123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313 |
- // SPDX-License-Identifier: GPL-2.0+
- /*
- *
- * Copyright (c) 2015 Free Electrons
- * Copyright (c) 2015 NextThing Co.
- * Copyright (c) 2018 Microchip Technology, Inc.
- * Copyright (c) 2021 Bootlin
- *
- * Maxime Ripard <maxime.ripard@free-electrons.com>
- * Eugen Hristev <eugen.hristev@microchip.com>
- * Kory Maincent <kory.maincent@bootlin.com>
- *
- */
- #define LOG_CATEGORY UCLASS_W1
- #include <common.h>
- #include <dm.h>
- #include <log.h>
- #include <w1.h>
- #include <w1-eeprom.h>
- #include <dm/device-internal.h>
- #define W1_MATCH_ROM 0x55
- #define W1_SKIP_ROM 0xcc
- #define W1_SEARCH 0xf0
- struct w1_bus {
- u64 search_id;
- };
- int w1_bus_find_dev(const struct udevice *bus, u64 id, struct udevice
- **devp)
- {
- struct udevice *dev;
- u8 family = id & 0xff;
- int ret;
- for (ret = uclass_first_device(UCLASS_W1_EEPROM, &dev);
- !ret && dev;
- uclass_next_device(&dev)) {
- if (ret || !dev) {
- debug("cannot find w1 eeprom dev\n");
- return -ENODEV;
- }
- if (dev_get_driver_data(dev) == family) {
- *devp = dev;
- return 0;
- }
- }
- return -ENODEV;
- }
- int w1_register_new_device(u64 id, struct udevice *bus)
- {
- u8 family = id & 0xff;
- int n_ents, ret = 0;
- struct udevice *dev;
- struct w1_driver_entry *start, *entry;
- start = ll_entry_start(struct w1_driver_entry, w1_driver_entry);
- n_ents = ll_entry_count(struct w1_driver_entry, w1_driver_entry);
- for (entry = start; entry != start + n_ents; entry++) {
- const u8 *match_family;
- const struct driver *drv;
- struct w1_device *w1;
- for (match_family = entry->family; match_family;
- match_family++) {
- if (*match_family != family)
- continue;
- ret = w1_bus_find_dev(bus, id, &dev);
- /* If nothing in the device tree, bind a device */
- if (ret == -ENODEV) {
- drv = entry->driver;
- ret = device_bind(bus, drv, drv->name,
- NULL, ofnode_null(), &dev);
- if (ret)
- return ret;
- }
- device_probe(dev);
- w1 = dev_get_parent_plat(dev);
- w1->id = id;
- return 0;
- }
- }
- debug("%s: No matches found: error %d\n", __func__, ret);
- return ret;
- }
- static int w1_enumerate(struct udevice *bus)
- {
- const struct w1_ops *ops = device_get_ops(bus);
- struct w1_bus *w1 = dev_get_uclass_priv(bus);
- u64 last_rn, rn = w1->search_id, tmp64;
- bool last_device = false;
- int search_bit, desc_bit = 64;
- int last_zero = -1;
- u8 triplet_ret = 0;
- int i;
- if (!ops->reset || !ops->write_byte || !ops->triplet)
- return -ENOSYS;
- while (!last_device) {
- last_rn = rn;
- rn = 0;
- /*
- * Reset bus and all 1-wire device state machines
- * so they can respond to our requests.
- *
- * Return 0 - device(s) present, 1 - no devices present.
