Linux 4.1.16

[linux/fpc-iii.git] / drivers / gpio / gpio-zynq.c

/*
 * Xilinx Zynq GPIO device driver
 *
 * Copyright (C) 2009 - 2014 Xilinx, Inc.
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2 of the License, or (at your option) any later
 * version.
 */

#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/gpio/driver.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>

#define DRIVER_NAME "zynq-gpio"

/* Maximum banks */
#define ZYNQ_GPIO_MAX_BANK      4

#define ZYNQ_GPIO_BANK0_NGPIO   32
#define ZYNQ_GPIO_BANK1_NGPIO   22
#define ZYNQ_GPIO_BANK2_NGPIO   32
#define ZYNQ_GPIO_BANK3_NGPIO   32

#define ZYNQ_GPIO_NR_GPIOS      (ZYNQ_GPIO_BANK0_NGPIO + \
                                 ZYNQ_GPIO_BANK1_NGPIO + \
                                 ZYNQ_GPIO_BANK2_NGPIO + \
                                 ZYNQ_GPIO_BANK3_NGPIO)

#define ZYNQ_GPIO_BANK0_PIN_MIN 0
#define ZYNQ_GPIO_BANK0_PIN_MAX (ZYNQ_GPIO_BANK0_PIN_MIN + \
                                        ZYNQ_GPIO_BANK0_NGPIO - 1)
#define ZYNQ_GPIO_BANK1_PIN_MIN (ZYNQ_GPIO_BANK0_PIN_MAX + 1)
#define ZYNQ_GPIO_BANK1_PIN_MAX (ZYNQ_GPIO_BANK1_PIN_MIN + \
                                        ZYNQ_GPIO_BANK1_NGPIO - 1)
#define ZYNQ_GPIO_BANK2_PIN_MIN (ZYNQ_GPIO_BANK1_PIN_MAX + 1)
#define ZYNQ_GPIO_BANK2_PIN_MAX (ZYNQ_GPIO_BANK2_PIN_MIN + \
                                        ZYNQ_GPIO_BANK2_NGPIO - 1)
#define ZYNQ_GPIO_BANK3_PIN_MIN (ZYNQ_GPIO_BANK2_PIN_MAX + 1)
#define ZYNQ_GPIO_BANK3_PIN_MAX (ZYNQ_GPIO_BANK3_PIN_MIN + \
                                        ZYNQ_GPIO_BANK3_NGPIO - 1)


/* Register offsets for the GPIO device */
/* LSW Mask & Data -WO */
#define ZYNQ_GPIO_DATA_LSW_OFFSET(BANK) (0x000 + (8 * BANK))
/* MSW Mask & Data -WO */
#define ZYNQ_GPIO_DATA_MSW_OFFSET(BANK) (0x004 + (8 * BANK))
/* Data Register-RW */
#define ZYNQ_GPIO_DATA_RO_OFFSET(BANK)  (0x060 + (4 * BANK))
/* Direction mode reg-RW */
#define ZYNQ_GPIO_DIRM_OFFSET(BANK)     (0x204 + (0x40 * BANK))
/* Output enable reg-RW */
#define ZYNQ_GPIO_OUTEN_OFFSET(BANK)    (0x208 + (0x40 * BANK))
/* Interrupt mask reg-RO */
#define ZYNQ_GPIO_INTMASK_OFFSET(BANK)  (0x20C + (0x40 * BANK))
/* Interrupt enable reg-WO */
#define ZYNQ_GPIO_INTEN_OFFSET(BANK)    (0x210 + (0x40 * BANK))
/* Interrupt disable reg-WO */
#define ZYNQ_GPIO_INTDIS_OFFSET(BANK)   (0x214 + (0x40 * BANK))
/* Interrupt status reg-RO */
#define ZYNQ_GPIO_INTSTS_OFFSET(BANK)   (0x218 + (0x40 * BANK))
/* Interrupt type reg-RW */
#define ZYNQ_GPIO_INTTYPE_OFFSET(BANK)  (0x21C + (0x40 * BANK))
/* Interrupt polarity reg-RW */
#define ZYNQ_GPIO_INTPOL_OFFSET(BANK)   (0x220 + (0x40 * BANK))
/* Interrupt on any, reg-RW */
#define ZYNQ_GPIO_INTANY_OFFSET(BANK)   (0x224 + (0x40 * BANK))

