// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * TI DaVinci GPIO Support
 *
 * Copyright (c) 2006-2007 David Brownell
 * Copyright (c) 2007, MontaVista Software, Inc. <source@mvista.com>
 */

#include <linux/gpio/driver.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/platform_data/gpio-davinci.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/spinlock.h>

#include <asm-generic/gpio.h>

#define MAX_REGS_BANKS 5
#define MAX_INT_PER_BANK 32

struct davinci_gpio_regs {
        u32     dir;
        u32     out_data;
        u32     set_data;
        u32     clr_data;
        u32     in_data;
        u32     set_rising;
        u32     clr_rising;
        u32     set_falling;
        u32     clr_falling;
        u32     intstat;
};

typedef struct irq_chip *(*gpio_get_irq_chip_cb_t)(unsigned int irq);

#define BINTEN  0x8 /* GPIO Interrupt Per-Bank Enable Register */

static void __iomem *gpio_base;
static unsigned int offset_array[5] = {0x10, 0x38, 0x60, 0x88, 0xb0};

struct davinci_gpio_irq_data {
        void __iomem                    *regs;
        struct davinci_gpio_controller  *chip;
        int                             bank_num;
};

struct davinci_gpio_controller {
        struct gpio_chip        chip;
        struct irq_domain       *irq_domain;
        /* Serialize access to GPIO registers */
        spinlock_t              lock;
        void __iomem            *regs[MAX_REGS_BANKS];
        int                     gpio_unbanked;
        int                     irqs[MAX_INT_PER_BANK];
};

static inline u32 __gpio_mask(unsigned gpio)
{
        return 1 << (gpio % 32);
}

static inline struct davinci_gpio_regs __iomem *irq2regs(struct irq_data *d)
{
        struct davinci_gpio_regs __iomem *g;

        g = (__force struct davinci_gpio_regs __iomem *)irq_data_get_irq_chip_data(d);

        return g;
}

static int davinci_gpio_irq_setup(struct platform_device *pdev);

/*--------------------------------------------------------------------------*/

/* board setup code *MUST* setup pinmux and enable the GPIO clock. */
static inline int __davinci_direction(struct gpio_chip *chip,
                        unsigned offset, bool out, int value)
{
        struct davinci_gpio_controller *d = gpiochip_get_data(chip);
        struct davinci_gpio_regs __iomem *g;
        unsigned long flags;
        u32 temp;
        int bank = offset / 32;
        u32 mask = __gpio_mask(offset);

        g = d->regs[bank];
        spin_lock_irqsave(&d->lock, flags);
        temp = readl_relaxed(&g->dir);
        if (out) {
                temp &= ~mask;
                writel_relaxed(mask, value ? &g->set_data : &g->clr_data);
        } else {
                temp |= mask;
        }
        writel_relaxed(temp, &g->dir);
        spin_unlock_irqrestore(&d->lock, flags);

        return 0;
}

static int davinci_direction_in(struct gpio_chip *chip, unsigned offset)
{
        return __davinci_direction(chip, offset, false, 0);
}

static int
davinci_direction_out(struct gpio_chip *chip, unsigned offset, int value)
{
        return __davinci_direction(chip, offset, true, value);
}

/*
 * Read the pin's value (works even if it's set up as output);
 * returns zero/nonzero.
 *
 * Note that changes are synched to the GPIO clock, so reading values back
 * right after you've set them may give old values.
 */
static int davinci_gpio_get(struct gpio_chip *chip, unsigned offset)
{
        struct davinci_gpio_controller *d = gpiochip_get_data(chip);
        struct davinci_gpio_regs __iomem *g;
        int bank = offset / 32;

        g = d->regs[bank];

        return !!(__gpio_mask(offset) & readl_relaxed(&g->in_data));
}

/*
 * Assuming the pin is muxed as a gpio output, set its output value.
 */
static void
davinci_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
        struct davinci_gpio_controller *d = gpiochip_get_data(chip);
        struct davinci_gpio_regs __iomem *g;
        int bank = offset / 32;

        g = d->regs[bank];

        writel_relaxed(__gpio_mask(offset),
                       value ? &g->set_data : &g->clr_data);
}

static struct davinci_gpio_platform_data *
davinci_gpio_get_pdata(struct platform_device *pdev)
{
        struct device_node *dn = pdev->dev.of_node;
        struct davinci_gpio_platform_data *pdata;
        int ret;
        u32 val;

        if (!IS_ENABLED(CONFIG_OF) || !pdev->dev.of_node)
                return dev_get_platdata(&pdev->dev);

