/*
 * Rotary counter driver for Analog Devices Blackfin Processors
 *
 * Copyright 2008-2009 Analog Devices Inc.
 * Licensed under the GPL-2 or later.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/slab.h>

#include <asm/portmux.h>
#include <asm/bfin_rotary.h>

static const u16 per_cnt[] = {
        P_CNT_CUD,
        P_CNT_CDG,
        P_CNT_CZM,
        0
};

struct bfin_rot {
        struct input_dev *input;
        int irq;
        unsigned int up_key;
        unsigned int down_key;
        unsigned int button_key;
        unsigned int rel_code;
        unsigned short cnt_config;
        unsigned short cnt_imask;
        unsigned short cnt_debounce;
};

static void report_key_event(struct input_dev *input, int keycode)
{
        /* simulate a press-n-release */
        input_report_key(input, keycode, 1);
        input_sync(input);
        input_report_key(input, keycode, 0);
        input_sync(input);
}

static void report_rotary_event(struct bfin_rot *rotary, int delta)
{
        struct input_dev *input = rotary->input;

        if (rotary->up_key) {
                report_key_event(input,
                                 delta > 0 ? rotary->up_key : rotary->down_key);
        } else {
                input_report_rel(input, rotary->rel_code, delta);
                input_sync(input);
        }
}

static irqreturn_t bfin_rotary_isr(int irq, void *dev_id)
{
        struct platform_device *pdev = dev_id;
        struct bfin_rot *rotary = platform_get_drvdata(pdev);
        int delta;

        switch (bfin_read_CNT_STATUS()) {

        case ICII:
                break;

        case UCII:
        case DCII:
                delta = bfin_read_CNT_COUNTER();
                if (delta)
                        report_rotary_event(rotary, delta);
                break;

        case CZMII:
                report_key_event(rotary->input, rotary->button_key);
                break;

        default:
                break;
        }

        bfin_write_CNT_COMMAND(W1LCNT_ZERO);    /* Clear COUNTER */
        bfin_write_CNT_STATUS(-1);      /* Clear STATUS */

        return IRQ_HANDLED;
}

static int __devinit bfin_rotary_probe(struct platform_device *pdev)
{
        struct bfin_rotary_platform_data *pdata = pdev->dev.platform_data;
        struct bfin_rot *rotary;
        struct input_dev *input;
        int error;

        /* Basic validation */
        if ((pdata->rotary_up_key && !pdata->rotary_down_key) ||
            (!pdata->rotary_up_key && pdata->rotary_down_key)) {
                return -EINVAL;
        }

        error = peripheral_request_list(per_cnt, dev_name(&pdev->dev));
        if (error) {
                dev_err(&pdev->dev, "requesting peripherals failed\n");
                return error;
        }

        rotary = kzalloc(sizeof(struct bfin_rot), GFP_KERNEL);
        input = input_allocate_device();
        if (!rotary || !input) {
                error = -ENOMEM;
                goto out1;
        }

        rotary->input = input;

        rotary->up_key = pdata->rotary_up_key;
        rotary->down_key = pdata->rotary_down_key;
        rotary->button_key = pdata->rotary_button_key;
        rotary->rel_code = pdata->rotary_rel_code;

        error = rotary->irq = platform_get_irq(pdev, 0);
        if (error < 0)
                goto out1;

        input->name = pdev->name;
        input->phys = "bfin-rotary/input0";
        input->dev.parent = &pdev->dev;

        input_set_drvdata(input, rotary);

        input->id.bustype = BUS_HOST;
        input->id.vendor = 0x0001;
        input->id.product = 0x0001;
        input->id.version = 0x0100;

        if (rotary->up_key) {
                __set_bit(EV_KEY, input->evbit);
                __set_bit(rotary->up_key, input->keybit);
                __set_bit(rotary->down_key, input->keybit);
        } else {
                __set_bit(EV_REL, input->evbit);
                __set_bit(rotary->rel_code, input->relbit);
        }

