mfd: Add Raspberry Pi Sense HAT core driver

[mirror_ubuntu-zesty-kernel.git] / drivers / gpio / gpio-mvebu.c

/*
 * GPIO driver for Marvell SoCs
 *
 * Copyright (C) 2012 Marvell
 *
 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
 * Andrew Lunn <andrew@lunn.ch>
 * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2.  This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 *
 * This driver is a fairly straightforward GPIO driver for the
 * complete family of Marvell EBU SoC platforms (Orion, Dove,
 * Kirkwood, Discovery, Armada 370/XP). The only complexity of this
 * driver is the different register layout that exists between the
 * non-SMP platforms (Orion, Dove, Kirkwood, Armada 370) and the SMP
 * platforms (MV78200 from the Discovery family and the Armada
 * XP). Therefore, this driver handles three variants of the GPIO
 * block:
 * - the basic variant, called "orion-gpio", with the simplest
 *   register set. Used on Orion, Dove, Kirkwoord, Armada 370 and
 *   non-SMP Discovery systems
 * - the mv78200 variant for MV78200 Discovery systems. This variant
 *   turns the edge mask and level mask registers into CPU0 edge
 *   mask/level mask registers, and adds CPU1 edge mask/level mask
 *   registers.
 * - the armadaxp variant for Armada XP systems. This variant keeps
 *   the normal cause/edge mask/level mask registers when the global
 *   interrupts are used, but adds per-CPU cause/edge mask/level mask
 *   registers n a separate memory area for the per-CPU GPIO
 *   interrupts.
 */

#include <linux/err.h>
#include <linux/init.h>
#include <linux/gpio.h>
#include <linux/irq.h>
#include <linux/slab.h>
#include <linux/irqdomain.h>
#include <linux/io.h>
#include <linux/of_irq.h>
#include <linux/of_device.h>
#include <linux/clk.h>
#include <linux/pinctrl/consumer.h>
#include <linux/irqchip/chained_irq.h>

/*
 * GPIO unit register offsets.
 */
#define GPIO_OUT_OFF            0x0000
#define GPIO_IO_CONF_OFF        0x0004
#define GPIO_BLINK_EN_OFF       0x0008
#define GPIO_IN_POL_OFF         0x000c
#define GPIO_DATA_IN_OFF        0x0010
#define GPIO_EDGE_CAUSE_OFF     0x0014
#define GPIO_EDGE_MASK_OFF      0x0018
#define GPIO_LEVEL_MASK_OFF     0x001c

/* The MV78200 has per-CPU registers for edge mask and level mask */
#define GPIO_EDGE_MASK_MV78200_OFF(cpu)   ((cpu) ? 0x30 : 0x18)
#define GPIO_LEVEL_MASK_MV78200_OFF(cpu)  ((cpu) ? 0x34 : 0x1C)

/* The Armada XP has per-CPU registers for interrupt cause, interrupt
 * mask and interrupt level mask. Those are relative to the
 * percpu_membase. */
#define GPIO_EDGE_CAUSE_ARMADAXP_OFF(cpu) ((cpu) * 0x4)
#define GPIO_EDGE_MASK_ARMADAXP_OFF(cpu)  (0x10 + (cpu) * 0x4)
#define GPIO_LEVEL_MASK_ARMADAXP_OFF(cpu) (0x20 + (cpu) * 0x4)

#define MVEBU_GPIO_SOC_VARIANT_ORION    0x1
#define MVEBU_GPIO_SOC_VARIANT_MV78200  0x2
#define MVEBU_GPIO_SOC_VARIANT_ARMADAXP 0x3

#define MVEBU_MAX_GPIO_PER_BANK         32

struct mvebu_gpio_chip {
        struct gpio_chip   chip;
        spinlock_t         lock;
        void __iomem      *membase;
        void __iomem      *percpu_membase;
        int                irqbase;
        struct irq_domain *domain;
        int                soc_variant;

        /* Used to preserve GPIO registers across suspend/resume */
        u32                out_reg;
        u32                io_conf_reg;
        u32                blink_en_reg;
        u32                in_pol_reg;
        u32                edge_mask_regs[4];
        u32                level_mask_regs[4];
};

