/*
 * Driver for the Atmel PIO4 controller
 *
 * Copyright (C) 2015 Atmel,
 *               2015 Ludovic Desroches <ludovic.desroches@atmel.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/clk.h>
#include <linux/gpio/driver.h>
/* FIXME: needed for gpio_to_irq(), get rid of this */
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pinctrl/pinconf.h>
#include <linux/pinctrl/pinconf-generic.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/pinmux.h>
#include <linux/slab.h>
#include "core.h"
#include "pinconf.h"
#include "pinctrl-utils.h"

/*
 * Warning:
 * In order to not introduce confusion between Atmel PIO groups and pinctrl
 * framework groups, Atmel PIO groups will be called banks, line is kept to
 * designed the pin id into this bank.
 */

#define ATMEL_PIO_MSKR          0x0000
#define ATMEL_PIO_CFGR          0x0004
#define         ATMEL_PIO_CFGR_FUNC_MASK        GENMASK(2, 0)
#define         ATMEL_PIO_DIR_MASK              BIT(8)
#define         ATMEL_PIO_PUEN_MASK             BIT(9)
#define         ATMEL_PIO_PDEN_MASK             BIT(10)
#define         ATMEL_PIO_IFEN_MASK             BIT(12)
#define         ATMEL_PIO_IFSCEN_MASK           BIT(13)
#define         ATMEL_PIO_OPD_MASK              BIT(14)
#define         ATMEL_PIO_SCHMITT_MASK          BIT(15)
#define         ATMEL_PIO_CFGR_EVTSEL_MASK      GENMASK(26, 24)
#define         ATMEL_PIO_CFGR_EVTSEL_FALLING   (0 << 24)
#define         ATMEL_PIO_CFGR_EVTSEL_RISING    (1 << 24)
#define         ATMEL_PIO_CFGR_EVTSEL_BOTH      (2 << 24)
#define         ATMEL_PIO_CFGR_EVTSEL_LOW       (3 << 24)
#define         ATMEL_PIO_CFGR_EVTSEL_HIGH      (4 << 24)
#define ATMEL_PIO_PDSR          0x0008
#define ATMEL_PIO_LOCKSR        0x000C
#define ATMEL_PIO_SODR          0x0010
#define ATMEL_PIO_CODR          0x0014
#define ATMEL_PIO_ODSR          0x0018
#define ATMEL_PIO_IER           0x0020
#define ATMEL_PIO_IDR           0x0024
#define ATMEL_PIO_IMR           0x0028
#define ATMEL_PIO_ISR           0x002C
#define ATMEL_PIO_IOFR          0x003C

#define ATMEL_PIO_NPINS_PER_BANK        32
#define ATMEL_PIO_BANK(pin_id)          (pin_id / ATMEL_PIO_NPINS_PER_BANK)
#define ATMEL_PIO_LINE(pin_id)          (pin_id % ATMEL_PIO_NPINS_PER_BANK)
#define ATMEL_PIO_BANK_OFFSET           0x40

#define ATMEL_GET_PIN_NO(pinfunc)       ((pinfunc) & 0xff)
#define ATMEL_GET_PIN_FUNC(pinfunc)     ((pinfunc >> 16) & 0xf)
#define ATMEL_GET_PIN_IOSET(pinfunc)    ((pinfunc >> 20) & 0xf)

struct atmel_pioctrl_data {
        unsigned nbanks;
};

struct atmel_group {
        const char *name;
        u32 pin;
};

struct atmel_pin {
        unsigned pin_id;
        unsigned mux;
        unsigned ioset;
        unsigned bank;
        unsigned line;
        const char *device;
};

/**
 * struct atmel_pioctrl - Atmel PIO controller (pinmux + gpio)
 * @reg_base: base address of the controller.
 * @clk: clock of the controller.
 * @nbanks: number of PIO groups, it can vary depending on the SoC.
 * @pinctrl_dev: pinctrl device registered.
 * @groups: groups table to provide group name and pin in the group to pinctrl.
 * @group_names: group names table to provide all the group/pin names to
 *     pinctrl or gpio.
 * @pins: pins table used for both pinctrl and gpio. pin_id, bank and line
 *     fields are set at probe time. Other ones are set when parsing dt
 *     pinctrl.
 * @npins: number of pins.
 * @gpio_chip: gpio chip registered.
 * @irq_domain: irq domain for the gpio controller.
 * @irqs: table containing the hw irq number of the bank. The index of the
 *     table is the bank id.
 * @dev: device entry for the Atmel PIO controller.
 * @node: node of the Atmel PIO controller.
 */
struct atmel_pioctrl {
        void __iomem            *reg_base;
        struct clk              *clk;
        unsigned                nbanks;
        struct pinctrl_dev      *pinctrl_dev;
        struct atmel_group      *groups;
        const char * const      *group_names;
        struct atmel_pin        **pins;
        unsigned                npins;
        struct gpio_chip        *gpio_chip;
        struct irq_domain       *irq_domain;
        int                     *irqs;
        unsigned                *pm_wakeup_sources;
        unsigned                *pm_suspend_backup;
        struct device           *dev;
        struct device_node      *node;
};

static const char * const atmel_functions[] = {
        "GPIO", "A", "B", "C", "D", "E", "F", "G"
};

