay.dts
  41 +++ b/arch/arm/boot/dts/w1-gpio-pullup-overlay.dts
  42 @@ -1,4 +1,4 @@
  43 -// Definitions for lirc-rpi module
  44 +// Definitions for w1-gpio module (with external pullup)
  45  /dts-v1/;
  46  /plugin/;
  47
  48 @@ -14,6 +14,7 @@
  49                                 pinctrl-names = "default";
  50                                 pinctrl-0 = <&w1_pins>;
  51                                 gpios = <&gpio 4 0>, <&gpio 5 1>;
  52 +                               rpi,parasitic-power = <0>;
  53                                 status = "okay";
  54                         };
  55                 };
  56 @@ -33,7 +34,8 @@
  57         __overrides__ {
  58                 gpiopin =       <&w1>,"gpios:4",
  59                                 <&w1_pins>,"brcm,pins:0";
  60 -               pullup =        <&w1>,"gpios:16",
  61 +               extpullup =     <&w1>,"gpios:16",
  62                                 <&w1_pins>,"brcm,pins:4";
  63 +               pullup =        <&w1>,"rpi,parasitic-power:0";
  64         };
  65  };
  66 diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c
  67 index 61be2cd..54c0313 100644
  68 --- a/drivers/w1/masters/w1-gpio.c
  69 +++ b/drivers/w1/masters/w1-gpio.c
  70 @@ -23,10 +23,14 @@
  71  #include "../w1.h"
  72  #include "../w1_int.h"
  73
  74 -static int w1_gpio_pullup = -1;
  75 -static int w1_gpio_pullup_orig = -1;
  76 +static int w1_gpio_pullup = 0;
  77 +static int w1_gpio_pullup_orig = 0;
  78  module_param_named(pullup, w1_gpio_pullup, int, 0);
  79 -MODULE_PARM_DESC(pullup, "GPIO pin pullup number");
  80 +MODULE_PARM_DESC(pullup, "Enable parasitic power (power on data) mode");
  81 +static int w1_gpio_pullup_pin = -1;
  82 +static int w1_gpio_pullup_pin_orig = -1;
  83 +module_param_named(extpullup, w1_gpio_pullup_pin, int, 0);
  84 +MODULE_PARM_DESC(extpullup, "GPIO external pullup pin number");
  85  static int w1_gpio_pin = -1;
  86  static int w1_gpio_pin_orig = -1;
  87  module_param_named(gpiopin, w1_gpio_pin, int, 0);
  88 @@ -99,6 +103,7 @@ static int w1_gpio_probe_dt(struct platform_device *pdev)
  89         struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
  90         struct device_node *np = pdev->dev.of_node;
  91         int gpio;
  92 +       u32 value;
  93
  94         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
  95         if (!pdata)
  96 @@ -107,6 +112,9 @@ static int w1_gpio_probe_dt(struct platform_device *pdev)
  97         if (of_get_property(np, "linux,open-drain", NULL))
  98                 pdata->is_open_drain = 1;
  99
 100 +       if (of_property_read_u32(np, "rpi,parasitic-power", &value) == 0)
 101 +           pdata->parasitic_power = (value != 0);
 102 +
 103         gpio = of_get_gpio(np, 0);
 104         if (gpio < 0) {
 105                 if (gpio != -EPROBE_DEFER)
 106 @@ -122,7 +130,7 @@ static int w1_gpio_probe_dt(struct platform_device *pdev)
 107         if (gpio == -EPROBE_DEFER)
 108                 return gpio;
 109         /* ignore other errors as the pullup gpio is optional */
 110 -       pdata->ext_pullup_enable_pin = gpio;
 111 +       pdata->ext_pullup_enable_pin = (gpio >= 0) ? gpio : -1;
 112
 113         pdev->dev.platform_data = pdata;
 114
 115 @@ -158,17 +166,20 @@ static int w1_gpio_probe(struct platform_device *pdev)
 116         }
 117
 118         w1_gpio_pin_orig = pdata->pin;
 119 -       w1_gpio_pullup_orig = pdata->ext_pullup_enable_pin;
 120 +       w1_gpio_pullup_pin_orig = pdata->ext_pullup_enable_pin;
 121 +       w1_gpio_pullup_orig = pdata->parasitic_power;
 122
 123         if(gpio_is_valid(w1_gpio_pin)) {
 124                 pdata->pin = w1_gpio_pin;
 125                 pdata->ext_pullup_enable_pin = -1;
 126 +               pdata->parasitic_power = -1;
 127         }
 128 -       if(gpio_is_valid(w1_gpio_pullup)) {
 129 -               pdata->ext_pullup_enable_pin = w1_gpio_pullup;
 130 +       pdata->parasitic_power |= w1_gpio_pullup;
 131 +       if(gpio_is_valid(w1_gpio_pullup_pin)) {
 132 +               pdata->ext_pullup_enable_pin = w1_gpio_pullup_pin;
 133         }
 134
 135 -       dev_info(&pdev->dev, "gpio pin %d, gpio pullup pin %d\n", pdata->pin, pdata->ext_pullup_enable_pin);
 136 +       dev_info(&pdev->dev, "gpio pin %d, external pullup pin %d, parasitic power %d\n", pdata->pin, pdata->ext_pullup_enable_pin, pdata->parasitic_power);
 137
 138         err = devm_gpio_request(&pdev->dev, pdata->pin, "w1");
 139         if (err) {
 140 @@ -199,10 +210,10 @@ static int w1_gpio_probe(struct platform_device *pdev)
 141                 master->set_pullup = w1_gpio_set_pullup;
 142         }
 143
 144 -       if (gpio_is_valid(w1_gpio_pullup)) {
 145 +       if (pdata->parasitic_power) {
 146                 if (pdata->is_open_drain)
 147 -                       printk(KERN_ERR "w1-gpio 'pullup' option "
 148 -                              "doesn't work with open drain GPIO\n");
 149 +                       printk(KERN_ERR "w1-gpio 'pullup'(parasitic power) "
 150 +                              "option doesn't work with open drain GPIO\n");
 151                 else
 152                         master->bitbang_pullup = w1_gpio_bitbang_pullup;
 153         }
 154 @@ -238,7 +249,8 @@ static int w1_gpio_remove(struct platform_device *pdev)
 155         w1_remove_master_device(master);
 156
 157         pdata->pin = w1_gpio_pin_orig;
 158 -       pdata->ext_pullup_enable_pin = w1_gpio_pullup_orig;
 159 +       pdata->ext_pullup_enable_pin = w1_gpio_pullup_pin_orig;
 160 +       pdata->parasitic_power = w1_gpio_pullup_orig;
 161
 162         return 0;
 163  }
 164 diff --git a/include/linux/w1-gpio.h b/include/linux/w1-gpio.h
 165 index d58594a..feae942 100644
 166 --- a/include/linux/w1-gpio.h
 167 +++ b/include/linux/w1-gpio.h
 168 @@ -18,6 +18,7 @@
 169  struct w1_gpio_platform_data {
 170         unsigned int pin;
 171         unsigned int is_open_drain:1;
 172 +       unsigned int parasitic_power:1;
 173         void (*enable_external_pullup)(int enable);
 174         unsigned int ext_pullup_enable_pin;
 175         unsigned int pullup_duration;
 176 --
 177 1.8.3.2
 178