/*
 * Copyright 2015 Red Hat Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Authors: Ben Skeggs <bskeggs@redhat.com>
 */
#include "bus.h"
#include "pad.h"

#include <core/option.h>

/*******************************************************************************
 * i2c-algo-bit
 ******************************************************************************/
static int
nvkm_i2c_bus_pre_xfer(struct i2c_adapter *adap)
{
        struct nvkm_i2c_bus *bus = container_of(adap, typeof(*bus), i2c);
        return nvkm_i2c_bus_acquire(bus);
}

static void
nvkm_i2c_bus_post_xfer(struct i2c_adapter *adap)
{
        struct nvkm_i2c_bus *bus = container_of(adap, typeof(*bus), i2c);
        return nvkm_i2c_bus_release(bus);
}

static void
nvkm_i2c_bus_setscl(void *data, int state)
{
        struct nvkm_i2c_bus *bus = data;
        bus->func->drive_scl(bus, state);
}

static void
nvkm_i2c_bus_setsda(void *data, int state)
{
        struct nvkm_i2c_bus *bus = data;
        bus->func->drive_sda(bus, state);
}

static int
nvkm_i2c_bus_getscl(void *data)
{
        struct nvkm_i2c_bus *bus = data;
        return bus->func->sense_scl(bus);
}

static int
nvkm_i2c_bus_getsda(void *data)
{
        struct nvkm_i2c_bus *bus = data;
        return bus->func->sense_sda(bus);
}

/*******************************************************************************
 * !i2c-algo-bit (off-chip i2c bus / hw i2c / internal bit-banging algo)
 ******************************************************************************/
static int
nvkm_i2c_bus_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
        struct nvkm_i2c_bus *bus = container_of(adap, typeof(*bus), i2c);
        int ret;

        ret = nvkm_i2c_bus_acquire(bus);
        if (ret)
                return ret;

        ret = bus->func->xfer(bus, msgs, num);
        nvkm_i2c_bus_release(bus);
        return ret;
}

static u32
nvkm_i2c_bus_func(struct i2c_adapter *adap)
{
        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}

static const struct i2c_algorithm
nvkm_i2c_bus_algo = {
        .master_xfer = nvkm_i2c_bus_xfer,
        .functionality = nvkm_i2c_bus_func,
};

/*******************************************************************************
 * nvkm_i2c_bus base
 ******************************************************************************/
void
nvkm_i2c_bus_init(struct nvkm_i2c_bus *bus)
{
        BUS_TRACE(bus, "init");
        if (bus->func->init)
                bus->func->init(bus);

        mutex_lock(&bus->mutex);
        bus->enabled = true;
        mutex_unlock(&bus->mutex);
}

void
nvkm_i2c_bus_fini(struct nvkm_i2c_bus *bus)
{
        BUS_TRACE(bus, "fini");
        mutex_lock(&bus->mutex);
        bus->enabled = false;
        mutex_unlock(&bus->mutex);
}

void
nvkm_i2c_bus_release(struct nvkm_i2c_bus *bus)
{
        struct nvkm_i2c_pad *pad = bus->pad;
        BUS_TRACE(bus, "release");
        nvkm_i2c_pad_release(pad);
        mutex_unlock(&bus->mutex);
}

int
nvkm_i2c_bus_acquire(struct nvkm_i2c_bus *bus)
{
        struct nvkm_i2c_pad *pad = bus->pad;
        int ret;

        BUS_TRACE(bus, "acquire");
        mutex_lock(&bus->mutex);

        if (bus->enabled)
                ret = nvkm_i2c_pad_acquire(pad, NVKM_I2C_PAD_I2C);
        else
                ret = -EIO;

        if (ret)
                mutex_unlock(&bus->mutex);
        return ret;
}

int
nvkm_i2c_bus_probe(struct nvkm_i2c_bus *bus, const char *what,
                   struct nvkm_i2c_bus_probe *info,
                   bool (*match)(struct nvkm_i2c_bus *,
                                 struct i2c_board_info *, void *), void *data)
{
        int i;

