/*
 * Copyright (C) 2015-2017 Broadcom
 *
 * 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.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/bitops.h>
#include <linux/gpio/driver.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/module.h>
#include <linux/irqdomain.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/interrupt.h>

enum gio_reg_index {
        GIO_REG_ODEN = 0,
        GIO_REG_DATA,
        GIO_REG_IODIR,
        GIO_REG_EC,
        GIO_REG_EI,
        GIO_REG_MASK,
        GIO_REG_LEVEL,
        GIO_REG_STAT,
        NUMBER_OF_GIO_REGISTERS
};

#define GIO_BANK_SIZE           (NUMBER_OF_GIO_REGISTERS * sizeof(u32))
#define GIO_BANK_OFF(bank, off) (((bank) * GIO_BANK_SIZE) + (off * sizeof(u32)))
#define GIO_ODEN(bank)          GIO_BANK_OFF(bank, GIO_REG_ODEN)
#define GIO_DATA(bank)          GIO_BANK_OFF(bank, GIO_REG_DATA)
#define GIO_IODIR(bank)         GIO_BANK_OFF(bank, GIO_REG_IODIR)
#define GIO_EC(bank)            GIO_BANK_OFF(bank, GIO_REG_EC)
#define GIO_EI(bank)            GIO_BANK_OFF(bank, GIO_REG_EI)
#define GIO_MASK(bank)          GIO_BANK_OFF(bank, GIO_REG_MASK)
#define GIO_LEVEL(bank)         GIO_BANK_OFF(bank, GIO_REG_LEVEL)
#define GIO_STAT(bank)          GIO_BANK_OFF(bank, GIO_REG_STAT)

struct brcmstb_gpio_bank {
        struct list_head node;
        int id;
        struct gpio_chip gc;
        struct brcmstb_gpio_priv *parent_priv;
        u32 width;
        u32 wake_active;
        u32 saved_regs[GIO_REG_STAT]; /* Don't save and restore GIO_REG_STAT */
};

struct brcmstb_gpio_priv {
        struct list_head bank_list;
        void __iomem *reg_base;
        struct platform_device *pdev;
        struct irq_domain *irq_domain;
        struct irq_chip irq_chip;
        int parent_irq;
        int gpio_base;
        int num_gpios;
        int parent_wake_irq;
};

#define MAX_GPIO_PER_BANK       32
#define GPIO_BANK(gpio)         ((gpio) >> 5)
/* assumes MAX_GPIO_PER_BANK is a multiple of 2 */
#define GPIO_BIT(gpio)          ((gpio) & (MAX_GPIO_PER_BANK - 1))

static inline struct brcmstb_gpio_priv *
brcmstb_gpio_gc_to_priv(struct gpio_chip *gc)
{
        struct brcmstb_gpio_bank *bank = gpiochip_get_data(gc);
        return bank->parent_priv;
}

static unsigned long
__brcmstb_gpio_get_active_irqs(struct brcmstb_gpio_bank *bank)
{
        void __iomem *reg_base = bank->parent_priv->reg_base;

        return bank->gc.read_reg(reg_base + GIO_STAT(bank->id)) &
               bank->gc.read_reg(reg_base + GIO_MASK(bank->id));
}

static unsigned long
brcmstb_gpio_get_active_irqs(struct brcmstb_gpio_bank *bank)
{
        unsigned long status;
        unsigned long flags;

        spin_lock_irqsave(&bank->gc.bgpio_lock, flags);
        status = __brcmstb_gpio_get_active_irqs(bank);
        spin_unlock_irqrestore(&bank->gc.bgpio_lock, flags);

        return status;
}

static int brcmstb_gpio_hwirq_to_offset(irq_hw_number_t hwirq,
                                        struct brcmstb_gpio_bank *bank)
{
        return hwirq - (bank->gc.base - bank->parent_priv->gpio_base);
}

static void brcmstb_gpio_set_imask(struct brcmstb_gpio_bank *bank,
                unsigned int hwirq, bool enable)
{
        struct gpio_chip *gc = &bank->gc;
        struct brcmstb_gpio_priv *priv = bank->parent_priv;
        u32 mask = BIT(brcmstb_gpio_hwirq_to_offset(hwirq, bank));
        u32 imask;
        unsigned long flags;