/*
 * Functions returning addresses of individual registers for a given
 * GPIO controller.
 */
static inline void __iomem *mvebu_gpioreg_out(struct mvebu_gpio_chip *mvchip)
{
        return mvchip->membase + GPIO_OUT_OFF;
}

static inline void __iomem *mvebu_gpioreg_blink(struct mvebu_gpio_chip *mvchip)
{
        return mvchip->membase + GPIO_BLINK_EN_OFF;
}

static inline void __iomem *
mvebu_gpioreg_io_conf(struct mvebu_gpio_chip *mvchip)
{
        return mvchip->membase + GPIO_IO_CONF_OFF;
}

static inline void __iomem *mvebu_gpioreg_in_pol(struct mvebu_gpio_chip *mvchip)
{
        return mvchip->membase + GPIO_IN_POL_OFF;
}

static inline void __iomem *
mvebu_gpioreg_data_in(struct mvebu_gpio_chip *mvchip)
{
        return mvchip->membase + GPIO_DATA_IN_OFF;
}

static inline void __iomem *
mvebu_gpioreg_edge_cause(struct mvebu_gpio_chip *mvchip)
{
        int cpu;

        switch (mvchip->soc_variant) {
        case MVEBU_GPIO_SOC_VARIANT_ORION:
        case MVEBU_GPIO_SOC_VARIANT_MV78200:
                return mvchip->membase + GPIO_EDGE_CAUSE_OFF;
        case MVEBU_GPIO_SOC_VARIANT_ARMADAXP:
                cpu = smp_processor_id();
                return mvchip->percpu_membase +
                        GPIO_EDGE_CAUSE_ARMADAXP_OFF(cpu);
        default:
                BUG();
        }
}

static inline void __iomem *
mvebu_gpioreg_edge_mask(struct mvebu_gpio_chip *mvchip)
{
        int cpu;

        switch (mvchip->soc_variant) {
        case MVEBU_GPIO_SOC_VARIANT_ORION:
                return mvchip->membase + GPIO_EDGE_MASK_OFF;
        case MVEBU_GPIO_SOC_VARIANT_MV78200:
                cpu = smp_processor_id();
                return mvchip->membase + GPIO_EDGE_MASK_MV78200_OFF(cpu);
        case MVEBU_GPIO_SOC_VARIANT_ARMADAXP:
                cpu = smp_processor_id();
                return mvchip->percpu_membase +
                        GPIO_EDGE_MASK_ARMADAXP_OFF(cpu);
        default:
                BUG();
        }
}

static void __iomem *mvebu_gpioreg_level_mask(struct mvebu_gpio_chip *mvchip)
{
        int cpu;

        switch (mvchip->soc_variant) {
        case MVEBU_GPIO_SOC_VARIANT_ORION:
                return mvchip->membase + GPIO_LEVEL_MASK_OFF;
        case MVEBU_GPIO_SOC_VARIANT_MV78200:
                cpu = smp_processor_id();
                return mvchip->membase + GPIO_LEVEL_MASK_MV78200_OFF(cpu);
        case MVEBU_GPIO_SOC_VARIANT_ARMADAXP:
                cpu = smp_processor_id();
                return mvchip->percpu_membase +
                        GPIO_LEVEL_MASK_ARMADAXP_OFF(cpu);
        default:
                BUG();
        }
}

/*
 * Functions implementing the gpio_chip methods
 */

static void mvebu_gpio_set(struct gpio_chip *chip, unsigned pin, int value)
{
        struct mvebu_gpio_chip *mvchip = gpiochip_get_data(chip);
        unsigned long flags;
        u32 u;

        spin_lock_irqsave(&mvchip->lock, flags);
        u = readl_relaxed(mvebu_gpioreg_out(mvchip));
        if (value)
                u |= 1 << pin;
        else
                u &= ~(1 << pin);
        writel_relaxed(u, mvebu_gpioreg_out(mvchip));
        spin_unlock_irqrestore(&mvchip->lock, flags);
}

