1 // SPDX-License-Identifier: GPL-2.0+
4 * Copyright (c) 2015 Free Electrons
5 * Copyright (c) 2015 NextThing Co.
6 * Copyright (c) 2018 Microchip Technology, Inc.
8 * Maxime Ripard <maxime.ripard@free-electrons.com>
9 * Eugen Hristev <eugen.hristev@microchip.com>
16 #include <w1-eeprom.h>
18 #include <dm/device-internal.h>
20 #define W1_MATCH_ROM 0x55
21 #define W1_SKIP_ROM 0xcc
22 #define W1_SEARCH 0xf0
28 static int w1_enumerate(struct udevice *bus)
30 const struct w1_ops *ops = device_get_ops(bus);
31 struct w1_bus *w1 = dev_get_uclass_priv(bus);
32 u64 last_rn, rn = w1->search_id, tmp64;
33 bool last_device = false;
34 int search_bit, desc_bit = 64;
39 if (!ops->reset || !ops->write_byte || !ops->triplet)
42 while (!last_device) {
47 * Reset bus and all 1-wire device state machines
48 * so they can respond to our requests.
50 * Return 0 - device(s) present, 1 - no devices present.
52 if (ops->reset(bus)) {
53 debug("%s: No devices present on the wire.\n",
58 /* Start the search */
59 ops->write_byte(bus, W1_SEARCH);
60 for (i = 0; i < 64; ++i) {
61 /* Determine the direction/search bit */
63 /* took the 0 path last time, so take the 1 path */
65 else if (i > desc_bit)
66 /* take the 0 path on the next branch */
69 search_bit = ((last_rn >> i) & 0x1);
71 /* Read two bits and write one bit */
72 triplet_ret = ops->triplet(bus, search_bit);
74 /* quit if no device responded */
75 if ((triplet_ret & 0x03) == 0x03)
78 /* If both directions were valid, and we took the 0 path... */
82 /* extract the direction taken & update the device number */
83 tmp64 = (triplet_ret >> 2);
87 /* last device or error, aborting here */
88 if ((triplet_ret & 0x03) == 0x03)
91 if ((triplet_ret & 0x03) != 0x03) {
92 if (desc_bit == last_zero || last_zero < 0) {
100 debug("%s: Detected new device 0x%llx (family 0x%x)\n",
101 bus->name, rn, (u8)(rn & 0xff));
103 /* attempt to register as w1-eeprom device */
104 w1_eeprom_register_new_device(rn);
111 int w1_get_bus(int busnum, struct udevice **busp)
117 for (ret = uclass_first_device(UCLASS_W1, &dev);
119 uclass_next_device(&dev), i++) {
121 debug("Cannot find w1 bus %d\n", busnum);
132 u8 w1_get_device_family(struct udevice *dev)
134 struct w1_device *w1 = dev_get_parent_platdata(dev);
136 return w1->id & 0xff;
139 int w1_reset_select(struct udevice *dev)
141 struct w1_device *w1 = dev_get_parent_platdata(dev);
142 struct udevice *bus = dev_get_parent(dev);
143 const struct w1_ops *ops = device_get_ops(bus);
146 if (!ops->reset || !ops->write_byte)
151 ops->write_byte(bus, W1_MATCH_ROM);
153 for (i = 0; i < sizeof(w1->id); i++)
154 ops->write_byte(bus, (w1->id >> (i * 8)) & 0xff);
159 int w1_read_byte(struct udevice *dev)
161 struct udevice *bus = dev_get_parent(dev);
162 const struct w1_ops *ops = device_get_ops(bus);
167 return ops->read_byte(bus);
170 int w1_read_buf(struct udevice *dev, u8 *buf, unsigned int count)
174 for (i = 0; i < count; i++) {
175 ret = w1_read_byte(dev);
185 int w1_write_byte(struct udevice *dev, u8 byte)
187 struct udevice *bus = dev_get_parent(dev);
188 const struct w1_ops *ops = device_get_ops(bus);
190 if (!ops->write_byte)
193 ops->write_byte(bus, byte);
198 static int w1_post_probe(struct udevice *bus)
211 ret = uclass_get(UCLASS_W1, &uc);
215 uclass_foreach_dev(bus, uc) {
216 ret = device_probe(bus);
217 if (ret == -ENODEV) { /* No such device. */
218 printf("W1 controller not available.\n");
222 if (ret) { /* Other error. */
223 printf("W1 controller probe failed.\n");
230 UCLASS_DRIVER(w1) = {
233 .flags = DM_UC_FLAG_SEQ_ALIAS,
234 .per_device_auto_alloc_size = sizeof(struct w1_bus),
235 .post_probe = w1_post_probe,
236 #if CONFIG_IS_ENABLED(OF_CONTROL)
237 .post_bind = dm_scan_fdt_dev,
239 .per_child_platdata_auto_alloc_size = sizeof(struct w1_device),