/*
 * Copyright (C) 2010 OKI SEMICONDUCTOR Co., LTD.
 *
 * 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; version 2 of the License.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 */
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/gpio.h>

#define PCH_GPIO_ALL_PINS       0xfff /* Mask for GPIO pins 0 to 11 */
#define GPIO_NUM_PINS   12      /* Specifies number of GPIO PINS GPIO0-GPIO11 */

struct pch_regs {
        u32     ien;
        u32     istatus;
        u32     idisp;
        u32     iclr;
        u32     imask;
        u32     imaskclr;
        u32     po;
        u32     pi;
        u32     pm;
        u32     im0;
        u32     im1;
        u32     reserved[4];
        u32     reset;
};

/**
 * struct pch_gpio_reg_data - The register store data.
 * @po_reg:     To store contents of PO register.
 * @pm_reg:     To store contents of PM register.
 */
struct pch_gpio_reg_data {
        u32 po_reg;
        u32 pm_reg;
};

/**
 * struct pch_gpio - GPIO private data structure.
 * @base:                       PCI base address of Memory mapped I/O register.
 * @reg:                        Memory mapped PCH GPIO register list.
 * @dev:                        Pointer to device structure.
 * @gpio:                       Data for GPIO infrastructure.
 * @pch_gpio_reg:               Memory mapped Register data is saved here
 *                              when suspend.
 */
struct pch_gpio {
        void __iomem *base;
        struct pch_regs __iomem *reg;
        struct device *dev;
        struct gpio_chip gpio;
        struct pch_gpio_reg_data pch_gpio_reg;
        struct mutex lock;
};

static void pch_gpio_set(struct gpio_chip *gpio, unsigned nr, int val)
{
        u32 reg_val;
        struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio);

        mutex_lock(&chip->lock);
        reg_val = ioread32(&chip->reg->po);
        if (val)
                reg_val |= (1 << nr);
        else
                reg_val &= ~(1 << nr);

        iowrite32(reg_val, &chip->reg->po);
        mutex_unlock(&chip->lock);
}

static int pch_gpio_get(struct gpio_chip *gpio, unsigned nr)
{
        struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio);

        return ioread32(&chip->reg->pi) & (1 << nr);
}

static int pch_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,
                                     int val)
{
        struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio);
        u32 pm;
        u32 reg_val;

        mutex_lock(&chip->lock);
        pm = ioread32(&chip->reg->pm) & PCH_GPIO_ALL_PINS;
        pm |= (1 << nr);
        iowrite32(pm, &chip->reg->pm);

        reg_val = ioread32(&chip->reg->po);
        if (val)
                reg_val |= (1 << nr);
        else
                reg_val &= ~(1 << nr);

        mutex_unlock(&chip->lock);

        return 0;
}

static int pch_gpio_direction_input(struct gpio_chip *gpio, unsigned nr)
{
        struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio);
        u32 pm;

        mutex_lock(&chip->lock);
        pm = ioread32(&chip->reg->pm) & PCH_GPIO_ALL_PINS; /*bits 0-11*/
        pm &= ~(1 << nr);
        iowrite32(pm, &chip->reg->pm);
        mutex_unlock(&chip->lock);

        return 0;
}

/*
 * Save register configuration and disable interrupts.
 */
static void pch_gpio_save_reg_conf(struct pch_gpio *chip)
{
        chip->pch_gpio_reg.po_reg = ioread32(&chip->reg->po);
        chip->pch_gpio_reg.pm_reg = ioread32(&chip->reg->pm);
}

/*
 * This function restores the register configuration of the GPIO device.
 */
static void pch_gpio_restore_reg_conf(struct pch_gpio *chip)
{
        /* to store contents of PO register */
        iowrite32(chip->pch_gpio_reg.po_reg, &chip->reg->po);
        /* to store contents of PM register */
        iowrite32(chip->pch_gpio_reg.pm_reg, &chip->reg->pm);
}

static void pch_gpio_setup(struct pch_gpio *chip)
{
        struct gpio_chip *gpio = &chip->gpio;

        gpio->label = dev_name(chip->dev);
        gpio->owner = THIS_MODULE;
        gpio->direction_input = pch_gpio_direction_input;
        gpio->get = pch_gpio_get;
        gpio->direction_output = pch_gpio_direction_output;
        gpio->set = pch_gpio_set;
        gpio->dbg_show = NULL;
        gpio->base = -1;
        gpio->ngpio = GPIO_NUM_PINS;
        gpio->can_sleep = 0;
}