/* --- GPIO --- */
static unsigned int atmel_gpio_read(struct atmel_pioctrl *atmel_pioctrl,
                                    unsigned int bank, unsigned int reg)
{
        return readl_relaxed(atmel_pioctrl->reg_base
                             + ATMEL_PIO_BANK_OFFSET * bank + reg);
}

static void atmel_gpio_write(struct atmel_pioctrl *atmel_pioctrl,
                             unsigned int bank, unsigned int reg,
                             unsigned int val)
{
        writel_relaxed(val, atmel_pioctrl->reg_base
                       + ATMEL_PIO_BANK_OFFSET * bank + reg);
}

static void atmel_gpio_irq_ack(struct irq_data *d)
{
        /*
         * Nothing to do, interrupt is cleared when reading the status
         * register.
         */
}

static int atmel_gpio_irq_set_type(struct irq_data *d, unsigned type)
{
        struct atmel_pioctrl *atmel_pioctrl = irq_data_get_irq_chip_data(d);
        struct atmel_pin *pin = atmel_pioctrl->pins[d->hwirq];
        unsigned reg;

        atmel_gpio_write(atmel_pioctrl, pin->bank, ATMEL_PIO_MSKR,
                         BIT(pin->line));
        reg = atmel_gpio_read(atmel_pioctrl, pin->bank, ATMEL_PIO_CFGR);
        reg &= (~ATMEL_PIO_CFGR_EVTSEL_MASK);

        switch (type) {
        case IRQ_TYPE_EDGE_RISING:
                irq_set_handler_locked(d, handle_edge_irq);
                reg |= ATMEL_PIO_CFGR_EVTSEL_RISING;
                break;
        case IRQ_TYPE_EDGE_FALLING:
                irq_set_handler_locked(d, handle_edge_irq);
                reg |= ATMEL_PIO_CFGR_EVTSEL_FALLING;
                break;
        case IRQ_TYPE_EDGE_BOTH:
                irq_set_handler_locked(d, handle_edge_irq);
                reg |= ATMEL_PIO_CFGR_EVTSEL_BOTH;
                break;
        case IRQ_TYPE_LEVEL_LOW:
                irq_set_handler_locked(d, handle_level_irq);
                reg |= ATMEL_PIO_CFGR_EVTSEL_LOW;
                break;
        case IRQ_TYPE_LEVEL_HIGH:
                irq_set_handler_locked(d, handle_level_irq);
                reg |= ATMEL_PIO_CFGR_EVTSEL_HIGH;
                break;
        case IRQ_TYPE_NONE:
        default:
                return -EINVAL;
        }

        atmel_gpio_write(atmel_pioctrl, pin->bank, ATMEL_PIO_CFGR, reg);

        return 0;
}

static void atmel_gpio_irq_mask(struct irq_data *d)
{
        struct atmel_pioctrl *atmel_pioctrl = irq_data_get_irq_chip_data(d);
        struct atmel_pin *pin = atmel_pioctrl->pins[d->hwirq];

        atmel_gpio_write(atmel_pioctrl, pin->bank, ATMEL_PIO_IDR,
                         BIT(pin->line));
}

static void atmel_gpio_irq_unmask(struct irq_data *d)
{
        struct atmel_pioctrl *atmel_pioctrl = irq_data_get_irq_chip_data(d);
        struct atmel_pin *pin = atmel_pioctrl->pins[d->hwirq];

        atmel_gpio_write(atmel_pioctrl, pin->bank, ATMEL_PIO_IER,
                         BIT(pin->line));
}

#ifdef CONFIG_PM_SLEEP

static int atmel_gpio_irq_set_wake(struct irq_data *d, unsigned int on)
{
        struct atmel_pioctrl *atmel_pioctrl = irq_data_get_irq_chip_data(d);
        int bank = ATMEL_PIO_BANK(d->hwirq);
        int line = ATMEL_PIO_LINE(d->hwirq);

        /* The gpio controller has one interrupt line per bank. */
        irq_set_irq_wake(atmel_pioctrl->irqs[bank], on);

        if (on)
                atmel_pioctrl->pm_wakeup_sources[bank] |= BIT(line);
        else
                atmel_pioctrl->pm_wakeup_sources[bank] &= ~(BIT(line));

        return 0;
}
#else
#define atmel_gpio_irq_set_wake NULL
#endif /* CONFIG_PM_SLEEP */

static struct irq_chip atmel_gpio_irq_chip = {
        .name           = "GPIO",
        .irq_ack        = atmel_gpio_irq_ack,
        .irq_mask       = atmel_gpio_irq_mask,
        .irq_unmask     = atmel_gpio_irq_unmask,
        .irq_set_type   = atmel_gpio_irq_set_type,
        .irq_set_wake   = atmel_gpio_irq_set_wake,
};

static void atmel_gpio_irq_handler(struct irq_desc *desc)
{
        unsigned int irq = irq_desc_get_irq(desc);
        struct atmel_pioctrl *atmel_pioctrl = irq_desc_get_handler_data(desc);
        struct irq_chip *chip = irq_desc_get_chip(desc);
        unsigned long isr;
        int n, bank = -1;

