// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Linux multi-function-device driver (MFD) for the integrated peripherals
 * of the VIA VX855 chipset
 *
 * Copyright (C) 2009 VIA Technologies, Inc.
 * Copyright (C) 2010 One Laptop per Child
 * Author: Harald Welte <HaraldWelte@viatech.com>
 * All rights reserved.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/pci.h>
#include <linux/mfd/core.h>

/* offset into pci config space indicating the 16bit register containing
 * the power management IO space base */
#define VX855_CFG_PMIO_OFFSET   0x88

/* ACPI I/O Space registers */
#define VX855_PMIO_ACPI         0x00
#define VX855_PMIO_ACPI_LEN     0x0b

/* Processor Power Management */
#define VX855_PMIO_PPM          0x10
#define VX855_PMIO_PPM_LEN      0x08

/* General Purpose Power Management */
#define VX855_PMIO_GPPM         0x20
#define VX855_PMIO_R_GPI        0x48
#define VX855_PMIO_R_GPO        0x4c
#define VX855_PMIO_GPPM_LEN     0x33

#define VSPIC_MMIO_SIZE 0x1000

static struct resource vx855_gpio_resources[] = {
        {
                .flags = IORESOURCE_IO,
        },
        {
                .flags = IORESOURCE_IO,
        },
};

static const struct mfd_cell vx855_cells[] = {
        {
                .name = "vx855_gpio",
                .num_resources = ARRAY_SIZE(vx855_gpio_resources),
                .resources = vx855_gpio_resources,

                /* we must ignore resource conflicts, for reasons outlined in
                 * the vx855_gpio driver */
                .ignore_resource_conflicts = true,
        },
};

static int vx855_probe(struct pci_dev *pdev,
                                 const struct pci_device_id *id)
{
        int ret;
        u16 gpio_io_offset;

        ret = pci_enable_device(pdev);
        if (ret)
                return -ENODEV;

        pci_read_config_word(pdev, VX855_CFG_PMIO_OFFSET, &gpio_io_offset);
        if (!gpio_io_offset) {
                dev_warn(&pdev->dev,
                        "BIOS did not assign PMIO base offset?!?\n");
                ret = -ENODEV;
                goto out;
        }

        /* mask out the lowest seven bits, as they are always zero, but
         * hardware returns them as 0x01 */
        gpio_io_offset &= 0xff80;

        /* As the region identified here includes many non-GPIO things, we
         * only work with the specific registers that concern us. */
        vx855_gpio_resources[0].start = gpio_io_offset + VX855_PMIO_R_GPI;
        vx855_gpio_resources[0].end = vx855_gpio_resources[0].start + 3;
        vx855_gpio_resources[1].start = gpio_io_offset + VX855_PMIO_R_GPO;
        vx855_gpio_resources[1].end = vx855_gpio_resources[1].start + 3;

        ret = mfd_add_devices(&pdev->dev, -1, vx855_cells, ARRAY_SIZE(vx855_cells),
                        NULL, 0, NULL);

        /* we always return -ENODEV here in order to enable other
         * drivers like old, not-yet-platform_device ported i2c-viapro */
        return -ENODEV;
out:
        pci_disable_device(pdev);
        return ret;
}

static void vx855_remove(struct pci_dev *pdev)
{
        mfd_remove_devices(&pdev->dev);
        pci_disable_device(pdev);
}

static const struct pci_device_id vx855_pci_tbl[] = {
        { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_VX855) },
        { 0, }
};
MODULE_DEVICE_TABLE(pci, vx855_pci_tbl);

static struct pci_driver vx855_pci_driver = {
        .name           = "vx855",
        .id_table       = vx855_pci_tbl,
        .probe          = vx855_probe,
        .remove         = vx855_remove,
};

module_pci_driver(vx855_pci_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>");
MODULE_DESCRIPTION("Driver for the VIA VX855 chipset");