        spin_lock_irqsave(&gc->bgpio_lock, flags);
        imask = gc->read_reg(priv->reg_base + GIO_MASK(bank->id));
        if (enable)
                imask |= mask;
        else
                imask &= ~mask;
        gc->write_reg(priv->reg_base + GIO_MASK(bank->id), imask);
        spin_unlock_irqrestore(&gc->bgpio_lock, flags);
}

static int brcmstb_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
{
        struct brcmstb_gpio_priv *priv = brcmstb_gpio_gc_to_priv(gc);
        /* gc_offset is relative to this gpio_chip; want real offset */
        int hwirq = offset + (gc->base - priv->gpio_base);

        if (hwirq >= priv->num_gpios)
                return -ENXIO;
        return irq_create_mapping(priv->irq_domain, hwirq);
}

/* -------------------- IRQ chip functions -------------------- */

static void brcmstb_gpio_irq_mask(struct irq_data *d)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
        struct brcmstb_gpio_bank *bank = gpiochip_get_data(gc);

        brcmstb_gpio_set_imask(bank, d->hwirq, false);
}

static void brcmstb_gpio_irq_unmask(struct irq_data *d)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
        struct brcmstb_gpio_bank *bank = gpiochip_get_data(gc);

        brcmstb_gpio_set_imask(bank, d->hwirq, true);
}

static void brcmstb_gpio_irq_ack(struct irq_data *d)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
        struct brcmstb_gpio_bank *bank = gpiochip_get_data(gc);
        struct brcmstb_gpio_priv *priv = bank->parent_priv;
        u32 mask = BIT(brcmstb_gpio_hwirq_to_offset(d->hwirq, bank));

        gc->write_reg(priv->reg_base + GIO_STAT(bank->id), mask);
}

static int brcmstb_gpio_irq_set_type(struct irq_data *d, unsigned int type)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
        struct brcmstb_gpio_bank *bank = gpiochip_get_data(gc);
        struct brcmstb_gpio_priv *priv = bank->parent_priv;
        u32 mask = BIT(brcmstb_gpio_hwirq_to_offset(d->hwirq, bank));
        u32 edge_insensitive, iedge_insensitive;
        u32 edge_config, iedge_config;
        u32 level, ilevel;
        unsigned long flags;

        switch (type) {
        case IRQ_TYPE_LEVEL_LOW:
                level = mask;
                edge_config = 0;
                edge_insensitive = 0;
                break;
        case IRQ_TYPE_LEVEL_HIGH:
                level = mask;
                edge_config = mask;
                edge_insensitive = 0;
                break;
        case IRQ_TYPE_EDGE_FALLING:
                level = 0;
                edge_config = 0;
                edge_insensitive = 0;
                break;
        case IRQ_TYPE_EDGE_RISING:
                level = 0;
                edge_config = mask;
                edge_insensitive = 0;
                break;
        case IRQ_TYPE_EDGE_BOTH:
                level = 0;
                edge_config = 0;  /* don't care, but want known value */
                edge_insensitive = mask;
                break;
        default:
                return -EINVAL;
        }

        spin_lock_irqsave(&bank->gc.bgpio_lock, flags);

        iedge_config = bank->gc.read_reg(priv->reg_base +
                        GIO_EC(bank->id)) & ~mask;
        iedge_insensitive = bank->gc.read_reg(priv->reg_base +
                        GIO_EI(bank->id)) & ~mask;
        ilevel = bank->gc.read_reg(priv->reg_base +
                        GIO_LEVEL(bank->id)) & ~mask;

        bank->gc.write_reg(priv->reg_base + GIO_EC(bank->id),
                        iedge_config | edge_config);
        bank->gc.write_reg(priv->reg_base + GIO_EI(bank->id),
                        iedge_insensitive | edge_insensitive);
        bank->gc.write_reg(priv->reg_base + GIO_LEVEL(bank->id),
                        ilevel | level);

