root/drivers/gpio/gpio-lpc18xx.c
// SPDX-License-Identifier: GPL-2.0
/*
 * GPIO driver for NXP LPC18xx/43xx.
 *
 * Copyright (C) 2018 Vladimir Zapolskiy <vz@mleia.com>
 * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
 *
 */

#include <linux/clk.h>
#include <linux/gpio/driver.h>
#include <linux/io.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>

/* LPC18xx GPIO register offsets */
#define LPC18XX_REG_DIR(n)      (0x2000 + n * sizeof(u32))

#define LPC18XX_MAX_PORTS       8
#define LPC18XX_PINS_PER_PORT   32

/* LPC18xx GPIO pin interrupt controller register offsets */
#define LPC18XX_GPIO_PIN_IC_ISEL        0x00
#define LPC18XX_GPIO_PIN_IC_IENR        0x04
#define LPC18XX_GPIO_PIN_IC_SIENR       0x08
#define LPC18XX_GPIO_PIN_IC_CIENR       0x0c
#define LPC18XX_GPIO_PIN_IC_IENF        0x10
#define LPC18XX_GPIO_PIN_IC_SIENF       0x14
#define LPC18XX_GPIO_PIN_IC_CIENF       0x18
#define LPC18XX_GPIO_PIN_IC_RISE        0x1c
#define LPC18XX_GPIO_PIN_IC_FALL        0x20
#define LPC18XX_GPIO_PIN_IC_IST         0x24

#define NR_LPC18XX_GPIO_PIN_IC_IRQS     8

struct lpc18xx_gpio_pin_ic {
        void __iomem *base;
        struct irq_domain *domain;
        struct raw_spinlock lock;
        struct gpio_chip *gpio;
};

struct lpc18xx_gpio_chip {
        struct gpio_chip gpio;
        void __iomem *base;
        struct lpc18xx_gpio_pin_ic *pin_ic;
        spinlock_t lock;
};

static inline void lpc18xx_gpio_pin_ic_isel(struct lpc18xx_gpio_pin_ic *ic,
                                            u32 pin, bool set)
{
        u32 val = readl_relaxed(ic->base + LPC18XX_GPIO_PIN_IC_ISEL);

        if (set)
                val &= ~BIT(pin);
        else
                val |= BIT(pin);

        writel_relaxed(val, ic->base + LPC18XX_GPIO_PIN_IC_ISEL);
}

static inline void lpc18xx_gpio_pin_ic_set(struct lpc18xx_gpio_pin_ic *ic,
                                           u32 pin, u32 reg)
{
        writel_relaxed(BIT(pin), ic->base + reg);
}

static void lpc18xx_gpio_pin_ic_mask(struct irq_data *d)
{
        struct lpc18xx_gpio_pin_ic *ic = d->chip_data;
        u32 type = irqd_get_trigger_type(d);
        irq_hw_number_t hwirq = irqd_to_hwirq(d);

        raw_spin_lock(&ic->lock);

        if (type & IRQ_TYPE_LEVEL_MASK || type & IRQ_TYPE_EDGE_RISING)
                lpc18xx_gpio_pin_ic_set(ic, d->hwirq,
                                        LPC18XX_GPIO_PIN_IC_CIENR);

        if (type & IRQ_TYPE_EDGE_FALLING)
                lpc18xx_gpio_pin_ic_set(ic, d->hwirq,
                                        LPC18XX_GPIO_PIN_IC_CIENF);

        raw_spin_unlock(&ic->lock);

        irq_chip_mask_parent(d);

        gpiochip_disable_irq(ic->gpio, hwirq);
}

static void lpc18xx_gpio_pin_ic_unmask(struct irq_data *d)
{
        struct lpc18xx_gpio_pin_ic *ic = d->chip_data;
        u32 type = irqd_get_trigger_type(d);
        irq_hw_number_t hwirq = irqd_to_hwirq(d);

        gpiochip_enable_irq(ic->gpio, hwirq);

        raw_spin_lock(&ic->lock);

        if (type & IRQ_TYPE_LEVEL_MASK || type & IRQ_TYPE_EDGE_RISING)
                lpc18xx_gpio_pin_ic_set(ic, d->hwirq,
                                        LPC18XX_GPIO_PIN_IC_SIENR);

        if (type & IRQ_TYPE_EDGE_FALLING)
                lpc18xx_gpio_pin_ic_set(ic, d->hwirq,
                                        LPC18XX_GPIO_PIN_IC_SIENF);

        raw_spin_unlock(&ic->lock);

        irq_chip_unmask_parent(d);
}

static void lpc18xx_gpio_pin_ic_eoi(struct irq_data *d)
{
        struct lpc18xx_gpio_pin_ic *ic = d->chip_data;
        u32 type = irqd_get_trigger_type(d);

        raw_spin_lock(&ic->lock);

        if (type & IRQ_TYPE_EDGE_BOTH)
                lpc18xx_gpio_pin_ic_set(ic, d->hwirq,
                                        LPC18XX_GPIO_PIN_IC_IST);

