git.librecmc.org Git - librecmc/librecmc.git/blob

   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 Index: linux-4.9.111/drivers/w1/masters/w1-gpio.c
  32 ===================================================================
  33 --- linux-4.9.111.orig/drivers/w1/masters/w1-gpio.c
  34 +++ linux-4.9.111/drivers/w1/masters/w1-gpio.c
  35 @@ -23,6 +23,19 @@
  36  #include "../w1.h"
  37  #include "../w1_int.h"
  38
  39 +static int w1_gpio_pullup = 0;
  40 +static int w1_gpio_pullup_orig = 0;
  41 +module_param_named(pullup, w1_gpio_pullup, int, 0);
  42 +MODULE_PARM_DESC(pullup, "Enable parasitic power (power on data) mode");
  43 +static int w1_gpio_pullup_pin = -1;
  44 +static int w1_gpio_pullup_pin_orig = -1;
  45 +module_param_named(extpullup, w1_gpio_pullup_pin, int, 0);
  46 +MODULE_PARM_DESC(extpullup, "GPIO external pullup pin number");
  47 +static int w1_gpio_pin = -1;
  48 +static int w1_gpio_pin_orig = -1;
  49 +module_param_named(gpiopin, w1_gpio_pin, int, 0);
  50 +MODULE_PARM_DESC(gpiopin, "GPIO pin number");
  51 +
  52  static u8 w1_gpio_set_pullup(void *data, int delay)
  53  {
  54         struct w1_gpio_platform_data *pdata = data;
  55 @@ -67,6 +80,16 @@ static u8 w1_gpio_read_bit(void *data)
  56         return gpio_get_value(pdata->pin) ? 1 : 0;
  57  }
  58
  59 +static void w1_gpio_bitbang_pullup(void *data, u8 on)
  60 +{
  61 +       struct w1_gpio_platform_data *pdata = data;
  62 +
  63 +       if (on)
  64 +               gpio_direction_output(pdata->pin, 1);
  65 +       else
  66 +               gpio_direction_input(pdata->pin);
  67 +}
  68 +
  69  #if defined(CONFIG_OF)
  70  static const struct of_device_id w1_gpio_dt_ids[] = {
  71         { .compatible = "w1-gpio" },
  72 @@ -80,6 +103,7 @@ static int w1_gpio_probe_dt(struct platf
  73         struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
  74         struct device_node *np = pdev->dev.of_node;
  75         int gpio;
  76 +       u32 value;
  77
  78         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
  79         if (!pdata)
  80 @@ -88,6 +112,9 @@ static int w1_gpio_probe_dt(struct platf
  81         if (of_get_property(np, "linux,open-drain", NULL))
  82                 pdata->is_open_drain = 1;
  83
  84 +       if (of_property_read_u32(np, "rpi,parasitic-power", &value) == 0)
  85 +           pdata->parasitic_power = (value != 0);
  86 +
  87         gpio = of_get_gpio(np, 0);
  88         if (gpio < 0) {
  89                 if (gpio != -EPROBE_DEFER)
  90 @@ -103,7 +130,7 @@ static int w1_gpio_probe_dt(struct platf
  91         if (gpio == -EPROBE_DEFER)
  92                 return gpio;
  93         /* ignore other errors as the pullup gpio is optional */
  94 -       pdata->ext_pullup_enable_pin = gpio;
  95 +       pdata->ext_pullup_enable_pin = (gpio >= 0) ? gpio : -1;
  96
  97         pdev->dev.platform_data = pdata;
  98
  99 @@ -135,6 +162,22 @@ static int w1_gpio_probe(struct platform
 100                 return -ENOMEM;
 101         }
 102
 103 +       w1_gpio_pin_orig = pdata->pin;
 104 +       w1_gpio_pullup_pin_orig = pdata->ext_pullup_enable_pin;
 105 +       w1_gpio_pullup_orig = pdata->parasitic_power;
 106 +
 107 +       if(gpio_is_valid(w1_gpio_pin)) {
 108 +               pdata->pin = w1_gpio_pin;
 109 +               pdata->ext_pullup_enable_pin = -1;
 110 +               pdata->parasitic_power = -1;
 111 +       }
 112 +       pdata->parasitic_power |= w1_gpio_pullup;
 113 +       if(gpio_is_valid(w1_gpio_pullup_pin)) {
 114 +               pdata->ext_pullup_enable_pin = w1_gpio_pullup_pin;
 115 +       }
 116 +
 117 +       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);
 118 +
 119         err = devm_gpio_request(&pdev->dev, pdata->pin, "w1");
 120         if (err) {
 121                 dev_err(&pdev->dev, "gpio_request (pin) failed\n");
 122 @@ -164,6 +207,14 @@ static int w1_gpio_probe(struct platform
 123                 master->set_pullup = w1_gpio_set_pullup;
 124         }
 125
 126 +       if (pdata->parasitic_power) {
 127 +               if (pdata->is_open_drain)
 128 +                       printk(KERN_ERR "w1-gpio 'pullup'(parasitic power) "
 129 +                              "option doesn't work with open drain GPIO\n");
 130 +               else
 131 +                       master->bitbang_pullup = w1_gpio_bitbang_pullup;
 132 +       }
 133 +
 134         err = w1_add_master_device(master);
 135         if (err) {
 136                 dev_err(&pdev->dev, "w1_add_master device failed\n");
 137 @@ -194,6 +245,10 @@ static int w1_gpio_remove(struct platfor
 138
 139         w1_remove_master_device(master);
 140
 141 +       pdata->pin = w1_gpio_pin_orig;
 142 +       pdata->ext_pullup_enable_pin = w1_gpio_pullup_pin_orig;
 143 +       pdata->parasitic_power = w1_gpio_pullup_orig;
 144 +
 145         return 0;
 146  }
 147
 148 Index: linux-4.9.111/drivers/w1/w1.h
 149 ===================================================================
 150 --- linux-4.9.111.orig/drivers/w1/w1.h
 151 +++ linux-4.9.111/drivers/w1/w1.h
 152 @@ -173,6 +173,12 @@ struct w1_bus_master
 153
 154         u8              (*set_pullup)(void *, int);
 155
 156 +       /**
 157 +        * Turns the pullup on/off in bitbanging mode, takes an on/off argument.