- */
- if (ops->reset(bus)) {
- debug("%s: No devices present on the wire.\n",
- __func__);
- break;
- }
- /* Start the search */
- ops->write_byte(bus, W1_SEARCH);
- for (i = 0; i < 64; ++i) {
- /* Determine the direction/search bit */
- if (i == desc_bit)
- /* took the 0 path last time, so take the 1 path */
- search_bit = 1;
- else if (i > desc_bit)
- /* take the 0 path on the next branch */
- search_bit = 0;
- else
- search_bit = ((last_rn >> i) & 0x1);
- /* Read two bits and write one bit */
- triplet_ret = ops->triplet(bus, search_bit);
- /* quit if no device responded */
- if ((triplet_ret & 0x03) == 0x03)
- break;
- /* If both directions were valid, and we took the 0 path... */
- if (triplet_ret == 0)
- last_zero = i;
- /* extract the direction taken & update the device number */
- tmp64 = (triplet_ret >> 2);
- rn |= (tmp64 << i);
- }
- if ((triplet_ret & 0x03) != 0x03) {
- if (desc_bit == last_zero || last_zero < 0) {
- last_device = 1;
- w1->search_id = 0;
- } else {
- w1->search_id = rn;
- }
- desc_bit = last_zero;
- debug("%s: Detected new device 0x%llx (family 0x%x)\n",
- bus->name, rn, (u8)(rn & 0xff));
- /* attempt to register as w1 device */
- w1_register_new_device(rn, bus);
- }
- }
- return 0;
- }
- int w1_get_bus(int busnum, struct udevice **busp)
- {
- int ret, i = 0;
- struct udevice *dev;
- for (ret = uclass_first_device(UCLASS_W1, &dev);
- dev && !ret;
- ret = uclass_next_device(&dev), i++) {
- if (i == busnum) {
- *busp = dev;
- return 0;
- }
- }
- if (!ret) {
- debug("Cannot find w1 bus %d\n", busnum);
- ret = -ENODEV;
- }
- return ret;
- }
- u8 w1_get_device_family(struct udevice *dev)
- {
- struct w1_device *w1 = dev_get_parent_plat(dev);
- return w1->id & 0xff;
- }
- int w1_reset_select(struct udevice *dev)
- {
- struct w1_device *w1 = dev_get_parent_plat(dev);
- struct udevice *bus = dev_get_parent(dev);
- const struct w1_ops *ops = device_get_ops(bus);
- int i;
- if (!ops->reset || !ops->write_byte)
- return -ENOSYS;
- ops->reset(bus);
- ops->write_byte(bus, W1_MATCH_ROM);
- for (i = 0; i < sizeof(w1->id); i++)
- ops->write_byte(bus, (w1->id >> (i * 8)) & 0xff);
- return 0;
- }
- int w1_read_byte(struct udevice *dev)
- {
- struct udevice *bus = dev_get_parent(dev);
- const struct w1_ops *ops = device_get_ops(bus);
- if (!ops->read_byte)
- return -ENOSYS;
- return ops->read_byte(bus);
- }
- int w1_read_buf(struct udevice *dev, u8 *buf, unsigned int count)
- {
- int i, ret;
- for (i = 0; i < count; i++) {
- ret = w1_read_byte(dev);
- if (ret < 0)
- return ret;
- buf[i] = ret & 0xff;
- }
- return 0;
- }
- int w1_write_byte(struct udevice *dev, u8 byte)
- {
- struct udevice *bus = dev_get_parent(dev);
- const struct w1_ops *ops = device_get_ops(bus);
- if (!ops->write_byte)
- return -ENOSYS;
- ops->write_byte(bus, byte);
- return 0;
- }
- static int w1_post_probe(struct udevice *bus)
- {
- w1_enumerate(bus);
- return 0;
- }
- int w1_init(void)
- {
- struct udevice *bus;
- struct uclass *uc;
- int ret;
- ret = uclass_get(UCLASS_W1, &uc);
- if (ret)
- return ret;
- uclass_foreach_dev(bus, uc) {
- ret = device_probe(bus);
- if (ret == -ENODEV) { /* No such device. */
- printf("W1 controller not available.\n");
- continue;
- }
- if (ret) { /* Other error. */
- printf("W1 controller probe failed.\n");
- continue;
- }
- }
- return 0;
- }
- UCLASS_DRIVER(w1) = {
- .name = "w1",
- .id = UCLASS_W1,
- .flags = DM_UC_FLAG_SEQ_ALIAS,
- .per_device_auto = sizeof(struct w1_bus),
- .post_probe = w1_post_probe,
- #if CONFIG_IS_ENABLED(OF_CONTROL)
- .post_bind = dm_scan_fdt_dev,
- #endif
- .per_child_plat_auto = sizeof(struct w1_device),
- };
|