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

        ret = of_property_read_u32(dn, "ti,ngpio", &val);
        if (ret)
                goto of_err;

        pdata->ngpio = val;

        ret = of_property_read_u32(dn, "ti,davinci-gpio-unbanked", &val);
        if (ret)
                goto of_err;

        pdata->gpio_unbanked = val;

        return pdata;

of_err:
        dev_err(&pdev->dev, "Populating pdata from DT failed: err %d\n", ret);
        return NULL;
}

static int davinci_gpio_probe(struct platform_device *pdev)
{
        int bank, i, ret = 0;
        unsigned int ngpio, nbank, nirq;
        struct davinci_gpio_controller *chips;
        struct davinci_gpio_platform_data *pdata;
        struct device *dev = &pdev->dev;

        pdata = davinci_gpio_get_pdata(pdev);
        if (!pdata) {
                dev_err(dev, "No platform data found\n");
                return -EINVAL;
        }

        dev->platform_data = pdata;

        /*
         * The gpio banks conceptually expose a segmented bitmap,
         * and "ngpio" is one more than the largest zero-based
         * bit index that's valid.
         */
        ngpio = pdata->ngpio;
        if (ngpio == 0) {
                dev_err(dev, "How many GPIOs?\n");
                return -EINVAL;
        }

        if (WARN_ON(ARCH_NR_GPIOS < ngpio))
                ngpio = ARCH_NR_GPIOS;

        /*
         * If there are unbanked interrupts then the number of
         * interrupts is equal to number of gpios else all are banked so
         * number of interrupts is equal to number of banks(each with 16 gpios)
         */
        if (pdata->gpio_unbanked)
                nirq = pdata->gpio_unbanked;
        else
                nirq = DIV_ROUND_UP(ngpio, 16);

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

        gpio_base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(gpio_base))
                return PTR_ERR(gpio_base);

        for (i = 0; i < nirq; i++) {
                chips->irqs[i] = platform_get_irq(pdev, i);
                if (chips->irqs[i] < 0)
                        return dev_err_probe(dev, chips->irqs[i], "IRQ not populated\n");
        }

        chips->chip.label = dev_name(dev);

        chips->chip.direction_input = davinci_direction_in;
        chips->chip.get = davinci_gpio_get;
        chips->chip.direction_output = davinci_direction_out;
        chips->chip.set = davinci_gpio_set;

        chips->chip.ngpio = ngpio;
        chips->chip.base = pdata->no_auto_base ? pdata->base : -1;

#ifdef CONFIG_OF_GPIO
        chips->chip.of_gpio_n_cells = 2;
        chips->chip.parent = dev;
        chips->chip.of_node = dev->of_node;
        chips->chip.request = gpiochip_generic_request;
        chips->chip.free = gpiochip_generic_free;
#endif
        spin_lock_init(&chips->lock);

        nbank = DIV_ROUND_UP(ngpio, 32);
        for (bank = 0; bank < nbank; bank++)
                chips->regs[bank] = gpio_base + offset_array[bank];

        ret = devm_gpiochip_add_data(dev, &chips->chip, chips);
        if (ret)
                return ret;

        platform_set_drvdata(pdev, chips);
        ret = davinci_gpio_irq_setup(pdev);
        if (ret)
                return ret;

        return 0;
}

/*--------------------------------------------------------------------------*/
/*
 * We expect irqs will normally be set up as input pins, but they can also be
 * used as output pins ... which is convenient for testing.
 *
 * NOTE:  The first few GPIOs also have direct INTC hookups in addition
 * to their GPIOBNK0 irq, with a bit less overhead.
 *
 * All those INTC hookups (direct, plus several IRQ banks) can also
 * serve as EDMA event triggers.
 */

static void gpio_irq_disable(struct irq_data *d)
{
        struct davinci_gpio_regs __iomem *g = irq2regs(d);
        uintptr_t mask = (uintptr_t)irq_data_get_irq_handler_data(d);

