target/linux/brcm2708/patches-3.18/0021-enabling-the-realtime-clock-1-wire-chip-DS1307-and-1.patch

   1 From bd7d1508a83c544f2d52f668ebabe55c2ea207c5 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 021/114] enabling the realtime clock 1-wire chip DS1307 and
   5  1-wire on 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  arch/arm/mach-bcm2708/bcm2708.c | 29 ++++++++++++++++++++++
  23  drivers/w1/masters/w1-gpio.c    | 55 +++++++++++++++++++++++++++++++++++++----
  24  drivers/w1/w1.h                 |  6 +++++
  25  drivers/w1/w1_int.c             | 14 +++++++++++
  26  drivers/w1/w1_io.c              | 18 +++++++++++---
  27  5 files changed, 114 insertions(+), 8 deletions(-)
  28
  29 diff --git a/arch/arm/mach-bcm2708/bcm2708.c b/arch/arm/mach-bcm2708/bcm2708.c
  30 index 82f56fb..7dd89a7f 100644
  31 --- a/arch/arm/mach-bcm2708/bcm2708.c
  32 +++ b/arch/arm/mach-bcm2708/bcm2708.c
  33 @@ -32,6 +32,7 @@
  34  #include <linux/io.h>
  35  #include <linux/module.h>
  36  #include <linux/spi/spi.h>
  37 +#include <linux/w1-gpio.h>
  38
  39  #include <linux/version.h>
  40  #include <linux/clkdev.h>
  41 @@ -76,12 +77,19 @@
  42   */
  43  #define DMA_MASK_BITS_COMMON 32
  44
  45 +// use GPIO 4 for the one-wire GPIO pin, if enabled
  46 +#define W1_GPIO 4
  47 +// ensure one-wire GPIO pullup is disabled by default
  48 +#define W1_PULLUP -1
  49 +
  50  /* command line parameters */
  51  static unsigned boardrev, serial;
  52  static unsigned uart_clock;
  53  static unsigned disk_led_gpio = 16;
  54  static unsigned disk_led_active_low = 1;
  55  static unsigned reboot_part = 0;
  56 +static unsigned w1_gpio_pin = W1_GPIO;
  57 +static unsigned w1_gpio_pullup = W1_PULLUP;
  58
  59  static void __init bcm2708_init_led(void);
  60
  61 @@ -258,6 +266,20 @@ static struct platform_device bcm2708_dmaman_device = {
  62         .num_resources = ARRAY_SIZE(bcm2708_dmaman_resources),
  63  };
  64
  65 +#if defined(CONFIG_W1_MASTER_GPIO) || defined(CONFIG_W1_MASTER_GPIO_MODULE)
  66 +static struct w1_gpio_platform_data w1_gpio_pdata = {
  67 +       .pin = W1_GPIO,
  68 +        .ext_pullup_enable_pin = W1_PULLUP,
  69 +       .is_open_drain = 0,
  70 +};
  71 +
  72 +static struct platform_device w1_device = {
  73 +       .name = "w1-gpio",
  74 +       .id = -1,
  75 +       .dev.platform_data = &w1_gpio_pdata,
  76 +};
  77 +#endif
  78 +
  79  static u64 fb_dmamask = DMA_BIT_MASK(DMA_MASK_BITS_COMMON);
  80
  81  static struct platform_device bcm2708_fb_device = {
  82 @@ -652,6 +674,11 @@ void __init bcm2708_init(void)
  83  #ifdef CONFIG_BCM2708_GPIO
  84         bcm_register_device(&bcm2708_gpio_device);
  85  #endif
  86 +#if defined(CONFIG_W1_MASTER_GPIO) || defined(CONFIG_W1_MASTER_GPIO_MODULE)
  87 +       w1_gpio_pdata.pin = w1_gpio_pin;
  88 +       w1_gpio_pdata.ext_pullup_enable_pin = w1_gpio_pullup;
  89 +       platform_device_register(&w1_device);
  90 +#endif
  91         bcm_register_device(&bcm2708_systemtimer_device);
  92         bcm_register_device(&bcm2708_fb_device);
  93         bcm_register_device(&bcm2708_usb_device);
  94 @@ -853,3 +880,5 @@ module_param(uart_clock, uint, 0644);
  95  module_param(disk_led_gpio, uint, 0644);
  96  module_param(disk_led_active_low, uint, 0644);
  97  module_param(reboot_part, uint, 0644);
  98 +module_param(w1_gpio_pin, uint, 0644);
  99 +module_param(w1_gpio_pullup, uint, 0644);
 100 diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c
 101 index 1d111e5..61be2cd 100644
 102 --- a/drivers/w1/masters/w1-gpio.c
 103 +++ b/drivers/w1/masters/w1-gpio.c
 104 @@ -23,6 +23,15 @@
 105  #include "../w1.h"
 106  #include "../w1_int.h"
 107
 108 +static int w1_gpio_pullup = -1;
 109 +static int w1_gpio_pullup_orig = -1;
 110 +module_param_named(pullup, w1_gpio_pullup, int, 0);
 111 +MODULE_PARM_DESC(pullup, "GPIO pin pullup number");