/* Disable all interrupts mask */
#define ZYNQ_GPIO_IXR_DISABLE_ALL       0xFFFFFFFF

/* Mid pin number of a bank */
#define ZYNQ_GPIO_MID_PIN_NUM 16

/* GPIO upper 16 bit mask */
#define ZYNQ_GPIO_UPPER_MASK 0xFFFF0000

/**
 * struct zynq_gpio - gpio device private data structure
 * @chip:       instance of the gpio_chip
 * @base_addr:  base address of the GPIO device
 * @clk:        clock resource for this controller
 * @irq:        interrupt for the GPIO device
 */
struct zynq_gpio {
        struct gpio_chip chip;
        void __iomem *base_addr;
        struct clk *clk;
        int irq;
};

static struct irq_chip zynq_gpio_level_irqchip;
static struct irq_chip zynq_gpio_edge_irqchip;
/**
 * zynq_gpio_get_bank_pin - Get the bank number and pin number within that bank
 * for a given pin in the GPIO device
 * @pin_num:    gpio pin number within the device
 * @bank_num:   an output parameter used to return the bank number of the gpio
 *              pin
 * @bank_pin_num: an output parameter used to return pin number within a bank
 *                for the given gpio pin
 *
 * Returns the bank number and pin offset within the bank.
 */
static inline void zynq_gpio_get_bank_pin(unsigned int pin_num,
                                          unsigned int *bank_num,
                                          unsigned int *bank_pin_num)
{
        switch (pin_num) {
        case ZYNQ_GPIO_BANK0_PIN_MIN ... ZYNQ_GPIO_BANK0_PIN_MAX:
                *bank_num = 0;
                *bank_pin_num = pin_num;
                break;
        case ZYNQ_GPIO_BANK1_PIN_MIN ... ZYNQ_GPIO_BANK1_PIN_MAX:
                *bank_num = 1;
                *bank_pin_num = pin_num - ZYNQ_GPIO_BANK1_PIN_MIN;
                break;
        case ZYNQ_GPIO_BANK2_PIN_MIN ... ZYNQ_GPIO_BANK2_PIN_MAX:
                *bank_num = 2;
                *bank_pin_num = pin_num - ZYNQ_GPIO_BANK2_PIN_MIN;
                break;
        case ZYNQ_GPIO_BANK3_PIN_MIN ... ZYNQ_GPIO_BANK3_PIN_MAX:
                *bank_num = 3;
                *bank_pin_num = pin_num - ZYNQ_GPIO_BANK3_PIN_MIN;
                break;
        default:
                WARN(true, "invalid GPIO pin number: %u", pin_num);
                *bank_num = 0;
                *bank_pin_num = 0;
                break;
        }
}

static const unsigned int zynq_gpio_bank_offset[] = {
        ZYNQ_GPIO_BANK0_PIN_MIN,
        ZYNQ_GPIO_BANK1_PIN_MIN,
        ZYNQ_GPIO_BANK2_PIN_MIN,
        ZYNQ_GPIO_BANK3_PIN_MIN,
};

/**
 * zynq_gpio_get_value - Get the state of the specified pin of GPIO device
 * @chip:       gpio_chip instance to be worked on
 * @pin:        gpio pin number within the device
 *
 * This function reads the state of the specified pin of the GPIO device.
 *
 * Return: 0 if the pin is low, 1 if pin is high.
 */
static int zynq_gpio_get_value(struct gpio_chip *chip, unsigned int pin)
{
        u32 data;
        unsigned int bank_num, bank_pin_num;
        struct zynq_gpio *gpio = container_of(chip, struct zynq_gpio, chip);

        zynq_gpio_get_bank_pin(pin, &bank_num, &bank_pin_num);

        data = readl_relaxed(gpio->base_addr +
                             ZYNQ_GPIO_DATA_RO_OFFSET(bank_num));

        return (data >> bank_pin_num) & 1;
}

/**
 * zynq_gpio_set_value - Modify the state of the pin with specified value
 * @chip:       gpio_chip instance to be worked on
 * @pin:        gpio pin number within the device
 * @state:      value used to modify the state of the specified pin
 *
 * This function calculates the register offset (i.e to lower 16 bits or
 * upper 16 bits) based on the given pin number and sets the state of a
 * gpio pin to the specified value. The state is either 0 or non-zero.
 */
static void zynq_gpio_set_value(struct gpio_chip *chip, unsigned int pin,
                                int state)
{
        unsigned int reg_offset, bank_num, bank_pin_num;
        struct zynq_gpio *gpio = container_of(chip, struct zynq_gpio, chip);