        raw_spin_unlock(&ic->lock);

        irq_chip_eoi_parent(d);
}

static int lpc18xx_gpio_pin_ic_set_type(struct irq_data *d, unsigned int type)
{
        struct lpc18xx_gpio_pin_ic *ic = d->chip_data;

        raw_spin_lock(&ic->lock);

        if (type & IRQ_TYPE_LEVEL_HIGH) {
                lpc18xx_gpio_pin_ic_isel(ic, d->hwirq, true);
                lpc18xx_gpio_pin_ic_set(ic, d->hwirq,
                                        LPC18XX_GPIO_PIN_IC_SIENF);
        } else if (type & IRQ_TYPE_LEVEL_LOW) {
                lpc18xx_gpio_pin_ic_isel(ic, d->hwirq, true);
                lpc18xx_gpio_pin_ic_set(ic, d->hwirq,
                                        LPC18XX_GPIO_PIN_IC_CIENF);
        } else {
                lpc18xx_gpio_pin_ic_isel(ic, d->hwirq, false);
        }

        raw_spin_unlock(&ic->lock);

        return 0;
}

static const struct irq_chip lpc18xx_gpio_pin_ic = {
        .name           = "LPC18xx GPIO pin",
        .irq_mask       = lpc18xx_gpio_pin_ic_mask,
        .irq_unmask     = lpc18xx_gpio_pin_ic_unmask,
        .irq_eoi        = lpc18xx_gpio_pin_ic_eoi,
        .irq_set_type   = lpc18xx_gpio_pin_ic_set_type,
        .flags          = IRQCHIP_IMMUTABLE | IRQCHIP_SET_TYPE_MASKED,
        GPIOCHIP_IRQ_RESOURCE_HELPERS,
};

static int lpc18xx_gpio_pin_ic_domain_alloc(struct irq_domain *domain,
                                            unsigned int virq,
                                            unsigned int nr_irqs, void *data)
{
        struct irq_fwspec parent_fwspec, *fwspec = data;
        struct lpc18xx_gpio_pin_ic *ic = domain->host_data;
        irq_hw_number_t hwirq;
        int ret;

        if (nr_irqs != 1)
                return -EINVAL;

        hwirq = fwspec->param[0];
        if (hwirq >= NR_LPC18XX_GPIO_PIN_IC_IRQS)
                return -EINVAL;

        /*
         * All LPC18xx/LPC43xx GPIO pin hardware interrupts are translated
         * into edge interrupts 32...39 on parent Cortex-M3/M4 NVIC
         */
        parent_fwspec.fwnode = domain->parent->fwnode;
        parent_fwspec.param_count = 1;
        parent_fwspec.param[0] = hwirq + 32;

        ret = irq_domain_alloc_irqs_parent(domain, virq, 1, &parent_fwspec);
        if (ret < 0) {
                pr_err("failed to allocate parent irq %u: %d\n",
                       parent_fwspec.param[0], ret);
                return ret;
        }

        return irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
                                             &lpc18xx_gpio_pin_ic, ic);
}

static const struct irq_domain_ops lpc18xx_gpio_pin_ic_domain_ops = {
        .alloc  = lpc18xx_gpio_pin_ic_domain_alloc,
        .xlate  = irq_domain_xlate_twocell,
        .free   = irq_domain_free_irqs_common,
};

static int lpc18xx_gpio_pin_ic_probe(struct lpc18xx_gpio_chip *gc)
{
        struct device *dev = gc->gpio.parent;
        struct irq_domain *parent_domain;
        struct device_node *parent_node;
        struct lpc18xx_gpio_pin_ic *ic;
        struct resource res;
        int ret, index;

        parent_node = of_irq_find_parent(dev->of_node);
        if (!parent_node)
                return -ENXIO;

        parent_domain = irq_find_host(parent_node);
        of_node_put(parent_node);
        if (!parent_domain)
                return -ENXIO;

        ic = devm_kzalloc(dev, sizeof(*ic), GFP_KERNEL);
        if (!ic)
                return -ENOMEM;

        index = of_property_match_string(dev->of_node, "reg-names",
                                         "gpio-pin-ic");
        if (index < 0) {
                ret = -ENODEV;
                goto free_ic;
        }

        ret = of_address_to_resource(dev->of_node, index, &res);
        if (ret < 0)
                goto free_ic;

        ic->base = devm_ioremap_resource(dev, &res);
        if (IS_ERR(ic->base)) {
                ret = PTR_ERR(ic->base);
                goto free_ic;
        }

        raw_spin_lock_init(&ic->lock);

        ic->domain = irq_domain_create_hierarchy(parent_domain, 0, NR_LPC18XX_GPIO_PIN_IC_IRQS,
                                                 dev_fwnode(dev), &lpc18xx_gpio_pin_ic_domain_ops,
                                                 ic);
        if (!ic->domain) {
                pr_err("unable to add irq domain\n");
                ret = -ENODEV;
                goto free_iomap;
        }