 112 +static int w1_gpio_pin = -1;
 113 +static int w1_gpio_pin_orig = -1;
 114 +module_param_named(gpiopin, w1_gpio_pin, int, 0);
 115 +MODULE_PARM_DESC(gpiopin, "GPIO pin number");
 116 +
 117  static u8 w1_gpio_set_pullup(void *data, int delay)
 118  {
 119         struct w1_gpio_platform_data *pdata = data;
 120 @@ -67,6 +76,16 @@ static u8 w1_gpio_read_bit(void *data)
 121         return gpio_get_value(pdata->pin) ? 1 : 0;
 122  }
 123
 124 +static void w1_gpio_bitbang_pullup(void *data, u8 on)
 125 +{
 126 +       struct w1_gpio_platform_data *pdata = data;
 127 +
 128 +       if (on)
 129 +               gpio_direction_output(pdata->pin, 1);
 130 +       else
 131 +               gpio_direction_input(pdata->pin);
 132 +}
 133 +
 134  #if defined(CONFIG_OF)
 135  static struct of_device_id w1_gpio_dt_ids[] = {
 136         { .compatible = "w1-gpio" },
 137 @@ -113,13 +132,15 @@ static int w1_gpio_probe_dt(struct platform_device *pdev)
 138  static int w1_gpio_probe(struct platform_device *pdev)
 139  {
 140         struct w1_bus_master *master;
 141 -       struct w1_gpio_platform_data *pdata;
 142 +       struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
 143         int err;
 144
 145 -       if (of_have_populated_dt()) {
 146 -               err = w1_gpio_probe_dt(pdev);
 147 -               if (err < 0)
 148 -                       return err;
 149 +       if(pdata == NULL) {
 150 +               if (of_have_populated_dt()) {
 151 +                       err = w1_gpio_probe_dt(pdev);
 152 +                       if (err < 0)
 153 +                               return err;
 154 +               }
 155         }
 156
 157         pdata = dev_get_platdata(&pdev->dev);
 158 @@ -136,6 +157,19 @@ static int w1_gpio_probe(struct platform_device *pdev)
 159                 return -ENOMEM;
 160         }
 161
 162 +       w1_gpio_pin_orig = pdata->pin;
 163 +       w1_gpio_pullup_orig = pdata->ext_pullup_enable_pin;
 164 +
 165 +       if(gpio_is_valid(w1_gpio_pin)) {
 166 +               pdata->pin = w1_gpio_pin;
 167 +               pdata->ext_pullup_enable_pin = -1;
 168 +       }
 169 +       if(gpio_is_valid(w1_gpio_pullup)) {
 170 +               pdata->ext_pullup_enable_pin = w1_gpio_pullup;
 171 +       }
 172 +
 173 +       dev_info(&pdev->dev, "gpio pin %d, gpio pullup pin %d\n", pdata->pin, pdata->ext_pullup_enable_pin);
 174 +
 175         err = devm_gpio_request(&pdev->dev, pdata->pin, "w1");
 176         if (err) {
 177                 dev_err(&pdev->dev, "gpio_request (pin) failed\n");
 178 @@ -165,6 +199,14 @@ static int w1_gpio_probe(struct platform_device *pdev)
 179                 master->set_pullup = w1_gpio_set_pullup;
 180         }
 181
 182 +       if (gpio_is_valid(w1_gpio_pullup)) {
 183 +               if (pdata->is_open_drain)
 184 +                       printk(KERN_ERR "w1-gpio 'pullup' option "
 185 +                              "doesn't work with open drain GPIO\n");
 186 +               else
 187 +                       master->bitbang_pullup = w1_gpio_bitbang_pullup;
 188 +       }
 189 +
 190         err = w1_add_master_device(master);
 191         if (err) {
 192                 dev_err(&pdev->dev, "w1_add_master device failed\n");
 193 @@ -195,6 +237,9 @@ static int w1_gpio_remove(struct platform_device *pdev)
 194
 195         w1_remove_master_device(master);
 196
 197 +       pdata->pin = w1_gpio_pin_orig;
 198 +       pdata->ext_pullup_enable_pin = w1_gpio_pullup_orig;
 199 +
 200         return 0;
 201  }
 202
 203 diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h
 204 index 56a49ba..881d728 100644
 205 --- a/drivers/w1/w1.h
 206 +++ b/drivers/w1/w1.h
 207 @@ -171,6 +171,12 @@ struct w1_bus_master
 208
 209         u8              (*set_pullup)(void *, int);
 210
 211 +       /**
 212 +        * Turns the pullup on/off in bitbanging mode, takes an on/off argument.