        writel_relaxed(mask, &g->clr_falling);
        writel_relaxed(mask, &g->clr_rising);
}

static void gpio_irq_enable(struct irq_data *d)
{
        struct davinci_gpio_regs __iomem *g = irq2regs(d);
        uintptr_t mask = (uintptr_t)irq_data_get_irq_handler_data(d);
        unsigned status = irqd_get_trigger_type(d);

        status &= IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING;
        if (!status)
                status = IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING;

        if (status & IRQ_TYPE_EDGE_FALLING)
                writel_relaxed(mask, &g->set_falling);
        if (status & IRQ_TYPE_EDGE_RISING)
                writel_relaxed(mask, &g->set_rising);
}

static int gpio_irq_type(struct irq_data *d, unsigned trigger)
{
        if (trigger & ~(IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
                return -EINVAL;

        return 0;
}

static struct irq_chip gpio_irqchip = {
        .name           = "GPIO",
        .irq_enable     = gpio_irq_enable,
        .irq_disable    = gpio_irq_disable,
        .irq_set_type   = gpio_irq_type,
        .flags          = IRQCHIP_SET_TYPE_MASKED,
};

static void gpio_irq_handler(struct irq_desc *desc)
{
        struct davinci_gpio_regs __iomem *g;
        u32 mask = 0xffff;
        int bank_num;
        struct davinci_gpio_controller *d;
        struct davinci_gpio_irq_data *irqdata;

        irqdata = (struct davinci_gpio_irq_data *)irq_desc_get_handler_data(desc);
        bank_num = irqdata->bank_num;
        g = irqdata->regs;
        d = irqdata->chip;

        /* we only care about one bank */
        if ((bank_num % 2) == 1)
                mask <<= 16;

        /* temporarily mask (level sensitive) parent IRQ */
        chained_irq_enter(irq_desc_get_chip(desc), desc);
        while (1) {
                u32             status;
                int             bit;
                irq_hw_number_t hw_irq;

                /* ack any irqs */
                status = readl_relaxed(&g->intstat) & mask;
                if (!status)
                        break;
                writel_relaxed(status, &g->intstat);

                /* now demux them to the right lowlevel handler */

                while (status) {
                        bit = __ffs(status);
                        status &= ~BIT(bit);
                        /* Max number of gpios per controller is 144 so
                         * hw_irq will be in [0..143]
                         */
                        hw_irq = (bank_num / 2) * 32 + bit;

                        generic_handle_irq(
                                irq_find_mapping(d->irq_domain, hw_irq));
                }
        }
        chained_irq_exit(irq_desc_get_chip(desc), desc);
        /* now it may re-trigger */
}

static int gpio_to_irq_banked(struct gpio_chip *chip, unsigned offset)
{
        struct davinci_gpio_controller *d = gpiochip_get_data(chip);

        if (d->irq_domain)
                return irq_create_mapping(d->irq_domain, offset);
        else
                return -ENXIO;
}

static int gpio_to_irq_unbanked(struct gpio_chip *chip, unsigned offset)
{
        struct davinci_gpio_controller *d = gpiochip_get_data(chip);

        /*
         * NOTE:  we assume for now that only irqs in the first gpio_chip
         * can provide direct-mapped IRQs to AINTC (up to 32 GPIOs).
         */
        if (offset < d->gpio_unbanked)
                return d->irqs[offset];
        else
                return -ENODEV;
}

static int gpio_irq_type_unbanked(struct irq_data *data, unsigned trigger)
{
        struct davinci_gpio_controller *d;
        struct davinci_gpio_regs __iomem *g;
        u32 mask, i;

        d = (struct davinci_gpio_controller *)irq_data_get_irq_handler_data(data);
        g = (struct davinci_gpio_regs __iomem *)d->regs[0];
        for (i = 0; i < MAX_INT_PER_BANK; i++)
                if (data->irq == d->irqs[i])
                        break;

        if (i == MAX_INT_PER_BANK)
                return -EINVAL;

        mask = __gpio_mask(i);

        if (trigger & ~(IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
                return -EINVAL;

