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 --- a/arch/arm/mach-bcm2708/bcm2708.c
  30 +++ b/arch/arm/mach-bcm2708/bcm2708.c
  31 @@ -32,6 +32,7 @@
  32  #include <linux/io.h>
  33  #include <linux/module.h>
  34  #include <linux/spi/spi.h>
  35 +#include <linux/w1-gpio.h>
  36
  37  #include <linux/version.h>
  38  #include <linux/clkdev.h>
  39 @@ -76,12 +77,19 @@
  40   */
  41  #define DMA_MASK_BITS_COMMON 32
  42
  43 +// use GPIO 4 for the one-wire GPIO pin, if enabled
  44 +#define W1_GPIO 4
  45 +// ensure one-wire GPIO pullup is disabled by default
  46 +#define W1_PULLUP -1
  47 +
  48  /* command line parameters */
  49  static unsigned boardrev, serial;
  50  static unsigned uart_clock;
  51  static unsigned disk_led_gpio = 16;
  52  static unsigned disk_led_active_low = 1;
  53  static unsigned reboot_part = 0;
  54 +static unsigned w1_gpio_pin = W1_GPIO;
  55 +static unsigned w1_gpio_pullup = W1_PULLUP;
  56
  57  static void __init bcm2708_init_led(void);
  58
  59 @@ -258,6 +266,20 @@ static struct platform_device bcm2708_dm
  60         .num_resources = ARRAY_SIZE(bcm2708_dmaman_resources),
  61  };
  62
  63 +#if defined(CONFIG_W1_MASTER_GPIO) || defined(CONFIG_W1_MASTER_GPIO_MODULE)
  64 +static struct w1_gpio_platform_data w1_gpio_pdata = {
  65 +       .pin = W1_GPIO,
  66 +        .ext_pullup_enable_pin = W1_PULLUP,
  67 +       .is_open_drain = 0,
  68 +};
  69 +
  70 +static struct platform_device w1_device = {
  71 +       .name = "w1-gpio",
  72 +       .id = -1,
  73 +       .dev.platform_data = &w1_gpio_pdata,
  74 +};
  75 +#endif
  76 +
  77  static u64 fb_dmamask = DMA_BIT_MASK(DMA_MASK_BITS_COMMON);
  78
  79  static struct platform_device bcm2708_fb_device = {
  80 @@ -652,6 +674,11 @@ void __init bcm2708_init(void)
  81  #ifdef CONFIG_BCM2708_GPIO
  82         bcm_register_device(&bcm2708_gpio_device);
  83  #endif
  84 +#if defined(CONFIG_W1_MASTER_GPIO) || defined(CONFIG_W1_MASTER_GPIO_MODULE)
  85 +       w1_gpio_pdata.pin = w1_gpio_pin;
  86 +       w1_gpio_pdata.ext_pullup_enable_pin = w1_gpio_pullup;
  87 +       platform_device_register(&w1_device);
  88 +#endif
  89         bcm_register_device(&bcm2708_systemtimer_device);
  90         bcm_register_device(&bcm2708_fb_device);
  91         bcm_register_device(&bcm2708_usb_device);
  92 @@ -853,3 +880,5 @@ module_param(uart_clock, uint, 0644);
  93  module_param(disk_led_gpio, uint, 0644);
  94  module_param(disk_led_active_low, uint, 0644);
  95  module_param(reboot_part, uint, 0644);
  96 +module_param(w1_gpio_pin, uint, 0644);
  97 +module_param(w1_gpio_pullup, uint, 0644);
  98 --- a/drivers/w1/masters/w1-gpio.c
  99 +++ b/drivers/w1/masters/w1-gpio.c
 100 @@ -23,6 +23,15 @@
 101  #include "../w1.h"
 102  #include "../w1_int.h"
 103
 104 +static int w1_gpio_pullup = -1;
 105 +static int w1_gpio_pullup_orig = -1;
 106 +module_param_named(pullup, w1_gpio_pullup, int, 0);
 107 +MODULE_PARM_DESC(pullup, "GPIO pin pullup number");
 108 +static int w1_gpio_pin = -1;
 109 +static int w1_gpio_pin_orig = -1;
 110 +module_param_named(gpiopin, w1_gpio_pin, int, 0);
 111 +MODULE_PARM_DESC(gpiopin, "GPIO pin number");
 112 +
 113  static u8 w1_gpio_set_pullup(void *data, int delay)
 114  {
 115         struct w1_gpio_platform_data *pdata = data;
 116 @@ -67,6 +76,16 @@ static u8 w1_gpio_read_bit(void *data)
 117         return gpio_get_value(pdata->pin) ? 1 : 0;
 118  }
 119
 120 +static void w1_gpio_bitbang_pullup(void *data, u8 on)
 121 +{
 122 +       struct w1_gpio_platform_data *pdata = data;
 123 +
 124 +       if (on)
 125 +               gpio_direction_output(pdata->pin, 1);
 126 +       else
 127 +               gpio_direction_input(pdata->pin);
 128 +}
 129 +
 130  #if defined(CONFIG_OF)
 131  static struct of_device_id w1_gpio_dt_ids[] = {
 132         { .compatible = "w1-gpio" },
 133 @@ -113,13 +132,15 @@ static int w1_gpio_probe_dt(struct platf
 134  static int w1_gpio_probe(struct platform_device *pdev)
 135  {
 136         struct w1_bus_master *master;
 137 -       struct w1_gpio_platform_data *pdata;
 138 +       struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
 139         int err;
 140
 141 -       if (of_have_populated_dt()) {
 142 -               err = w1_gpio_probe_dt(pdev);
 143 -               if (err < 0)
 144 -                       return err;
 145 +       if(pdata == NULL) {
 146 +               if (of_have_populated_dt()) {
 147 +                       err = w1_gpio_probe_dt(pdev);
 148 +                       if (err < 0)
 149 +                               return err;
 150 +               }
 151         }
 152
 153         pdata = dev_get_platdata(&pdev->dev);
 154 @@ -136,6 +157,19 @@ static int w1_gpio_probe(struct platform
