target/linux/brcm2708/patches-4.9/950-0058-enabling-the-realtime-clock-1-wire-chip-DS1307-and-1.patch

   1 From 5edc95eee5ef69d7bfe03eede0e711e8f196dedc Mon Sep 17 00:00:00 2001
   2 From: popcornmix <popcornmix@gmail.com>
   3 Date: Wed, 8 May 2013 11:46:50 +0100
   4 Subject: [PATCH] enabling the realtime clock 1-wire chip DS1307 and 1-wire on
   5  GPIO4 (as a module)
   6
   7 1-wire: Add support for configuring pin for w1-gpio kernel module
   8 See: https://github.com/raspberrypi/linux/pull/457
   9
  10 Add bitbanging pullups, use them for w1-gpio
  11
  12 Allows parasite power to work, uses module option pullup=1
  13
  14 bcm2708: Ensure 1-wire pullup is disabled by default, and expose as module parameter
  15
  16 Signed-off-by: Alex J Lennon <ajlennon@dynamicdevices.co.uk>
  17
  18 w1-gpio: Add gpiopin module parameter and correctly free up gpio pull-up pin, if set
  19
  20 Signed-off-by: Alex J Lennon <ajlennon@dynamicdevices.co.uk>
  21
  22 w1-gpio: Sort out the pullup/parasitic power tangle
  23 ---
  24  drivers/w1/masters/w1-gpio.c | 69 ++++++++++++++++++++++++++++++++++++++++----
  25  drivers/w1/w1.h              |  6 ++++
  26  drivers/w1/w1_int.c          | 14 +++++++++
  27  drivers/w1/w1_io.c           | 18 ++++++++++--
  28  include/linux/w1-gpio.h      |  1 +
  29  5 files changed, 99 insertions(+), 9 deletions(-)
  30
  31 --- a/drivers/w1/masters/w1-gpio.c
  32 +++ b/drivers/w1/masters/w1-gpio.c
  33 @@ -23,6 +23,19 @@
  34  #include "../w1.h"
  35  #include "../w1_int.h"
  36
  37 +static int w1_gpio_pullup = 0;
  38 +static int w1_gpio_pullup_orig = 0;
  39 +module_param_named(pullup, w1_gpio_pullup, int, 0);
  40 +MODULE_PARM_DESC(pullup, "Enable parasitic power (power on data) mode");
  41 +static int w1_gpio_pullup_pin = -1;
  42 +static int w1_gpio_pullup_pin_orig = -1;
  43 +module_param_named(extpullup, w1_gpio_pullup_pin, int, 0);
  44 +MODULE_PARM_DESC(extpullup, "GPIO external pullup pin number");
  45 +static int w1_gpio_pin = -1;
  46 +static int w1_gpio_pin_orig = -1;
  47 +module_param_named(gpiopin, w1_gpio_pin, int, 0);
  48 +MODULE_PARM_DESC(gpiopin, "GPIO pin number");
  49 +
  50  static u8 w1_gpio_set_pullup(void *data, int delay)
  51  {
  52         struct w1_gpio_platform_data *pdata = data;
  53 @@ -67,6 +80,16 @@ static u8 w1_gpio_read_bit(void *data)
  54         return gpio_get_value(pdata->pin) ? 1 : 0;
  55  }
  56
  57 +static void w1_gpio_bitbang_pullup(void *data, u8 on)
  58 +{
  59 +       struct w1_gpio_platform_data *pdata = data;
  60 +
  61 +       if (on)
  62 +               gpio_direction_output(pdata->pin, 1);
  63 +       else
  64 +               gpio_direction_input(pdata->pin);
  65 +}
  66 +
  67  #if defined(CONFIG_OF)
  68  static const struct of_device_id w1_gpio_dt_ids[] = {
  69         { .compatible = "w1-gpio" },
  70 @@ -80,6 +103,7 @@ static int w1_gpio_probe_dt(struct platf
  71         struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
  72         struct device_node *np = pdev->dev.of_node;
  73         int gpio;
  74 +       u32 value;
  75
  76         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
  77         if (!pdata)
  78 @@ -88,6 +112,9 @@ static int w1_gpio_probe_dt(struct platf
  79         if (of_get_property(np, "linux,open-drain", NULL))
  80                 pdata->is_open_drain = 1;
  81
  82 +       if (of_property_read_u32(np, "rpi,parasitic-power", &value) == 0)
  83 +           pdata->parasitic_power = (value != 0);
  84 +
  85         gpio = of_get_gpio(np, 0);
  86         if (gpio < 0) {
  87                 if (gpio != -EPROBE_DEFER)
  88 @@ -103,7 +130,7 @@ static int w1_gpio_probe_dt(struct platf
  89         if (gpio == -EPROBE_DEFER)
  90                 return gpio;
  91         /* ignore other errors as the pullup gpio is optional */
  92 -       pdata->ext_pullup_enable_pin = gpio;
  93 +       pdata->ext_pullup_enable_pin = (gpio >= 0) ? gpio : -1;
  94
  95         pdev->dev.platform_data = pdata;
  96
  97 @@ -135,6 +162,22 @@ static int w1_gpio_probe(struct platform
  98                 return -ENOMEM;
  99         }
 100
 101 +       w1_gpio_pin_orig = pdata->pin;
 102 +       w1_gpio_pullup_pin_orig = pdata->ext_pullup_enable_pin;
 103 +       w1_gpio_pullup_orig = pdata->parasitic_power;
 104 +
 105 +       if(gpio_is_valid(w1_gpio_pin)) {
 106 +               pdata->pin = w1_gpio_pin;
 107 +               pdata->ext_pullup_enable_pin = -1;
 108 +               pdata->parasitic_power = -1;
 109 +       }
 110 +       pdata->parasitic_power |= w1_gpio_pullup;
 111 +       if(gpio_is_valid(w1_gpio_pullup_pin)) {
 112 +               pdata->ext_pullup_enable_pin = w1_gpio_pullup_pin;
