target/linux/brcm2708/patches-4.1/0119-Merge-pull-request-1059-from-pelwell-rpi-4.0.y.patch

   1 From 0dd4dae3071d135836946ab1b990061c0899e9b5 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <pelwell@users.noreply.github.com>
   3 Date: Mon, 13 Jul 2015 13:25:31 +0100
   4 Subject: [PATCH 119/121] Merge pull request #1059 from pelwell/rpi-4.0.y
   5
   6 w1_therm: Back-port locking improvements from 4.2-rc1
   7 ---
   8  Documentation/ABI/stable/sysfs-driver-w1_ds28ea00 |   6 +
   9  Documentation/w1/slaves/w1_therm                  |  11 +-
  10  drivers/w1/slaves/w1_therm.c                      | 162 ++++++++++++++++++++--
  11  3 files changed, 163 insertions(+), 16 deletions(-)
  12  create mode 100644 Documentation/ABI/stable/sysfs-driver-w1_ds28ea00
  13
  14 --- /dev/null
  15 +++ b/Documentation/ABI/stable/sysfs-driver-w1_ds28ea00
  16 @@ -0,0 +1,6 @@
  17 +What:          /sys/bus/w1/devices/.../w1_seq
  18 +Date:          Apr 2015
  19 +Contact:       Matt Campbell <mattrcampbell@gmail.com>
  20 +Description:   Support for the DS28EA00 chain sequence function
  21 +               see Documentation/w1/slaves/w1_therm for detailed information
  22 +Users:         any user space application which wants to communicate with DS28EA00
  23 --- a/Documentation/w1/slaves/w1_therm
  24 +++ b/Documentation/w1/slaves/w1_therm
  25 @@ -11,12 +11,14 @@ Author: Evgeniy Polyakov <johnpol@2ka.mi
  26  Description
  27  -----------
  28
  29 -w1_therm provides basic temperature conversion for ds18*20 devices.
  30 +w1_therm provides basic temperature conversion for ds18*20 devices, and the
  31 +ds28ea00 device.
  32  supported family codes:
  33  W1_THERM_DS18S20       0x10
  34  W1_THERM_DS1822                0x22
  35  W1_THERM_DS18B20       0x28
  36  W1_THERM_DS1825                0x3B
  37 +W1_THERM_DS28EA00      0x42
  38
  39  Support is provided through the sysfs w1_slave file.  Each open and
  40  read sequence will initiate a temperature conversion then provide two
  41 @@ -48,3 +50,10 @@ resistor).  The DS18b20 temperature sens
  42  maximum current draw of 1.5mA and that a 5k pullup resistor is not
  43  sufficient.  The strong pullup is designed to provide the additional
  44  current required.
  45 +
  46 +The DS28EA00 provides an additional two pins for implementing a sequence
  47 +detection algorithm.  This feature allows you to determine the physical
  48 +location of the chip in the 1-wire bus without needing pre-existing
  49 +knowledge of the bus ordering.  Support is provided through the sysfs
  50 +w1_seq file.  The file will contain a single line with an integer value
  51 +representing the device index in the bus starting at 0.
  52 --- a/drivers/w1/slaves/w1_therm.c
  53 +++ b/drivers/w1/slaves/w1_therm.c
  54 @@ -59,16 +59,32 @@ MODULE_ALIAS("w1-family-" __stringify(W1
  55  static int w1_strong_pullup = 1;
  56  module_param_named(strong_pullup, w1_strong_pullup, int, 0);
  57
  58 +struct w1_therm_family_data {
  59 +       uint8_t rom[9];
  60 +       atomic_t refcnt;
  61 +};
  62 +
  63 +/* return the address of the refcnt in the family data */
  64 +#define THERM_REFCNT(family_data) \
  65 +       (&((struct w1_therm_family_data*)family_data)->refcnt)
  66 +
  67  static int w1_therm_add_slave(struct w1_slave *sl)
  68  {
  69 -       sl->family_data = kzalloc(9, GFP_KERNEL);
  70 +       sl->family_data = kzalloc(sizeof(struct w1_therm_family_data),
  71 +               GFP_KERNEL);
  72         if (!sl->family_data)
  73                 return -ENOMEM;
  74 +       atomic_set(THERM_REFCNT(sl->family_data), 1);
  75         return 0;
  76  }
  77
  78  static void w1_therm_remove_slave(struct w1_slave *sl)
  79  {
  80 +       int refcnt = atomic_sub_return(1, THERM_REFCNT(sl->family_data));
  81 +       while(refcnt) {
  82 +               msleep(1000);
  83 +               refcnt = atomic_read(THERM_REFCNT(sl->family_data));
  84 +       }
  85         kfree(sl->family_data);
  86         sl->family_data = NULL;
  87  }
  88 @@ -76,13 +92,24 @@ static void w1_therm_remove_slave(struct
  89  static ssize_t w1_slave_show(struct device *device,