        if (rotary->button_key) {
                __set_bit(EV_KEY, input->evbit);
                __set_bit(rotary->button_key, input->keybit);
        }

        error = request_irq(rotary->irq, bfin_rotary_isr,
                            0, dev_name(&pdev->dev), pdev);
        if (error) {
                dev_err(&pdev->dev,
                        "unable to claim irq %d; error %d\n",
                        rotary->irq, error);
                goto out1;
        }

        error = input_register_device(input);
        if (error) {
                dev_err(&pdev->dev,
                        "unable to register input device (%d)\n", error);
                goto out2;
        }

        if (pdata->rotary_button_key)
                bfin_write_CNT_IMASK(CZMIE);

        if (pdata->mode & ROT_DEBE)
                bfin_write_CNT_DEBOUNCE(pdata->debounce & DPRESCALE);

        if (pdata->mode)
                bfin_write_CNT_CONFIG(bfin_read_CNT_CONFIG() |
                                        (pdata->mode & ~CNTE));

        bfin_write_CNT_IMASK(bfin_read_CNT_IMASK() | UCIE | DCIE);
        bfin_write_CNT_CONFIG(bfin_read_CNT_CONFIG() | CNTE);

        platform_set_drvdata(pdev, rotary);
        device_init_wakeup(&pdev->dev, 1);

        return 0;

out2:
        free_irq(rotary->irq, pdev);
out1:
        input_free_device(input);
        kfree(rotary);
        peripheral_free_list(per_cnt);

        return error;
}

static int __devexit bfin_rotary_remove(struct platform_device *pdev)
{
        struct bfin_rot *rotary = platform_get_drvdata(pdev);

        bfin_write_CNT_CONFIG(0);
        bfin_write_CNT_IMASK(0);

        free_irq(rotary->irq, pdev);
        input_unregister_device(rotary->input);
        peripheral_free_list(per_cnt);

        kfree(rotary);
        platform_set_drvdata(pdev, NULL);

        return 0;
}

#ifdef CONFIG_PM
static int bfin_rotary_suspend(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct bfin_rot *rotary = platform_get_drvdata(pdev);

        rotary->cnt_config = bfin_read_CNT_CONFIG();
        rotary->cnt_imask = bfin_read_CNT_IMASK();
        rotary->cnt_debounce = bfin_read_CNT_DEBOUNCE();

        if (device_may_wakeup(&pdev->dev))
                enable_irq_wake(rotary->irq);

        return 0;
}

static int bfin_rotary_resume(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct bfin_rot *rotary = platform_get_drvdata(pdev);

        bfin_write_CNT_DEBOUNCE(rotary->cnt_debounce);
        bfin_write_CNT_IMASK(rotary->cnt_imask);
        bfin_write_CNT_CONFIG(rotary->cnt_config & ~CNTE);

        if (device_may_wakeup(&pdev->dev))
                disable_irq_wake(rotary->irq);

        if (rotary->cnt_config & CNTE)
                bfin_write_CNT_CONFIG(rotary->cnt_config);

        return 0;
}

static const struct dev_pm_ops bfin_rotary_pm_ops = {
        .suspend        = bfin_rotary_suspend,
        .resume         = bfin_rotary_resume,
};
#endif

static struct platform_driver bfin_rotary_device_driver = {
        .probe          = bfin_rotary_probe,
        .remove         = __devexit_p(bfin_rotary_remove),
        .driver         = {
                .name   = "bfin-rotary",
                .owner  = THIS_MODULE,
#ifdef CONFIG_PM
                .pm     = &bfin_rotary_pm_ops,
#endif
        },
};

static int __init bfin_rotary_init(void)
{
        return platform_driver_register(&bfin_rotary_device_driver);
}
module_init(bfin_rotary_init);

static void __exit bfin_rotary_exit(void)
{
        platform_driver_unregister(&bfin_rotary_device_driver);
}
module_exit(bfin_rotary_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
MODULE_DESCRIPTION("Rotary Counter driver for Blackfin Processors");
MODULE_ALIAS("platform:bfin-rotary");