        zynq_gpio_get_bank_pin(pin, &bank_num, &bank_pin_num);

        if (bank_pin_num >= ZYNQ_GPIO_MID_PIN_NUM) {
                /* only 16 data bits in bit maskable reg */
                bank_pin_num -= ZYNQ_GPIO_MID_PIN_NUM;
                reg_offset = ZYNQ_GPIO_DATA_MSW_OFFSET(bank_num);
        } else {
                reg_offset = ZYNQ_GPIO_DATA_LSW_OFFSET(bank_num);
        }

        /*
         * get the 32 bit value to be written to the mask/data register where
         * the upper 16 bits is the mask and lower 16 bits is the data
         */
        state = !!state;
        state = ~(1 << (bank_pin_num + ZYNQ_GPIO_MID_PIN_NUM)) &
                ((state << bank_pin_num) | ZYNQ_GPIO_UPPER_MASK);

        writel_relaxed(state, gpio->base_addr + reg_offset);
}

/**
 * zynq_gpio_dir_in - Set the direction of the specified GPIO pin as input
 * @chip:       gpio_chip instance to be worked on
 * @pin:        gpio pin number within the device
 *
 * This function uses the read-modify-write sequence to set the direction of
 * the gpio pin as input.
 *
 * Return: 0 always
 */
static int zynq_gpio_dir_in(struct gpio_chip *chip, unsigned int pin)
{
        u32 reg;
        unsigned int bank_num, bank_pin_num;
        struct zynq_gpio *gpio = container_of(chip, struct zynq_gpio, chip);

        zynq_gpio_get_bank_pin(pin, &bank_num, &bank_pin_num);

        /* bank 0 pins 7 and 8 are special and cannot be used as inputs */
        if (bank_num == 0 && (bank_pin_num == 7 || bank_pin_num == 8))
                return -EINVAL;

        /* clear the bit in direction mode reg to set the pin as input */
        reg = readl_relaxed(gpio->base_addr + ZYNQ_GPIO_DIRM_OFFSET(bank_num));
        reg &= ~BIT(bank_pin_num);
        writel_relaxed(reg, gpio->base_addr + ZYNQ_GPIO_DIRM_OFFSET(bank_num));

        return 0;
}

/**
 * zynq_gpio_dir_out - Set the direction of the specified GPIO pin as output
 * @chip:       gpio_chip instance to be worked on
 * @pin:        gpio pin number within the device
 * @state:      value to be written to specified pin
 *
 * This function sets the direction of specified GPIO pin as output, configures
 * the Output Enable register for the pin and uses zynq_gpio_set to set
 * the state of the pin to the value specified.
 *
 * Return: 0 always
 */
static int zynq_gpio_dir_out(struct gpio_chip *chip, unsigned int pin,
                             int state)
{
        u32 reg;
        unsigned int bank_num, bank_pin_num;
        struct zynq_gpio *gpio = container_of(chip, struct zynq_gpio, chip);

        zynq_gpio_get_bank_pin(pin, &bank_num, &bank_pin_num);

        /* set the GPIO pin as output */
        reg = readl_relaxed(gpio->base_addr + ZYNQ_GPIO_DIRM_OFFSET(bank_num));
        reg |= BIT(bank_pin_num);
        writel_relaxed(reg, gpio->base_addr + ZYNQ_GPIO_DIRM_OFFSET(bank_num));

        /* configure the output enable reg for the pin */
        reg = readl_relaxed(gpio->base_addr + ZYNQ_GPIO_OUTEN_OFFSET(bank_num));
        reg |= BIT(bank_pin_num);
        writel_relaxed(reg, gpio->base_addr + ZYNQ_GPIO_OUTEN_OFFSET(bank_num));

        /* set the state of the pin */
        zynq_gpio_set_value(chip, pin, state);
        return 0;
}