        /* Find from which bank is the irq received. */
        for (n = 0; n < atmel_pioctrl->nbanks; n++) {
                if (atmel_pioctrl->irqs[n] == irq) {
                        bank = n;
                        break;
                }
        }

        if (bank < 0) {
                dev_err(atmel_pioctrl->dev,
                        "no bank associated to irq %u\n", irq);
                return;
        }

        chained_irq_enter(chip, desc);

        for (;;) {
                isr = (unsigned long)atmel_gpio_read(atmel_pioctrl, bank,
                                                     ATMEL_PIO_ISR);
                isr &= (unsigned long)atmel_gpio_read(atmel_pioctrl, bank,
                                                      ATMEL_PIO_IMR);
                if (!isr)
                        break;

                for_each_set_bit(n, &isr, BITS_PER_LONG)
                        generic_handle_irq(gpio_to_irq(bank *
                                        ATMEL_PIO_NPINS_PER_BANK + n));
        }

        chained_irq_exit(chip, desc);
}

static int atmel_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
        struct atmel_pioctrl *atmel_pioctrl = gpiochip_get_data(chip);
        struct atmel_pin *pin = atmel_pioctrl->pins[offset];
        unsigned reg;

        atmel_gpio_write(atmel_pioctrl, pin->bank, ATMEL_PIO_MSKR,
                         BIT(pin->line));
        reg = atmel_gpio_read(atmel_pioctrl, pin->bank, ATMEL_PIO_CFGR);
        reg &= ~ATMEL_PIO_DIR_MASK;
        atmel_gpio_write(atmel_pioctrl, pin->bank, ATMEL_PIO_CFGR, reg);

        return 0;
}

static int atmel_gpio_get(struct gpio_chip *chip, unsigned offset)
{
        struct atmel_pioctrl *atmel_pioctrl = gpiochip_get_data(chip);
        struct atmel_pin *pin = atmel_pioctrl->pins[offset];
        unsigned reg;

        reg = atmel_gpio_read(atmel_pioctrl, pin->bank, ATMEL_PIO_PDSR);

        return !!(reg & BIT(pin->line));
}

static int atmel_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
                                       int value)
{
        struct atmel_pioctrl *atmel_pioctrl = gpiochip_get_data(chip);
        struct atmel_pin *pin = atmel_pioctrl->pins[offset];
        unsigned reg;

        atmel_gpio_write(atmel_pioctrl, pin->bank,
                         value ? ATMEL_PIO_SODR : ATMEL_PIO_CODR,
                         BIT(pin->line));

        atmel_gpio_write(atmel_pioctrl, pin->bank, ATMEL_PIO_MSKR,
                         BIT(pin->line));
        reg = atmel_gpio_read(atmel_pioctrl, pin->bank, ATMEL_PIO_CFGR);
        reg |= ATMEL_PIO_DIR_MASK;
        atmel_gpio_write(atmel_pioctrl, pin->bank, ATMEL_PIO_CFGR, reg);

        return 0;
}

static void atmel_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
{
        struct atmel_pioctrl *atmel_pioctrl = gpiochip_get_data(chip);
        struct atmel_pin *pin = atmel_pioctrl->pins[offset];

        atmel_gpio_write(atmel_pioctrl, pin->bank,
                         val ? ATMEL_PIO_SODR : ATMEL_PIO_CODR,
                         BIT(pin->line));
}

static int atmel_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
{
        struct atmel_pioctrl *atmel_pioctrl = gpiochip_get_data(chip);

        return irq_find_mapping(atmel_pioctrl->irq_domain, offset);
}

static struct gpio_chip atmel_gpio_chip = {
        .direction_input        = atmel_gpio_direction_input,
        .get                    = atmel_gpio_get,
        .direction_output       = atmel_gpio_direction_output,
        .set                    = atmel_gpio_set,
        .to_irq                 = atmel_gpio_to_irq,
        .base                   = 0,
};

/* --- PINCTRL --- */
static unsigned int atmel_pin_config_read(struct pinctrl_dev *pctldev,
                                          unsigned pin_id)
{
        struct atmel_pioctrl *atmel_pioctrl = pinctrl_dev_get_drvdata(pctldev);
        unsigned bank = atmel_pioctrl->pins[pin_id]->bank;
        unsigned line = atmel_pioctrl->pins[pin_id]->line;
        void __iomem *addr = atmel_pioctrl->reg_base
                             + bank * ATMEL_PIO_BANK_OFFSET;

        writel_relaxed(BIT(line), addr + ATMEL_PIO_MSKR);
        /* Have to set MSKR first, to access the right pin CFGR. */
        wmb();

        return readl_relaxed(addr + ATMEL_PIO_CFGR);
}

static void atmel_pin_config_write(struct pinctrl_dev *pctldev,
                                   unsigned pin_id, u32 conf)
{
        struct atmel_pioctrl *atmel_pioctrl = pinctrl_dev_get_drvdata(pctldev);
        unsigned bank = atmel_pioctrl->pins[pin_id]->bank;
        unsigned line = atmel_pioctrl->pins[pin_id]->line;
        void __iomem *addr = atmel_pioctrl->reg_base
                             + bank * ATMEL_PIO_BANK_OFFSET;

        writel_relaxed(BIT(line), addr + ATMEL_PIO_MSKR);
        /* Have to set MSKR first, to access the right pin CFGR. */
        wmb();
        writel_relaxed(conf, addr + ATMEL_PIO_CFGR);
}