static int mvebu_gpio_get(struct gpio_chip *chip, unsigned pin)
{
        struct mvebu_gpio_chip *mvchip = gpiochip_get_data(chip);
        u32 u;

        if (readl_relaxed(mvebu_gpioreg_io_conf(mvchip)) & (1 << pin)) {
                u = readl_relaxed(mvebu_gpioreg_data_in(mvchip)) ^
                        readl_relaxed(mvebu_gpioreg_in_pol(mvchip));
        } else {
                u = readl_relaxed(mvebu_gpioreg_out(mvchip));
        }

        return (u >> pin) & 1;
}

static void mvebu_gpio_blink(struct gpio_chip *chip, unsigned pin, int value)
{
        struct mvebu_gpio_chip *mvchip = gpiochip_get_data(chip);
        unsigned long flags;
        u32 u;

        spin_lock_irqsave(&mvchip->lock, flags);
        u = readl_relaxed(mvebu_gpioreg_blink(mvchip));
        if (value)
                u |= 1 << pin;
        else
                u &= ~(1 << pin);
        writel_relaxed(u, mvebu_gpioreg_blink(mvchip));
        spin_unlock_irqrestore(&mvchip->lock, flags);
}

static int mvebu_gpio_direction_input(struct gpio_chip *chip, unsigned pin)
{
        struct mvebu_gpio_chip *mvchip = gpiochip_get_data(chip);
        unsigned long flags;
        int ret;
        u32 u;

        /* Check with the pinctrl driver whether this pin is usable as
         * an input GPIO */
        ret = pinctrl_gpio_direction_input(chip->base + pin);
        if (ret)
                return ret;

        spin_lock_irqsave(&mvchip->lock, flags);
        u = readl_relaxed(mvebu_gpioreg_io_conf(mvchip));
        u |= 1 << pin;
        writel_relaxed(u, mvebu_gpioreg_io_conf(mvchip));
        spin_unlock_irqrestore(&mvchip->lock, flags);

        return 0;
}

static int mvebu_gpio_direction_output(struct gpio_chip *chip, unsigned pin,
                                       int value)
{
        struct mvebu_gpio_chip *mvchip = gpiochip_get_data(chip);
        unsigned long flags;
        int ret;
        u32 u;

        /* Check with the pinctrl driver whether this pin is usable as
         * an output GPIO */
        ret = pinctrl_gpio_direction_output(chip->base + pin);
        if (ret)
                return ret;

        mvebu_gpio_blink(chip, pin, 0);
        mvebu_gpio_set(chip, pin, value);

        spin_lock_irqsave(&mvchip->lock, flags);
        u = readl_relaxed(mvebu_gpioreg_io_conf(mvchip));
        u &= ~(1 << pin);
        writel_relaxed(u, mvebu_gpioreg_io_conf(mvchip));
        spin_unlock_irqrestore(&mvchip->lock, flags);

        return 0;
}

static int mvebu_gpio_to_irq(struct gpio_chip *chip, unsigned pin)
{
        struct mvebu_gpio_chip *mvchip = gpiochip_get_data(chip);
        return irq_create_mapping(mvchip->domain, pin);
}

/*
 * Functions implementing the irq_chip methods
 */
static void mvebu_gpio_irq_ack(struct irq_data *d)
{
        struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
        struct mvebu_gpio_chip *mvchip = gc->private;
        u32 mask = d->mask;

        irq_gc_lock(gc);
        writel_relaxed(~mask, mvebu_gpioreg_edge_cause(mvchip));
        irq_gc_unlock(gc);
}

static void mvebu_gpio_edge_irq_mask(struct irq_data *d)
{
        struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
        struct mvebu_gpio_chip *mvchip = gc->private;
        struct irq_chip_type *ct = irq_data_get_chip_type(d);
        u32 mask = d->mask;

        irq_gc_lock(gc);
        ct->mask_cache_priv &= ~mask;

        writel_relaxed(ct->mask_cache_priv, mvebu_gpioreg_edge_mask(mvchip));
        irq_gc_unlock(gc);
}