        ic->gpio = &gc->gpio;
        gc->pin_ic = ic;

        return 0;

free_iomap:
        devm_iounmap(dev, ic->base);
free_ic:
        devm_kfree(dev, ic);

        return ret;
}

static int lpc18xx_gpio_set(struct gpio_chip *chip, unsigned int offset,
                            int value)
{
        struct lpc18xx_gpio_chip *gc = gpiochip_get_data(chip);

        writeb(value ? 1 : 0, gc->base + offset);

        return 0;
}

static int lpc18xx_gpio_get(struct gpio_chip *chip, unsigned offset)
{
        struct lpc18xx_gpio_chip *gc = gpiochip_get_data(chip);
        return !!readb(gc->base + offset);
}

static int lpc18xx_gpio_direction(struct gpio_chip *chip, unsigned offset,
                                  bool out)
{
        struct lpc18xx_gpio_chip *gc = gpiochip_get_data(chip);
        unsigned long flags;
        u32 port, pin, dir;

        port = offset / LPC18XX_PINS_PER_PORT;
        pin  = offset % LPC18XX_PINS_PER_PORT;

        spin_lock_irqsave(&gc->lock, flags);
        dir = readl(gc->base + LPC18XX_REG_DIR(port));
        if (out)
                dir |= BIT(pin);
        else
                dir &= ~BIT(pin);
        writel(dir, gc->base + LPC18XX_REG_DIR(port));
        spin_unlock_irqrestore(&gc->lock, flags);

        return 0;
}

static int lpc18xx_gpio_direction_input(struct gpio_chip *chip,
                                        unsigned offset)
{
        return lpc18xx_gpio_direction(chip, offset, false);
}

static int lpc18xx_gpio_direction_output(struct gpio_chip *chip,
                                         unsigned offset, int value)
{
        lpc18xx_gpio_set(chip, offset, value);
        return lpc18xx_gpio_direction(chip, offset, true);
}

static const struct gpio_chip lpc18xx_chip = {
        .label                  = "lpc18xx/43xx-gpio",
        .request                = gpiochip_generic_request,
        .free                   = gpiochip_generic_free,
        .direction_input        = lpc18xx_gpio_direction_input,
        .direction_output       = lpc18xx_gpio_direction_output,
        .set                    = lpc18xx_gpio_set,
        .get                    = lpc18xx_gpio_get,
        .ngpio                  = LPC18XX_MAX_PORTS * LPC18XX_PINS_PER_PORT,
        .owner                  = THIS_MODULE,
};

static int lpc18xx_gpio_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct lpc18xx_gpio_chip *gc;
        int index, ret;
        struct clk *clk;

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

        gc->gpio = lpc18xx_chip;
        platform_set_drvdata(pdev, gc);

        index = of_property_match_string(dev->of_node, "reg-names", "gpio");
        if (index < 0) {
                /* To support backward compatibility take the first resource */
                gc->base = devm_platform_ioremap_resource(pdev, 0);
        } else {
                struct resource res;

                ret = of_address_to_resource(dev->of_node, index, &res);
                if (ret < 0)
                        return ret;

                gc->base = devm_ioremap_resource(dev, &res);
        }
        if (IS_ERR(gc->base))
                return PTR_ERR(gc->base);

        clk = devm_clk_get_enabled(dev, NULL);
        if (IS_ERR(clk)) {
                dev_err(dev, "input clock not found\n");
                return PTR_ERR(clk);
        }

        spin_lock_init(&gc->lock);

        gc->gpio.parent = dev;

        ret = devm_gpiochip_add_data(dev, &gc->gpio, gc);
        if (ret)
                return dev_err_probe(dev, ret, "failed to add gpio chip\n");

        /* On error GPIO pin interrupt controller just won't be registered */
        lpc18xx_gpio_pin_ic_probe(gc);

        return 0;
}

static void lpc18xx_gpio_remove(struct platform_device *pdev)
{
        struct lpc18xx_gpio_chip *gc = platform_get_drvdata(pdev);

        if (gc->pin_ic)
                irq_domain_remove(gc->pin_ic->domain);
}

static const struct of_device_id lpc18xx_gpio_match[] = {
        { .compatible = "nxp,lpc1850-gpio" },
        { }
};
MODULE_DEVICE_TABLE(of, lpc18xx_gpio_match);

static struct platform_driver lpc18xx_gpio_driver = {
        .probe  = lpc18xx_gpio_probe,
        .remove = lpc18xx_gpio_remove,
        .driver = {
                .name           = "lpc18xx-gpio",
                .of_match_table = lpc18xx_gpio_match,
        },
};
module_platform_driver(lpc18xx_gpio_driver);

MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
MODULE_AUTHOR("Vladimir Zapolskiy <vz@mleia.com>");
MODULE_DESCRIPTION("GPIO driver for LPC18xx/43xx");
MODULE_LICENSE("GPL v2");