mirror of
https://github.com/brain-hackers/u-boot-brain
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240 lines
4.7 KiB
C
240 lines
4.7 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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*
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* Copyright (c) 2015 Free Electrons
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* Copyright (c) 2015 NextThing Co.
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* Copyright (c) 2018 Microchip Technology, Inc.
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*
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* Maxime Ripard <maxime.ripard@free-electrons.com>
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* Eugen Hristev <eugen.hristev@microchip.com>
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*
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*/
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#include <common.h>
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#include <dm.h>
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#include <log.h>
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#include <w1.h>
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#include <w1-eeprom.h>
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#include <dm/device-internal.h>
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#define W1_MATCH_ROM 0x55
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#define W1_SKIP_ROM 0xcc
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#define W1_SEARCH 0xf0
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struct w1_bus {
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u64 search_id;
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};
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static int w1_enumerate(struct udevice *bus)
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{
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const struct w1_ops *ops = device_get_ops(bus);
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struct w1_bus *w1 = dev_get_uclass_priv(bus);
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u64 last_rn, rn = w1->search_id, tmp64;
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bool last_device = false;
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int search_bit, desc_bit = 64;
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int last_zero = -1;
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u8 triplet_ret = 0;
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int i;
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if (!ops->reset || !ops->write_byte || !ops->triplet)
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return -ENOSYS;
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while (!last_device) {
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last_rn = rn;
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rn = 0;
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/*
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* Reset bus and all 1-wire device state machines
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* so they can respond to our requests.
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*
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* Return 0 - device(s) present, 1 - no devices present.
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*/
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if (ops->reset(bus)) {
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debug("%s: No devices present on the wire.\n",
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__func__);
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break;
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}
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/* Start the search */
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ops->write_byte(bus, W1_SEARCH);
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for (i = 0; i < 64; ++i) {
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/* Determine the direction/search bit */
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if (i == desc_bit)
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/* took the 0 path last time, so take the 1 path */
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search_bit = 1;
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else if (i > desc_bit)
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/* take the 0 path on the next branch */
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search_bit = 0;
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else
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search_bit = ((last_rn >> i) & 0x1);
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/* Read two bits and write one bit */
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triplet_ret = ops->triplet(bus, search_bit);
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/* quit if no device responded */
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if ((triplet_ret & 0x03) == 0x03)
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break;
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/* If both directions were valid, and we took the 0 path... */
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if (triplet_ret == 0)
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last_zero = i;
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/* extract the direction taken & update the device number */
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tmp64 = (triplet_ret >> 2);
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rn |= (tmp64 << i);
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}
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if ((triplet_ret & 0x03) != 0x03) {
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if (desc_bit == last_zero || last_zero < 0) {
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last_device = 1;
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w1->search_id = 0;
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} else {
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w1->search_id = rn;
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}
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desc_bit = last_zero;
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debug("%s: Detected new device 0x%llx (family 0x%x)\n",
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bus->name, rn, (u8)(rn & 0xff));
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/* attempt to register as w1-eeprom device */
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w1_eeprom_register_new_device(rn);
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}
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}
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return 0;
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}
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int w1_get_bus(int busnum, struct udevice **busp)
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{
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int ret, i = 0;
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struct udevice *dev;
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for (ret = uclass_first_device(UCLASS_W1, &dev);
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dev && !ret;
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ret = uclass_next_device(&dev), i++) {
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if (i == busnum) {
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*busp = dev;
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return 0;
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}
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}
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if (!ret) {
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debug("Cannot find w1 bus %d\n", busnum);
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ret = -ENODEV;
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}
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return ret;
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}
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u8 w1_get_device_family(struct udevice *dev)
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{
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struct w1_device *w1 = dev_get_parent_platdata(dev);
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return w1->id & 0xff;
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}
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int w1_reset_select(struct udevice *dev)
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{
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struct w1_device *w1 = dev_get_parent_platdata(dev);
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struct udevice *bus = dev_get_parent(dev);
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const struct w1_ops *ops = device_get_ops(bus);
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int i;
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if (!ops->reset || !ops->write_byte)
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return -ENOSYS;
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ops->reset(bus);
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ops->write_byte(bus, W1_MATCH_ROM);
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for (i = 0; i < sizeof(w1->id); i++)
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ops->write_byte(bus, (w1->id >> (i * 8)) & 0xff);
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return 0;
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}
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int w1_read_byte(struct udevice *dev)
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{
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struct udevice *bus = dev_get_parent(dev);
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const struct w1_ops *ops = device_get_ops(bus);
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if (!ops->read_byte)
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return -ENOSYS;
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return ops->read_byte(bus);
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}
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int w1_read_buf(struct udevice *dev, u8 *buf, unsigned int count)
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{
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int i, ret;
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for (i = 0; i < count; i++) {
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ret = w1_read_byte(dev);
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if (ret < 0)
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return ret;
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buf[i] = ret & 0xff;
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}
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return 0;
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}
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int w1_write_byte(struct udevice *dev, u8 byte)
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{
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struct udevice *bus = dev_get_parent(dev);
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const struct w1_ops *ops = device_get_ops(bus);
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if (!ops->write_byte)
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return -ENOSYS;
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ops->write_byte(bus, byte);
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return 0;
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}
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static int w1_post_probe(struct udevice *bus)
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{
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w1_enumerate(bus);
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return 0;
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}
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int w1_init(void)
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{
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struct udevice *bus;
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struct uclass *uc;
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int ret;
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ret = uclass_get(UCLASS_W1, &uc);
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if (ret)
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return ret;
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uclass_foreach_dev(bus, uc) {
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ret = device_probe(bus);
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if (ret == -ENODEV) { /* No such device. */
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printf("W1 controller not available.\n");
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continue;
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}
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if (ret) { /* Other error. */
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printf("W1 controller probe failed.\n");
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continue;
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}
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}
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return 0;
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}
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UCLASS_DRIVER(w1) = {
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.name = "w1",
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.id = UCLASS_W1,
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.flags = DM_UC_FLAG_SEQ_ALIAS,
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.per_device_auto_alloc_size = sizeof(struct w1_bus),
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.post_probe = w1_post_probe,
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#if CONFIG_IS_ENABLED(OF_CONTROL)
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.post_bind = dm_scan_fdt_dev,
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#endif
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.per_child_platdata_auto_alloc_size = sizeof(struct w1_device),
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};
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