static int atmel_pctl_get_groups_count(struct pinctrl_dev *pctldev)
{
        struct atmel_pioctrl *atmel_pioctrl = pinctrl_dev_get_drvdata(pctldev);

        return atmel_pioctrl->npins;
}

static const char *atmel_pctl_get_group_name(struct pinctrl_dev *pctldev,
                                             unsigned selector)
{
        struct atmel_pioctrl *atmel_pioctrl = pinctrl_dev_get_drvdata(pctldev);

        return atmel_pioctrl->groups[selector].name;
}

static int atmel_pctl_get_group_pins(struct pinctrl_dev *pctldev,
                                     unsigned selector, const unsigned **pins,
                                     unsigned *num_pins)
{
        struct atmel_pioctrl *atmel_pioctrl = pinctrl_dev_get_drvdata(pctldev);

        *pins = (unsigned *)&atmel_pioctrl->groups[selector].pin;
        *num_pins = 1;

        return 0;
}

static struct atmel_group *
atmel_pctl_find_group_by_pin(struct pinctrl_dev *pctldev, unsigned pin)
{
        struct atmel_pioctrl *atmel_pioctrl = pinctrl_dev_get_drvdata(pctldev);
        int i;

        for (i = 0; i < atmel_pioctrl->npins; i++) {
                struct atmel_group *grp = atmel_pioctrl->groups + i;

                if (grp->pin == pin)
                        return grp;
        }

        return NULL;
}

static int atmel_pctl_xlate_pinfunc(struct pinctrl_dev *pctldev,
                                    struct device_node *np,
                                    u32 pinfunc, const char **grp_name,
                                    const char **func_name)
{
        struct atmel_pioctrl *atmel_pioctrl = pinctrl_dev_get_drvdata(pctldev);
        unsigned pin_id, func_id;
        struct atmel_group *grp;

        pin_id = ATMEL_GET_PIN_NO(pinfunc);
        func_id = ATMEL_GET_PIN_FUNC(pinfunc);

        if (func_id >= ARRAY_SIZE(atmel_functions))
                return -EINVAL;

        *func_name = atmel_functions[func_id];

        grp = atmel_pctl_find_group_by_pin(pctldev, pin_id);
        if (!grp)
                return -EINVAL;
        *grp_name = grp->name;

        atmel_pioctrl->pins[pin_id]->mux = func_id;
        atmel_pioctrl->pins[pin_id]->ioset = ATMEL_GET_PIN_IOSET(pinfunc);
        /* Want the device name not the group one. */
        if (np->parent == atmel_pioctrl->node)
                atmel_pioctrl->pins[pin_id]->device = np->name;
        else
                atmel_pioctrl->pins[pin_id]->device = np->parent->name;

        return 0;
}

static int atmel_pctl_dt_subnode_to_map(struct pinctrl_dev *pctldev,
                                        struct device_node *np,
                                        struct pinctrl_map **map,
                                        unsigned *reserved_maps,
                                        unsigned *num_maps)
{
        unsigned num_pins, num_configs, reserve;
        unsigned long *configs;
        struct property *pins;
        bool has_config;
        u32 pinfunc;
        int ret, i;

        pins = of_find_property(np, "pinmux", NULL);
        if (!pins)
                return -EINVAL;

        ret = pinconf_generic_parse_dt_config(np, pctldev, &configs,
                                              &num_configs);
        if (ret < 0) {
                dev_err(pctldev->dev, "%s: could not parse node property\n",
                        of_node_full_name(np));
                return ret;
        }

        if (num_configs)
                has_config = true;

        num_pins = pins->length / sizeof(u32);
        if (!num_pins) {
                dev_err(pctldev->dev, "no pins found in node %s\n",
                        of_node_full_name(np));
                ret = -EINVAL;
                goto exit;
        }

        /*
         * Reserve maps, at least there is a mux map and an optional conf
         * map for each pin.
         */
        reserve = 1;
        if (has_config && num_pins >= 1)
                reserve++;
        reserve *= num_pins;
        ret = pinctrl_utils_reserve_map(pctldev, map, reserved_maps, num_maps,
                                        reserve);
        if (ret < 0)
                goto exit;

        for (i = 0; i < num_pins; i++) {
                const char *group, *func;

                ret = of_property_read_u32_index(np, "pinmux", i, &pinfunc);
                if (ret)
                        goto exit;

                ret = atmel_pctl_xlate_pinfunc(pctldev, np, pinfunc, &group,
                                               &func);
                if (ret)
                        goto exit;

                pinctrl_utils_add_map_mux(pctldev, map, reserved_maps, num_maps,
                                          group, func);

                if (has_config) {
                        ret = pinctrl_utils_add_map_configs(pctldev, map,
                                        reserved_maps, num_maps, group,
                                        configs, num_configs,
                                        PIN_MAP_TYPE_CONFIGS_GROUP);
                        if (ret < 0)
                                goto exit;
                }
        }

exit:
        kfree(configs);
        return ret;
}

static int atmel_pctl_dt_node_to_map(struct pinctrl_dev *pctldev,
                                     struct device_node *np_config,
                                     struct pinctrl_map **map,
                                     unsigned *num_maps)
{
        struct device_node *np;
        unsigned reserved_maps;
        int ret;

