/*
 * ChromeOS EC multi-function device
 *
 * Copyright (C) 2012 Google, Inc
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * The ChromeOS EC multi function device is used to mux all the requests
 * to the EC device for its multiple features: keyboard controller,
 * battery charging and regulator control, firmware update.
 */

#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/mfd/core.h>
#include <linux/mfd/cros_ec.h>
#include <linux/mfd/cros_ec_commands.h>

int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
                       struct cros_ec_msg *msg)
{
        uint8_t *out;
        int csum, i;

        BUG_ON(msg->out_len > EC_HOST_PARAM_SIZE);
        out = ec_dev->dout;
        out[0] = EC_CMD_VERSION0 + msg->version;
        out[1] = msg->cmd;
        out[2] = msg->out_len;
        csum = out[0] + out[1] + out[2];
        for (i = 0; i < msg->out_len; i++)
                csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->out_buf[i];
        out[EC_MSG_TX_HEADER_BYTES + msg->out_len] = (uint8_t)(csum & 0xff);

        return EC_MSG_TX_PROTO_BYTES + msg->out_len;
}
EXPORT_SYMBOL(cros_ec_prepare_tx);

static int cros_ec_command_sendrecv(struct cros_ec_device *ec_dev,
                uint16_t cmd, void *out_buf, int out_len,
                void *in_buf, int in_len)
{
        struct cros_ec_msg msg;

        msg.version = cmd >> 8;
        msg.cmd = cmd & 0xff;
        msg.out_buf = out_buf;
        msg.out_len = out_len;
        msg.in_buf = in_buf;
        msg.in_len = in_len;

        return ec_dev->command_xfer(ec_dev, &msg);
}

static int cros_ec_command_recv(struct cros_ec_device *ec_dev,
                uint16_t cmd, void *buf, int buf_len)
{
        return cros_ec_command_sendrecv(ec_dev, cmd, NULL, 0, buf, buf_len);
}

static int cros_ec_command_send(struct cros_ec_device *ec_dev,
                uint16_t cmd, void *buf, int buf_len)
{
        return cros_ec_command_sendrecv(ec_dev, cmd, buf, buf_len, NULL, 0);
}

static irqreturn_t ec_irq_thread(int irq, void *data)
{
        struct cros_ec_device *ec_dev = data;

        if (device_may_wakeup(ec_dev->dev))
                pm_wakeup_event(ec_dev->dev, 0);

        blocking_notifier_call_chain(&ec_dev->event_notifier, 1, ec_dev);

        return IRQ_HANDLED;
}

static struct mfd_cell cros_devs[] = {
        {
                .name = "cros-ec-keyb",
                .id = 1,
                .of_compatible = "google,cros-ec-keyb",
        },
};

int cros_ec_register(struct cros_ec_device *ec_dev)
{
        struct device *dev = ec_dev->dev;
        int err = 0;

        BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->event_notifier);

        ec_dev->command_send = cros_ec_command_send;
        ec_dev->command_recv = cros_ec_command_recv;
        ec_dev->command_sendrecv = cros_ec_command_sendrecv;

        if (ec_dev->din_size) {
                ec_dev->din = kmalloc(ec_dev->din_size, GFP_KERNEL);
                if (!ec_dev->din) {
                        err = -ENOMEM;
                        goto fail_din;
                }
        }
        if (ec_dev->dout_size) {
                ec_dev->dout = kmalloc(ec_dev->dout_size, GFP_KERNEL);
                if (!ec_dev->dout) {
                        err = -ENOMEM;
                        goto fail_dout;
                }
        }

        if (!ec_dev->irq) {
                dev_dbg(dev, "no valid IRQ: %d\n", ec_dev->irq);
                goto fail_irq;
        }

        err = request_threaded_irq(ec_dev->irq, NULL, ec_irq_thread,
                                   IRQF_TRIGGER_LOW | IRQF_ONESHOT,
                                   "chromeos-ec", ec_dev);
        if (err) {
                dev_err(dev, "request irq %d: error %d\n", ec_dev->irq, err);
                goto fail_irq;
        }

        err = mfd_add_devices(dev, 0, cros_devs,
                              ARRAY_SIZE(cros_devs),
                              NULL, ec_dev->irq, NULL);
        if (err) {
                dev_err(dev, "failed to add mfd devices\n");
                goto fail_mfd;
        }

        dev_info(dev, "Chrome EC (%s)\n", ec_dev->name);

        return 0;

fail_mfd:
        free_irq(ec_dev->irq, ec_dev);
fail_irq:
        kfree(ec_dev->dout);
fail_dout:
        kfree(ec_dev->din);
fail_din:
        return err;
}
EXPORT_SYMBOL(cros_ec_register);

int cros_ec_remove(struct cros_ec_device *ec_dev)
{
        mfd_remove_devices(ec_dev->dev);
        free_irq(ec_dev->irq, ec_dev);
        kfree(ec_dev->dout);
        kfree(ec_dev->din);

        return 0;
}
EXPORT_SYMBOL(cros_ec_remove);

#ifdef CONFIG_PM_SLEEP
int cros_ec_suspend(struct cros_ec_device *ec_dev)
{
        struct device *dev = ec_dev->dev;

        if (device_may_wakeup(dev))
                ec_dev->wake_enabled = !enable_irq_wake(ec_dev->irq);

        disable_irq(ec_dev->irq);
        ec_dev->was_wake_device = ec_dev->wake_enabled;

        return 0;
}
EXPORT_SYMBOL(cros_ec_suspend);

int cros_ec_resume(struct cros_ec_device *ec_dev)
{
        enable_irq(ec_dev->irq);

        if (ec_dev->wake_enabled) {
                disable_irq_wake(ec_dev->irq);
                ec_dev->wake_enabled = 0;
        }

        return 0;
}
EXPORT_SYMBOL(cros_ec_resume);

#endif