// SPDX-License-Identifier: GPL-2.0+
/*
 * Generic driver for memory-mapped GPIO controllers.
 *
 * Copyright 2008 MontaVista Software, Inc.
 * Copyright 2008,2010 Anton Vorontsov <cbouatmailru@gmail.com>
 *
 * ....``.```~~~~````.`.`.`.`.```````'',,,.........`````......`.......
 * ...``                                                         ```````..
 * ..The simplest form of a GPIO controller that the driver supports is``
 *  `.just a single "data" register, where GPIO state can be read and/or `
 *    `,..written. ,,..``~~~~ .....``.`.`.~~.```.`.........``````.```````
 *        `````````
                                    ___
_/~~|___/~|   . ```~~~~~~       ___/___\___     ,~.`.`.`.`````.~~...,,,,...
__________|~$@~~~        %~    /o*o*o*o*o*o\   .. Implementing such a GPIO .
o        `                     ~~~~\___/~~~~    ` controller in FPGA is ,.`
                                                 `....trivial..'~`.```.```
 *                                                    ```````
 *  .```````~~~~`..`.``.``.
 * .  The driver supports  `...       ,..```.`~~~```````````````....````.``,,
 * .   big-endian notation, just`.  .. A bit more sophisticated controllers ,
 *  . register the device with -be`. .with a pair of set/clear-bit registers ,
 *   `.. suffix.  ```~~`````....`.`   . affecting the data register and the .`
 *     ``.`.``...```                  ```.. output pins are also supported.`
 *                        ^^             `````.`````````.,``~``~``~~``````
 *                                                   .                  ^^
 *   ,..`.`.`...````````````......`.`.`.`.`.`..`.`.`..
 * .. The expectation is that in at least some cases .    ,-~~~-,
 *  .this will be used with roll-your-own ASIC/FPGA .`     \   /
 *  .logic in Verilog or VHDL. ~~~`````````..`````~~`       \ /
 *  ..````````......```````````                             \o_
 *                                                           |
 *                              ^^                          / \
 *
 *           ...`````~~`.....``.`..........``````.`.``.```........``.
 *            `  8, 16, 32 and 64 bits registers are supported, and``.
 *            . the number of GPIOs is determined by the width of   ~
 *             .. the registers. ,............```.`.`..`.`.~~~.`.`.`~
 *               `.......````.```
 */

#include <linux/init.h>
#include <linux/err.h>
#include <linux/bug.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/compiler.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/log2.h>
#include <linux/ioport.h>
#include <linux/io.h>
#include <linux/gpio/driver.h>
#include <linux/slab.h>
#include <linux/bitops.h>
#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>
#include <linux/of.h>
#include <linux/of_device.h>

static void bgpio_write8(void __iomem *reg, unsigned long data)
{
        writeb(data, reg);
}

static unsigned long bgpio_read8(void __iomem *reg)
{
        return readb(reg);
}

static void bgpio_write16(void __iomem *reg, unsigned long data)
{
        writew(data, reg);
}

static unsigned long bgpio_read16(void __iomem *reg)
{
        return readw(reg);
}

static void bgpio_write32(void __iomem *reg, unsigned long data)
{
        writel(data, reg);
}

static unsigned long bgpio_read32(void __iomem *reg)
{
        return readl(reg);
}

#if BITS_PER_LONG >= 64
static void bgpio_write64(void __iomem *reg, unsigned long data)
{
        writeq(data, reg);
}

static unsigned long bgpio_read64(void __iomem *reg)
{
        return readq(reg);
}
#endif /* BITS_PER_LONG >= 64 */

static void bgpio_write16be(void __iomem *reg, unsigned long data)
{
        iowrite16be(data, reg);
}

static unsigned long bgpio_read16be(void __iomem *reg)
{
        return ioread16be(reg);
}

static void bgpio_write32be(void __iomem *reg, unsigned long data)
{
        iowrite32be(data, reg);
}

static unsigned long bgpio_read32be(void __iomem *reg)
{
        return ioread32be(reg);
}

static unsigned long bgpio_line2mask(struct gpio_chip *gc, unsigned int line)
{
        if (gc->be_bits)
                return BIT(gc->bgpio_bits - 1 - line);
        return BIT(line);
}

static int bgpio_get_set(struct gpio_chip *gc, unsigned int gpio)
{
        unsigned long pinmask = bgpio_line2mask(gc, gpio);
        bool dir = !!(gc->bgpio_dir & pinmask);

        if (dir)
                return !!(gc->read_reg(gc->reg_set) & pinmask);
        else
                return !!(gc->read_reg(gc->reg_dat) & pinmask);
}