        *map = NULL;
        *num_maps = 0;
        reserved_maps = 0;

        /*
         * If all the pins of a device have the same configuration (or no one),
         * it is useless to add a subnode, so directly parse node referenced by
         * phandle.
         */
        ret = atmel_pctl_dt_subnode_to_map(pctldev, np_config, map,
                                           &reserved_maps, num_maps);
        if (ret) {
                for_each_child_of_node(np_config, np) {
                        ret = atmel_pctl_dt_subnode_to_map(pctldev, np, map,
                                                    &reserved_maps, num_maps);
                        if (ret < 0)
                                break;
                }
        }

        if (ret < 0) {
                pinctrl_utils_free_map(pctldev, *map, *num_maps);
                dev_err(pctldev->dev, "can't create maps for node %s\n",
                        np_config->full_name);
        }

        return ret;
}

static const struct pinctrl_ops atmel_pctlops = {
        .get_groups_count       = atmel_pctl_get_groups_count,
        .get_group_name         = atmel_pctl_get_group_name,
        .get_group_pins         = atmel_pctl_get_group_pins,
        .dt_node_to_map         = atmel_pctl_dt_node_to_map,
        .dt_free_map            = pinctrl_utils_free_map,
};

static int atmel_pmx_get_functions_count(struct pinctrl_dev *pctldev)
{
        return ARRAY_SIZE(atmel_functions);
}

static const char *atmel_pmx_get_function_name(struct pinctrl_dev *pctldev,
                                               unsigned selector)
{
        return atmel_functions[selector];
}

static int atmel_pmx_get_function_groups(struct pinctrl_dev *pctldev,
                                         unsigned selector,
                                         const char * const **groups,
                                         unsigned * const num_groups)
{
        struct atmel_pioctrl *atmel_pioctrl = pinctrl_dev_get_drvdata(pctldev);

        *groups = atmel_pioctrl->group_names;
        *num_groups = atmel_pioctrl->npins;

        return 0;
}

static int atmel_pmx_set_mux(struct pinctrl_dev *pctldev,
                             unsigned function,
                             unsigned group)
{
        struct atmel_pioctrl *atmel_pioctrl = pinctrl_dev_get_drvdata(pctldev);
        unsigned pin;
        u32 conf;

        dev_dbg(pctldev->dev, "enable function %s group %s\n",
                atmel_functions[function], atmel_pioctrl->groups[group].name);

        pin = atmel_pioctrl->groups[group].pin;
        conf = atmel_pin_config_read(pctldev, pin);
        conf &= (~ATMEL_PIO_CFGR_FUNC_MASK);
        conf |= (function & ATMEL_PIO_CFGR_FUNC_MASK);
        dev_dbg(pctldev->dev, "pin: %u, conf: 0x%08x\n", pin, conf);
        atmel_pin_config_write(pctldev, pin, conf);

        return 0;
}

static const struct pinmux_ops atmel_pmxops = {
        .get_functions_count    = atmel_pmx_get_functions_count,
        .get_function_name      = atmel_pmx_get_function_name,
        .get_function_groups    = atmel_pmx_get_function_groups,
        .set_mux                = atmel_pmx_set_mux,
};

static int atmel_conf_pin_config_group_get(struct pinctrl_dev *pctldev,
                                           unsigned group,
                                           unsigned long *config)
{
        struct atmel_pioctrl *atmel_pioctrl = pinctrl_dev_get_drvdata(pctldev);
        unsigned param = pinconf_to_config_param(*config), arg = 0;
        struct atmel_group *grp = atmel_pioctrl->groups + group;
        unsigned pin_id = grp->pin;
        u32 res;

        res = atmel_pin_config_read(pctldev, pin_id);

        switch (param) {
        case PIN_CONFIG_BIAS_PULL_UP:
                if (!(res & ATMEL_PIO_PUEN_MASK))
                        return -EINVAL;
                arg = 1;
                break;
        case PIN_CONFIG_BIAS_PULL_DOWN:
                if ((res & ATMEL_PIO_PUEN_MASK) ||
                    (!(res & ATMEL_PIO_PDEN_MASK)))
                        return -EINVAL;
                arg = 1;
                break;
        case PIN_CONFIG_BIAS_DISABLE:
                if ((res & ATMEL_PIO_PUEN_MASK) ||
                    ((res & ATMEL_PIO_PDEN_MASK)))
                        return -EINVAL;
                arg = 1;
                break;
        case PIN_CONFIG_DRIVE_OPEN_DRAIN:
                if (!(res & ATMEL_PIO_OPD_MASK))
                        return -EINVAL;
                arg = 1;
                break;
        case PIN_CONFIG_INPUT_SCHMITT_ENABLE:
                if (!(res & ATMEL_PIO_SCHMITT_MASK))
                        return -EINVAL;
                arg = 1;
                break;
        default:
                return -ENOTSUPP;
        }