/**
 * zynq_gpio_irq_mask - Disable the interrupts for a gpio pin
 * @irq_data:   per irq and chip data passed down to chip functions
 *
 * This function calculates gpio pin number from irq number and sets the
 * bit in the Interrupt Disable register of the corresponding bank to disable
 * interrupts for that pin.
 */
static void zynq_gpio_irq_mask(struct irq_data *irq_data)
{
        unsigned int device_pin_num, bank_num, bank_pin_num;
        struct zynq_gpio *gpio = irq_data_get_irq_chip_data(irq_data);

        device_pin_num = irq_data->hwirq;
        zynq_gpio_get_bank_pin(device_pin_num, &bank_num, &bank_pin_num);
        writel_relaxed(BIT(bank_pin_num),
                       gpio->base_addr + ZYNQ_GPIO_INTDIS_OFFSET(bank_num));
}

/**
 * zynq_gpio_irq_unmask - Enable the interrupts for a gpio pin
 * @irq_data:   irq data containing irq number of gpio pin for the interrupt
 *              to enable
 *
 * This function calculates the gpio pin number from irq number and sets the
 * bit in the Interrupt Enable register of the corresponding bank to enable
 * interrupts for that pin.
 */
static void zynq_gpio_irq_unmask(struct irq_data *irq_data)
{
        unsigned int device_pin_num, bank_num, bank_pin_num;
        struct zynq_gpio *gpio = irq_data_get_irq_chip_data(irq_data);

        device_pin_num = irq_data->hwirq;
        zynq_gpio_get_bank_pin(device_pin_num, &bank_num, &bank_pin_num);
        writel_relaxed(BIT(bank_pin_num),
                       gpio->base_addr + ZYNQ_GPIO_INTEN_OFFSET(bank_num));
}

/**
 * zynq_gpio_irq_ack - Acknowledge the interrupt of a gpio pin
 * @irq_data:   irq data containing irq number of gpio pin for the interrupt
 *              to ack
 *
 * This function calculates gpio pin number from irq number and sets the bit
 * in the Interrupt Status Register of the corresponding bank, to ACK the irq.
 */
static void zynq_gpio_irq_ack(struct irq_data *irq_data)
{
        unsigned int device_pin_num, bank_num, bank_pin_num;
        struct zynq_gpio *gpio = irq_data_get_irq_chip_data(irq_data);

        device_pin_num = irq_data->hwirq;
        zynq_gpio_get_bank_pin(device_pin_num, &bank_num, &bank_pin_num);
        writel_relaxed(BIT(bank_pin_num),
                       gpio->base_addr + ZYNQ_GPIO_INTSTS_OFFSET(bank_num));
}

/**
 * zynq_gpio_irq_enable - Enable the interrupts for a gpio pin
 * @irq_data:   irq data containing irq number of gpio pin for the interrupt
 *              to enable
 *
 * Clears the INTSTS bit and unmasks the given interrrupt.
 */
static void zynq_gpio_irq_enable(struct irq_data *irq_data)
{
        /*
         * The Zynq GPIO controller does not disable interrupt detection when
         * the interrupt is masked and only disables the propagation of the
         * interrupt. This means when the controller detects an interrupt
         * condition while the interrupt is logically disabled it will propagate
         * that interrupt event once the interrupt is enabled. This will cause
         * the interrupt consumer to see spurious interrupts to prevent this
         * first make sure that the interrupt is not asserted and then enable
         * it.
         */
        zynq_gpio_irq_ack(irq_data);
        zynq_gpio_irq_unmask(irq_data);
}

/**
 * zynq_gpio_set_irq_type - Set the irq type for a gpio pin
 * @irq_data:   irq data containing irq number of gpio pin
 * @type:       interrupt type that is to be set for the gpio pin
 *
 * This function gets the gpio pin number and its bank from the gpio pin number
 * and configures the INT_TYPE, INT_POLARITY and INT_ANY registers.
 *
 * Return: 0, negative error otherwise.
 * TYPE-EDGE_RISING,  INT_TYPE - 1, INT_POLARITY - 1,  INT_ANY - 0;
 * TYPE-EDGE_FALLING, INT_TYPE - 1, INT_POLARITY - 0,  INT_ANY - 0;
 * TYPE-EDGE_BOTH,    INT_TYPE - 1, INT_POLARITY - NA, INT_ANY - 1;
 * TYPE-LEVEL_HIGH,   INT_TYPE - 0, INT_POLARITY - 1,  INT_ANY - NA;
 * TYPE-LEVEL_LOW,    INT_TYPE - 0, INT_POLARITY - 0,  INT_ANY - NA
 */
static int zynq_gpio_set_irq_type(struct irq_data *irq_data, unsigned int type)
{
        u32 int_type, int_pol, int_any;
        unsigned int device_pin_num, bank_num, bank_pin_num;
        struct zynq_gpio *gpio = irq_data_get_irq_chip_data(irq_data);