        spin_unlock_irqrestore(&bank->gc.bgpio_lock, flags);
        return 0;
}

static int brcmstb_gpio_priv_set_wake(struct brcmstb_gpio_priv *priv,
                unsigned int enable)
{
        int ret = 0;

        if (enable)
                ret = enable_irq_wake(priv->parent_wake_irq);
        else
                ret = disable_irq_wake(priv->parent_wake_irq);
        if (ret)
                dev_err(&priv->pdev->dev, "failed to %s wake-up interrupt\n",
                                enable ? "enable" : "disable");
        return ret;
}

static int brcmstb_gpio_irq_set_wake(struct irq_data *d, unsigned int enable)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
        struct brcmstb_gpio_bank *bank = gpiochip_get_data(gc);
        struct brcmstb_gpio_priv *priv = bank->parent_priv;
        u32 mask = BIT(brcmstb_gpio_hwirq_to_offset(d->hwirq, bank));

        /*
         * Do not do anything specific for now, suspend/resume callbacks will
         * configure the interrupt mask appropriately
         */
        if (enable)
                bank->wake_active |= mask;
        else
                bank->wake_active &= ~mask;

        return brcmstb_gpio_priv_set_wake(priv, enable);
}

static irqreturn_t brcmstb_gpio_wake_irq_handler(int irq, void *data)
{
        struct brcmstb_gpio_priv *priv = data;

        if (!priv || irq != priv->parent_wake_irq)
                return IRQ_NONE;

        /* Nothing to do */
        return IRQ_HANDLED;
}

static void brcmstb_gpio_irq_bank_handler(struct brcmstb_gpio_bank *bank)
{
        struct brcmstb_gpio_priv *priv = bank->parent_priv;
        struct irq_domain *domain = priv->irq_domain;
        int hwbase = bank->gc.base - priv->gpio_base;
        unsigned long status;

        while ((status = brcmstb_gpio_get_active_irqs(bank))) {
                unsigned int irq, offset;

                for_each_set_bit(offset, &status, 32) {
                        if (offset >= bank->width)
                                dev_warn(&priv->pdev->dev,
                                         "IRQ for invalid GPIO (bank=%d, offset=%d)\n",
                                         bank->id, offset);
                        irq = irq_linear_revmap(domain, hwbase + offset);
                        generic_handle_irq(irq);
                }
        }
}

/* Each UPG GIO block has one IRQ for all banks */
static void brcmstb_gpio_irq_handler(struct irq_desc *desc)
{
        struct brcmstb_gpio_priv *priv = irq_desc_get_handler_data(desc);
        struct irq_chip *chip = irq_desc_get_chip(desc);
        struct brcmstb_gpio_bank *bank;

        /* Interrupts weren't properly cleared during probe */
        BUG_ON(!priv || !chip);

        chained_irq_enter(chip, desc);
        list_for_each_entry(bank, &priv->bank_list, node)
                brcmstb_gpio_irq_bank_handler(bank);
        chained_irq_exit(chip, desc);
}

static struct brcmstb_gpio_bank *brcmstb_gpio_hwirq_to_bank(
                struct brcmstb_gpio_priv *priv, irq_hw_number_t hwirq)
{
        struct brcmstb_gpio_bank *bank;
        int i = 0;

        /* banks are in descending order */
        list_for_each_entry_reverse(bank, &priv->bank_list, node) {
                i += bank->gc.ngpio;
                if (hwirq < i)
                        return bank;
        }
        return NULL;
}

/*
 * This lock class tells lockdep that GPIO irqs are in a different
 * category than their parents, so it won't report false recursion.
 */
static struct lock_class_key brcmstb_gpio_irq_lock_class;
static struct lock_class_key brcmstb_gpio_irq_request_class;


static int brcmstb_gpio_irq_map(struct irq_domain *d, unsigned int irq,
                irq_hw_number_t hwirq)
{
        struct brcmstb_gpio_priv *priv = d->host_data;
        struct brcmstb_gpio_bank *bank =
                brcmstb_gpio_hwirq_to_bank(priv, hwirq);
        struct platform_device *pdev = priv->pdev;
        int ret;