        *config = pinconf_to_config_packed(param, arg);
        return 0;
}

static int atmel_conf_pin_config_group_set(struct pinctrl_dev *pctldev,
                                           unsigned group,
                                           unsigned long *configs,
                                           unsigned num_configs)
{
        struct atmel_pioctrl *atmel_pioctrl = pinctrl_dev_get_drvdata(pctldev);
        struct atmel_group *grp = atmel_pioctrl->groups + group;
        unsigned bank, pin, pin_id = grp->pin;
        u32 mask, conf = 0;
        int i;

        conf = atmel_pin_config_read(pctldev, pin_id);

        for (i = 0; i < num_configs; i++) {
                unsigned param = pinconf_to_config_param(configs[i]);
                unsigned arg = pinconf_to_config_argument(configs[i]);

                dev_dbg(pctldev->dev, "%s: pin=%u, config=0x%lx\n",
                        __func__, pin_id, configs[i]);

                switch (param) {
                case PIN_CONFIG_BIAS_DISABLE:
                        conf &= (~ATMEL_PIO_PUEN_MASK);
                        conf &= (~ATMEL_PIO_PDEN_MASK);
                        break;
                case PIN_CONFIG_BIAS_PULL_UP:
                        conf |= ATMEL_PIO_PUEN_MASK;
                        conf &= (~ATMEL_PIO_PDEN_MASK);
                        break;
                case PIN_CONFIG_BIAS_PULL_DOWN:
                        conf |= ATMEL_PIO_PDEN_MASK;
                        conf &= (~ATMEL_PIO_PUEN_MASK);
                        break;
                case PIN_CONFIG_DRIVE_OPEN_DRAIN:
                        if (arg == 0)
                                conf &= (~ATMEL_PIO_OPD_MASK);
                        else
                                conf |= ATMEL_PIO_OPD_MASK;
                        break;
                case PIN_CONFIG_INPUT_SCHMITT_ENABLE:
                        if (arg == 0)
                                conf |= ATMEL_PIO_SCHMITT_MASK;
                        else
                                conf &= (~ATMEL_PIO_SCHMITT_MASK);
                        break;
                case PIN_CONFIG_INPUT_DEBOUNCE:
                        if (arg == 0) {
                                conf &= (~ATMEL_PIO_IFEN_MASK);
                                conf &= (~ATMEL_PIO_IFSCEN_MASK);
                        } else {
                                /*
                                 * We don't care about the debounce value for several reasons:
                                 * - can't have different debounce periods inside a same group,
                                 * - the register to configure this period is a secure register.
                                 * The debouncing filter can filter a pulse with a duration of less
                                 * than 1/2 slow clock period.
                                 */
                                conf |= ATMEL_PIO_IFEN_MASK;
                                conf |= ATMEL_PIO_IFSCEN_MASK;
                        }
                        break;
                case PIN_CONFIG_OUTPUT:
                        conf |= ATMEL_PIO_DIR_MASK;
                        bank = ATMEL_PIO_BANK(pin_id);
                        pin = ATMEL_PIO_LINE(pin_id);
                        mask = 1 << pin;

                        if (arg == 0) {
                                writel_relaxed(mask, atmel_pioctrl->reg_base +
                                        bank * ATMEL_PIO_BANK_OFFSET +
                                        ATMEL_PIO_CODR);
                        } else {
                                writel_relaxed(mask, atmel_pioctrl->reg_base +
                                        bank * ATMEL_PIO_BANK_OFFSET +
                                        ATMEL_PIO_SODR);
                        }
                        break;
                default:
                        dev_warn(pctldev->dev,
                                 "unsupported configuration parameter: %u\n",
                                 param);
                        continue;
                }
        }

        dev_dbg(pctldev->dev, "%s: reg=0x%08x\n", __func__, conf);
        atmel_pin_config_write(pctldev, pin_id, conf);

        return 0;
}

static void atmel_conf_pin_config_dbg_show(struct pinctrl_dev *pctldev,
                                           struct seq_file *s, unsigned pin_id)
{
        struct atmel_pioctrl *atmel_pioctrl = pinctrl_dev_get_drvdata(pctldev);
        u32 conf;

        if (!atmel_pioctrl->pins[pin_id]->device)
                return;

        if (atmel_pioctrl->pins[pin_id])
                seq_printf(s, " (%s, ioset %u) ",
                           atmel_pioctrl->pins[pin_id]->device,
                           atmel_pioctrl->pins[pin_id]->ioset);

        conf = atmel_pin_config_read(pctldev, pin_id);
        if (conf & ATMEL_PIO_PUEN_MASK)
                seq_printf(s, "%s ", "pull-up");
        if (conf & ATMEL_PIO_PDEN_MASK)
                seq_printf(s, "%s ", "pull-down");
        if (conf & ATMEL_PIO_IFEN_MASK)
                seq_printf(s, "%s ", "debounce");
        if (conf & ATMEL_PIO_OPD_MASK)
                seq_printf(s, "%s ", "open-drain");
        if (conf & ATMEL_PIO_SCHMITT_MASK)
                seq_printf(s, "%s ", "schmitt");
}

static const struct pinconf_ops atmel_confops = {
        .pin_config_group_get   = atmel_conf_pin_config_group_get,
        .pin_config_group_set   = atmel_conf_pin_config_group_set,
        .pin_config_dbg_show    = atmel_conf_pin_config_dbg_show,
};

static struct pinctrl_desc atmel_pinctrl_desc = {
        .name           = "atmel_pinctrl",
        .confops        = &atmel_confops,
        .pctlops        = &atmel_pctlops,
        .pmxops         = &atmel_pmxops,
};

static int __maybe_unused atmel_pctrl_suspend(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct atmel_pioctrl *atmel_pioctrl = platform_get_drvdata(pdev);
        int i;