/*
 * This assumes that the bits in the GPIO register are in native endianness.
 * We only assign the function pointer if we have that.
 */
static int bgpio_get_set_multiple(struct gpio_chip *gc, unsigned long *mask,
                                  unsigned long *bits)
{
        unsigned long get_mask = 0;
        unsigned long set_mask = 0;

        /* Make sure we first clear any bits that are zero when we read the register */
        *bits &= ~*mask;

        set_mask = *mask & gc->bgpio_dir;
        get_mask = *mask & ~gc->bgpio_dir;

        if (set_mask)
                *bits |= gc->read_reg(gc->reg_set) & set_mask;
        if (get_mask)
                *bits |= gc->read_reg(gc->reg_dat) & get_mask;

        return 0;
}

static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
{
        return !!(gc->read_reg(gc->reg_dat) & bgpio_line2mask(gc, gpio));
}

/*
 * This only works if the bits in the GPIO register are in native endianness.
 */
static int bgpio_get_multiple(struct gpio_chip *gc, unsigned long *mask,
                              unsigned long *bits)
{
        /* Make sure we first clear any bits that are zero when we read the register */
        *bits &= ~*mask;
        *bits |= gc->read_reg(gc->reg_dat) & *mask;
        return 0;
}

/*
 * With big endian mirrored bit order it becomes more tedious.
 */
static int bgpio_get_multiple_be(struct gpio_chip *gc, unsigned long *mask,
                                 unsigned long *bits)
{
        unsigned long readmask = 0;
        unsigned long val;
        int bit;

        /* Make sure we first clear any bits that are zero when we read the register */
        *bits &= ~*mask;

        /* Create a mirrored mask */
        bit = -1;
        while ((bit = find_next_bit(mask, gc->ngpio, bit + 1)) < gc->ngpio)
                readmask |= bgpio_line2mask(gc, bit);

        /* Read the register */
        val = gc->read_reg(gc->reg_dat) & readmask;

        /*
         * Mirror the result into the "bits" result, this will give line 0
         * in bit 0 ... line 31 in bit 31 for a 32bit register.
         */
        bit = -1;
        while ((bit = find_next_bit(&val, gc->ngpio, bit + 1)) < gc->ngpio)
                *bits |= bgpio_line2mask(gc, bit);

        return 0;
}

static void bgpio_set_none(struct gpio_chip *gc, unsigned int gpio, int val)
{
}

static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
{
        unsigned long mask = bgpio_line2mask(gc, gpio);
        unsigned long flags;

        spin_lock_irqsave(&gc->bgpio_lock, flags);

        if (val)
                gc->bgpio_data |= mask;
        else
                gc->bgpio_data &= ~mask;

        gc->write_reg(gc->reg_dat, gc->bgpio_data);

        spin_unlock_irqrestore(&gc->bgpio_lock, flags);
}

static void bgpio_set_with_clear(struct gpio_chip *gc, unsigned int gpio,
                                 int val)
{
        unsigned long mask = bgpio_line2mask(gc, gpio);

        if (val)
                gc->write_reg(gc->reg_set, mask);
        else
                gc->write_reg(gc->reg_clr, mask);
}

static void bgpio_set_set(struct gpio_chip *gc, unsigned int gpio, int val)
{
        unsigned long mask = bgpio_line2mask(gc, gpio);
        unsigned long flags;

        spin_lock_irqsave(&gc->bgpio_lock, flags);

        if (val)
                gc->bgpio_data |= mask;
        else
                gc->bgpio_data &= ~mask;

        gc->write_reg(gc->reg_set, gc->bgpio_data);

        spin_unlock_irqrestore(&gc->bgpio_lock, flags);
}

static void bgpio_multiple_get_masks(struct gpio_chip *gc,
                                     unsigned long *mask, unsigned long *bits,
                                     unsigned long *set_mask,
                                     unsigned long *clear_mask)
{
        int i;

