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