  90         struct device_attribute *attr, char *buf);
  91
  92 +static ssize_t w1_seq_show(struct device *device,
  93 +       struct device_attribute *attr, char *buf);
  94 +
  95  static DEVICE_ATTR_RO(w1_slave);
  96 +static DEVICE_ATTR_RO(w1_seq);
  97
  98  static struct attribute *w1_therm_attrs[] = {
  99         &dev_attr_w1_slave.attr,
 100         NULL,
 101  };
 102 +
 103 +static struct attribute *w1_ds28ea00_attrs[] = {
 104 +       &dev_attr_w1_slave.attr,
 105 +       &dev_attr_w1_seq.attr,
 106 +       NULL,
 107 +};
 108  ATTRIBUTE_GROUPS(w1_therm);
 109 +ATTRIBUTE_GROUPS(w1_ds28ea00);
 110
 111  static struct w1_family_ops w1_therm_fops = {
 112         .add_slave      = w1_therm_add_slave,
 113 @@ -90,6 +117,12 @@ static struct w1_family_ops w1_therm_fop
 114         .groups         = w1_therm_groups,
 115  };
 116
 117 +static struct w1_family_ops w1_ds28ea00_fops = {
 118 +       .add_slave      = w1_therm_add_slave,
 119 +       .remove_slave   = w1_therm_remove_slave,
 120 +       .groups         = w1_ds28ea00_groups,
 121 +};
 122 +
 123  static struct w1_family w1_therm_family_DS18S20 = {
 124         .fid = W1_THERM_DS18S20,
 125         .fops = &w1_therm_fops,
 126 @@ -107,7 +140,7 @@ static struct w1_family w1_therm_family_
 127
 128  static struct w1_family w1_therm_family_DS28EA00 = {
 129         .fid = W1_THERM_DS28EA00,
 130 -       .fops = &w1_therm_fops,
 131 +       .fops = &w1_ds28ea00_fops,
 132  };
 133
 134  static struct w1_family w1_therm_family_DS1825 = {
 135 @@ -194,13 +227,22 @@ static ssize_t w1_slave_show(struct devi
 136         struct w1_slave *sl = dev_to_w1_slave(device);
 137         struct w1_master *dev = sl->master;
 138         u8 rom[9], crc, verdict, external_power;
 139 -       int i, max_trying = 10;
 140 +       int i, ret, max_trying = 10;
 141         ssize_t c = PAGE_SIZE;
 142 +       u8 *family_data = sl->family_data;
 143
 144 -       i = mutex_lock_interruptible(&dev->bus_mutex);
 145 -       if (i != 0)
 146 -               return i;
 147 +       ret = mutex_lock_interruptible(&dev->bus_mutex);
 148 +       if (ret != 0)
 149 +               goto post_unlock;
 150 +
 151 +       if(!sl->family_data)
 152 +       {
 153 +               ret = -ENODEV;
 154 +               goto pre_unlock;
 155 +       }
 156
 157 +       /* prevent the slave from going away in sleep */
 158 +       atomic_inc(THERM_REFCNT(family_data));
 159         memset(rom, 0, sizeof(rom));
 160
 161         while (max_trying--) {
 162 @@ -230,17 +272,19 @@ static ssize_t w1_slave_show(struct devi
 163                                 mutex_unlock(&dev->bus_mutex);
 164
 165                                 sleep_rem = msleep_interruptible(tm);
 166 -                               if (sleep_rem != 0)
 167 -                                       return -EINTR;
 168 +                               if (sleep_rem != 0) {
 169 +                                       ret = -EINTR;
 170 +                                       goto post_unlock;
 171 +                               }
 172
 173 -                               i = mutex_lock_interruptible(&dev->bus_mutex);
 174 -                               if (i != 0)
 175 -                                       return i;
 176 +                               ret = mutex_lock_interruptible(&dev->bus_mutex);
 177 +                               if (ret != 0)
 178 +                                       goto post_unlock;
 179                         } else if (!w1_strong_pullup) {
 180                                 sleep_rem = msleep_interruptible(tm);
 181                                 if (sleep_rem != 0) {
 182 -                                       mutex_unlock(&dev->bus_mutex);
 183 -                                       return -EINTR;
 184 +                                       ret = -EINTR;
 185 +                                       goto pre_unlock;
 186                                 }
 187                         }
 188
 189 @@ -269,19 +313,107 @@ static ssize_t w1_slave_show(struct devi
 190         c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n",
 191                            crc, (verdict) ? "YES" : "NO");