static void mvebu_gpio_edge_irq_unmask(struct irq_data *d)
{
        struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
        struct mvebu_gpio_chip *mvchip = gc->private;
        struct irq_chip_type *ct = irq_data_get_chip_type(d);
        u32 mask = d->mask;

        irq_gc_lock(gc);
        ct->mask_cache_priv |= mask;
        writel_relaxed(ct->mask_cache_priv, mvebu_gpioreg_edge_mask(mvchip));
        irq_gc_unlock(gc);
}

static void mvebu_gpio_level_irq_mask(struct irq_data *d)
{
        struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
        struct mvebu_gpio_chip *mvchip = gc->private;
        struct irq_chip_type *ct = irq_data_get_chip_type(d);
        u32 mask = d->mask;

        irq_gc_lock(gc);
        ct->mask_cache_priv &= ~mask;
        writel_relaxed(ct->mask_cache_priv, mvebu_gpioreg_level_mask(mvchip));
        irq_gc_unlock(gc);
}

static void mvebu_gpio_level_irq_unmask(struct irq_data *d)
{
        struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
        struct mvebu_gpio_chip *mvchip = gc->private;
        struct irq_chip_type *ct = irq_data_get_chip_type(d);
        u32 mask = d->mask;

        irq_gc_lock(gc);
        ct->mask_cache_priv |= mask;
        writel_relaxed(ct->mask_cache_priv, mvebu_gpioreg_level_mask(mvchip));
        irq_gc_unlock(gc);
}

/*****************************************************************************
 * MVEBU GPIO IRQ
 *
 * GPIO_IN_POL register controls whether GPIO_DATA_IN will hold the same
 * value of the line or the opposite value.
 *
 * Level IRQ handlers: DATA_IN is used directly as cause register.
 *                     Interrupt are masked by LEVEL_MASK registers.
 * Edge IRQ handlers:  Change in DATA_IN are latched in EDGE_CAUSE.
 *                     Interrupt are masked by EDGE_MASK registers.
 * Both-edge handlers: Similar to regular Edge handlers, but also swaps
 *                     the polarity to catch the next line transaction.
 *                     This is a race condition that might not perfectly
 *                     work on some use cases.
 *
 * Every eight GPIO lines are grouped (OR'ed) before going up to main
 * cause register.
 *
 *                    EDGE  cause    mask
 *        data-in   /--------| |-----| |----\
 *     -----| |-----                         ---- to main cause reg
 *           X      \----------------| |----/
 *        polarity    LEVEL          mask
 *
 ****************************************************************************/

static int mvebu_gpio_irq_set_type(struct irq_data *d, unsigned int type)
{
        struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
        struct irq_chip_type *ct = irq_data_get_chip_type(d);
        struct mvebu_gpio_chip *mvchip = gc->private;
        int pin;
        u32 u;

        pin = d->hwirq;

        u = readl_relaxed(mvebu_gpioreg_io_conf(mvchip)) & (1 << pin);
        if (!u)
                return -EINVAL;

        type &= IRQ_TYPE_SENSE_MASK;
        if (type == IRQ_TYPE_NONE)
                return -EINVAL;

        /* Check if we need to change chip and handler */
        if (!(ct->type & type))
                if (irq_setup_alt_chip(d, type))
                        return -EINVAL;

        /*
         * Configure interrupt polarity.
         */
        switch (type) {
        case IRQ_TYPE_EDGE_RISING:
        case IRQ_TYPE_LEVEL_HIGH:
                u = readl_relaxed(mvebu_gpioreg_in_pol(mvchip));
                u &= ~(1 << pin);
                writel_relaxed(u, mvebu_gpioreg_in_pol(mvchip));
                break;
        case IRQ_TYPE_EDGE_FALLING:
        case IRQ_TYPE_LEVEL_LOW:
                u = readl_relaxed(mvebu_gpioreg_in_pol(mvchip));
                u |= 1 << pin;
                writel_relaxed(u, mvebu_gpioreg_in_pol(mvchip));
                break;
        case IRQ_TYPE_EDGE_BOTH: {
                u32 v;

                v = readl_relaxed(mvebu_gpioreg_in_pol(mvchip)) ^
                        readl_relaxed(mvebu_gpioreg_data_in(mvchip));

