root/drivers/gpio/gpio-mlxbf3.c
// SPDX-License-Identifier: GPL-2.0-only OR BSD-3-Clause
/* Copyright (C) 2022 NVIDIA CORPORATION & AFFILIATES */

#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gpio/driver.h>
#include <linux/gpio/generic.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/types.h>

/*
 * There are 2 YU GPIO blocks:
 * gpio[0]: HOST_GPIO0->HOST_GPIO31
 * gpio[1]: HOST_GPIO32->HOST_GPIO55
 */
#define MLXBF3_GPIO_MAX_PINS_PER_BLOCK 32
#define MLXBF3_GPIO_MAX_PINS_BLOCK0    32
#define MLXBF3_GPIO_MAX_PINS_BLOCK1    24

/*
 * fw_gpio[x] block registers and their offset
 */
#define MLXBF_GPIO_FW_OUTPUT_ENABLE_SET   0x00
#define MLXBF_GPIO_FW_DATA_OUT_SET        0x04

#define MLXBF_GPIO_FW_OUTPUT_ENABLE_CLEAR 0x00
#define MLXBF_GPIO_FW_DATA_OUT_CLEAR      0x04

#define MLXBF_GPIO_CAUSE_RISE_EN          0x00
#define MLXBF_GPIO_CAUSE_FALL_EN          0x04
#define MLXBF_GPIO_READ_DATA_IN           0x08

#define MLXBF_GPIO_CAUSE_OR_CAUSE_EVTEN0  0x00
#define MLXBF_GPIO_CAUSE_OR_EVTEN0        0x14
#define MLXBF_GPIO_CAUSE_OR_CLRCAUSE      0x18

#define MLXBF_GPIO_CLR_ALL_INTS           GENMASK(31, 0)

struct mlxbf3_gpio_context {
        struct gpio_generic_chip chip;

        /* YU GPIO block address */
        void __iomem *gpio_set_io;
        void __iomem *gpio_clr_io;
        void __iomem *gpio_io;

        /* YU GPIO cause block address */
        void __iomem *gpio_cause_io;
};

static void mlxbf3_gpio_irq_enable(struct irq_data *irqd)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
        struct mlxbf3_gpio_context *gs = gpiochip_get_data(gc);
        irq_hw_number_t offset = irqd_to_hwirq(irqd);
        u32 val;

        gpiochip_enable_irq(gc, offset);

        guard(gpio_generic_lock_irqsave)(&gs->chip);

        writel(BIT(offset), gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_CLRCAUSE);

        val = readl(gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_EVTEN0);
        val |= BIT(offset);
        writel(val, gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_EVTEN0);
}

static void mlxbf3_gpio_irq_disable(struct irq_data *irqd)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
        struct mlxbf3_gpio_context *gs = gpiochip_get_data(gc);
        irq_hw_number_t offset = irqd_to_hwirq(irqd);
        u32 val;

        scoped_guard(gpio_generic_lock_irqsave, &gs->chip) {
                val = readl(gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_EVTEN0);
                val &= ~BIT(offset);
                writel(val, gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_EVTEN0);

                writel(BIT(offset), gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_CLRCAUSE);
        }

        gpiochip_disable_irq(gc, offset);
}

static irqreturn_t mlxbf3_gpio_irq_handler(int irq, void *ptr)
{
        struct mlxbf3_gpio_context *gs = ptr;
        struct gpio_chip *gc = &gs->chip.gc;
        unsigned long pending;
        u32 level;

        pending = readl(gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_CAUSE_EVTEN0);
        writel(pending, gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_CLRCAUSE);

        for_each_set_bit(level, &pending, gc->ngpio)
                generic_handle_domain_irq(gc->irq.domain, level);

        return IRQ_RETVAL(pending);
}

static int
mlxbf3_gpio_irq_set_type(struct irq_data *irqd, unsigned int type)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
        struct mlxbf3_gpio_context *gs = gpiochip_get_data(gc);
        irq_hw_number_t offset = irqd_to_hwirq(irqd);
        u32 val;

        scoped_guard(gpio_generic_lock_irqsave, &gs->chip) {
                switch (type & IRQ_TYPE_SENSE_MASK) {
                case IRQ_TYPE_EDGE_BOTH:
                        val = readl(gs->gpio_io + MLXBF_GPIO_CAUSE_FALL_EN);
                        val |= BIT(offset);
                        writel(val, gs->gpio_io + MLXBF_GPIO_CAUSE_FALL_EN);
                        val = readl(gs->gpio_io + MLXBF_GPIO_CAUSE_RISE_EN);
                        val |= BIT(offset);
                        writel(val, gs->gpio_io + MLXBF_GPIO_CAUSE_RISE_EN);
                        break;
                case IRQ_TYPE_EDGE_RISING:
                        val = readl(gs->gpio_io + MLXBF_GPIO_CAUSE_RISE_EN);
                        val |= BIT(offset);
                        writel(val, gs->gpio_io + MLXBF_GPIO_CAUSE_RISE_EN);
                        break;
                case IRQ_TYPE_EDGE_FALLING:
                        val = readl(gs->gpio_io + MLXBF_GPIO_CAUSE_FALL_EN);
                        val |= BIT(offset);
                        writel(val, gs->gpio_io + MLXBF_GPIO_CAUSE_FALL_EN);
                        break;
                default:
                        return -EINVAL;
                }
        }

        irq_set_handler_locked(irqd, handle_edge_irq);

        return 0;
}

/* This function needs to be defined for handle_edge_irq() */
static void mlxbf3_gpio_irq_ack(struct irq_data *data)
{
}

