root/drivers/gpio/gpio-visconti.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Toshiba Visconti GPIO Support
 *
 * (C) Copyright 2020 Toshiba Electronic Devices & Storage Corporation
 * (C) Copyright 2020 TOSHIBA CORPORATION
 *
 * Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
 */

#include <linux/bitops.h>
#include <linux/gpio/driver.h>
#include <linux/gpio/generic.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/seq_file.h>

/* register offset */
#define GPIO_DIR        0x00
#define GPIO_IDATA      0x08
#define GPIO_ODATA      0x10
#define GPIO_OSET       0x18
#define GPIO_OCLR       0x20
#define GPIO_INTMODE    0x30

#define BASE_HW_IRQ 24

struct visconti_gpio {
        void __iomem *base;
        spinlock_t lock; /* protect gpio register */
        struct gpio_generic_chip chip;
        struct device *dev;
};

static int visconti_gpio_irq_set_type(struct irq_data *d, unsigned int type)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
        struct visconti_gpio *priv = gpiochip_get_data(gc);
        u32 offset = irqd_to_hwirq(d);
        u32 bit = BIT(offset);
        u32 intc_type = IRQ_TYPE_EDGE_RISING;
        u32 intmode, odata;
        int ret = 0;
        unsigned long flags;

        spin_lock_irqsave(&priv->lock, flags);

        odata = readl(priv->base + GPIO_ODATA);
        intmode = readl(priv->base + GPIO_INTMODE);

        switch (type) {
        case IRQ_TYPE_EDGE_RISING:
                odata &= ~bit;
                intmode &= ~bit;
                break;
        case IRQ_TYPE_EDGE_FALLING:
                odata |= bit;
                intmode &= ~bit;
                break;
        case IRQ_TYPE_EDGE_BOTH:
                intmode |= bit;
                break;
        case IRQ_TYPE_LEVEL_HIGH:
                intc_type = IRQ_TYPE_LEVEL_HIGH;
                odata &= ~bit;
                intmode &= ~bit;
                break;
        case IRQ_TYPE_LEVEL_LOW:
                intc_type = IRQ_TYPE_LEVEL_HIGH;
                odata |= bit;
                intmode &= ~bit;
                break;
        default:
                ret = -EINVAL;
                goto err;
        }

        writel(odata, priv->base + GPIO_ODATA);
        writel(intmode, priv->base + GPIO_INTMODE);
        irq_set_irq_type(offset, intc_type);

        ret = irq_chip_set_type_parent(d, type);
err:
        spin_unlock_irqrestore(&priv->lock, flags);
        return ret;
}

static int visconti_gpio_child_to_parent_hwirq(struct gpio_chip *gc,
                                               unsigned int child,
                                               unsigned int child_type,
                                               unsigned int *parent,
                                               unsigned int *parent_type)
{
        /* Interrupts 0..15 mapped to interrupts 24..39 on the GIC */
        if (child < 16) {
                /* All these interrupts are level high in the CPU */
                *parent_type = IRQ_TYPE_LEVEL_HIGH;
                *parent = child + BASE_HW_IRQ;
                return 0;
        }
        return -EINVAL;
}

static int visconti_gpio_populate_parent_fwspec(struct gpio_chip *chip,
                                                union gpio_irq_fwspec *gfwspec,
                                                unsigned int parent_hwirq,
                                                unsigned int parent_type)
{
        struct irq_fwspec *fwspec = &gfwspec->fwspec;

        fwspec->fwnode = chip->irq.parent_domain->fwnode;
        fwspec->param_count = 3;
        fwspec->param[0] = 0;
        fwspec->param[1] = parent_hwirq;
        fwspec->param[2] = parent_type;

        return 0;
}

static void visconti_gpio_mask_irq(struct irq_data *d)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);

        irq_chip_mask_parent(d);
        gpiochip_disable_irq(gc, irqd_to_hwirq(d));
}

static void visconti_gpio_unmask_irq(struct irq_data *d)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);

        gpiochip_enable_irq(gc, irqd_to_hwirq(d));
        irq_chip_unmask_parent(d);
}

static void visconti_gpio_irq_print_chip(struct irq_data *d, struct seq_file *p)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
        struct visconti_gpio *priv = gpiochip_get_data(gc);

        seq_puts(p, dev_name(priv->dev));
}

static const struct irq_chip visconti_gpio_irq_chip = {
        .irq_mask = visconti_gpio_mask_irq,
        .irq_unmask = visconti_gpio_unmask_irq,
        .irq_eoi = irq_chip_eoi_parent,
        .irq_set_type = visconti_gpio_irq_set_type,
        .irq_print_chip = visconti_gpio_irq_print_chip,
        .flags = IRQCHIP_SET_TYPE_MASKED | IRQCHIP_MASK_ON_SUSPEND |
                 IRQCHIP_IMMUTABLE,
        GPIOCHIP_IRQ_RESOURCE_HELPERS,
};

static int visconti_gpio_probe(struct platform_device *pdev)
{
        struct gpio_generic_chip_config config;
        struct device *dev = &pdev->dev;
        struct visconti_gpio *priv;
        struct gpio_irq_chip *girq;
        struct irq_domain *parent;
        struct device_node *irq_parent;
        int ret;

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

        spin_lock_init(&priv->lock);
        priv->dev = dev;

        priv->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(priv->base))
                return PTR_ERR(priv->base);

        irq_parent = of_irq_find_parent(dev->of_node);
        if (!irq_parent) {
                dev_err(dev, "No IRQ parent node\n");
                return -ENODEV;
        }

        parent = irq_find_host(irq_parent);
        of_node_put(irq_parent);
        if (!parent) {
                dev_err(dev, "No IRQ parent domain\n");
                return -ENODEV;
        }

        config = (struct gpio_generic_chip_config) {
                .dev = dev,
                .sz = 4,
                .dat = priv->base + GPIO_IDATA,
                .set = priv->base + GPIO_OSET,
                .clr = priv->base + GPIO_OCLR,
                .dirout = priv->base + GPIO_DIR,
        };

        ret = gpio_generic_chip_init(&priv->chip, &config);
        if (ret) {
                dev_err(dev, "unable to init generic GPIO\n");
                return ret;
        }

        girq = &priv->chip.gc.irq;
        gpio_irq_chip_set_chip(girq, &visconti_gpio_irq_chip);
        girq->fwnode = dev_fwnode(dev);
        girq->parent_domain = parent;
        girq->child_to_parent_hwirq = visconti_gpio_child_to_parent_hwirq;
        girq->populate_parent_alloc_arg = visconti_gpio_populate_parent_fwspec;
        girq->default_type = IRQ_TYPE_NONE;
        girq->handler = handle_level_irq;

        return devm_gpiochip_add_data(dev, &priv->chip.gc, priv);
}

static const struct of_device_id visconti_gpio_of_match[] = {
        { .compatible = "toshiba,gpio-tmpv7708", },
        { /* end of table */ }
};
MODULE_DEVICE_TABLE(of, visconti_gpio_of_match);

static struct platform_driver visconti_gpio_driver = {
        .probe          = visconti_gpio_probe,
        .driver         = {
                .name   = "visconti_gpio",
                .of_match_table = visconti_gpio_of_match,
        }
};
module_platform_driver(visconti_gpio_driver);

MODULE_AUTHOR("Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>");
MODULE_DESCRIPTION("Toshiba Visconti GPIO Driver");
MODULE_LICENSE("GPL v2");