        *set_mask = 0;
        *clear_mask = 0;

        for (i = 0; i < gc->bgpio_bits; i++) {
                if (*mask == 0)
                        break;
                if (__test_and_clear_bit(i, mask)) {
                        if (test_bit(i, bits))
                                *set_mask |= bgpio_line2mask(gc, i);
                        else
                                *clear_mask |= bgpio_line2mask(gc, i);
                }
        }
}

static void bgpio_set_multiple_single_reg(struct gpio_chip *gc,
                                          unsigned long *mask,
                                          unsigned long *bits,
                                          void __iomem *reg)
{
        unsigned long flags;
        unsigned long set_mask, clear_mask;

        spin_lock_irqsave(&gc->bgpio_lock, flags);

        bgpio_multiple_get_masks(gc, mask, bits, &set_mask, &clear_mask);

        gc->bgpio_data |= set_mask;
        gc->bgpio_data &= ~clear_mask;

        gc->write_reg(reg, gc->bgpio_data);

        spin_unlock_irqrestore(&gc->bgpio_lock, flags);
}

static void bgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
                               unsigned long *bits)
{
        bgpio_set_multiple_single_reg(gc, mask, bits, gc->reg_dat);
}

static void bgpio_set_multiple_set(struct gpio_chip *gc, unsigned long *mask,
                                   unsigned long *bits)
{
        bgpio_set_multiple_single_reg(gc, mask, bits, gc->reg_set);
}

static void bgpio_set_multiple_with_clear(struct gpio_chip *gc,
                                          unsigned long *mask,
                                          unsigned long *bits)
{
        unsigned long set_mask, clear_mask;

        bgpio_multiple_get_masks(gc, mask, bits, &set_mask, &clear_mask);

        if (set_mask)
                gc->write_reg(gc->reg_set, set_mask);
        if (clear_mask)
                gc->write_reg(gc->reg_clr, clear_mask);
}

static int bgpio_simple_dir_in(struct gpio_chip *gc, unsigned int gpio)
{
        return 0;
}

static int bgpio_dir_out_err(struct gpio_chip *gc, unsigned int gpio,
                                int val)
{
        return -EINVAL;
}

static int bgpio_simple_dir_out(struct gpio_chip *gc, unsigned int gpio,
                                int val)
{
        gc->set(gc, gpio, val);

        return 0;
}

static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
{
        unsigned long flags;

        spin_lock_irqsave(&gc->bgpio_lock, flags);

        gc->bgpio_dir &= ~bgpio_line2mask(gc, gpio);

        if (gc->reg_dir_in)
                gc->write_reg(gc->reg_dir_in, ~gc->bgpio_dir);
        if (gc->reg_dir_out)
                gc->write_reg(gc->reg_dir_out, gc->bgpio_dir);

        spin_unlock_irqrestore(&gc->bgpio_lock, flags);

        return 0;
}

static int bgpio_get_dir(struct gpio_chip *gc, unsigned int gpio)
{
        /* Return 0 if output, 1 if input */
        if (gc->bgpio_dir_unreadable) {
                if (gc->bgpio_dir & bgpio_line2mask(gc, gpio))
                        return GPIO_LINE_DIRECTION_OUT;
                return GPIO_LINE_DIRECTION_IN;
        }

        if (gc->reg_dir_out) {
                if (gc->read_reg(gc->reg_dir_out) & bgpio_line2mask(gc, gpio))
                        return GPIO_LINE_DIRECTION_OUT;
                return GPIO_LINE_DIRECTION_IN;
        }

        if (gc->reg_dir_in)
                if (!(gc->read_reg(gc->reg_dir_in) & bgpio_line2mask(gc, gpio)))
                        return GPIO_LINE_DIRECTION_OUT;

        return GPIO_LINE_DIRECTION_IN;
}

static void bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
{
        unsigned long flags;

        spin_lock_irqsave(&gc->bgpio_lock, flags);

        gc->bgpio_dir |= bgpio_line2mask(gc, gpio);

        if (gc->reg_dir_in)
                gc->write_reg(gc->reg_dir_in, ~gc->bgpio_dir);
        if (gc->reg_dir_out)
                gc->write_reg(gc->reg_dir_out, gc->bgpio_dir);

        spin_unlock_irqrestore(&gc->bgpio_lock, flags);
}

static int bgpio_dir_out_dir_first(struct gpio_chip *gc, unsigned int gpio,
                                   int val)
{
        bgpio_dir_out(gc, gpio, val);
        gc->set(gc, gpio, val);
        return 0;
}

static int bgpio_dir_out_val_first(struct gpio_chip *gc, unsigned int gpio,
                                   int val)
{
        gc->set(gc, gpio, val);
        bgpio_dir_out(gc, gpio, val);
        return 0;
}

static int bgpio_setup_accessors(struct device *dev,
                                 struct gpio_chip *gc,
                                 bool byte_be)
{