        BUS_DBG(bus, "probing %ss", what);
        for (i = 0; info[i].dev.addr; i++) {
                u8 orig_udelay = 0;

                if ((bus->i2c.algo == &i2c_bit_algo) && (info[i].udelay != 0)) {
                        struct i2c_algo_bit_data *algo = bus->i2c.algo_data;
                        BUS_DBG(bus, "%dms delay instead of %dms",
                                     info[i].udelay, algo->udelay);
                        orig_udelay = algo->udelay;
                        algo->udelay = info[i].udelay;
                }

                if (nvkm_probe_i2c(&bus->i2c, info[i].dev.addr) &&
                    (!match || match(bus, &info[i].dev, data))) {
                        BUS_DBG(bus, "detected %s: %s",
                                what, info[i].dev.type);
                        return i;
                }

                if (orig_udelay) {
                        struct i2c_algo_bit_data *algo = bus->i2c.algo_data;
                        algo->udelay = orig_udelay;
                }
        }

        BUS_DBG(bus, "no devices found.");
        return -ENODEV;
}

void
nvkm_i2c_bus_del(struct nvkm_i2c_bus **pbus)
{
        struct nvkm_i2c_bus *bus = *pbus;
        if (bus && !WARN_ON(!bus->func)) {
                BUS_TRACE(bus, "dtor");
                list_del(&bus->head);
                i2c_del_adapter(&bus->i2c);
                kfree(bus->i2c.algo_data);
                kfree(*pbus);
                *pbus = NULL;
        }
}

int
nvkm_i2c_bus_ctor(const struct nvkm_i2c_bus_func *func,
                  struct nvkm_i2c_pad *pad, int id,
                  struct nvkm_i2c_bus *bus)
{
        struct nvkm_device *device = pad->i2c->subdev.device;
        struct i2c_algo_bit_data *bit;
#ifndef CONFIG_NOUVEAU_I2C_INTERNAL_DEFAULT
        const bool internal = false;
#else
        const bool internal = true;
#endif
        int ret;

        bus->func = func;
        bus->pad = pad;
        bus->id = id;
        mutex_init(&bus->mutex);
        list_add_tail(&bus->head, &pad->i2c->bus);
        BUS_TRACE(bus, "ctor");

        snprintf(bus->i2c.name, sizeof(bus->i2c.name), "nvkm-%s-bus-%04x",
                 dev_name(device->dev), id);
        bus->i2c.owner = THIS_MODULE;
        bus->i2c.dev.parent = device->dev;

        if ( bus->func->drive_scl &&
            !nvkm_boolopt(device->cfgopt, "NvI2C", internal)) {
                if (!(bit = kzalloc(sizeof(*bit), GFP_KERNEL)))
                        return -ENOMEM;
                bit->udelay = 10;
                bit->timeout = usecs_to_jiffies(2200);
                bit->data = bus;
                bit->pre_xfer = nvkm_i2c_bus_pre_xfer;
                bit->post_xfer = nvkm_i2c_bus_post_xfer;
                bit->setscl = nvkm_i2c_bus_setscl;
                bit->setsda = nvkm_i2c_bus_setsda;
                bit->getscl = nvkm_i2c_bus_getscl;
                bit->getsda = nvkm_i2c_bus_getsda;
                bus->i2c.algo_data = bit;
                ret = i2c_bit_add_bus(&bus->i2c);
        } else {
                bus->i2c.algo = &nvkm_i2c_bus_algo;
                ret = i2c_add_adapter(&bus->i2c);
        }

        return ret;
}

int
nvkm_i2c_bus_new_(const struct nvkm_i2c_bus_func *func,
                  struct nvkm_i2c_pad *pad, int id,
                  struct nvkm_i2c_bus **pbus)
{
        if (!(*pbus = kzalloc(sizeof(**pbus), GFP_KERNEL)))
                return -ENOMEM;
        return nvkm_i2c_bus_ctor(func, pad, id, *pbus);
}