        /*
         * For each bank, save IMR to restore it later and disable all GPIO
         * interrupts excepting the ones marked as wakeup sources.
         */
        for (i = 0; i < atmel_pioctrl->nbanks; i++) {
                atmel_pioctrl->pm_suspend_backup[i] =
                        atmel_gpio_read(atmel_pioctrl, i, ATMEL_PIO_IMR);
                atmel_gpio_write(atmel_pioctrl, i, ATMEL_PIO_IDR,
                                 ~atmel_pioctrl->pm_wakeup_sources[i]);
        }

        return 0;
}

static int __maybe_unused atmel_pctrl_resume(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct atmel_pioctrl *atmel_pioctrl = platform_get_drvdata(pdev);
        int i;

        for (i = 0; i < atmel_pioctrl->nbanks; i++)
                atmel_gpio_write(atmel_pioctrl, i, ATMEL_PIO_IER,
                                 atmel_pioctrl->pm_suspend_backup[i]);

        return 0;
}

static const struct dev_pm_ops atmel_pctrl_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(atmel_pctrl_suspend, atmel_pctrl_resume)
};

/*
 * The number of banks can be different from a SoC to another one.
 * We can have up to 16 banks.
 */
static const struct atmel_pioctrl_data atmel_sama5d2_pioctrl_data = {
        .nbanks         = 4,
};

static const struct of_device_id atmel_pctrl_of_match[] = {
        {
                .compatible = "atmel,sama5d2-pinctrl",
                .data = &atmel_sama5d2_pioctrl_data,
        }, {
                /* sentinel */
        }
};

static int atmel_pinctrl_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct pinctrl_pin_desc *pin_desc;
        const char **group_names;
        const struct of_device_id *match;
        int i, ret;
        struct resource *res;
        struct atmel_pioctrl *atmel_pioctrl;
        struct atmel_pioctrl_data *atmel_pioctrl_data;

        atmel_pioctrl = devm_kzalloc(dev, sizeof(*atmel_pioctrl), GFP_KERNEL);
        if (!atmel_pioctrl)
                return -ENOMEM;
        atmel_pioctrl->dev = dev;
        atmel_pioctrl->node = dev->of_node;
        platform_set_drvdata(pdev, atmel_pioctrl);

        match = of_match_node(atmel_pctrl_of_match, dev->of_node);
        if (!match) {
                dev_err(dev, "unknown compatible string\n");
                return -ENODEV;
        }
        atmel_pioctrl_data = (struct atmel_pioctrl_data *)match->data;
        atmel_pioctrl->nbanks = atmel_pioctrl_data->nbanks;
        atmel_pioctrl->npins = atmel_pioctrl->nbanks * ATMEL_PIO_NPINS_PER_BANK;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res) {
                dev_err(dev, "unable to get atmel pinctrl resource\n");
                return -EINVAL;
        }
        atmel_pioctrl->reg_base = devm_ioremap_resource(dev, res);
        if (IS_ERR(atmel_pioctrl->reg_base))
                return -EINVAL;

        atmel_pioctrl->clk = devm_clk_get(dev, NULL);
        if (IS_ERR(atmel_pioctrl->clk)) {
                dev_err(dev, "failed to get clock\n");
                return PTR_ERR(atmel_pioctrl->clk);
        }

        atmel_pioctrl->pins = devm_kzalloc(dev, sizeof(*atmel_pioctrl->pins)
                        * atmel_pioctrl->npins, GFP_KERNEL);
        if (!atmel_pioctrl->pins)
                return -ENOMEM;

        pin_desc = devm_kzalloc(dev, sizeof(*pin_desc)
                        * atmel_pioctrl->npins, GFP_KERNEL);
        if (!pin_desc)
                return -ENOMEM;
        atmel_pinctrl_desc.pins = pin_desc;
        atmel_pinctrl_desc.npins = atmel_pioctrl->npins;

        /* One pin is one group since a pin can achieve all functions. */
        group_names = devm_kzalloc(dev, sizeof(*group_names)
                        * atmel_pioctrl->npins, GFP_KERNEL);
        if (!group_names)
                return -ENOMEM;
        atmel_pioctrl->group_names = group_names;

        atmel_pioctrl->groups = devm_kzalloc(&pdev->dev,
                        sizeof(*atmel_pioctrl->groups) * atmel_pioctrl->npins,
                        GFP_KERNEL);
        if (!atmel_pioctrl->groups)
                return -ENOMEM;
        for (i = 0 ; i < atmel_pioctrl->npins; i++) {
                struct atmel_group *group = atmel_pioctrl->groups + i;
                unsigned bank = ATMEL_PIO_BANK(i);
                unsigned line = ATMEL_PIO_LINE(i);

                atmel_pioctrl->pins[i] = devm_kzalloc(dev,
                                sizeof(**atmel_pioctrl->pins), GFP_KERNEL);
                if (!atmel_pioctrl->pins[i])
                        return -ENOMEM;

                atmel_pioctrl->pins[i]->pin_id = i;
                atmel_pioctrl->pins[i]->bank = bank;
                atmel_pioctrl->pins[i]->line = line;