        switch (gc->bgpio_bits) {
        case 8:
                gc->read_reg    = bgpio_read8;
                gc->write_reg   = bgpio_write8;
                break;
        case 16:
                if (byte_be) {
                        gc->read_reg    = bgpio_read16be;
                        gc->write_reg   = bgpio_write16be;
                } else {
                        gc->read_reg    = bgpio_read16;
                        gc->write_reg   = bgpio_write16;
                }
                break;
        case 32:
                if (byte_be) {
                        gc->read_reg    = bgpio_read32be;
                        gc->write_reg   = bgpio_write32be;
                } else {
                        gc->read_reg    = bgpio_read32;
                        gc->write_reg   = bgpio_write32;
                }
                break;
#if BITS_PER_LONG >= 64
        case 64:
                if (byte_be) {
                        dev_err(dev,
                                "64 bit big endian byte order unsupported\n");
                        return -EINVAL;
                } else {
                        gc->read_reg    = bgpio_read64;
                        gc->write_reg   = bgpio_write64;
                }
                break;
#endif /* BITS_PER_LONG >= 64 */
        default:
                dev_err(dev, "unsupported data width %u bits\n", gc->bgpio_bits);
                return -EINVAL;
        }

        return 0;
}

/*
 * Create the device and allocate the resources.  For setting GPIO's there are
 * three supported configurations:
 *
 *      - single input/output register resource (named "dat").
 *      - set/clear pair (named "set" and "clr").
 *      - single output register resource and single input resource ("set" and
 *      dat").
 *
 * For the single output register, this drives a 1 by setting a bit and a zero
 * by clearing a bit.  For the set clr pair, this drives a 1 by setting a bit
 * in the set register and clears it by setting a bit in the clear register.
 * The configuration is detected by which resources are present.
 *
 * For setting the GPIO direction, there are three supported configurations:
 *
 *      - simple bidirection GPIO that requires no configuration.
 *      - an output direction register (named "dirout") where a 1 bit
 *      indicates the GPIO is an output.
 *      - an input direction register (named "dirin") where a 1 bit indicates
 *      the GPIO is an input.
 */
static int bgpio_setup_io(struct gpio_chip *gc,
                          void __iomem *dat,
                          void __iomem *set,
                          void __iomem *clr,
                          unsigned long flags)
{

        gc->reg_dat = dat;
        if (!gc->reg_dat)
                return -EINVAL;

        if (set && clr) {
                gc->reg_set = set;
                gc->reg_clr = clr;
                gc->set = bgpio_set_with_clear;
                gc->set_multiple = bgpio_set_multiple_with_clear;
        } else if (set && !clr) {
                gc->reg_set = set;
                gc->set = bgpio_set_set;
                gc->set_multiple = bgpio_set_multiple_set;
        } else if (flags & BGPIOF_NO_OUTPUT) {
                gc->set = bgpio_set_none;
                gc->set_multiple = NULL;
        } else {
                gc->set = bgpio_set;
                gc->set_multiple = bgpio_set_multiple;
        }

        if (!(flags & BGPIOF_UNREADABLE_REG_SET) &&
            (flags & BGPIOF_READ_OUTPUT_REG_SET)) {
                gc->get = bgpio_get_set;
                if (!gc->be_bits)
                        gc->get_multiple = bgpio_get_set_multiple;
                /*
                 * We deliberately avoid assigning the ->get_multiple() call
                 * for big endian mirrored registers which are ALSO reflecting
                 * their value in the set register when used as output. It is
                 * simply too much complexity, let the GPIO core fall back to
                 * reading each line individually in that fringe case.
                 */
        } else {
                gc->get = bgpio_get;
                if (gc->be_bits)
                        gc->get_multiple = bgpio_get_multiple_be;
                else
                        gc->get_multiple = bgpio_get_multiple;
        }

        return 0;
}

static int bgpio_setup_direction(struct gpio_chip *gc,
                                 void __iomem *dirout,
                                 void __iomem *dirin,
                                 unsigned long flags)
{
        if (dirout || dirin) {
                gc->reg_dir_out = dirout;
                gc->reg_dir_in = dirin;
                if (flags & BGPIOF_NO_SET_ON_INPUT)
                        gc->direction_output = bgpio_dir_out_dir_first;
                else
                        gc->direction_output = bgpio_dir_out_val_first;
                gc->direction_input = bgpio_dir_in;
                gc->get_direction = bgpio_get_dir;
        } else {
                if (flags & BGPIOF_NO_OUTPUT)
                        gc->direction_output = bgpio_dir_out_err;
                else
                        gc->direction_output = bgpio_simple_dir_out;
                gc->direction_input = bgpio_simple_dir_in;
        }