                /*
                 * set initial polarity based on current input level
                 */
                u = readl_relaxed(mvebu_gpioreg_in_pol(mvchip));
                if (v & (1 << pin))
                        u |= 1 << pin;          /* falling */
                else
                        u &= ~(1 << pin);       /* rising */
                writel_relaxed(u, mvebu_gpioreg_in_pol(mvchip));
                break;
        }
        }
        return 0;
}

static void mvebu_gpio_irq_handler(struct irq_desc *desc)
{
        struct mvebu_gpio_chip *mvchip = irq_desc_get_handler_data(desc);
        struct irq_chip *chip = irq_desc_get_chip(desc);
        u32 cause, type;
        int i;

        if (mvchip == NULL)
                return;

        chained_irq_enter(chip, desc);

        cause = readl_relaxed(mvebu_gpioreg_data_in(mvchip)) &
                readl_relaxed(mvebu_gpioreg_level_mask(mvchip));
        cause |= readl_relaxed(mvebu_gpioreg_edge_cause(mvchip)) &
                readl_relaxed(mvebu_gpioreg_edge_mask(mvchip));

        for (i = 0; i < mvchip->chip.ngpio; i++) {
                int irq;

                irq = irq_find_mapping(mvchip->domain, i);

                if (!(cause & (1 << i)))
                        continue;

                type = irq_get_trigger_type(irq);
                if ((type & IRQ_TYPE_SENSE_MASK) == IRQ_TYPE_EDGE_BOTH) {
                        /* Swap polarity (race with GPIO line) */
                        u32 polarity;

                        polarity = readl_relaxed(mvebu_gpioreg_in_pol(mvchip));
                        polarity ^= 1 << i;
                        writel_relaxed(polarity, mvebu_gpioreg_in_pol(mvchip));
                }

                generic_handle_irq(irq);
        }

        chained_irq_exit(chip, desc);
}

#ifdef CONFIG_DEBUG_FS
#include <linux/seq_file.h>

static void mvebu_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
{
        struct mvebu_gpio_chip *mvchip = gpiochip_get_data(chip);
        u32 out, io_conf, blink, in_pol, data_in, cause, edg_msk, lvl_msk;
        int i;

        out     = readl_relaxed(mvebu_gpioreg_out(mvchip));
        io_conf = readl_relaxed(mvebu_gpioreg_io_conf(mvchip));
        blink   = readl_relaxed(mvebu_gpioreg_blink(mvchip));
        in_pol  = readl_relaxed(mvebu_gpioreg_in_pol(mvchip));
        data_in = readl_relaxed(mvebu_gpioreg_data_in(mvchip));
        cause   = readl_relaxed(mvebu_gpioreg_edge_cause(mvchip));
        edg_msk = readl_relaxed(mvebu_gpioreg_edge_mask(mvchip));
        lvl_msk = readl_relaxed(mvebu_gpioreg_level_mask(mvchip));

        for (i = 0; i < chip->ngpio; i++) {
                const char *label;
                u32 msk;
                bool is_out;

                label = gpiochip_is_requested(chip, i);
                if (!label)
                        continue;

                msk = 1 << i;
                is_out = !(io_conf & msk);

                seq_printf(s, " gpio-%-3d (%-20.20s)", chip->base + i, label);

                if (is_out) {
                        seq_printf(s, " out %s %s\n",
                                   out & msk ? "hi" : "lo",
                                   blink & msk ? "(blink )" : "");
                        continue;
                }

                seq_printf(s, " in  %s (act %s) - IRQ",
                           (data_in ^ in_pol) & msk  ? "hi" : "lo",
                           in_pol & msk ? "lo" : "hi");
                if (!((edg_msk | lvl_msk) & msk)) {
                        seq_puts(s, " disabled\n");
                        continue;
                }
                if (edg_msk & msk)
                        seq_puts(s, " edge ");
                if (lvl_msk & msk)
                        seq_puts(s, " level");
                seq_printf(s, " (%s)\n", cause & msk ? "pending" : "clear  ");
        }
}
#else
#define mvebu_gpio_dbg_show NULL
#endif