 155                 return -ENOMEM;
 156         }
 157
 158 +       w1_gpio_pin_orig = pdata->pin;
 159 +       w1_gpio_pullup_orig = pdata->ext_pullup_enable_pin;
 160 +
 161 +       if(gpio_is_valid(w1_gpio_pin)) {
 162 +               pdata->pin = w1_gpio_pin;
 163 +               pdata->ext_pullup_enable_pin = -1;
 164 +       }
 165 +       if(gpio_is_valid(w1_gpio_pullup)) {
 166 +               pdata->ext_pullup_enable_pin = w1_gpio_pullup;
 167 +       }
 168 +
 169 +       dev_info(&pdev->dev, "gpio pin %d, gpio pullup pin %d\n", pdata->pin, pdata->ext_pullup_enable_pin);
 170 +
 171         err = devm_gpio_request(&pdev->dev, pdata->pin, "w1");
 172         if (err) {
 173                 dev_err(&pdev->dev, "gpio_request (pin) failed\n");
 174 @@ -165,6 +199,14 @@ static int w1_gpio_probe(struct platform
 175                 master->set_pullup = w1_gpio_set_pullup;
 176         }
 177
 178 +       if (gpio_is_valid(w1_gpio_pullup)) {
 179 +               if (pdata->is_open_drain)
 180 +                       printk(KERN_ERR "w1-gpio 'pullup' option "
 181 +                              "doesn't work with open drain GPIO\n");
 182 +               else
 183 +                       master->bitbang_pullup = w1_gpio_bitbang_pullup;
 184 +       }
 185 +
 186         err = w1_add_master_device(master);
 187         if (err) {
 188                 dev_err(&pdev->dev, "w1_add_master device failed\n");
 189 @@ -195,6 +237,9 @@ static int w1_gpio_remove(struct platfor
 190
 191         w1_remove_master_device(master);
 192
 193 +       pdata->pin = w1_gpio_pin_orig;
 194 +       pdata->ext_pullup_enable_pin = w1_gpio_pullup_orig;
 195 +
 196         return 0;
 197  }
 198
 199 --- a/drivers/w1/w1.h
 200 +++ b/drivers/w1/w1.h
 201 @@ -171,6 +171,12 @@ struct w1_bus_master
 202
 203         u8              (*set_pullup)(void *, int);
 204
 205 +       /**
 206 +        * Turns the pullup on/off in bitbanging mode, takes an on/off argument.
 207 +        * @return -1=Error, 0=completed
 208 +        */
 209 +       void (*bitbang_pullup) (void *, u8);
 210 +
 211         void            (*search)(void *, struct w1_master *,
 212                 u8, w1_slave_found_callback);
 213  };
 214 --- a/drivers/w1/w1_int.c
 215 +++ b/drivers/w1/w1_int.c
 216 @@ -123,6 +123,20 @@ int w1_add_master_device(struct w1_bus_m
 217                 return(-EINVAL);
 218         }
 219
 220 +       /* bitbanging hardware uses bitbang_pullup, other hardware uses set_pullup
 221 +        * and takes care of timing itself */
 222 +       if (!master->write_byte && !master->touch_bit && master->set_pullup) {
 223 +               printk(KERN_ERR "w1_add_master_device: set_pullup requires "
 224 +                       "write_byte or touch_bit, disabling\n");
 225 +               master->set_pullup = NULL;
 226 +       }
 227 +
 228 +       if (master->set_pullup && master->bitbang_pullup) {
 229 +               printk(KERN_ERR "w1_add_master_device: set_pullup should not "
 230 +                      "be set when bitbang_pullup is used, disabling\n");
 231 +               master->set_pullup = NULL;
 232 +       }
 233 +
 234         /* Lock until the device is added (or not) to w1_masters. */
 235         mutex_lock(&w1_mlock);
 236         /* Search for the first available id (starting at 1). */
 237 --- a/drivers/w1/w1_io.c
 238 +++ b/drivers/w1/w1_io.c
 239 @@ -134,10 +134,22 @@ static void w1_pre_write(struct w1_maste
 240  static void w1_post_write(struct w1_master *dev)
 241  {
 242         if (dev->pullup_duration) {
 243 -               if (dev->enable_pullup && dev->bus_master->set_pullup)
 244 -                       dev->bus_master->set_pullup(dev->bus_master->data, 0);
 245 -               else
 246 +               if (dev->enable_pullup) {
 247 +                       if (dev->bus_master->set_pullup) {
 248 +                               dev->bus_master->set_pullup(dev->
 249 +                                                           bus_master->data,
 250 +                                                           0);
 251 +                       } else if (dev->bus_master->bitbang_pullup) {
 252 +                               dev->bus_master->
 253 +                                   bitbang_pullup(dev->bus_master->data, 1);
 254                         msleep(dev->pullup_duration);
 255 +                               dev->bus_master->
 256 +                                   bitbang_pullup(dev->bus_master->data, 0);
 257 +                       }
 258 +               } else {
 259 +                       msleep(dev->pullup_duration);
 260 +               }
 261 +
 262                 dev->pullup_duration = 0;
 263         }
 264  }