        if (!bank)
                return -EINVAL;

        dev_dbg(&pdev->dev, "Mapping irq %d for gpio line %d (bank %d)\n",
                irq, (int)hwirq, bank->id);
        ret = irq_set_chip_data(irq, &bank->gc);
        if (ret < 0)
                return ret;
        irq_set_lockdep_class(irq, &brcmstb_gpio_irq_lock_class,
                              &brcmstb_gpio_irq_request_class);
        irq_set_chip_and_handler(irq, &priv->irq_chip, handle_level_irq);
        irq_set_noprobe(irq);
        return 0;
}

static void brcmstb_gpio_irq_unmap(struct irq_domain *d, unsigned int irq)
{
        irq_set_chip_and_handler(irq, NULL, NULL);
        irq_set_chip_data(irq, NULL);
}

static const struct irq_domain_ops brcmstb_gpio_irq_domain_ops = {
        .map = brcmstb_gpio_irq_map,
        .unmap = brcmstb_gpio_irq_unmap,
        .xlate = irq_domain_xlate_twocell,
};

/* Make sure that the number of banks matches up between properties */
static int brcmstb_gpio_sanity_check_banks(struct device *dev,
                struct device_node *np, struct resource *res)
{
        int res_num_banks = resource_size(res) / GIO_BANK_SIZE;
        int num_banks =
                of_property_count_u32_elems(np, "brcm,gpio-bank-widths");

        if (res_num_banks != num_banks) {
                dev_err(dev, "Mismatch in banks: res had %d, bank-widths had %d\n",
                                res_num_banks, num_banks);
                return -EINVAL;
        } else {
                return 0;
        }
}

static int brcmstb_gpio_remove(struct platform_device *pdev)
{
        struct brcmstb_gpio_priv *priv = platform_get_drvdata(pdev);
        struct brcmstb_gpio_bank *bank;
        int offset, ret = 0, virq;

        if (!priv) {
                dev_err(&pdev->dev, "called %s without drvdata!\n", __func__);
                return -EFAULT;
        }

        if (priv->parent_irq > 0)
                irq_set_chained_handler_and_data(priv->parent_irq, NULL, NULL);

        /* Remove all IRQ mappings and delete the domain */
        if (priv->irq_domain) {
                for (offset = 0; offset < priv->num_gpios; offset++) {
                        virq = irq_find_mapping(priv->irq_domain, offset);
                        irq_dispose_mapping(virq);
                }
                irq_domain_remove(priv->irq_domain);
        }

        /*
         * You can lose return values below, but we report all errors, and it's
         * more important to actually perform all of the steps.
         */
        list_for_each_entry(bank, &priv->bank_list, node)
                gpiochip_remove(&bank->gc);

        return ret;
}

static int brcmstb_gpio_of_xlate(struct gpio_chip *gc,
                const struct of_phandle_args *gpiospec, u32 *flags)
{
        struct brcmstb_gpio_priv *priv = brcmstb_gpio_gc_to_priv(gc);
        struct brcmstb_gpio_bank *bank = gpiochip_get_data(gc);
        int offset;

        if (gc->of_gpio_n_cells != 2) {
                WARN_ON(1);
                return -EINVAL;
        }

        if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
                return -EINVAL;

        offset = gpiospec->args[0] - (gc->base - priv->gpio_base);
        if (offset >= gc->ngpio || offset < 0)
                return -EINVAL;

        if (unlikely(offset >= bank->width)) {
                dev_warn_ratelimited(&priv->pdev->dev,
                        "Received request for invalid GPIO offset %d\n",
                        gpiospec->args[0]);
        }

        if (flags)
                *flags = gpiospec->args[1];

        return offset;
}

/* priv->parent_irq and priv->num_gpios must be set before calling */
static int brcmstb_gpio_irq_setup(struct platform_device *pdev,
                struct brcmstb_gpio_priv *priv)
{
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
        int err;