static const struct of_device_id mvebu_gpio_of_match[] = {
        {
                .compatible = "marvell,orion-gpio",
                .data       = (void *) MVEBU_GPIO_SOC_VARIANT_ORION,
        },
        {
                .compatible = "marvell,mv78200-gpio",
                .data       = (void *) MVEBU_GPIO_SOC_VARIANT_MV78200,
        },
        {
                .compatible = "marvell,armadaxp-gpio",
                .data       = (void *) MVEBU_GPIO_SOC_VARIANT_ARMADAXP,
        },
        {
                /* sentinel */
        },
};

static int mvebu_gpio_suspend(struct platform_device *pdev, pm_message_t state)
{
        struct mvebu_gpio_chip *mvchip = platform_get_drvdata(pdev);
        int i;

        mvchip->out_reg = readl(mvebu_gpioreg_out(mvchip));
        mvchip->io_conf_reg = readl(mvebu_gpioreg_io_conf(mvchip));
        mvchip->blink_en_reg = readl(mvebu_gpioreg_blink(mvchip));
        mvchip->in_pol_reg = readl(mvebu_gpioreg_in_pol(mvchip));

        switch (mvchip->soc_variant) {
        case MVEBU_GPIO_SOC_VARIANT_ORION:
                mvchip->edge_mask_regs[0] =
                        readl(mvchip->membase + GPIO_EDGE_MASK_OFF);
                mvchip->level_mask_regs[0] =
                        readl(mvchip->membase + GPIO_LEVEL_MASK_OFF);
                break;
        case MVEBU_GPIO_SOC_VARIANT_MV78200:
                for (i = 0; i < 2; i++) {
                        mvchip->edge_mask_regs[i] =
                                readl(mvchip->membase +
                                      GPIO_EDGE_MASK_MV78200_OFF(i));
                        mvchip->level_mask_regs[i] =
                                readl(mvchip->membase +
                                      GPIO_LEVEL_MASK_MV78200_OFF(i));
                }
                break;
        case MVEBU_GPIO_SOC_VARIANT_ARMADAXP:
                for (i = 0; i < 4; i++) {
                        mvchip->edge_mask_regs[i] =
                                readl(mvchip->membase +
                                      GPIO_EDGE_MASK_ARMADAXP_OFF(i));
                        mvchip->level_mask_regs[i] =
                                readl(mvchip->membase +
                                      GPIO_LEVEL_MASK_ARMADAXP_OFF(i));
                }
                break;
        default:
                BUG();
        }

        return 0;
}

static int mvebu_gpio_resume(struct platform_device *pdev)
{
        struct mvebu_gpio_chip *mvchip = platform_get_drvdata(pdev);
        int i;

        writel(mvchip->out_reg, mvebu_gpioreg_out(mvchip));
        writel(mvchip->io_conf_reg, mvebu_gpioreg_io_conf(mvchip));
        writel(mvchip->blink_en_reg, mvebu_gpioreg_blink(mvchip));
        writel(mvchip->in_pol_reg, mvebu_gpioreg_in_pol(mvchip));

        switch (mvchip->soc_variant) {
        case MVEBU_GPIO_SOC_VARIANT_ORION:
                writel(mvchip->edge_mask_regs[0],
                       mvchip->membase + GPIO_EDGE_MASK_OFF);
                writel(mvchip->level_mask_regs[0],
                       mvchip->membase + GPIO_LEVEL_MASK_OFF);
                break;
        case MVEBU_GPIO_SOC_VARIANT_MV78200:
                for (i = 0; i < 2; i++) {
                        writel(mvchip->edge_mask_regs[i],
                               mvchip->membase + GPIO_EDGE_MASK_MV78200_OFF(i));
                        writel(mvchip->level_mask_regs[i],
                               mvchip->membase +
                               GPIO_LEVEL_MASK_MV78200_OFF(i));
                }
                break;
        case MVEBU_GPIO_SOC_VARIANT_ARMADAXP:
                for (i = 0; i < 4; i++) {
                        writel(mvchip->edge_mask_regs[i],
                               mvchip->membase +
                               GPIO_EDGE_MASK_ARMADAXP_OFF(i));
                        writel(mvchip->level_mask_regs[i],
                               mvchip->membase +
                               GPIO_LEVEL_MASK_ARMADAXP_OFF(i));
                }
                break;
        default:
                BUG();
        }