        return 0;
}

static int bgpio_request(struct gpio_chip *chip, unsigned gpio_pin)
{
        if (gpio_pin < chip->ngpio)
                return 0;

        return -EINVAL;
}

/**
 * bgpio_init() - Initialize generic GPIO accessor functions
 * @gc: the GPIO chip to set up
 * @dev: the parent device of the new GPIO chip (compulsory)
 * @sz: the size (width) of the MMIO registers in bytes, typically 1, 2 or 4
 * @dat: MMIO address for the register to READ the value of the GPIO lines, it
 *      is expected that a 1 in the corresponding bit in this register means the
 *      line is asserted
 * @set: MMIO address for the register to SET the value of the GPIO lines, it is
 *      expected that we write the line with 1 in this register to drive the GPIO line
 *      high.
 * @clr: MMIO address for the register to CLEAR the value of the GPIO lines, it is
 *      expected that we write the line with 1 in this register to drive the GPIO line
 *      low. It is allowed to leave this address as NULL, in that case the SET register
 *      will be assumed to also clear the GPIO lines, by actively writing the line
 *      with 0.
 * @dirout: MMIO address for the register to set the line as OUTPUT. It is assumed
 *      that setting a line to 1 in this register will turn that line into an
 *      output line. Conversely, setting the line to 0 will turn that line into
 *      an input.
 * @dirin: MMIO address for the register to set this line as INPUT. It is assumed
 *      that setting a line to 1 in this register will turn that line into an
 *      input line. Conversely, setting the line to 0 will turn that line into
 *      an output.
 * @flags: Different flags that will affect the behaviour of the device, such as
 *      endianness etc.
 */
int bgpio_init(struct gpio_chip *gc, struct device *dev,
               unsigned long sz, void __iomem *dat, void __iomem *set,
               void __iomem *clr, void __iomem *dirout, void __iomem *dirin,
               unsigned long flags)
{
        int ret;

        if (!is_power_of_2(sz))
                return -EINVAL;

        gc->bgpio_bits = sz * 8;
        if (gc->bgpio_bits > BITS_PER_LONG)
                return -EINVAL;

        spin_lock_init(&gc->bgpio_lock);
        gc->parent = dev;
        gc->label = dev_name(dev);
        gc->base = -1;
        gc->ngpio = gc->bgpio_bits;
        gc->request = bgpio_request;
        gc->be_bits = !!(flags & BGPIOF_BIG_ENDIAN);

        ret = bgpio_setup_io(gc, dat, set, clr, flags);
        if (ret)
                return ret;

        ret = bgpio_setup_accessors(dev, gc, flags & BGPIOF_BIG_ENDIAN_BYTE_ORDER);
        if (ret)
                return ret;

        ret = bgpio_setup_direction(gc, dirout, dirin, flags);
        if (ret)
                return ret;

        gc->bgpio_data = gc->read_reg(gc->reg_dat);
        if (gc->set == bgpio_set_set &&
                        !(flags & BGPIOF_UNREADABLE_REG_SET))
                gc->bgpio_data = gc->read_reg(gc->reg_set);

        if (flags & BGPIOF_UNREADABLE_REG_DIR)
                gc->bgpio_dir_unreadable = true;

        /*
         * Inspect hardware to find initial direction setting.
         */
        if ((gc->reg_dir_out || gc->reg_dir_in) &&
            !(flags & BGPIOF_UNREADABLE_REG_DIR)) {
                if (gc->reg_dir_out)
                        gc->bgpio_dir = gc->read_reg(gc->reg_dir_out);
                else if (gc->reg_dir_in)
                        gc->bgpio_dir = ~gc->read_reg(gc->reg_dir_in);
                /*
                 * If we have two direction registers, synchronise
                 * input setting to output setting, the library
                 * can not handle a line being input and output at
                 * the same time.
                 */
                if (gc->reg_dir_out && gc->reg_dir_in)
                        gc->write_reg(gc->reg_dir_in, ~gc->bgpio_dir);
        }

        return ret;
}
EXPORT_SYMBOL_GPL(bgpio_init);