        priv->irq_domain =
                irq_domain_add_linear(np, priv->num_gpios,
                                      &brcmstb_gpio_irq_domain_ops,
                                      priv);
        if (!priv->irq_domain) {
                dev_err(dev, "Couldn't allocate IRQ domain\n");
                return -ENXIO;
        }

        if (of_property_read_bool(np, "wakeup-source")) {
                priv->parent_wake_irq = platform_get_irq(pdev, 1);
                if (priv->parent_wake_irq < 0) {
                        priv->parent_wake_irq = 0;
                        dev_warn(dev,
                                "Couldn't get wake IRQ - GPIOs will not be able to wake from sleep");
                } else {
                        /*
                         * Set wakeup capability so we can process boot-time
                         * "wakeups" (e.g., from S5 cold boot)
                         */
                        device_set_wakeup_capable(dev, true);
                        device_wakeup_enable(dev);
                        err = devm_request_irq(dev, priv->parent_wake_irq,
                                               brcmstb_gpio_wake_irq_handler,
                                               IRQF_SHARED,
                                               "brcmstb-gpio-wake", priv);

                        if (err < 0) {
                                dev_err(dev, "Couldn't request wake IRQ");
                                goto out_free_domain;
                        }
                }
        }

        priv->irq_chip.name = dev_name(dev);
        priv->irq_chip.irq_disable = brcmstb_gpio_irq_mask;
        priv->irq_chip.irq_mask = brcmstb_gpio_irq_mask;
        priv->irq_chip.irq_unmask = brcmstb_gpio_irq_unmask;
        priv->irq_chip.irq_ack = brcmstb_gpio_irq_ack;
        priv->irq_chip.irq_set_type = brcmstb_gpio_irq_set_type;

        if (priv->parent_wake_irq)
                priv->irq_chip.irq_set_wake = brcmstb_gpio_irq_set_wake;

        irq_set_chained_handler_and_data(priv->parent_irq,
                                         brcmstb_gpio_irq_handler, priv);
        irq_set_status_flags(priv->parent_irq, IRQ_DISABLE_UNLAZY);

        return 0;

out_free_domain:
        irq_domain_remove(priv->irq_domain);

        return err;
}

static void brcmstb_gpio_bank_save(struct brcmstb_gpio_priv *priv,
                                   struct brcmstb_gpio_bank *bank)
{
        struct gpio_chip *gc = &bank->gc;
        unsigned int i;

        for (i = 0; i < GIO_REG_STAT; i++)
                bank->saved_regs[i] = gc->read_reg(priv->reg_base +
                                                   GIO_BANK_OFF(bank->id, i));
}

static void brcmstb_gpio_quiesce(struct device *dev, bool save)
{
        struct brcmstb_gpio_priv *priv = dev_get_drvdata(dev);
        struct brcmstb_gpio_bank *bank;
        struct gpio_chip *gc;
        u32 imask;

        /* disable non-wake interrupt */
        if (priv->parent_irq >= 0)
                disable_irq(priv->parent_irq);

        list_for_each_entry(bank, &priv->bank_list, node) {
                gc = &bank->gc;

                if (save)
                        brcmstb_gpio_bank_save(priv, bank);

                /* Unmask GPIOs which have been flagged as wake-up sources */
                if (priv->parent_wake_irq)
                        imask = bank->wake_active;
                else
                        imask = 0;
                gc->write_reg(priv->reg_base + GIO_MASK(bank->id),
                               imask);
        }
}

static void brcmstb_gpio_shutdown(struct platform_device *pdev)
{
        /* Enable GPIO for S5 cold boot */
        brcmstb_gpio_quiesce(&pdev->dev, false);
}

