/*
 * wm831x-auxadc.c  --  AUXADC for Wolfson WM831x PMICs
 *
 * Copyright 2009-2011 Wolfson Microelectronics PLC.
 *
 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/mfd/core.h>
#include <linux/slab.h>
#include <linux/list.h>

#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/pdata.h>
#include <linux/mfd/wm831x/irq.h>
#include <linux/mfd/wm831x/auxadc.h>
#include <linux/mfd/wm831x/otp.h>
#include <linux/mfd/wm831x/regulator.h>

struct wm831x_auxadc_req {
        struct list_head list;
        enum wm831x_auxadc input;
        int val;
        struct completion done;
};

static int wm831x_auxadc_read_irq(struct wm831x *wm831x,
                                  enum wm831x_auxadc input)
{
        struct wm831x_auxadc_req *req;
        int ret;
        bool ena = false;

        req = kzalloc(sizeof(*req), GFP_KERNEL);
        if (!req)
                return -ENOMEM;

        init_completion(&req->done);
        req->input = input;
        req->val = -ETIMEDOUT;

        mutex_lock(&wm831x->auxadc_lock);

        /* Enqueue the request */
        list_add(&req->list, &wm831x->auxadc_pending);

        ena = !wm831x->auxadc_active;

        if (ena) {
                ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
                                      WM831X_AUX_ENA, WM831X_AUX_ENA);
                if (ret != 0) {
                        dev_err(wm831x->dev, "Failed to enable AUXADC: %d\n",
                                ret);
                        goto out;
                }
        }

        /* Enable the conversion if not already running */
        if (!(wm831x->auxadc_active & (1 << input))) {
                ret = wm831x_set_bits(wm831x, WM831X_AUXADC_SOURCE,
                                      1 << input, 1 << input);
                if (ret != 0) {
                        dev_err(wm831x->dev,
                                "Failed to set AUXADC source: %d\n", ret);
                        goto out;
                }

                wm831x->auxadc_active |= 1 << input;
        }

        /* We convert at the fastest rate possible */
        if (ena) {
                ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
                                      WM831X_AUX_CVT_ENA |
                                      WM831X_AUX_RATE_MASK,
                                      WM831X_AUX_CVT_ENA |
                                      WM831X_AUX_RATE_MASK);
                if (ret != 0) {
                        dev_err(wm831x->dev, "Failed to start AUXADC: %d\n",
                                ret);
                        goto out;
                }
        }

        mutex_unlock(&wm831x->auxadc_lock);

        /* Wait for an interrupt */
        wait_for_completion_timeout(&req->done, msecs_to_jiffies(500));

        mutex_lock(&wm831x->auxadc_lock);

        list_del(&req->list);
        ret = req->val;

out:
        mutex_unlock(&wm831x->auxadc_lock);

        kfree(req);

        return ret;
}

static irqreturn_t wm831x_auxadc_irq(int irq, void *irq_data)
{
        struct wm831x *wm831x = irq_data;
        struct wm831x_auxadc_req *req;
        int ret, input, val;

        ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA);
        if (ret < 0) {
                dev_err(wm831x->dev,
                        "Failed to read AUXADC data: %d\n", ret);
                return IRQ_NONE;
        }

        input = ((ret & WM831X_AUX_DATA_SRC_MASK)
                 >> WM831X_AUX_DATA_SRC_SHIFT) - 1;

        if (input == 14)
                input = WM831X_AUX_CAL;

        val = ret & WM831X_AUX_DATA_MASK;

        mutex_lock(&wm831x->auxadc_lock);

        /* Disable this conversion, we're about to complete all users */
        wm831x_set_bits(wm831x, WM831X_AUXADC_SOURCE,
                        1 << input, 0);
        wm831x->auxadc_active &= ~(1 << input);

        /* Turn off the entire convertor if idle */
        if (!wm831x->auxadc_active)
                wm831x_reg_write(wm831x, WM831X_AUXADC_CONTROL, 0);

        /* Wake up any threads waiting for this request */
        list_for_each_entry(req, &wm831x->auxadc_pending, list) {
                if (req->input == input) {
                        req->val = val;
                        complete(&req->done);
                }
        }

        mutex_unlock(&wm831x->auxadc_lock);

        return IRQ_HANDLED;
}

static int wm831x_auxadc_read_polled(struct wm831x *wm831x,
                                     enum wm831x_auxadc input)
{
        int ret, src, timeout;

        mutex_lock(&wm831x->auxadc_lock);

        ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
                              WM831X_AUX_ENA, WM831X_AUX_ENA);
        if (ret < 0) {
                dev_err(wm831x->dev, "Failed to enable AUXADC: %d\n", ret);
                goto out;
        }

        /* We force a single source at present */
        src = input;
        ret = wm831x_reg_write(wm831x, WM831X_AUXADC_SOURCE,
                               1 << src);
        if (ret < 0) {
                dev_err(wm831x->dev, "Failed to set AUXADC source: %d\n", ret);
                goto out;
        }

        ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
                              WM831X_AUX_CVT_ENA, WM831X_AUX_CVT_ENA);
        if (ret < 0) {
                dev_err(wm831x->dev, "Failed to start AUXADC: %d\n", ret);
                goto disable;
        }

        /* If we're not using interrupts then poll the
         * interrupt status register */
        timeout = 5;
        while (timeout) {
                msleep(1);

                ret = wm831x_reg_read(wm831x,
                                      WM831X_INTERRUPT_STATUS_1);
                if (ret < 0) {
                        dev_err(wm831x->dev,
                                "ISR 1 read failed: %d\n", ret);
                        goto disable;
                }

                /* Did it complete? */
                if (ret & WM831X_AUXADC_DATA_EINT) {
                        wm831x_reg_write(wm831x,
                                         WM831X_INTERRUPT_STATUS_1,
                                         WM831X_AUXADC_DATA_EINT);
                        break;
                } else {
                        dev_err(wm831x->dev,
                                "AUXADC conversion timeout\n");
                        ret = -EBUSY;
                        goto disable;
                }
        }

        ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA);
        if (ret < 0) {
                dev_err(wm831x->dev,
                        "Failed to read AUXADC data: %d\n", ret);
                goto disable;
        }

        src = ((ret & WM831X_AUX_DATA_SRC_MASK)
               >> WM831X_AUX_DATA_SRC_SHIFT) - 1;

        if (src == 14)
                src = WM831X_AUX_CAL;

        if (src != input) {
                dev_err(wm831x->dev, "Data from source %d not %d\n",
                        src, input);
                ret = -EINVAL;
        } else {
                ret &= WM831X_AUX_DATA_MASK;
        }

disable:
        wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL, WM831X_AUX_ENA, 0);
out:
        mutex_unlock(&wm831x->auxadc_lock);
        return ret;
}

/**
 * wm831x_auxadc_read: Read a value from the WM831x AUXADC
 *
 * @wm831x: Device to read from.
 * @input: AUXADC input to read.
 */
int wm831x_auxadc_read(struct wm831x *wm831x, enum wm831x_auxadc input)
{
        return wm831x->auxadc_read(wm831x, input);
}
EXPORT_SYMBOL_GPL(wm831x_auxadc_read);

/**
 * wm831x_auxadc_read_uv: Read a voltage from the WM831x AUXADC
 *
 * @wm831x: Device to read from.
 * @input: AUXADC input to read.
 */
int wm831x_auxadc_read_uv(struct wm831x *wm831x, enum wm831x_auxadc input)
{
        int ret;

        ret = wm831x_auxadc_read(wm831x, input);
        if (ret < 0)
                return ret;

        ret *= 1465;

        return ret;
}
EXPORT_SYMBOL_GPL(wm831x_auxadc_read_uv);

void wm831x_auxadc_init(struct wm831x *wm831x)
{
        int ret;

        mutex_init(&wm831x->auxadc_lock);
        INIT_LIST_HEAD(&wm831x->auxadc_pending);

        if (wm831x->irq) {
                wm831x->auxadc_read = wm831x_auxadc_read_irq;

                ret = request_threaded_irq(wm831x_irq(wm831x,
                                                      WM831X_IRQ_AUXADC_DATA),
                                           NULL, wm831x_auxadc_irq, 0,
                                           "auxadc", wm831x);
                if (ret < 0) {
                        dev_err(wm831x->dev, "AUXADC IRQ request failed: %d\n",
                                ret);
                        wm831x->auxadc_read = NULL;
                }
        }

        if (!wm831x->auxadc_read)
                wm831x->auxadc_read = wm831x_auxadc_read_polled;
}