root/drivers/gpio/gpio-max77620.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * MAXIM MAX77620 GPIO driver
 *
 * Copyright (c) 2016, NVIDIA CORPORATION.  All rights reserved.
 */

#include <linux/gpio/driver.h>
#include <linux/interrupt.h>
#include <linux/mfd/max77620.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>

#define GPIO_REG_ADDR(offset) (MAX77620_REG_GPIO0 + offset)

struct max77620_gpio {
        struct gpio_chip        gpio_chip;
        struct regmap           *rmap;
        struct device           *dev;
        struct mutex            buslock; /* irq_bus_lock */
        unsigned int            irq_type[MAX77620_GPIO_NR];
        bool                    irq_enabled[MAX77620_GPIO_NR];
};

static irqreturn_t max77620_gpio_irqhandler(int irq, void *data)
{
        struct max77620_gpio *gpio = data;
        unsigned int value, offset;
        unsigned long pending;
        int err;

        err = regmap_read(gpio->rmap, MAX77620_REG_IRQ_LVL2_GPIO, &value);
        if (err < 0) {
                dev_err(gpio->dev, "REG_IRQ_LVL2_GPIO read failed: %d\n", err);
                return IRQ_NONE;
        }

        pending = value;

        for_each_set_bit(offset, &pending, MAX77620_GPIO_NR) {
                unsigned int virq;

                virq = irq_find_mapping(gpio->gpio_chip.irq.domain, offset);
                handle_nested_irq(virq);
        }

        return IRQ_HANDLED;
}

static void max77620_gpio_irq_mask(struct irq_data *data)
{
        struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
        struct max77620_gpio *gpio = gpiochip_get_data(chip);

        gpio->irq_enabled[data->hwirq] = false;
        gpiochip_disable_irq(chip, data->hwirq);
}

static void max77620_gpio_irq_unmask(struct irq_data *data)
{
        struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
        struct max77620_gpio *gpio = gpiochip_get_data(chip);

        gpiochip_enable_irq(chip, data->hwirq);
        gpio->irq_enabled[data->hwirq] = true;
}

static int max77620_gpio_set_irq_type(struct irq_data *data, unsigned int type)
{
        struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
        struct max77620_gpio *gpio = gpiochip_get_data(chip);
        unsigned int irq_type;

        switch (type) {
        case IRQ_TYPE_EDGE_RISING:
                irq_type = MAX77620_CNFG_GPIO_INT_RISING;
                break;

        case IRQ_TYPE_EDGE_FALLING:
                irq_type = MAX77620_CNFG_GPIO_INT_FALLING;
                break;

        case IRQ_TYPE_EDGE_BOTH:
                irq_type = MAX77620_CNFG_GPIO_INT_RISING |
                           MAX77620_CNFG_GPIO_INT_FALLING;
                break;

        default:
                return -EINVAL;
        }

        gpio->irq_type[data->hwirq] = irq_type;

        return 0;
}

static void max77620_gpio_bus_lock(struct irq_data *data)
{
        struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
        struct max77620_gpio *gpio = gpiochip_get_data(chip);

        mutex_lock(&gpio->buslock);
}

static void max77620_gpio_bus_sync_unlock(struct irq_data *data)
{
        struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
        struct max77620_gpio *gpio = gpiochip_get_data(chip);
        unsigned int value, offset = data->hwirq;
        int err;

        value = gpio->irq_enabled[offset] ? gpio->irq_type[offset] : 0;

        err = regmap_update_bits(gpio->rmap, GPIO_REG_ADDR(offset),
                                 MAX77620_CNFG_GPIO_INT_MASK, value);
        if (err < 0)
                dev_err(chip->parent, "failed to update interrupt mask: %d\n",
                        err);

        mutex_unlock(&gpio->buslock);
}

static const struct irq_chip max77620_gpio_irqchip = {
        .name           = "max77620-gpio",
        .irq_mask       = max77620_gpio_irq_mask,
        .irq_unmask     = max77620_gpio_irq_unmask,
        .irq_set_type   = max77620_gpio_set_irq_type,
        .irq_bus_lock   = max77620_gpio_bus_lock,
        .irq_bus_sync_unlock = max77620_gpio_bus_sync_unlock,
        .flags          = IRQCHIP_IMMUTABLE | IRQCHIP_MASK_ON_SUSPEND,
        GPIOCHIP_IRQ_RESOURCE_HELPERS,
};

static int max77620_gpio_get_dir(struct gpio_chip *gc, unsigned int offset)
{
        struct max77620_gpio *mgpio = gpiochip_get_data(gc);
        unsigned int val;
        int ret;

