target/linux/brcm2708/patches-4.9/0058-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 @@ -113,13 +140,15 @@ static int w1_gpio_probe_dt(struct platf
  98  static int w1_gpio_probe(struct platform_device *pdev)
  99  {
 100         struct w1_bus_master *master;
 101 -       struct w1_gpio_platform_data *pdata;
 102 +       struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
 103         int err;
 104
 105 -       if (of_have_populated_dt()) {
 106 -               err = w1_gpio_probe_dt(pdev);
 107 -               if (err < 0)
 108 -                       return err;
 109 +       if(pdata == NULL) {
 110 +               if (of_have_populated_dt()) {
 111 +                       err = w1_gpio_probe_dt(pdev);
 112 +                       if (err < 0)
 113 +                               return err;
 114 +               }
 115         }
 116
 117         pdata = dev_get_platdata(&pdev->dev);
 118 @@ -136,6 +165,22 @@ static int w1_gpio_probe(struct platform
 119                 return -ENOMEM;
 120         }
 121
 122 +       w1_gpio_pin_orig = pdata->pin;
 123 +       w1_gpio_pullup_pin_orig = pdata->ext_pullup_enable_pin;
 124 +       w1_gpio_pullup_orig = pdata->parasitic_power;
 125 +
 126 +       if(gpio_is_valid(w1_gpio_pin)) {
 127 +               pdata->pin = w1_gpio_pin;
 128 +               pdata->ext_pullup_enable_pin = -1;
 129 +               pdata->parasitic_power = -1;
 130 +       }
 131 +       pdata->parasitic_power |= w1_gpio_pullup;
 132 +       if(gpio_is_valid(w1_gpio_pullup_pin)) {
 133 +               pdata->ext_pullup_enable_pin = w1_gpio_pullup_pin;
 134 +       }
 135 +
 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                 dev_err(&pdev->dev, "gpio_request (pin) failed\n");
 141 @@ -165,6 +210,14 @@ static int w1_gpio_probe(struct platform
 142                 master->set_pullup = w1_gpio_set_pullup;
 143         }
 144
 145 +       if (pdata->parasitic_power) {
 146 +               if (pdata->is_open_drain)
 147 +                       printk(KERN_ERR "w1-gpio 'pullup'(parasitic power) "
 148 +                              "option doesn't work with open drain GPIO\n");
 149 +               else
 150 +                       master->bitbang_pullup = w1_gpio_bitbang_pullup;
 151 +       }
 152 +
 153         err = w1_add_master_device(master);
 154         if (err) {
 155                 dev_err(&pdev->dev, "w1_add_master device failed\n");
 156 @@ -195,6 +248,10 @@ static int w1_gpio_remove(struct platfor
 157
 158         w1_remove_master_device(master);
 159
 160 +       pdata->pin = w1_gpio_pin_orig;
 161 +       pdata->ext_pullup_enable_pin = w1_gpio_pullup_pin_orig;
 162 +       pdata->parasitic_power = w1_gpio_pullup_orig;
 163 +
 164         return 0;
 165  }
 166
 167 --- a/drivers/w1/w1.h
 168 +++ b/drivers/w1/w1.h
 169 @@ -173,6 +173,12 @@ struct w1_bus_master
 170
 171         u8              (*set_pullup)(void *, int);
 172
 173 +       /**
 174 +        * Turns the pullup on/off in bitbanging mode, takes an on/off argument.
 175 +        * @return -1=Error, 0=completed
 176 +        */
 177 +       void (*bitbang_pullup) (void *, u8);
 178 +
 179         void            (*search)(void *, struct w1_master *,
 180                 u8, w1_slave_found_callback);
 181  };
 182 --- a/drivers/w1/w1_int.c
 183 +++ b/drivers/w1/w1_int.c
 184 @@ -122,6 +122,20 @@ int w1_add_master_device(struct w1_bus_m
 185                 return(-EINVAL);
 186         }
 187
 188 +       /* bitbanging hardware uses bitbang_pullup, other hardware uses set_pullup
 189 +        * and takes care of timing itself */
 190 +       if (!master->write_byte && !master->touch_bit && master->set_pullup) {
 191 +               printk(KERN_ERR "w1_add_master_device: set_pullup requires "
 192 +                       "write_byte or touch_bit, disabling\n");
 193 +               master->set_pullup = NULL;
 194 +       }
 195 +
 196 +       if (master->set_pullup && master->bitbang_pullup) {
 197 +               printk(KERN_ERR "w1_add_master_device: set_pullup should not "
 198 +                      "be set when bitbang_pullup is used, disabling\n");
 199 +               master->set_pullup = NULL;
 200 +       }
 201 +
 202         /* Lock until the device is added (or not) to w1_masters. */
 203         mutex_lock(&w1_mlock);
 204         /* Search for the first available id (starting at 1). */
 205 --- a/drivers/w1/w1_io.c
 206 +++ b/drivers/w1/w1_io.c
 207 @@ -134,10 +134,22 @@ static void w1_pre_write(struct w1_maste
 208  static void w1_post_write(struct w1_master *dev)
 209  {
 210         if (dev->pullup_duration) {
 211 -               if (dev->enable_pullup && dev->bus_master->set_pullup)
 212 -                       dev->bus_master->set_pullup(dev->bus_master->data, 0);
 213 -               else
 214 +               if (dev->enable_pullup) {
 215 +                       if (dev->bus_master->set_pullup) {
 216 +                               dev->bus_master->set_pullup(dev->
 217 +                                                           bus_master->data,
 218 +                                                           0);
 219 +                       } else if (dev->bus_master->bitbang_pullup) {
 220 +                               dev->bus_master->
 221 +                                   bitbang_pullup(dev->bus_master->data, 1);
 222                         msleep(dev->pullup_duration);
 223 +                               dev->bus_master->
 224 +                                   bitbang_pullup(dev->bus_master->data, 0);
 225 +                       }
 226 +               } else {
 227 +                       msleep(dev->pullup_duration);
 228 +               }
 229 +
 230                 dev->pullup_duration = 0;
 231         }
 232  }
 233 --- a/include/linux/w1-gpio.h
 234 +++ b/include/linux/w1-gpio.h
 235 @@ -18,6 +18,7 @@
 236  struct w1_gpio_platform_data {
 237         unsigned int pin;
 238         unsigned int is_open_drain:1;
 239 +       unsigned int parasitic_power:1;
 240         void (*enable_external_pullup)(int enable);
 241         unsigned int ext_pullup_enable_pin;
 242         unsigned int pullup_duration;