 158 +        * @return -1=Error, 0=completed
 159 +        */
 160 +       void (*bitbang_pullup) (void *, u8);
 161 +
 162         void            (*search)(void *, struct w1_master *,
 163                 u8, w1_slave_found_callback);
 164  };
 165 Index: linux-4.9.111/drivers/w1/w1_int.c
 166 ===================================================================
 167 --- linux-4.9.111.orig/drivers/w1/w1_int.c
 168 +++ linux-4.9.111/drivers/w1/w1_int.c
 169 @@ -122,6 +122,20 @@ int w1_add_master_device(struct w1_bus_m
 170                 return(-EINVAL);
 171         }
 172
 173 +       /* bitbanging hardware uses bitbang_pullup, other hardware uses set_pullup
 174 +        * and takes care of timing itself */
 175 +       if (!master->write_byte && !master->touch_bit && master->set_pullup) {
 176 +               printk(KERN_ERR "w1_add_master_device: set_pullup requires "
 177 +                       "write_byte or touch_bit, disabling\n");
 178 +               master->set_pullup = NULL;
 179 +       }
 180 +
 181 +       if (master->set_pullup && master->bitbang_pullup) {
 182 +               printk(KERN_ERR "w1_add_master_device: set_pullup should not "
 183 +                      "be set when bitbang_pullup is used, disabling\n");
 184 +               master->set_pullup = NULL;
 185 +       }
 186 +
 187         /* Lock until the device is added (or not) to w1_masters. */
 188         mutex_lock(&w1_mlock);
 189         /* Search for the first available id (starting at 1). */
 190 Index: linux-4.9.111/drivers/w1/w1_io.c
 191 ===================================================================
 192 --- linux-4.9.111.orig/drivers/w1/w1_io.c
 193 +++ linux-4.9.111/drivers/w1/w1_io.c
 194 @@ -134,10 +134,22 @@ static void w1_pre_write(struct w1_maste
 195  static void w1_post_write(struct w1_master *dev)
 196  {
 197         if (dev->pullup_duration) {
 198 -               if (dev->enable_pullup && dev->bus_master->set_pullup)
 199 -                       dev->bus_master->set_pullup(dev->bus_master->data, 0);
 200 -               else
 201 +               if (dev->enable_pullup) {
 202 +                       if (dev->bus_master->set_pullup) {
 203 +                               dev->bus_master->set_pullup(dev->
 204 +                                                           bus_master->data,
 205 +                                                           0);
 206 +                       } else if (dev->bus_master->bitbang_pullup) {
 207 +                               dev->bus_master->
 208 +                                   bitbang_pullup(dev->bus_master->data, 1);
 209                         msleep(dev->pullup_duration);
 210 +                               dev->bus_master->
 211 +                                   bitbang_pullup(dev->bus_master->data, 0);
 212 +                       }
 213 +               } else {
 214 +                       msleep(dev->pullup_duration);
 215 +               }
 216 +
 217                 dev->pullup_duration = 0;
 218         }
 219  }
 220 Index: linux-4.9.111/include/linux/w1-gpio.h
 221 ===================================================================
 222 --- linux-4.9.111.orig/include/linux/w1-gpio.h
 223 +++ linux-4.9.111/include/linux/w1-gpio.h
 224 @@ -18,6 +18,7 @@
 225  struct w1_gpio_platform_data {
 226         unsigned int pin;
 227         unsigned int is_open_drain:1;
 228 +       unsigned int parasitic_power:1;
 229         void (*enable_external_pullup)(int enable);
 230         unsigned int ext_pullup_enable_pin;
 231         unsigned int pullup_duration;