drivers/w1/w1-uclass.c

   1 // SPDX-License-Identifier:     GPL-2.0+
   2 /*
   3  *
   4  * Copyright (c) 2015 Free Electrons
   5  * Copyright (c) 2015 NextThing Co.
   6  * Copyright (c) 2018 Microchip Technology, Inc.
   7  * Copyright (c) 2021 Bootlin
   8  *
   9  * Maxime Ripard <maxime.ripard@free-electrons.com>
  10  * Eugen Hristev <eugen.hristev@microchip.com>
  11  * Kory Maincent <kory.maincent@bootlin.com>
  12  *
  13  */
  14
  15 #define LOG_CATEGORY UCLASS_W1
  16
  17 #include <common.h>
  18 #include <dm.h>
  19 #include <log.h>
  20 #include <w1.h>
  21 #include <w1-eeprom.h>
  22
  23 #include <dm/device-internal.h>
  24
  25 #define W1_MATCH_ROM    0x55
  26 #define W1_SKIP_ROM     0xcc
  27 #define W1_SEARCH       0xf0
  28
  29 struct w1_bus {
  30         u64     search_id;
  31 };
  32
  33 int w1_bus_find_dev(const struct udevice *bus, u64 id, struct udevice
  34 **devp)
  35 {
  36         struct udevice *dev;
  37         u8 family = id & 0xff;
  38         int ret;
  39
  40         for (ret = uclass_first_device(UCLASS_W1_EEPROM, &dev);
  41                 !ret && dev;
  42                 uclass_next_device(&dev)) {
  43                 if (ret || !dev) {
  44                         debug("cannot find w1 eeprom dev\n");
  45                         return -ENODEV;
  46                 }
  47
  48                 if (dev_get_driver_data(dev) == family) {
  49                         *devp = dev;
  50                         return 0;
  51                 }
  52         }
  53
  54         return -ENODEV;
  55 }
  56
  57 int w1_register_new_device(u64 id, struct udevice *bus)
  58 {
  59         u8 family = id & 0xff;
  60         int n_ents, ret = 0;
  61         struct udevice *dev;
  62
  63         struct w1_driver_entry *start, *entry;
  64
  65         start = ll_entry_start(struct w1_driver_entry, w1_driver_entry);
  66         n_ents = ll_entry_count(struct w1_driver_entry, w1_driver_entry);
  67
  68         for (entry = start; entry != start + n_ents; entry++) {
  69                 const u8 *match_family;
  70                 const struct driver *drv;
  71                 struct w1_device *w1;
  72
  73                 for (match_family = entry->family; match_family;
  74                      match_family++) {
  75                         if (*match_family != family)
  76                                 continue;
  77
  78                         ret = w1_bus_find_dev(bus, id, &dev);
  79
  80                         /* If nothing in the device tree, bind a device */
  81                         if (ret == -ENODEV) {
  82                                 drv = entry->driver;
  83                                 ret = device_bind(bus, drv, drv->name,
  84                                                   NULL, ofnode_null(), &dev);
  85                                 if (ret)
  86                                         return ret;
  87                         }
  88
  89                         device_probe(dev);
  90
  91                         w1 = dev_get_parent_plat(dev);
  92                         w1->id = id;
  93
  94                         return 0;
  95                 }
  96         }
  97
  98         debug("%s: No matches found: error %d\n", __func__, ret);
  99
 100         return ret;
 101 }
 102
 103 static int w1_enumerate(struct udevice *bus)
 104 {
 105         const struct w1_ops *ops = device_get_ops(bus);
 106         struct w1_bus *w1 = dev_get_uclass_priv(bus);
 107         u64 last_rn, rn = w1->search_id, tmp64;
 108         bool last_device = false;
 109         int search_bit, desc_bit = 64;
 110         int last_zero = -1;
 111         u8 triplet_ret = 0;
 112         int i;
 113
 114         if (!ops->reset || !ops->write_byte || !ops->triplet)
 115                 return -ENOSYS;
 116
 117         while (!last_device) {
 118                 last_rn = rn;
 119                 rn = 0;
 120
 121                 /*
 122                  * Reset bus and all 1-wire device state machines
 123                  * so they can respond to our requests.
 124                  *
 125                  * Return 0 - device(s) present, 1 - no devices present.