                pin_desc[i].number = i;
                /* Pin naming convention: P(bank_name)(bank_pin_number). */
                pin_desc[i].name = kasprintf(GFP_KERNEL, "P%c%d",
                                             bank + 'A', line);

                group->name = group_names[i] = pin_desc[i].name;
                group->pin = pin_desc[i].number;

                dev_dbg(dev, "pin_id=%u, bank=%u, line=%u", i, bank, line);
        }

        atmel_pioctrl->gpio_chip = &atmel_gpio_chip;
        atmel_pioctrl->gpio_chip->of_node = dev->of_node;
        atmel_pioctrl->gpio_chip->ngpio = atmel_pioctrl->npins;
        atmel_pioctrl->gpio_chip->label = dev_name(dev);
        atmel_pioctrl->gpio_chip->parent = dev;
        atmel_pioctrl->gpio_chip->names = atmel_pioctrl->group_names;

        atmel_pioctrl->pm_wakeup_sources = devm_kzalloc(dev,
                        sizeof(*atmel_pioctrl->pm_wakeup_sources)
                        * atmel_pioctrl->nbanks, GFP_KERNEL);
        if (!atmel_pioctrl->pm_wakeup_sources)
                return -ENOMEM;

        atmel_pioctrl->pm_suspend_backup = devm_kzalloc(dev,
                        sizeof(*atmel_pioctrl->pm_suspend_backup)
                        * atmel_pioctrl->nbanks, GFP_KERNEL);
        if (!atmel_pioctrl->pm_suspend_backup)
                return -ENOMEM;

        atmel_pioctrl->irqs = devm_kzalloc(dev, sizeof(*atmel_pioctrl->irqs)
                        * atmel_pioctrl->nbanks, GFP_KERNEL);
        if (!atmel_pioctrl->irqs)
                return -ENOMEM;

        /* There is one controller but each bank has its own irq line. */
        for (i = 0; i < atmel_pioctrl->nbanks; i++) {
                res = platform_get_resource(pdev, IORESOURCE_IRQ, i);

                if (!res) {
                        dev_err(dev, "missing irq resource for group %c\n",
                                'A' + i);
                        return -EINVAL;
                }
                atmel_pioctrl->irqs[i] = res->start;
                irq_set_chained_handler(res->start, atmel_gpio_irq_handler);
                irq_set_handler_data(res->start, atmel_pioctrl);
                dev_dbg(dev, "bank %i: irq=%pr\n", i, res);
        }

        atmel_pioctrl->irq_domain = irq_domain_add_linear(dev->of_node,
                        atmel_pioctrl->gpio_chip->ngpio,
                        &irq_domain_simple_ops, NULL);
        if (!atmel_pioctrl->irq_domain) {
                dev_err(dev, "can't add the irq domain\n");
                return -ENODEV;
        }
        atmel_pioctrl->irq_domain->name = "atmel gpio";

        for (i = 0; i < atmel_pioctrl->npins; i++) {
                int irq = irq_create_mapping(atmel_pioctrl->irq_domain, i);

                irq_set_chip_and_handler(irq, &atmel_gpio_irq_chip,
                                         handle_simple_irq);
                irq_set_chip_data(irq, atmel_pioctrl);
                dev_dbg(dev,
                        "atmel gpio irq domain: hwirq: %d, linux irq: %d\n",
                        i, irq);
        }

        ret = clk_prepare_enable(atmel_pioctrl->clk);
        if (ret) {
                dev_err(dev, "failed to prepare and enable clock\n");
                goto clk_prepare_enable_error;
        }

        atmel_pioctrl->pinctrl_dev = devm_pinctrl_register(&pdev->dev,
                                                           &atmel_pinctrl_desc,
                                                           atmel_pioctrl);
        if (IS_ERR(atmel_pioctrl->pinctrl_dev)) {
                ret = PTR_ERR(atmel_pioctrl->pinctrl_dev);
                dev_err(dev, "pinctrl registration failed\n");
                goto clk_unprep;
        }

        ret = gpiochip_add_data(atmel_pioctrl->gpio_chip, atmel_pioctrl);
        if (ret) {
                dev_err(dev, "failed to add gpiochip\n");
                goto clk_unprep;
        }

        ret = gpiochip_add_pin_range(atmel_pioctrl->gpio_chip, dev_name(dev),
                                     0, 0, atmel_pioctrl->gpio_chip->ngpio);
        if (ret) {
                dev_err(dev, "failed to add gpio pin range\n");
                goto gpiochip_add_pin_range_error;
        }

        dev_info(&pdev->dev, "atmel pinctrl initialized\n");

        return 0;

gpiochip_add_pin_range_error:
        gpiochip_remove(atmel_pioctrl->gpio_chip);

clk_unprep:
        clk_disable_unprepare(atmel_pioctrl->clk);

clk_prepare_enable_error:
        irq_domain_remove(atmel_pioctrl->irq_domain);

        return ret;
}

static struct platform_driver atmel_pinctrl_driver = {
        .driver = {
                .name = "pinctrl-at91-pio4",
                .of_match_table = atmel_pctrl_of_match,
                .pm = &atmel_pctrl_pm_ops,
                .suppress_bind_attrs = true,
        },
        .probe = atmel_pinctrl_probe,
};
builtin_platform_driver(atmel_pinctrl_driver);