        writel_relaxed(mask, (trigger & IRQ_TYPE_EDGE_FALLING)
                     ? &g->set_falling : &g->clr_falling);
        writel_relaxed(mask, (trigger & IRQ_TYPE_EDGE_RISING)
                     ? &g->set_rising : &g->clr_rising);

        return 0;
}

static int
davinci_gpio_irq_map(struct irq_domain *d, unsigned int irq,
                     irq_hw_number_t hw)
{
        struct davinci_gpio_controller *chips =
                                (struct davinci_gpio_controller *)d->host_data;
        struct davinci_gpio_regs __iomem *g = chips->regs[hw / 32];

        irq_set_chip_and_handler_name(irq, &gpio_irqchip, handle_simple_irq,
                                "davinci_gpio");
        irq_set_irq_type(irq, IRQ_TYPE_NONE);
        irq_set_chip_data(irq, (__force void *)g);
        irq_set_handler_data(irq, (void *)(uintptr_t)__gpio_mask(hw));

        return 0;
}

static const struct irq_domain_ops davinci_gpio_irq_ops = {
        .map = davinci_gpio_irq_map,
        .xlate = irq_domain_xlate_onetwocell,
};

static struct irq_chip *davinci_gpio_get_irq_chip(unsigned int irq)
{
        static struct irq_chip_type gpio_unbanked;

        gpio_unbanked = *irq_data_get_chip_type(irq_get_irq_data(irq));

        return &gpio_unbanked.chip;
};

static struct irq_chip *keystone_gpio_get_irq_chip(unsigned int irq)
{
        static struct irq_chip gpio_unbanked;

        gpio_unbanked = *irq_get_chip(irq);
        return &gpio_unbanked;
};

static const struct of_device_id davinci_gpio_ids[];

/*
 * NOTE:  for suspend/resume, probably best to make a platform_device with
 * suspend_late/resume_resume calls hooking into results of the set_wake()
 * calls ... so if no gpios are wakeup events the clock can be disabled,
 * with outputs left at previously set levels, and so that VDD3P3V.IOPWDN0
 * (dm6446) can be set appropriately for GPIOV33 pins.
 */

static int davinci_gpio_irq_setup(struct platform_device *pdev)
{
        unsigned        gpio, bank;
        int             irq;
        int             ret;
        struct clk      *clk;
        u32             binten = 0;
        unsigned        ngpio;
        struct device *dev = &pdev->dev;
        struct davinci_gpio_controller *chips = platform_get_drvdata(pdev);
        struct davinci_gpio_platform_data *pdata = dev->platform_data;
        struct davinci_gpio_regs __iomem *g;
        struct irq_domain       *irq_domain = NULL;
        const struct of_device_id *match;
        struct irq_chip *irq_chip;
        struct davinci_gpio_irq_data *irqdata;
        gpio_get_irq_chip_cb_t gpio_get_irq_chip;

        /*
         * Use davinci_gpio_get_irq_chip by default to handle non DT cases
         */
        gpio_get_irq_chip = davinci_gpio_get_irq_chip;
        match = of_match_device(of_match_ptr(davinci_gpio_ids),
                                dev);
        if (match)
                gpio_get_irq_chip = (gpio_get_irq_chip_cb_t)match->data;

        ngpio = pdata->ngpio;

        clk = devm_clk_get(dev, "gpio");
        if (IS_ERR(clk)) {
                dev_err(dev, "Error %ld getting gpio clock\n", PTR_ERR(clk));
                return PTR_ERR(clk);
        }

        ret = clk_prepare_enable(clk);
        if (ret)
                return ret;

        if (!pdata->gpio_unbanked) {
                irq = devm_irq_alloc_descs(dev, -1, 0, ngpio, 0);
                if (irq < 0) {
                        dev_err(dev, "Couldn't allocate IRQ numbers\n");
                        clk_disable_unprepare(clk);
                        return irq;
                }

                irq_domain = irq_domain_add_legacy(dev->of_node, ngpio, irq, 0,
                                                        &davinci_gpio_irq_ops,
                                                        chips);
                if (!irq_domain) {
                        dev_err(dev, "Couldn't register an IRQ domain\n");
                        clk_disable_unprepare(clk);
                        return -ENODEV;
                }
        }

