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// SPDX-License-Identifier: GPL-2.0+
/*
*
* Copyright (c) 2015 Free Electrons
* Copyright (c) 2015 NextThing Co.
* Copyright (c) 2018 Microchip Technology, Inc.
*
* Maxime Ripard <maxime.ripard@free-electrons.com>
* Eugen Hristev <eugen.hristev@microchip.com>
*
*/
#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;
};
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-eeprom device */
w1_eeprom_register_new_device(rn);
}
}
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_platdata(dev);
return w1->id & 0xff;
}
int w1_reset_select(struct udevice *dev)
{
struct w1_device *w1 = dev_get_parent_platdata(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_alloc_size = sizeof(struct w1_bus),
.post_probe = w1_post_probe,
#if CONFIG_IS_ENABLED(OF_CONTROL)
.post_bind = dm_scan_fdt_dev,
#endif
.per_child_platdata_auto_alloc_size = sizeof(struct w1_device),
};
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