 113 +       }
 114 +
 115 +       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);
 116 +
 117         err = devm_gpio_request(&pdev->dev, pdata->pin, "w1");
 118         if (err) {
 119                 dev_err(&pdev->dev, "gpio_request (pin) failed\n");
 120 @@ -164,6 +207,14 @@ static int w1_gpio_probe(struct platform
 121                 master->set_pullup = w1_gpio_set_pullup;
 122         }
 123
 124 +       if (pdata->parasitic_power) {
 125 +               if (pdata->is_open_drain)
 126 +                       printk(KERN_ERR "w1-gpio 'pullup'(parasitic power) "
 127 +                              "option doesn't work with open drain GPIO\n");
 128 +               else
 129 +                       master->bitbang_pullup = w1_gpio_bitbang_pullup;
 130 +       }
 131 +
 132         err = w1_add_master_device(master);
 133         if (err) {
 134                 dev_err(&pdev->dev, "w1_add_master device failed\n");
 135 @@ -194,6 +245,10 @@ static int w1_gpio_remove(struct platfor
 136
 137         w1_remove_master_device(master);
 138
 139 +       pdata->pin = w1_gpio_pin_orig;
 140 +       pdata->ext_pullup_enable_pin = w1_gpio_pullup_pin_orig;
 141 +       pdata->parasitic_power = w1_gpio_pullup_orig;
 142 +
 143         return 0;
 144  }
 145
 146 --- a/drivers/w1/w1.h
 147 +++ b/drivers/w1/w1.h
 148 @@ -173,6 +173,12 @@ struct w1_bus_master
 149
 150         u8              (*set_pullup)(void *, int);
 151
 152 +       /**
 153 +        * Turns the pullup on/off in bitbanging mode, takes an on/off argument.
 154 +        * @return -1=Error, 0=completed
 155 +        */
 156 +       void (*bitbang_pullup) (void *, u8);
 157 +
 158         void            (*search)(void *, struct w1_master *,
 159                 u8, w1_slave_found_callback);
 160  };
 161 --- a/drivers/w1/w1_int.c
 162 +++ b/drivers/w1/w1_int.c
 163 @@ -122,6 +122,20 @@ int w1_add_master_device(struct w1_bus_m
 164                 return(-EINVAL);
 165         }
 166
 167 +       /* bitbanging hardware uses bitbang_pullup, other hardware uses set_pullup
 168 +        * and takes care of timing itself */
 169 +       if (!master->write_byte && !master->touch_bit && master->set_pullup) {
 170 +               printk(KERN_ERR "w1_add_master_device: set_pullup requires "
 171 +                       "write_byte or touch_bit, disabling\n");
 172 +               master->set_pullup = NULL;
 173 +       }
 174 +
 175 +       if (master->set_pullup && master->bitbang_pullup) {
 176 +               printk(KERN_ERR "w1_add_master_device: set_pullup should not "
 177 +                      "be set when bitbang_pullup is used, disabling\n");
 178 +               master->set_pullup = NULL;
 179 +       }
 180 +
 181         /* Lock until the device is added (or not) to w1_masters. */
 182         mutex_lock(&w1_mlock);
 183         /* Search for the first available id (starting at 1). */
 184 --- a/drivers/w1/w1_io.c
 185 +++ b/drivers/w1/w1_io.c
 186 @@ -134,10 +134,22 @@ static void w1_pre_write(struct w1_maste
 187  static void w1_post_write(struct w1_master *dev)
 188  {
 189         if (dev->pullup_duration) {
 190 -               if (dev->enable_pullup && dev->bus_master->set_pullup)
 191 -                       dev->bus_master->set_pullup(dev->bus_master->data, 0);
 192 -               else
 193 +               if (dev->enable_pullup) {
 194 +                       if (dev->bus_master->set_pullup) {
 195 +                               dev->bus_master->set_pullup(dev->
 196 +                                                           bus_master->data,
 197 +                                                           0);
 198 +                       } else if (dev->bus_master->bitbang_pullup) {
 199 +                               dev->bus_master->
 200 +                                   bitbang_pullup(dev->bus_master->data, 1);
 201                         msleep(dev->pullup_duration);
 202 +                               dev->bus_master->
 203 +                                   bitbang_pullup(dev->bus_master->data, 0);
 204 +                       }
 205 +               } else {
 206 +                       msleep(dev->pullup_duration);
 207 +               }
 208 +
 209                 dev->pullup_duration = 0;
 210         }
 211  }
 212 --- a/include/linux/w1-gpio.h
 213 +++ b/include/linux/w1-gpio.h
 214 @@ -18,6 +18,7 @@
 215  struct w1_gpio_platform_data {
 216         unsigned int pin;
 217         unsigned int is_open_drain:1;
 218 +       unsigned int parasitic_power:1;
 219         void (*enable_external_pullup)(int enable);
 220         unsigned int ext_pullup_enable_pin;
 221         unsigned int pullup_duration;