// 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 <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),
};