        return 0;
}

static int mvebu_gpio_probe(struct platform_device *pdev)
{
        struct mvebu_gpio_chip *mvchip;
        const struct of_device_id *match;
        struct device_node *np = pdev->dev.of_node;
        struct resource *res;
        struct irq_chip_generic *gc;
        struct irq_chip_type *ct;
        struct clk *clk;
        unsigned int ngpios;
        bool have_irqs;
        int soc_variant;
        int i, cpu, id;
        int err;

        match = of_match_device(mvebu_gpio_of_match, &pdev->dev);
        if (match)
                soc_variant = (int) match->data;
        else
                soc_variant = MVEBU_GPIO_SOC_VARIANT_ORION;

        /* Some gpio controllers do not provide irq support */
        have_irqs = of_irq_count(np) != 0;

        mvchip = devm_kzalloc(&pdev->dev, sizeof(struct mvebu_gpio_chip),
                              GFP_KERNEL);
        if (!mvchip)
                return -ENOMEM;

        platform_set_drvdata(pdev, mvchip);

        if (of_property_read_u32(pdev->dev.of_node, "ngpios", &ngpios)) {
                dev_err(&pdev->dev, "Missing ngpios OF property\n");
                return -ENODEV;
        }

        id = of_alias_get_id(pdev->dev.of_node, "gpio");
        if (id < 0) {
                dev_err(&pdev->dev, "Couldn't get OF id\n");
                return id;
        }

        clk = devm_clk_get(&pdev->dev, NULL);
        /* Not all SoCs require a clock.*/
        if (!IS_ERR(clk))
                clk_prepare_enable(clk);

        mvchip->soc_variant = soc_variant;
        mvchip->chip.label = dev_name(&pdev->dev);
        mvchip->chip.parent = &pdev->dev;
        mvchip->chip.request = gpiochip_generic_request;
        mvchip->chip.free = gpiochip_generic_free;
        mvchip->chip.direction_input = mvebu_gpio_direction_input;
        mvchip->chip.get = mvebu_gpio_get;
        mvchip->chip.direction_output = mvebu_gpio_direction_output;
        mvchip->chip.set = mvebu_gpio_set;
        if (have_irqs)
                mvchip->chip.to_irq = mvebu_gpio_to_irq;
        mvchip->chip.base = id * MVEBU_MAX_GPIO_PER_BANK;
        mvchip->chip.ngpio = ngpios;
        mvchip->chip.can_sleep = false;
        mvchip->chip.of_node = np;
        mvchip->chip.dbg_show = mvebu_gpio_dbg_show;

        spin_lock_init(&mvchip->lock);
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        mvchip->membase = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(mvchip->membase))
                return PTR_ERR(mvchip->membase);

        /* The Armada XP has a second range of registers for the
         * per-CPU registers */
        if (soc_variant == MVEBU_GPIO_SOC_VARIANT_ARMADAXP) {
                res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
                mvchip->percpu_membase = devm_ioremap_resource(&pdev->dev,
                                                               res);
                if (IS_ERR(mvchip->percpu_membase))
                        return PTR_ERR(mvchip->percpu_membase);
        }