        device_pin_num = irq_data->hwirq;
        zynq_gpio_get_bank_pin(device_pin_num, &bank_num, &bank_pin_num);

        int_type = readl_relaxed(gpio->base_addr +
                                 ZYNQ_GPIO_INTTYPE_OFFSET(bank_num));
        int_pol = readl_relaxed(gpio->base_addr +
                                ZYNQ_GPIO_INTPOL_OFFSET(bank_num));
        int_any = readl_relaxed(gpio->base_addr +
                                ZYNQ_GPIO_INTANY_OFFSET(bank_num));

        /*
         * based on the type requested, configure the INT_TYPE, INT_POLARITY
         * and INT_ANY registers
         */
        switch (type) {
        case IRQ_TYPE_EDGE_RISING:
                int_type |= BIT(bank_pin_num);
                int_pol |= BIT(bank_pin_num);
                int_any &= ~BIT(bank_pin_num);
                break;
        case IRQ_TYPE_EDGE_FALLING:
                int_type |= BIT(bank_pin_num);
                int_pol &= ~BIT(bank_pin_num);
                int_any &= ~BIT(bank_pin_num);
                break;
        case IRQ_TYPE_EDGE_BOTH:
                int_type |= BIT(bank_pin_num);
                int_any |= BIT(bank_pin_num);
                break;
        case IRQ_TYPE_LEVEL_HIGH:
                int_type &= ~BIT(bank_pin_num);
                int_pol |= BIT(bank_pin_num);
                break;
        case IRQ_TYPE_LEVEL_LOW:
                int_type &= ~BIT(bank_pin_num);
                int_pol &= ~BIT(bank_pin_num);
                break;
        default:
                return -EINVAL;
        }

        writel_relaxed(int_type,
                       gpio->base_addr + ZYNQ_GPIO_INTTYPE_OFFSET(bank_num));
        writel_relaxed(int_pol,
                       gpio->base_addr + ZYNQ_GPIO_INTPOL_OFFSET(bank_num));
        writel_relaxed(int_any,
                       gpio->base_addr + ZYNQ_GPIO_INTANY_OFFSET(bank_num));

        if (type & IRQ_TYPE_LEVEL_MASK) {
                __irq_set_chip_handler_name_locked(irq_data->irq,
                        &zynq_gpio_level_irqchip, handle_fasteoi_irq, NULL);
        } else {
                __irq_set_chip_handler_name_locked(irq_data->irq,
                        &zynq_gpio_edge_irqchip, handle_level_irq, NULL);
        }

        return 0;
}

static int zynq_gpio_set_wake(struct irq_data *data, unsigned int on)
{
        struct zynq_gpio *gpio = irq_data_get_irq_chip_data(data);

        irq_set_irq_wake(gpio->irq, on);

        return 0;
}

/* irq chip descriptor */
static struct irq_chip zynq_gpio_level_irqchip = {
        .name           = DRIVER_NAME,
        .irq_enable     = zynq_gpio_irq_enable,
        .irq_eoi        = zynq_gpio_irq_ack,
        .irq_mask       = zynq_gpio_irq_mask,
        .irq_unmask     = zynq_gpio_irq_unmask,
        .irq_set_type   = zynq_gpio_set_irq_type,
        .irq_set_wake   = zynq_gpio_set_wake,
        .flags          = IRQCHIP_EOI_THREADED | IRQCHIP_EOI_IF_HANDLED |
                          IRQCHIP_MASK_ON_SUSPEND,
};

static struct irq_chip zynq_gpio_edge_irqchip = {
        .name           = DRIVER_NAME,
        .irq_enable     = zynq_gpio_irq_enable,
        .irq_ack        = zynq_gpio_irq_ack,
        .irq_mask       = zynq_gpio_irq_mask,
        .irq_unmask     = zynq_gpio_irq_unmask,
        .irq_set_type   = zynq_gpio_set_irq_type,
        .irq_set_wake   = zynq_gpio_set_wake,
        .flags          = IRQCHIP_MASK_ON_SUSPEND,
};

