/*
 * Core driver for HTC PASIC3 LED/DS1WM chip.
 *
 * Copyright (C) 2006 Philipp Zabel <philipp.zabel@gmail.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; version 2 of the License.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>

#include <linux/gpio.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/mfd/core.h>
#include <linux/mfd/ds1wm.h>
#include <linux/mfd/htc-pasic3.h>
#include <linux/slab.h>

struct pasic3_data {
        void __iomem *mapping;
        unsigned int bus_shift;
};

#define REG_ADDR  5
#define REG_DATA  6

#define READ_MODE 0x80

/*
 * write to a secondary register on the PASIC3
 */
void pasic3_write_register(struct device *dev, u32 reg, u8 val)
{
        struct pasic3_data *asic = dev_get_drvdata(dev);
        int bus_shift = asic->bus_shift;
        void __iomem *addr = asic->mapping + (REG_ADDR << bus_shift);
        void __iomem *data = asic->mapping + (REG_DATA << bus_shift);

        __raw_writeb(~READ_MODE & reg, addr);
        __raw_writeb(val, data);
}
EXPORT_SYMBOL(pasic3_write_register); /* for leds-pasic3 */

/*
 * read from a secondary register on the PASIC3
 */
u8 pasic3_read_register(struct device *dev, u32 reg)
{
        struct pasic3_data *asic = dev_get_drvdata(dev);
        int bus_shift = asic->bus_shift;
        void __iomem *addr = asic->mapping + (REG_ADDR << bus_shift);
        void __iomem *data = asic->mapping + (REG_DATA << bus_shift);

        __raw_writeb(READ_MODE | reg, addr);
        return __raw_readb(data);
}
EXPORT_SYMBOL(pasic3_read_register); /* for leds-pasic3 */

/*
 * LEDs
 */

static struct mfd_cell led_cell __initdata = {
        .name = "leds-pasic3",
};

/*
 * DS1WM
 */

static int ds1wm_enable(struct platform_device *pdev)
{
        struct device *dev = pdev->dev.parent;
        int c;

        c = pasic3_read_register(dev, 0x28);
        pasic3_write_register(dev, 0x28, c & 0x7f);

        dev_dbg(dev, "DS1WM OWM_EN low (active) %02x\n", c & 0x7f);
        return 0;
}

static int ds1wm_disable(struct platform_device *pdev)
{
        struct device *dev = pdev->dev.parent;
        int c;

        c = pasic3_read_register(dev, 0x28);
        pasic3_write_register(dev, 0x28, c | 0x80);

        dev_dbg(dev, "DS1WM OWM_EN high (inactive) %02x\n", c | 0x80);
        return 0;
}

static struct ds1wm_driver_data ds1wm_pdata = {
        .active_high = 0,
        .reset_recover_delay = 1,
};

static struct resource ds1wm_resources[] __initdata = {
        [0] = {
                .start  = 0,
                .flags  = IORESOURCE_MEM,
        },
        [1] = {
                .start  = 0,
                .end    = 0,
                .flags  = IORESOURCE_IRQ,
        },
};

static const struct mfd_cell ds1wm_cell __initconst = {
        .name          = "ds1wm",
        .enable        = ds1wm_enable,
        .disable       = ds1wm_disable,
        .platform_data = &ds1wm_pdata,
        .pdata_size    = sizeof(ds1wm_pdata),
        .num_resources = 2,
        .resources     = ds1wm_resources,
};

static int __init pasic3_probe(struct platform_device *pdev)
{
        struct pasic3_platform_data *pdata = dev_get_platdata(&pdev->dev);
        struct device *dev = &pdev->dev;
        struct pasic3_data *asic;
        struct resource *r;
        int ret;
        int irq = 0;

        r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
        if (r) {
                ds1wm_resources[1].flags = IORESOURCE_IRQ | (r->flags &
                        (IORESOURCE_IRQ_HIGHEDGE | IORESOURCE_IRQ_LOWEDGE));
                irq = r->start;
        }

        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!r)
                return -ENXIO;

        if (!request_mem_region(r->start, resource_size(r), "pasic3"))
                return -EBUSY;

        asic = devm_kzalloc(dev, sizeof(struct pasic3_data), GFP_KERNEL);
        if (!asic)
                return -ENOMEM;

        platform_set_drvdata(pdev, asic);

        asic->mapping = ioremap(r->start, resource_size(r));
        if (!asic->mapping) {
                dev_err(dev, "couldn't ioremap PASIC3\n");
                return -ENOMEM;
        }

        /* calculate bus shift from mem resource */
        asic->bus_shift = (resource_size(r) - 5) >> 3;

        if (pdata && pdata->clock_rate) {
                ds1wm_pdata.clock_rate = pdata->clock_rate;
                /* the first 5 PASIC3 registers control the DS1WM */
                ds1wm_resources[0].end = (5 << asic->bus_shift) - 1;
                ret = mfd_add_devices(&pdev->dev, pdev->id,
                                      &ds1wm_cell, 1, r, irq, NULL);
                if (ret < 0)
                        dev_warn(dev, "failed to register DS1WM\n");
        }

        if (pdata && pdata->led_pdata) {
                led_cell.platform_data = pdata->led_pdata;
                led_cell.pdata_size = sizeof(struct pasic3_leds_machinfo);
                ret = mfd_add_devices(&pdev->dev, pdev->id, &led_cell, 1, r,
                                      0, NULL);
                if (ret < 0)
                        dev_warn(dev, "failed to register LED device\n");
        }

        return 0;
}

static int pasic3_remove(struct platform_device *pdev)
{
        struct pasic3_data *asic = platform_get_drvdata(pdev);
        struct resource *r;

        mfd_remove_devices(&pdev->dev);

        iounmap(asic->mapping);
        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        release_mem_region(r->start, resource_size(r));
        return 0;
}

MODULE_ALIAS("platform:pasic3");

static struct platform_driver pasic3_driver = {
        .driver         = {
                .name   = "pasic3",
        },
        .remove         = pasic3_remove,
};

module_platform_driver_probe(pasic3_driver, pasic3_probe);

MODULE_AUTHOR("Philipp Zabel <philipp.zabel@gmail.com>");
MODULE_DESCRIPTION("Core driver for HTC PASIC3");
MODULE_LICENSE("GPL");