        ret = regmap_read(mgpio->rmap, GPIO_REG_ADDR(offset), &val);
        if (ret < 0) {
                dev_err(mgpio->dev, "CNFG_GPIOx read failed: %d\n", ret);
                return ret;
        }

        if (val & MAX77620_CNFG_GPIO_DIR_MASK)
                return GPIO_LINE_DIRECTION_IN;
        else
                return GPIO_LINE_DIRECTION_OUT;
}

static int max77620_gpio_dir_input(struct gpio_chip *gc, unsigned int offset)
{
        struct max77620_gpio *mgpio = gpiochip_get_data(gc);
        int ret;

        ret = regmap_update_bits(mgpio->rmap, GPIO_REG_ADDR(offset),
                                 MAX77620_CNFG_GPIO_DIR_MASK,
                                 MAX77620_CNFG_GPIO_DIR_INPUT);
        if (ret < 0)
                dev_err(mgpio->dev, "CNFG_GPIOx dir update failed: %d\n", ret);

        return ret;
}

static int max77620_gpio_get(struct gpio_chip *gc, unsigned int offset)
{
        struct max77620_gpio *mgpio = gpiochip_get_data(gc);
        unsigned int val;
        int ret;

        ret = regmap_read(mgpio->rmap, GPIO_REG_ADDR(offset), &val);
        if (ret < 0) {
                dev_err(mgpio->dev, "CNFG_GPIOx read failed: %d\n", ret);
                return ret;
        }

        if  (val & MAX77620_CNFG_GPIO_DIR_MASK)
                return !!(val & MAX77620_CNFG_GPIO_INPUT_VAL_MASK);
        else
                return !!(val & MAX77620_CNFG_GPIO_OUTPUT_VAL_MASK);
}

static int max77620_gpio_dir_output(struct gpio_chip *gc, unsigned int offset,
                                    int value)
{
        struct max77620_gpio *mgpio = gpiochip_get_data(gc);
        u8 val;
        int ret;

        val = (value) ? MAX77620_CNFG_GPIO_OUTPUT_VAL_HIGH :
                                MAX77620_CNFG_GPIO_OUTPUT_VAL_LOW;

        ret = regmap_update_bits(mgpio->rmap, GPIO_REG_ADDR(offset),
                                 MAX77620_CNFG_GPIO_OUTPUT_VAL_MASK, val);
        if (ret < 0) {
                dev_err(mgpio->dev, "CNFG_GPIOx val update failed: %d\n", ret);
                return ret;
        }

        ret = regmap_update_bits(mgpio->rmap, GPIO_REG_ADDR(offset),
                                 MAX77620_CNFG_GPIO_DIR_MASK,
                                 MAX77620_CNFG_GPIO_DIR_OUTPUT);
        if (ret < 0)
                dev_err(mgpio->dev, "CNFG_GPIOx dir update failed: %d\n", ret);

        return ret;
}

static int max77620_gpio_set_debounce(struct max77620_gpio *mgpio,
                                      unsigned int offset,
                                      unsigned int debounce)
{
        u8 val;
        int ret;

        switch (debounce) {
        case 0:
                val = MAX77620_CNFG_GPIO_DBNC_None;
                break;
        case 1 ... 8000:
                val = MAX77620_CNFG_GPIO_DBNC_8ms;
                break;
        case 8001 ... 16000:
                val = MAX77620_CNFG_GPIO_DBNC_16ms;
                break;
        case 16001 ... 32000:
                val = MAX77620_CNFG_GPIO_DBNC_32ms;
                break;
        default:
                dev_err(mgpio->dev, "Illegal value %u\n", debounce);
                return -EINVAL;
        }

        ret = regmap_update_bits(mgpio->rmap, GPIO_REG_ADDR(offset),
                                 MAX77620_CNFG_GPIO_DBNC_MASK, val);
        if (ret < 0)
                dev_err(mgpio->dev, "CNFG_GPIOx_DBNC update failed: %d\n", ret);

        return ret;
}

static int max77620_gpio_set(struct gpio_chip *gc, unsigned int offset,
                             int value)
{
        struct max77620_gpio *mgpio = gpiochip_get_data(gc);
        u8 val;

        val = (value) ? MAX77620_CNFG_GPIO_OUTPUT_VAL_HIGH :
                                MAX77620_CNFG_GPIO_OUTPUT_VAL_LOW;

        return regmap_update_bits(mgpio->rmap, GPIO_REG_ADDR(offset),
                                  MAX77620_CNFG_GPIO_OUTPUT_VAL_MASK, val);
}

static int max77620_gpio_set_config(struct gpio_chip *gc, unsigned int offset,
                                    unsigned long config)
{
        struct max77620_gpio *mgpio = gpiochip_get_data(gc);