 192         if (verdict)
 193 -               memcpy(sl->family_data, rom, sizeof(rom));
 194 +               memcpy(family_data, rom, sizeof(rom));
 195         else
 196                 dev_warn(device, "Read failed CRC check\n");
 197
 198         for (i = 0; i < 9; ++i)
 199                 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ",
 200 -                             ((u8 *)sl->family_data)[i]);
 201 +                             ((u8 *)family_data)[i]);
 202
 203         c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n",
 204                 w1_convert_temp(rom, sl->family->fid));
 205 +       ret = PAGE_SIZE - c;
 206 +
 207 +pre_unlock:
 208         mutex_unlock(&dev->bus_mutex);
 209
 210 +post_unlock:
 211 +       atomic_dec(THERM_REFCNT(family_data));
 212 +       return ret;
 213 +}
 214 +
 215 +#define W1_42_CHAIN    0x99
 216 +#define W1_42_CHAIN_OFF        0x3C
 217 +#define W1_42_CHAIN_OFF_INV    0xC3
 218 +#define W1_42_CHAIN_ON 0x5A
 219 +#define W1_42_CHAIN_ON_INV     0xA5
 220 +#define W1_42_CHAIN_DONE 0x96
 221 +#define W1_42_CHAIN_DONE_INV 0x69
 222 +#define W1_42_COND_READ        0x0F
 223 +#define W1_42_SUCCESS_CONFIRM_BYTE 0xAA
 224 +#define W1_42_FINISHED_BYTE 0xFF
 225 +static ssize_t w1_seq_show(struct device *device,
 226 +       struct device_attribute *attr, char *buf)
 227 +{
 228 +       struct w1_slave *sl = dev_to_w1_slave(device);
 229 +       ssize_t c = PAGE_SIZE;
 230 +       int rv;
 231 +       int i;
 232 +       u8 ack;
 233 +       u64 rn;
 234 +       struct w1_reg_num *reg_num;
 235 +       int seq = 0;
 236 +
 237 +       mutex_lock(&sl->master->bus_mutex);
 238 +       /* Place all devices in CHAIN state */
 239 +       if (w1_reset_bus(sl->master))
 240 +               goto error;
 241 +       w1_write_8(sl->master, W1_SKIP_ROM);
 242 +       w1_write_8(sl->master, W1_42_CHAIN);
 243 +       w1_write_8(sl->master, W1_42_CHAIN_ON);
 244 +       w1_write_8(sl->master, W1_42_CHAIN_ON_INV);
 245 +       msleep(sl->master->pullup_duration);
 246 +
 247 +       /* check for acknowledgment */
 248 +       ack = w1_read_8(sl->master);
 249 +       if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
 250 +               goto error;
 251 +
 252 +       /* In case the bus fails to send 0xFF, limit*/
 253 +       for (i = 0; i <= 64; i++) {
 254 +               if (w1_reset_bus(sl->master))
 255 +                       goto error;
 256 +
 257 +               w1_write_8(sl->master, W1_42_COND_READ);
 258 +               rv = w1_read_block(sl->master, (u8 *)&rn, 8);
 259 +               reg_num = (struct w1_reg_num *) &rn;
 260 +               if (reg_num->family == W1_42_FINISHED_BYTE)
 261 +                       break;
 262 +               if (sl->reg_num.id == reg_num->id)
 263 +                       seq = i;
 264 +
 265 +               w1_write_8(sl->master, W1_42_CHAIN);
 266 +               w1_write_8(sl->master, W1_42_CHAIN_DONE);
 267 +               w1_write_8(sl->master, W1_42_CHAIN_DONE_INV);
 268 +               w1_read_block(sl->master, &ack, sizeof(ack));
 269 +
 270 +               /* check for acknowledgment */
 271 +               ack = w1_read_8(sl->master);
 272 +               if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
 273 +                       goto error;
 274 +
 275 +       }
 276 +
 277 +       /* Exit from CHAIN state */
 278 +       if (w1_reset_bus(sl->master))
 279 +               goto error;
 280 +       w1_write_8(sl->master, W1_SKIP_ROM);
 281 +       w1_write_8(sl->master, W1_42_CHAIN);
 282 +       w1_write_8(sl->master, W1_42_CHAIN_OFF);
 283 +       w1_write_8(sl->master, W1_42_CHAIN_OFF_INV);
 284 +
 285 +       /* check for acknowledgment */
 286 +       ack = w1_read_8(sl->master);
 287 +       if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
 288 +               goto error;
 289 +       mutex_unlock(&sl->master->bus_mutex);
 290 +
 291 +       c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", seq);
 292         return PAGE_SIZE - c;
 293 +error:
 294 +       mutex_unlock(&sl->master->bus_mutex);
 295 +       return -EIO;
 296  }
 297
 298  static int __init w1_therm_init(void)