static const struct irq_chip gpio_mlxbf3_irqchip = {
        .name = "MLNXBF33",
        .irq_ack = mlxbf3_gpio_irq_ack,
        .irq_set_type = mlxbf3_gpio_irq_set_type,
        .irq_enable = mlxbf3_gpio_irq_enable,
        .irq_disable = mlxbf3_gpio_irq_disable,
        .flags = IRQCHIP_IMMUTABLE,
        GPIOCHIP_IRQ_RESOURCE_HELPERS,
};

static int mlxbf3_gpio_add_pin_ranges(struct gpio_chip *chip)
{
        unsigned int id;

        switch(chip->ngpio) {
        case MLXBF3_GPIO_MAX_PINS_BLOCK0:
                id = 0;
                break;
        case MLXBF3_GPIO_MAX_PINS_BLOCK1:
                id = 1;
                break;
        default:
                return -EINVAL;
        }

        return gpiochip_add_pin_range(chip, "MLNXBF34:00",
                        chip->base, id * MLXBF3_GPIO_MAX_PINS_PER_BLOCK,
                        chip->ngpio);
}

static int mlxbf3_gpio_probe(struct platform_device *pdev)
{
        struct gpio_generic_chip_config config;
        struct device *dev = &pdev->dev;
        struct mlxbf3_gpio_context *gs;
        struct gpio_irq_chip *girq;
        struct gpio_chip *gc;
        int ret, irq;

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

        gs->gpio_io = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(gs->gpio_io))
                return PTR_ERR(gs->gpio_io);

        gs->gpio_cause_io = devm_platform_ioremap_resource(pdev, 1);
        if (IS_ERR(gs->gpio_cause_io))
                return PTR_ERR(gs->gpio_cause_io);

        gs->gpio_set_io = devm_platform_ioremap_resource(pdev, 2);
        if (IS_ERR(gs->gpio_set_io))
                return PTR_ERR(gs->gpio_set_io);

        gs->gpio_clr_io = devm_platform_ioremap_resource(pdev, 3);
        if (IS_ERR(gs->gpio_clr_io))
                return PTR_ERR(gs->gpio_clr_io);
        gc = &gs->chip.gc;

        config = (struct gpio_generic_chip_config) {
                .dev = dev,
                .sz = 4,
                .dat = gs->gpio_io + MLXBF_GPIO_READ_DATA_IN,
                .set = gs->gpio_set_io + MLXBF_GPIO_FW_DATA_OUT_SET,
                .clr = gs->gpio_clr_io + MLXBF_GPIO_FW_DATA_OUT_CLEAR,
                .dirout = gs->gpio_set_io + MLXBF_GPIO_FW_OUTPUT_ENABLE_SET,
                .dirin = gs->gpio_clr_io + MLXBF_GPIO_FW_OUTPUT_ENABLE_CLEAR,
        };

        ret = gpio_generic_chip_init(&gs->chip, &config);
        if (ret)
                return dev_err_probe(dev, ret,
                                     "%s: failed to initialize the generic GPIO chip",
                                     __func__);

        gc->request = gpiochip_generic_request;
        gc->free = gpiochip_generic_free;
        gc->owner = THIS_MODULE;
        gc->add_pin_ranges = mlxbf3_gpio_add_pin_ranges;

        irq = platform_get_irq_optional(pdev, 0);
        if (irq >= 0) {
                girq = &gs->chip.gc.irq;
                gpio_irq_chip_set_chip(girq, &gpio_mlxbf3_irqchip);
                girq->default_type = IRQ_TYPE_NONE;
                /* This will let us handle the parent IRQ in the driver */
                girq->num_parents = 0;
                girq->parents = NULL;
                girq->parent_handler = NULL;
                girq->handler = handle_bad_irq;

                /*
                 * Directly request the irq here instead of passing
                 * a flow-handler because the irq is shared.
                 */
                ret = devm_request_irq(dev, irq, mlxbf3_gpio_irq_handler,
                                       IRQF_SHARED, dev_name(dev), gs);
                if (ret)
                        return dev_err_probe(dev, ret, "failed to request IRQ");
        }

        platform_set_drvdata(pdev, gs);

        ret = devm_gpiochip_add_data(dev, gc, gs);
        if (ret)
                dev_err_probe(dev, ret, "Failed adding memory mapped gpiochip\n");

        return 0;
}

static void mlxbf3_gpio_shutdown(struct platform_device *pdev)
{
        struct mlxbf3_gpio_context *gs = platform_get_drvdata(pdev);

        /* Disable and clear all interrupts */
        writel(0, gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_EVTEN0);
        writel(MLXBF_GPIO_CLR_ALL_INTS, gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_CLRCAUSE);
}

static const struct acpi_device_id mlxbf3_gpio_acpi_match[] = {
        { "MLNXBF33", 0 },
        {}
};
MODULE_DEVICE_TABLE(acpi, mlxbf3_gpio_acpi_match);

static struct platform_driver mlxbf3_gpio_driver = {
        .driver = {
                .name = "mlxbf3_gpio",
                .acpi_match_table = mlxbf3_gpio_acpi_match,
        },
        .probe    = mlxbf3_gpio_probe,
        .shutdown = mlxbf3_gpio_shutdown,
};
module_platform_driver(mlxbf3_gpio_driver);

MODULE_SOFTDEP("pre: pinctrl-mlxbf3");
MODULE_DESCRIPTION("NVIDIA BlueField-3 GPIO Driver");
MODULE_AUTHOR("Asmaa Mnebhi <asmaa@nvidia.com>");
MODULE_LICENSE("Dual BSD/GPL");