        switch (pinconf_to_config_param(config)) {
        case PIN_CONFIG_DRIVE_OPEN_DRAIN:
                return regmap_update_bits(mgpio->rmap, GPIO_REG_ADDR(offset),
                                          MAX77620_CNFG_GPIO_DRV_MASK,
                                          MAX77620_CNFG_GPIO_DRV_OPENDRAIN);
        case PIN_CONFIG_DRIVE_PUSH_PULL:
                return regmap_update_bits(mgpio->rmap, GPIO_REG_ADDR(offset),
                                          MAX77620_CNFG_GPIO_DRV_MASK,
                                          MAX77620_CNFG_GPIO_DRV_PUSHPULL);
        case PIN_CONFIG_INPUT_DEBOUNCE:
                return max77620_gpio_set_debounce(mgpio, offset,
                        pinconf_to_config_argument(config));
        default:
                break;
        }

        return -ENOTSUPP;
}

static int max77620_gpio_irq_init_hw(struct gpio_chip *gc)
{
        struct max77620_gpio *gpio = gpiochip_get_data(gc);
        unsigned int i;
        int err;

        /*
         * GPIO interrupts may be left ON after bootloader, hence let's
         * pre-initialize hardware to the expected state by disabling all
         * the interrupts.
         */
        for (i = 0; i < MAX77620_GPIO_NR; i++) {
                err = regmap_update_bits(gpio->rmap, GPIO_REG_ADDR(i),
                                         MAX77620_CNFG_GPIO_INT_MASK, 0);
                if (err < 0) {
                        dev_err(gpio->dev,
                                "failed to disable interrupt: %d\n", err);
                        return err;
                }
        }

        return 0;
}

static int max77620_gpio_probe(struct platform_device *pdev)
{
        struct max77620_chip *chip =  dev_get_drvdata(pdev->dev.parent);
        struct max77620_gpio *mgpio;
        struct gpio_irq_chip *girq;
        unsigned int gpio_irq;
        int ret;

        ret = platform_get_irq(pdev, 0);
        if (ret < 0)
                return ret;

        gpio_irq = ret;

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

        mutex_init(&mgpio->buslock);
        mgpio->rmap = chip->rmap;
        mgpio->dev = &pdev->dev;

        mgpio->gpio_chip.label = pdev->name;
        mgpio->gpio_chip.parent = pdev->dev.parent;
        mgpio->gpio_chip.get_direction = max77620_gpio_get_dir;
        mgpio->gpio_chip.direction_input = max77620_gpio_dir_input;
        mgpio->gpio_chip.get = max77620_gpio_get;
        mgpio->gpio_chip.direction_output = max77620_gpio_dir_output;
        mgpio->gpio_chip.set = max77620_gpio_set;
        mgpio->gpio_chip.set_config = max77620_gpio_set_config;
        mgpio->gpio_chip.ngpio = MAX77620_GPIO_NR;
        mgpio->gpio_chip.can_sleep = 1;
        mgpio->gpio_chip.base = -1;

        girq = &mgpio->gpio_chip.irq;
        gpio_irq_chip_set_chip(girq, &max77620_gpio_irqchip);
        /* This will let us handle the parent IRQ in the driver */
        girq->parent_handler = NULL;
        girq->num_parents = 0;
        girq->parents = NULL;
        girq->default_type = IRQ_TYPE_NONE;
        girq->handler = handle_edge_irq;
        girq->init_hw = max77620_gpio_irq_init_hw;
        girq->threaded = true;

        ret = devm_gpiochip_add_data(&pdev->dev, &mgpio->gpio_chip, mgpio);
        if (ret < 0) {
                dev_err(&pdev->dev, "gpio_init: Failed to add max77620_gpio\n");
                return ret;
        }

        ret = devm_request_threaded_irq(&pdev->dev, gpio_irq, NULL,
                                        max77620_gpio_irqhandler, IRQF_ONESHOT,
                                        "max77620-gpio", mgpio);
        if (ret < 0) {
                dev_err(&pdev->dev, "failed to request IRQ: %d\n", ret);
                return ret;
        }

        return 0;
}

static const struct platform_device_id max77620_gpio_devtype[] = {
        { .name = "max77620-gpio", },
        { .name = "max20024-gpio", },
        { }
};
MODULE_DEVICE_TABLE(platform, max77620_gpio_devtype);

static struct platform_driver max77620_gpio_driver = {
        .driver.name    = "max77620-gpio",
        .probe          = max77620_gpio_probe,
        .id_table       = max77620_gpio_devtype,
};

module_platform_driver(max77620_gpio_driver);

MODULE_DESCRIPTION("GPIO interface for MAX77620 and MAX20024 PMIC");
MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
MODULE_AUTHOR("Chaitanya Bandi <bandik@nvidia.com>");
MODULE_LICENSE("GPL v2");