 213 +        * @return -1=Error, 0=completed
 214 +        */
 215 +       void (*bitbang_pullup) (void *, u8);
 216 +
 217         void            (*search)(void *, struct w1_master *,
 218                 u8, w1_slave_found_callback);
 219  };
 220 diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c
 221 index 47249a3..a4b4a8d 100644
 222 --- a/drivers/w1/w1_int.c
 223 +++ b/drivers/w1/w1_int.c
 224 @@ -123,6 +123,20 @@ int w1_add_master_device(struct w1_bus_master *master)
 225                 return(-EINVAL);
 226         }
 227
 228 +       /* bitbanging hardware uses bitbang_pullup, other hardware uses set_pullup
 229 +        * and takes care of timing itself */
 230 +       if (!master->write_byte && !master->touch_bit && master->set_pullup) {
 231 +               printk(KERN_ERR "w1_add_master_device: set_pullup requires "
 232 +                       "write_byte or touch_bit, disabling\n");
 233 +               master->set_pullup = NULL;
 234 +       }
 235 +
 236 +       if (master->set_pullup && master->bitbang_pullup) {
 237 +               printk(KERN_ERR "w1_add_master_device: set_pullup should not "
 238 +                      "be set when bitbang_pullup is used, disabling\n");
 239 +               master->set_pullup = NULL;
 240 +       }
 241 +
 242         /* Lock until the device is added (or not) to w1_masters. */
 243         mutex_lock(&w1_mlock);
 244         /* Search for the first available id (starting at 1). */
 245 diff --git a/drivers/w1/w1_io.c b/drivers/w1/w1_io.c
 246 index 2820924..fd0550f 100644
 247 --- a/drivers/w1/w1_io.c
 248 +++ b/drivers/w1/w1_io.c
 249 @@ -134,10 +134,22 @@ static void w1_pre_write(struct w1_master *dev)
 250  static void w1_post_write(struct w1_master *dev)
 251  {
 252         if (dev->pullup_duration) {
 253 -               if (dev->enable_pullup && dev->bus_master->set_pullup)
 254 -                       dev->bus_master->set_pullup(dev->bus_master->data, 0);
 255 -               else
 256 +               if (dev->enable_pullup) {
 257 +                       if (dev->bus_master->set_pullup) {
 258 +                               dev->bus_master->set_pullup(dev->
 259 +                                                           bus_master->data,
 260 +                                                           0);
 261 +                       } else if (dev->bus_master->bitbang_pullup) {
 262 +                               dev->bus_master->
 263 +                                   bitbang_pullup(dev->bus_master->data, 1);
 264 +                       msleep(dev->pullup_duration);
 265 +                               dev->bus_master->
 266 +                                   bitbang_pullup(dev->bus_master->data, 0);
 267 +                       }
 268 +               } else {
 269                         msleep(dev->pullup_duration);
 270 +               }
 271 +
 272                 dev->pullup_duration = 0;
 273         }
 274  }
 275 --
 276 1.8.3.2
 277