static void zynq_gpio_handle_bank_irq(struct zynq_gpio *gpio,
                                      unsigned int bank_num,
                                      unsigned long pending)
{
        unsigned int bank_offset = zynq_gpio_bank_offset[bank_num];
        struct irq_domain *irqdomain = gpio->chip.irqdomain;
        int offset;

        if (!pending)
                return;

        for_each_set_bit(offset, &pending, 32) {
                unsigned int gpio_irq;

                gpio_irq = irq_find_mapping(irqdomain, offset + bank_offset);
                generic_handle_irq(gpio_irq);
        }
}

/**
 * zynq_gpio_irqhandler - IRQ handler for the gpio banks of a gpio device
 * @irq:        irq number of the gpio bank where interrupt has occurred
 * @desc:       irq descriptor instance of the 'irq'
 *
 * This function reads the Interrupt Status Register of each bank to get the
 * gpio pin number which has triggered an interrupt. It then acks the triggered
 * interrupt and calls the pin specific handler set by the higher layer
 * application for that pin.
 * Note: A bug is reported if no handler is set for the gpio pin.
 */
static void zynq_gpio_irqhandler(unsigned int irq, struct irq_desc *desc)
{
        u32 int_sts, int_enb;
        unsigned int bank_num;
        struct zynq_gpio *gpio = irq_get_handler_data(irq);
        struct irq_chip *irqchip = irq_desc_get_chip(desc);

        chained_irq_enter(irqchip, desc);

        for (bank_num = 0; bank_num < ZYNQ_GPIO_MAX_BANK; bank_num++) {
                int_sts = readl_relaxed(gpio->base_addr +
                                        ZYNQ_GPIO_INTSTS_OFFSET(bank_num));
                int_enb = readl_relaxed(gpio->base_addr +
                                        ZYNQ_GPIO_INTMASK_OFFSET(bank_num));
                zynq_gpio_handle_bank_irq(gpio, bank_num, int_sts & ~int_enb);
        }

        chained_irq_exit(irqchip, desc);
}

static int __maybe_unused zynq_gpio_suspend(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        int irq = platform_get_irq(pdev, 0);
        struct irq_data *data = irq_get_irq_data(irq);

        if (!irqd_is_wakeup_set(data))
                return pm_runtime_force_suspend(dev);

        return 0;
}

static int __maybe_unused zynq_gpio_resume(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        int irq = platform_get_irq(pdev, 0);
        struct irq_data *data = irq_get_irq_data(irq);

        if (!irqd_is_wakeup_set(data))
                return pm_runtime_force_resume(dev);

        return 0;
}

static int __maybe_unused zynq_gpio_runtime_suspend(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct zynq_gpio *gpio = platform_get_drvdata(pdev);

        clk_disable_unprepare(gpio->clk);

        return 0;
}

static int __maybe_unused zynq_gpio_runtime_resume(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct zynq_gpio *gpio = platform_get_drvdata(pdev);

        return clk_prepare_enable(gpio->clk);
}

static int zynq_gpio_request(struct gpio_chip *chip, unsigned offset)
{
        int ret;

        ret = pm_runtime_get_sync(chip->dev);

        /*
         * If the device is already active pm_runtime_get() will return 1 on
         * success, but gpio_request still needs to return 0.
         */
        return ret < 0 ? ret : 0;
}

static void zynq_gpio_free(struct gpio_chip *chip, unsigned offset)
{
        pm_runtime_put(chip->dev);
}

static const struct dev_pm_ops zynq_gpio_dev_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(zynq_gpio_suspend, zynq_gpio_resume)
        SET_RUNTIME_PM_OPS(zynq_gpio_runtime_suspend,
                        zynq_gpio_runtime_resume, NULL)
};

/**
 * zynq_gpio_probe - Initialization method for a zynq_gpio device
 * @pdev:       platform device instance
 *
 * This function allocates memory resources for the gpio device and registers
 * all the banks of the device. It will also set up interrupts for the gpio
 * pins.
 * Note: Interrupts are disabled for all the banks during initialization.
 *
 * Return: 0 on success, negative error otherwise.
 */
static int zynq_gpio_probe(struct platform_device *pdev)
{
        int ret, bank_num;
        struct zynq_gpio *gpio;
        struct gpio_chip *chip;
        struct resource *res;