#ifdef CONFIG_PM_SLEEP
static void brcmstb_gpio_bank_restore(struct brcmstb_gpio_priv *priv,
                                      struct brcmstb_gpio_bank *bank)
{
        struct gpio_chip *gc = &bank->gc;
        unsigned int i;

        for (i = 0; i < GIO_REG_STAT; i++)
                gc->write_reg(priv->reg_base + GIO_BANK_OFF(bank->id, i),
                              bank->saved_regs[i]);
}

static int brcmstb_gpio_suspend(struct device *dev)
{
        brcmstb_gpio_quiesce(dev, true);
        return 0;
}

static int brcmstb_gpio_resume(struct device *dev)
{
        struct brcmstb_gpio_priv *priv = dev_get_drvdata(dev);
        struct brcmstb_gpio_bank *bank;
        bool need_wakeup_event = false;

        list_for_each_entry(bank, &priv->bank_list, node) {
                need_wakeup_event |= !!__brcmstb_gpio_get_active_irqs(bank);
                brcmstb_gpio_bank_restore(priv, bank);
        }

        if (priv->parent_wake_irq && need_wakeup_event)
                pm_wakeup_event(dev, 0);

        /* enable non-wake interrupt */
        if (priv->parent_irq >= 0)
                enable_irq(priv->parent_irq);

        return 0;
}

#else
#define brcmstb_gpio_suspend    NULL
#define brcmstb_gpio_resume     NULL
#endif /* CONFIG_PM_SLEEP */

static const struct dev_pm_ops brcmstb_gpio_pm_ops = {
        .suspend_noirq  = brcmstb_gpio_suspend,
        .resume_noirq = brcmstb_gpio_resume,
};

static void brcmstb_gpio_set_names(struct device *dev,
                                   struct brcmstb_gpio_bank *bank)
{
        struct device_node *np = dev->of_node;
        const char **names;
        int nstrings, base;
        unsigned int i;

        base = bank->id * MAX_GPIO_PER_BANK;

        nstrings = of_property_count_strings(np, "gpio-line-names");
        if (nstrings <= base)
                /* Line names not present */
                return;

        names = devm_kcalloc(dev, MAX_GPIO_PER_BANK, sizeof(*names),
                             GFP_KERNEL);
        if (!names)
                return;

        /*
         * Make sure to not index beyond the end of the number of descriptors
         * of the GPIO device.
         */
        for (i = 0; i < bank->width; i++) {
                const char *name;
                int ret;

                ret = of_property_read_string_index(np, "gpio-line-names",
                                                    base + i, &name);
                if (ret) {
                        if (ret != -ENODATA)
                                dev_err(dev, "unable to name line %d: %d\n",
                                        base + i, ret);
                        break;
                }
                if (*name)
                        names[i] = name;
        }

        bank->gc.names = names;
}

static int brcmstb_gpio_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
        void __iomem *reg_base;
        struct brcmstb_gpio_priv *priv;
        struct resource *res;
        struct property *prop;
        const __be32 *p;
        u32 bank_width;
        int num_banks = 0;
        int err;
        static int gpio_base;
        unsigned long flags = 0;
        bool need_wakeup_event = false;

        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;
        platform_set_drvdata(pdev, priv);
        INIT_LIST_HEAD(&priv->bank_list);

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        reg_base = devm_ioremap_resource(dev, res);
        if (IS_ERR(reg_base))
                return PTR_ERR(reg_base);

        priv->gpio_base = gpio_base;
        priv->reg_base = reg_base;
        priv->pdev = pdev;

        if (of_property_read_bool(np, "interrupt-controller")) {
                priv->parent_irq = platform_get_irq(pdev, 0);
                if (priv->parent_irq <= 0)
                        return -ENOENT;
        } else {
                priv->parent_irq = -ENOENT;
        }

        if (brcmstb_gpio_sanity_check_banks(dev, np, res))
                return -EINVAL;

        /*
         * MIPS endianness is configured by boot strap, which also reverses all
         * bus endianness (i.e., big-endian CPU + big endian bus ==> native
         * endian I/O).
         *
         * Other architectures (e.g., ARM) either do not support big endian, or
         * else leave I/O in little endian mode.
         */
#if defined(CONFIG_MIPS) && defined(__BIG_ENDIAN)
        flags = BGPIOF_BIG_ENDIAN_BYTE_ORDER;
#endif

        of_property_for_each_u32(np, "brcm,gpio-bank-widths", prop, p,
                        bank_width) {
                struct brcmstb_gpio_bank *bank;
                struct gpio_chip *gc;