 126                  */
 127                 if (ops->reset(bus)) {
 128                         debug("%s: No devices present on the wire.\n",
 129                               __func__);
 130                         break;
 131                 }
 132
 133                 /* Start the search */
 134                 ops->write_byte(bus, W1_SEARCH);
 135                 for (i = 0; i < 64; ++i) {
 136                         /* Determine the direction/search bit */
 137                         if (i == desc_bit)
 138                                 /* took the 0 path last time, so take the 1 path */
 139                                 search_bit = 1;
 140                         else if (i > desc_bit)
 141                                 /* take the 0 path on the next branch */
 142                                 search_bit = 0;
 143                         else
 144                                 search_bit = ((last_rn >> i) & 0x1);
 145
 146                         /* Read two bits and write one bit */
 147                         triplet_ret = ops->triplet(bus, search_bit);
 148
 149                         /* quit if no device responded */
 150                         if ((triplet_ret & 0x03) == 0x03)
 151                                 break;
 152
 153                         /* If both directions were valid, and we took the 0 path... */
 154                         if (triplet_ret == 0)
 155                                 last_zero = i;
 156
 157                         /* extract the direction taken & update the device number */
 158                         tmp64 = (triplet_ret >> 2);
 159                         rn |= (tmp64 << i);
 160                 }
 161
 162                 if ((triplet_ret & 0x03) != 0x03) {
 163                         if (desc_bit == last_zero || last_zero < 0) {
 164                                 last_device = 1;
 165                                 w1->search_id = 0;
 166                         } else {
 167                                 w1->search_id = rn;
 168                         }
 169                         desc_bit = last_zero;
 170
 171                         debug("%s: Detected new device 0x%llx (family 0x%x)\n",
 172                               bus->name, rn, (u8)(rn & 0xff));
 173
 174                         /* attempt to register as w1 device */
 175                         w1_register_new_device(rn, bus);
 176                 }
 177         }
 178
 179         return 0;
 180 }
 181
 182 int w1_get_bus(int busnum, struct udevice **busp)
 183 {
 184         int ret, i = 0;
 185
 186         struct udevice *dev;
 187
 188         for (ret = uclass_first_device(UCLASS_W1, &dev);
 189              dev && !ret;
 190              ret = uclass_next_device(&dev), i++) {
 191                 if (i == busnum) {
 192                         *busp = dev;
 193                         return 0;
 194                 }
 195         }
 196
 197         if (!ret) {
 198                 debug("Cannot find w1 bus %d\n", busnum);
 199                 ret = -ENODEV;
 200         }
 201
 202         return ret;
 203 }
 204
 205 u8 w1_get_device_family(struct udevice *dev)
 206 {
 207         struct w1_device *w1 = dev_get_parent_plat(dev);
 208
 209         return w1->id & 0xff;
 210 }
 211
 212 int w1_reset_select(struct udevice *dev)
 213 {
 214         struct w1_device *w1 = dev_get_parent_plat(dev);
 215         struct udevice *bus = dev_get_parent(dev);
 216         const struct w1_ops *ops = device_get_ops(bus);
 217         int i;
 218
 219         if (!ops->reset || !ops->write_byte)
 220                 return -ENOSYS;
 221
 222         ops->reset(bus);
 223
 224         ops->write_byte(bus, W1_MATCH_ROM);
 225
 226         for (i = 0; i < sizeof(w1->id); i++)
 227                 ops->write_byte(bus, (w1->id >> (i * 8)) & 0xff);
 228
 229         return 0;
 230 }
 231
 232 int w1_read_byte(struct udevice *dev)
 233 {
 234         struct udevice *bus = dev_get_parent(dev);
 235         const struct w1_ops *ops = device_get_ops(bus);
 236
 237         if (!ops->read_byte)
 238                 return -ENOSYS;
 239
 240         return ops->read_byte(bus);
 241 }
 242
 243 int w1_read_buf(struct udevice *dev, u8 *buf, unsigned int count)
 244 {
 245         int i, ret;
 246
 247         for (i = 0; i < count; i++) {
 248                 ret = w1_read_byte(dev);
 249                 if (ret < 0)
 250                         return ret;
 251
 252                 buf[i] = ret & 0xff;
 253         }
 254
 255         return 0;
 256 }
 257
 258 int w1_write_byte(struct udevice *dev, u8 byte)
 259 {
 260         struct udevice *bus = dev_get_parent(dev);
 261         const struct w1_ops *ops = device_get_ops(bus);
 262
 263         if (!ops->write_byte)
 264                 return -ENOSYS;
 265
 266         ops->write_byte(bus, byte);
 267
 268         return 0;
 269 }
 270
 271 static int w1_post_probe(struct udevice *bus)
 272 {
 273         w1_enumerate(bus);
 274
 275         return 0;
 276 }
 277
 278 int w1_init(void)
 279 {
 280         struct udevice *bus;
 281         struct uclass *uc;
 282         int ret;
 283
 284         ret = uclass_get(UCLASS_W1, &uc);
 285         if (ret)
 286                 return ret;
 287
 288         uclass_foreach_dev(bus, uc) {
 289                 ret = device_probe(bus);
 290                 if (ret == -ENODEV) {   /* No such device. */
 291                         printf("W1 controller not available.\n");
 292                         continue;
 293                 }
 294
 295                 if (ret) {              /* Other error. */
 296                         printf("W1 controller probe failed.\n");
 297                         continue;
 298                 }
 299         }
 300         return 0;
 301 }
 302
 303 UCLASS_DRIVER(w1) = {
 304         .name           = "w1",
 305         .id             = UCLASS_W1,
 306         .flags          = DM_UC_FLAG_SEQ_ALIAS,
 307         .per_device_auto        = sizeof(struct w1_bus),
 308         .post_probe     = w1_post_probe,
 309 #if CONFIG_IS_ENABLED(OF_CONTROL)
 310         .post_bind      = dm_scan_fdt_dev,
 311 #endif
 312         .per_child_plat_auto        = sizeof(struct w1_device),
 313 };