#if IS_ENABLED(CONFIG_GPIO_GENERIC_PLATFORM)

static void __iomem *bgpio_map(struct platform_device *pdev,
                               const char *name,
                               resource_size_t sane_sz)
{
        struct resource *r;
        resource_size_t sz;

        r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
        if (!r)
                return NULL;

        sz = resource_size(r);
        if (sz != sane_sz)
                return IOMEM_ERR_PTR(-EINVAL);

        return devm_ioremap_resource(&pdev->dev, r);
}

#ifdef CONFIG_OF
static const struct of_device_id bgpio_of_match[] = {
        { .compatible = "brcm,bcm6345-gpio" },
        { .compatible = "wd,mbl-gpio" },
        { .compatible = "ni,169445-nand-gpio" },
        { }
};
MODULE_DEVICE_TABLE(of, bgpio_of_match);

static struct bgpio_pdata *bgpio_parse_dt(struct platform_device *pdev,
                                          unsigned long *flags)
{
        struct bgpio_pdata *pdata;

        if (!of_match_device(bgpio_of_match, &pdev->dev))
                return NULL;

        pdata = devm_kzalloc(&pdev->dev, sizeof(struct bgpio_pdata),
                             GFP_KERNEL);
        if (!pdata)
                return ERR_PTR(-ENOMEM);

        pdata->base = -1;

        if (of_device_is_big_endian(pdev->dev.of_node))
                *flags |= BGPIOF_BIG_ENDIAN_BYTE_ORDER;

        if (of_property_read_bool(pdev->dev.of_node, "no-output"))
                *flags |= BGPIOF_NO_OUTPUT;

        return pdata;
}
#else
static struct bgpio_pdata *bgpio_parse_dt(struct platform_device *pdev,
                                          unsigned long *flags)
{
        return NULL;
}
#endif /* CONFIG_OF */

static int bgpio_pdev_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct resource *r;
        void __iomem *dat;
        void __iomem *set;
        void __iomem *clr;
        void __iomem *dirout;
        void __iomem *dirin;
        unsigned long sz;
        unsigned long flags = 0;
        int err;
        struct gpio_chip *gc;
        struct bgpio_pdata *pdata;

        pdata = bgpio_parse_dt(pdev, &flags);
        if (IS_ERR(pdata))
                return PTR_ERR(pdata);

        if (!pdata) {
                pdata = dev_get_platdata(dev);
                flags = pdev->id_entry->driver_data;
        }

        r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
        if (!r)
                return -EINVAL;

        sz = resource_size(r);

        dat = bgpio_map(pdev, "dat", sz);
        if (IS_ERR(dat))
                return PTR_ERR(dat);

        set = bgpio_map(pdev, "set", sz);
        if (IS_ERR(set))
                return PTR_ERR(set);

        clr = bgpio_map(pdev, "clr", sz);
        if (IS_ERR(clr))
                return PTR_ERR(clr);

        dirout = bgpio_map(pdev, "dirout", sz);
        if (IS_ERR(dirout))
                return PTR_ERR(dirout);

        dirin = bgpio_map(pdev, "dirin", sz);
        if (IS_ERR(dirin))
                return PTR_ERR(dirin);

        gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL);
        if (!gc)
                return -ENOMEM;

        err = bgpio_init(gc, dev, sz, dat, set, clr, dirout, dirin, flags);
        if (err)
                return err;

        if (pdata) {
                if (pdata->label)
                        gc->label = pdata->label;
                gc->base = pdata->base;
                if (pdata->ngpio > 0)
                        gc->ngpio = pdata->ngpio;
        }

        platform_set_drvdata(pdev, gc);

        return devm_gpiochip_add_data(&pdev->dev, gc, NULL);
}

static const struct platform_device_id bgpio_id_table[] = {
        {
                .name           = "basic-mmio-gpio",
                .driver_data    = 0,
        }, {
                .name           = "basic-mmio-gpio-be",
                .driver_data    = BGPIOF_BIG_ENDIAN,
        },
        { }
};
MODULE_DEVICE_TABLE(platform, bgpio_id_table);

static struct platform_driver bgpio_driver = {
        .driver = {
                .name = "basic-mmio-gpio",
                .of_match_table = of_match_ptr(bgpio_of_match),
        },
        .id_table = bgpio_id_table,
        .probe = bgpio_pdev_probe,
};

module_platform_driver(bgpio_driver);

#endif /* CONFIG_GPIO_GENERIC_PLATFORM */

MODULE_DESCRIPTION("Driver for basic memory-mapped GPIO controllers");
MODULE_AUTHOR("Anton Vorontsov <cbouatmailru@gmail.com>");
MODULE_LICENSE("GPL");