        /*
         * Mask and clear GPIO interrupts.
         */
        switch (soc_variant) {
        case MVEBU_GPIO_SOC_VARIANT_ORION:
                writel_relaxed(0, mvchip->membase + GPIO_EDGE_CAUSE_OFF);
                writel_relaxed(0, mvchip->membase + GPIO_EDGE_MASK_OFF);
                writel_relaxed(0, mvchip->membase + GPIO_LEVEL_MASK_OFF);
                break;
        case MVEBU_GPIO_SOC_VARIANT_MV78200:
                writel_relaxed(0, mvchip->membase + GPIO_EDGE_CAUSE_OFF);
                for (cpu = 0; cpu < 2; cpu++) {
                        writel_relaxed(0, mvchip->membase +
                                       GPIO_EDGE_MASK_MV78200_OFF(cpu));
                        writel_relaxed(0, mvchip->membase +
                                       GPIO_LEVEL_MASK_MV78200_OFF(cpu));
                }
                break;
        case MVEBU_GPIO_SOC_VARIANT_ARMADAXP:
                writel_relaxed(0, mvchip->membase + GPIO_EDGE_CAUSE_OFF);
                writel_relaxed(0, mvchip->membase + GPIO_EDGE_MASK_OFF);
                writel_relaxed(0, mvchip->membase + GPIO_LEVEL_MASK_OFF);
                for (cpu = 0; cpu < 4; cpu++) {
                        writel_relaxed(0, mvchip->percpu_membase +
                                       GPIO_EDGE_CAUSE_ARMADAXP_OFF(cpu));
                        writel_relaxed(0, mvchip->percpu_membase +
                                       GPIO_EDGE_MASK_ARMADAXP_OFF(cpu));
                        writel_relaxed(0, mvchip->percpu_membase +
                                       GPIO_LEVEL_MASK_ARMADAXP_OFF(cpu));
                }
                break;
        default:
                BUG();
        }

        devm_gpiochip_add_data(&pdev->dev, &mvchip->chip, mvchip);

        /* Some gpio controllers do not provide irq support */
        if (!have_irqs)
                return 0;

        mvchip->domain =
            irq_domain_add_linear(np, ngpios, &irq_generic_chip_ops, NULL);
        if (!mvchip->domain) {
                dev_err(&pdev->dev, "couldn't allocate irq domain %s (DT).\n",
                        mvchip->chip.label);
                return -ENODEV;
        }

        err = irq_alloc_domain_generic_chips(
            mvchip->domain, ngpios, 2, np->name, handle_level_irq,
            IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_LEVEL, 0, 0);
        if (err) {
                dev_err(&pdev->dev, "couldn't allocate irq chips %s (DT).\n",
                        mvchip->chip.label);
                goto err_domain;
        }

        /* NOTE: The common accessors cannot be used because of the percpu
         * access to the mask registers
         */
        gc = irq_get_domain_generic_chip(mvchip->domain, 0);
        gc->private = mvchip;
        ct = &gc->chip_types[0];
        ct->type = IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW;
        ct->chip.irq_mask = mvebu_gpio_level_irq_mask;
        ct->chip.irq_unmask = mvebu_gpio_level_irq_unmask;
        ct->chip.irq_set_type = mvebu_gpio_irq_set_type;
        ct->chip.name = mvchip->chip.label;

        ct = &gc->chip_types[1];
        ct->type = IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING;
        ct->chip.irq_ack = mvebu_gpio_irq_ack;
        ct->chip.irq_mask = mvebu_gpio_edge_irq_mask;
        ct->chip.irq_unmask = mvebu_gpio_edge_irq_unmask;
        ct->chip.irq_set_type = mvebu_gpio_irq_set_type;
        ct->handler = handle_edge_irq;
        ct->chip.name = mvchip->chip.label;

        /* Setup the interrupt handlers. Each chip can have up to 4
         * interrupt handlers, with each handler dealing with 8 GPIO
         * pins.
         */
        for (i = 0; i < 4; i++) {
                int irq = platform_get_irq(pdev, i);

                if (irq < 0)
                        continue;
                irq_set_chained_handler_and_data(irq, mvebu_gpio_irq_handler,
                                                 mvchip);
        }

        return 0;

err_domain:
        irq_domain_remove(mvchip->domain);

        return err;
}

static struct platform_driver mvebu_gpio_driver = {
        .driver         = {
                .name           = "mvebu-gpio",
                .of_match_table = mvebu_gpio_of_match,
        },
        .probe          = mvebu_gpio_probe,
        .suspend        = mvebu_gpio_suspend,
        .resume         = mvebu_gpio_resume,
};
builtin_platform_driver(mvebu_gpio_driver);