static int __devinit pch_gpio_probe(struct pci_dev *pdev,
                                    const struct pci_device_id *id)
{
        s32 ret;
        struct pch_gpio *chip;

        chip = kzalloc(sizeof(*chip), GFP_KERNEL);
        if (chip == NULL)
                return -ENOMEM;

        chip->dev = &pdev->dev;
        ret = pci_enable_device(pdev);
        if (ret) {
                dev_err(&pdev->dev, "%s : pci_enable_device FAILED", __func__);
                goto err_pci_enable;
        }

        ret = pci_request_regions(pdev, KBUILD_MODNAME);
        if (ret) {
                dev_err(&pdev->dev, "pci_request_regions FAILED-%d", ret);
                goto err_request_regions;
        }

        chip->base = pci_iomap(pdev, 1, 0);
        if (chip->base == 0) {
                dev_err(&pdev->dev, "%s : pci_iomap FAILED", __func__);
                ret = -ENOMEM;
                goto err_iomap;
        }

        chip->reg = chip->base;
        pci_set_drvdata(pdev, chip);
        mutex_init(&chip->lock);
        pch_gpio_setup(chip);
        ret = gpiochip_add(&chip->gpio);
        if (ret) {
                dev_err(&pdev->dev, "PCH gpio: Failed to register GPIO\n");
                goto err_gpiochip_add;
        }

        return 0;

err_gpiochip_add:
        pci_iounmap(pdev, chip->base);

err_iomap:
        pci_release_regions(pdev);

err_request_regions:
        pci_disable_device(pdev);

err_pci_enable:
        kfree(chip);
        dev_err(&pdev->dev, "%s Failed returns %d\n", __func__, ret);
        return ret;
}

static void __devexit pch_gpio_remove(struct pci_dev *pdev)
{
        int err;
        struct pch_gpio *chip = pci_get_drvdata(pdev);

        err = gpiochip_remove(&chip->gpio);
        if (err)
                dev_err(&pdev->dev, "Failed gpiochip_remove\n");

        pci_iounmap(pdev, chip->base);
        pci_release_regions(pdev);
        pci_disable_device(pdev);
        kfree(chip);
}

#ifdef CONFIG_PM
static int pch_gpio_suspend(struct pci_dev *pdev, pm_message_t state)
{
        s32 ret;
        struct pch_gpio *chip = pci_get_drvdata(pdev);

        pch_gpio_save_reg_conf(chip);
        pch_gpio_restore_reg_conf(chip);

        ret = pci_save_state(pdev);
        if (ret) {
                dev_err(&pdev->dev, "pci_save_state Failed-%d\n", ret);
                return ret;
        }
        pci_disable_device(pdev);
        pci_set_power_state(pdev, PCI_D0);
        ret = pci_enable_wake(pdev, PCI_D0, 1);
        if (ret)
                dev_err(&pdev->dev, "pci_enable_wake Failed -%d\n", ret);

        return 0;
}

static int pch_gpio_resume(struct pci_dev *pdev)
{
        s32 ret;
        struct pch_gpio *chip = pci_get_drvdata(pdev);

        ret = pci_enable_wake(pdev, PCI_D0, 0);

        pci_set_power_state(pdev, PCI_D0);
        ret = pci_enable_device(pdev);
        if (ret) {
                dev_err(&pdev->dev, "pci_enable_device Failed-%d ", ret);
                return ret;
        }
        pci_restore_state(pdev);

        iowrite32(0x01, &chip->reg->reset);
        iowrite32(0x00, &chip->reg->reset);
        pch_gpio_restore_reg_conf(chip);

        return 0;
}
#else
#define pch_gpio_suspend NULL
#define pch_gpio_resume NULL
#endif

static DEFINE_PCI_DEVICE_TABLE(pch_gpio_pcidev_id) = {
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x8803) },
        { 0, }
};
MODULE_DEVICE_TABLE(pci, pch_gpio_pcidev_id);

static struct pci_driver pch_gpio_driver = {
        .name = "pch_gpio",
        .id_table = pch_gpio_pcidev_id,
        .probe = pch_gpio_probe,
        .remove = __devexit_p(pch_gpio_remove),
        .suspend = pch_gpio_suspend,
        .resume = pch_gpio_resume
};

static int __init pch_gpio_pci_init(void)
{
        return pci_register_driver(&pch_gpio_driver);
}
module_init(pch_gpio_pci_init);

static void __exit pch_gpio_pci_exit(void)
{
        pci_unregister_driver(&pch_gpio_driver);
}
module_exit(pch_gpio_pci_exit);

MODULE_DESCRIPTION("PCH GPIO PCI Driver");
MODULE_LICENSE("GPL");