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

        platform_set_drvdata(pdev, gpio);

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        gpio->base_addr = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(gpio->base_addr))
                return PTR_ERR(gpio->base_addr);

        gpio->irq = platform_get_irq(pdev, 0);
        if (gpio->irq < 0) {
                dev_err(&pdev->dev, "invalid IRQ\n");
                return gpio->irq;
        }

        /* configure the gpio chip */
        chip = &gpio->chip;
        chip->label = "zynq_gpio";
        chip->owner = THIS_MODULE;
        chip->dev = &pdev->dev;
        chip->get = zynq_gpio_get_value;
        chip->set = zynq_gpio_set_value;
        chip->request = zynq_gpio_request;
        chip->free = zynq_gpio_free;
        chip->direction_input = zynq_gpio_dir_in;
        chip->direction_output = zynq_gpio_dir_out;
        chip->base = -1;
        chip->ngpio = ZYNQ_GPIO_NR_GPIOS;

        /* Enable GPIO clock */
        gpio->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(gpio->clk)) {
                dev_err(&pdev->dev, "input clock not found.\n");
                return PTR_ERR(gpio->clk);
        }
        ret = clk_prepare_enable(gpio->clk);
        if (ret) {
                dev_err(&pdev->dev, "Unable to enable clock.\n");
                return ret;
        }

        /* report a bug if gpio chip registration fails */
        ret = gpiochip_add(chip);
        if (ret) {
                dev_err(&pdev->dev, "Failed to add gpio chip\n");
                goto err_disable_clk;
        }

        /* disable interrupts for all banks */
        for (bank_num = 0; bank_num < ZYNQ_GPIO_MAX_BANK; bank_num++)
                writel_relaxed(ZYNQ_GPIO_IXR_DISABLE_ALL, gpio->base_addr +
                               ZYNQ_GPIO_INTDIS_OFFSET(bank_num));

        ret = gpiochip_irqchip_add(chip, &zynq_gpio_edge_irqchip, 0,
                                   handle_level_irq, IRQ_TYPE_NONE);
        if (ret) {
                dev_err(&pdev->dev, "Failed to add irq chip\n");
                goto err_rm_gpiochip;
        }

        gpiochip_set_chained_irqchip(chip, &zynq_gpio_edge_irqchip, gpio->irq,
                                     zynq_gpio_irqhandler);

        pm_runtime_set_active(&pdev->dev);
        pm_runtime_enable(&pdev->dev);

        return 0;

err_rm_gpiochip:
        gpiochip_remove(chip);
err_disable_clk:
        clk_disable_unprepare(gpio->clk);

        return ret;
}

/**
 * zynq_gpio_remove - Driver removal function
 * @pdev:       platform device instance
 *
 * Return: 0 always
 */
static int zynq_gpio_remove(struct platform_device *pdev)
{
        struct zynq_gpio *gpio = platform_get_drvdata(pdev);

        pm_runtime_get_sync(&pdev->dev);
        gpiochip_remove(&gpio->chip);
        clk_disable_unprepare(gpio->clk);
        device_set_wakeup_capable(&pdev->dev, 0);
        return 0;
}

static struct of_device_id zynq_gpio_of_match[] = {
        { .compatible = "xlnx,zynq-gpio-1.0", },
        { /* end of table */ }
};
MODULE_DEVICE_TABLE(of, zynq_gpio_of_match);

static struct platform_driver zynq_gpio_driver = {
        .driver = {
                .name = DRIVER_NAME,
                .pm = &zynq_gpio_dev_pm_ops,
                .of_match_table = zynq_gpio_of_match,
        },
        .probe = zynq_gpio_probe,
        .remove = zynq_gpio_remove,
};

/**
 * zynq_gpio_init - Initial driver registration call
 *
 * Return: value from platform_driver_register
 */
static int __init zynq_gpio_init(void)
{
        return platform_driver_register(&zynq_gpio_driver);
}
postcore_initcall(zynq_gpio_init);

MODULE_AUTHOR("Xilinx Inc.");
MODULE_DESCRIPTION("Zynq GPIO driver");
MODULE_LICENSE("GPL");