u-boot/drivers/w1/w1-uclass.c
Michal Suchanek 4954937d92 dm: treewide: Do not use the return value of simple uclass iterator
uclass_first_device/uclass_next_device return value will be removed,
don't use it.

With the current implementation dev is equivalent to !ret. It is
redundant to check both, ret check can be replaced with dev check, and
ret check inside the iteration is dead code.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
2022-10-29 07:36:33 -06:00

310 lines
6.1 KiB
C

// 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 <errno.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;
for (uclass_first_device(UCLASS_W1_EEPROM, &dev);
dev;
uclass_next_device(&dev)) {
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_check(UCLASS_W1, &dev);
dev;
ret = uclass_next_device_check(&dev), i++) {
if (i == busnum) {
if (ret) {
debug("Cannot probe w1 bus %d: %d (%s)\n",
busnum, ret, errno_str(ret));
return ret;
}
*busp = dev;
return 0;
}
}
debug("Cannot find w1 bus %d\n", busnum);
return -ENODEV;
}
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),
};