        /*
         * Arrange gpio_to_irq() support, handling either direct IRQs or
         * banked IRQs.  Having GPIOs in the first GPIO bank use direct
         * IRQs, while the others use banked IRQs, would need some setup
         * tweaks to recognize hardware which can do that.
         */
        chips->chip.to_irq = gpio_to_irq_banked;
        chips->irq_domain = irq_domain;

        /*
         * AINTC can handle direct/unbanked IRQs for GPIOs, with the GPIO
         * controller only handling trigger modes.  We currently assume no
         * IRQ mux conflicts; gpio_irq_type_unbanked() is only for GPIOs.
         */
        if (pdata->gpio_unbanked) {
                /* pass "bank 0" GPIO IRQs to AINTC */
                chips->chip.to_irq = gpio_to_irq_unbanked;
                chips->gpio_unbanked = pdata->gpio_unbanked;
                binten = GENMASK(pdata->gpio_unbanked / 16, 0);

                /* AINTC handles mask/unmask; GPIO handles triggering */
                irq = chips->irqs[0];
                irq_chip = gpio_get_irq_chip(irq);
                irq_chip->name = "GPIO-AINTC";
                irq_chip->irq_set_type = gpio_irq_type_unbanked;

                /* default trigger: both edges */
                g = chips->regs[0];
                writel_relaxed(~0, &g->set_falling);
                writel_relaxed(~0, &g->set_rising);

                /* set the direct IRQs up to use that irqchip */
                for (gpio = 0; gpio < pdata->gpio_unbanked; gpio++) {
                        irq_set_chip(chips->irqs[gpio], irq_chip);
                        irq_set_handler_data(chips->irqs[gpio], chips);
                        irq_set_status_flags(chips->irqs[gpio],
                                             IRQ_TYPE_EDGE_BOTH);
                }

                goto done;
        }

        /*
         * Or, AINTC can handle IRQs for banks of 16 GPIO IRQs, which we
         * then chain through our own handler.
         */
        for (gpio = 0, bank = 0; gpio < ngpio; bank++, gpio += 16) {
                /* disabled by default, enabled only as needed
                 * There are register sets for 32 GPIOs. 2 banks of 16
                 * GPIOs are covered by each set of registers hence divide by 2
                 */
                g = chips->regs[bank / 2];
                writel_relaxed(~0, &g->clr_falling);
                writel_relaxed(~0, &g->clr_rising);

                /*
                 * Each chip handles 32 gpios, and each irq bank consists of 16
                 * gpio irqs. Pass the irq bank's corresponding controller to
                 * the chained irq handler.
                 */
                irqdata = devm_kzalloc(&pdev->dev,
                                       sizeof(struct
                                              davinci_gpio_irq_data),
                                              GFP_KERNEL);
                if (!irqdata) {
                        clk_disable_unprepare(clk);
                        return -ENOMEM;
                }

                irqdata->regs = g;
                irqdata->bank_num = bank;
                irqdata->chip = chips;

                irq_set_chained_handler_and_data(chips->irqs[bank],
                                                 gpio_irq_handler, irqdata);

                binten |= BIT(bank);
        }

done:
        /*
         * BINTEN -- per-bank interrupt enable. genirq would also let these
         * bits be set/cleared dynamically.
         */
        writel_relaxed(binten, gpio_base + BINTEN);

        return 0;
}

static const struct of_device_id davinci_gpio_ids[] = {
        { .compatible = "ti,keystone-gpio", keystone_gpio_get_irq_chip},
        { .compatible = "ti,am654-gpio", keystone_gpio_get_irq_chip},
        { .compatible = "ti,dm6441-gpio", davinci_gpio_get_irq_chip},
        { /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, davinci_gpio_ids);

static struct platform_driver davinci_gpio_driver = {
        .probe          = davinci_gpio_probe,
        .driver         = {
                .name           = "davinci_gpio",
                .of_match_table = of_match_ptr(davinci_gpio_ids),
        },
};

/**
 * GPIO driver registration needs to be done before machine_init functions
 * access GPIO. Hence davinci_gpio_drv_reg() is a postcore_initcall.
 */
static int __init davinci_gpio_drv_reg(void)
{
        return platform_driver_register(&davinci_gpio_driver);
}
postcore_initcall(davinci_gpio_drv_reg);