                /*
                 * If bank_width is 0, then there is an empty bank in the
                 * register block. Special handling for this case.
                 */
                if (bank_width == 0) {
                        dev_dbg(dev, "Width 0 found: Empty bank @ %d\n",
                                num_banks);
                        num_banks++;
                        gpio_base += MAX_GPIO_PER_BANK;
                        continue;
                }

                bank = devm_kzalloc(dev, sizeof(*bank), GFP_KERNEL);
                if (!bank) {
                        err = -ENOMEM;
                        goto fail;
                }

                bank->parent_priv = priv;
                bank->id = num_banks;
                if (bank_width <= 0 || bank_width > MAX_GPIO_PER_BANK) {
                        dev_err(dev, "Invalid bank width %d\n", bank_width);
                        err = -EINVAL;
                        goto fail;
                } else {
                        bank->width = bank_width;
                }

                /*
                 * Regs are 4 bytes wide, have data reg, no set/clear regs,
                 * and direction bits have 0 = output and 1 = input
                 */
                gc = &bank->gc;
                err = bgpio_init(gc, dev, 4,
                                reg_base + GIO_DATA(bank->id),
                                NULL, NULL, NULL,
                                reg_base + GIO_IODIR(bank->id), flags);
                if (err) {
                        dev_err(dev, "bgpio_init() failed\n");
                        goto fail;
                }

                gc->of_node = np;
                gc->owner = THIS_MODULE;
                gc->label = devm_kasprintf(dev, GFP_KERNEL, "%pOF", dev->of_node);
                if (!gc->label) {
                        err = -ENOMEM;
                        goto fail;
                }
                gc->base = gpio_base;
                gc->of_gpio_n_cells = 2;
                gc->of_xlate = brcmstb_gpio_of_xlate;
                /* not all ngpio lines are valid, will use bank width later */
                gc->ngpio = MAX_GPIO_PER_BANK;
                if (priv->parent_irq > 0)
                        gc->to_irq = brcmstb_gpio_to_irq;

                /*
                 * Mask all interrupts by default, since wakeup interrupts may
                 * be retained from S5 cold boot
                 */
                need_wakeup_event |= !!__brcmstb_gpio_get_active_irqs(bank);
                gc->write_reg(reg_base + GIO_MASK(bank->id), 0);

                brcmstb_gpio_set_names(dev, bank);
                err = gpiochip_add_data(gc, bank);
                if (err) {
                        dev_err(dev, "Could not add gpiochip for bank %d\n",
                                        bank->id);
                        goto fail;
                }
                gpio_base += gc->ngpio;

                dev_dbg(dev, "bank=%d, base=%d, ngpio=%d, width=%d\n", bank->id,
                        gc->base, gc->ngpio, bank->width);

                /* Everything looks good, so add bank to list */
                list_add(&bank->node, &priv->bank_list);

                num_banks++;
        }

        priv->num_gpios = gpio_base - priv->gpio_base;
        if (priv->parent_irq > 0) {
                err = brcmstb_gpio_irq_setup(pdev, priv);
                if (err)
                        goto fail;
        }

        if (priv->parent_wake_irq && need_wakeup_event)
                pm_wakeup_event(dev, 0);

        return 0;

fail:
        (void) brcmstb_gpio_remove(pdev);
        return err;
}

static const struct of_device_id brcmstb_gpio_of_match[] = {
        { .compatible = "brcm,brcmstb-gpio" },
        {},
};

MODULE_DEVICE_TABLE(of, brcmstb_gpio_of_match);

static struct platform_driver brcmstb_gpio_driver = {
        .driver = {
                .name = "brcmstb-gpio",
                .of_match_table = brcmstb_gpio_of_match,
                .pm = &brcmstb_gpio_pm_ops,
        },
        .probe = brcmstb_gpio_probe,
        .remove = brcmstb_gpio_remove,
        .shutdown = brcmstb_gpio_shutdown,
};
module_platform_driver(brcmstb_gpio_driver);

MODULE_AUTHOR("Gregory Fong");
MODULE_DESCRIPTION("Driver for Broadcom BRCMSTB SoC UPG GPIO");
MODULE_LICENSE("GPL v2");