// SPDX-License-Identifier: GPL-2.0
/*
 * R-Car Generation 2 da9063(L)/da9210 regulator quirk
 *
 * Certain Gen2 development boards have an da9063 and one or more da9210
 * regulators. All of these regulators have their interrupt request lines
 * tied to the same interrupt pin (IRQ2) on the SoC.
 *
 * After cold boot or da9063-induced restart, both the da9063 and da9210 seem
 * to assert their interrupt request lines.  Hence as soon as one driver
 * requests this irq, it gets stuck in an interrupt storm, as it only manages
 * to deassert its own interrupt request line, and the other driver hasn't
 * installed an interrupt handler yet.
 *
 * To handle this, install a quirk that masks the interrupts in both the
 * da9063 and da9210.  This quirk has to run after the i2c master driver has
 * been initialized, but before the i2c slave drivers are initialized.
 *
 * Copyright (C) 2015 Glider bvba
 */

#include <linux/device.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/list.h>
#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/mfd/da9063/registers.h>

#define IRQC_BASE               0xe61c0000
#define IRQC_MONITOR            0x104   /* IRQn Signal Level Monitor Register */

#define REGULATOR_IRQ_MASK      BIT(2)  /* IRQ2, active low */

/* start of DA9210 System Control and Event Registers */
#define DA9210_REG_MASK_A               0x54

struct regulator_quirk {
        struct list_head                list;
        const struct of_device_id       *id;
        struct device_node              *np;
        struct of_phandle_args          irq_args;
        struct i2c_msg                  i2c_msg;
        bool                            shared; /* IRQ line is shared */
};

static LIST_HEAD(quirk_list);
static void __iomem *irqc;

/* first byte sets the memory pointer, following are consecutive reg values */
static u8 da9063_irq_clr[] = { DA9063_REG_IRQ_MASK_A, 0xff, 0xff, 0xff, 0xff };
static u8 da9210_irq_clr[] = { DA9210_REG_MASK_A, 0xff, 0xff };

static struct i2c_msg da9063_msg = {
        .len = ARRAY_SIZE(da9063_irq_clr),
        .buf = da9063_irq_clr,
};

static struct i2c_msg da9210_msg = {
        .len = ARRAY_SIZE(da9210_irq_clr),
        .buf = da9210_irq_clr,
};

static const struct of_device_id rcar_gen2_quirk_match[] = {
        { .compatible = "dlg,da9063", .data = &da9063_msg },
        { .compatible = "dlg,da9063l", .data = &da9063_msg },
        { .compatible = "dlg,da9210", .data = &da9210_msg },
        { /* sentinel */ }
};

static int regulator_quirk_notify(struct notifier_block *nb,
                                  unsigned long action, void *data)
{
        struct regulator_quirk *pos, *tmp;
        struct device *dev = data;
        struct i2c_client *client;
        static bool done;
        int ret;
        u32 mon;

        if (done)
                return 0;

        mon = ioread32(irqc + IRQC_MONITOR);
        dev_dbg(dev, "%s: %ld, IRQC_MONITOR = 0x%x\n", __func__, action, mon);
        if (mon & REGULATOR_IRQ_MASK)
                goto remove;

        if (action != BUS_NOTIFY_ADD_DEVICE || dev->type == &i2c_adapter_type)
                return 0;

        client = to_i2c_client(dev);
        dev_dbg(dev, "Detected %s\n", client->name);

        /*
         * Send message to all PMICs that share an IRQ line to deassert it.
         *
         * WARNING: This works only if all the PMICs are on the same I2C bus.
         */
        list_for_each_entry(pos, &quirk_list, list) {
                if (!pos->shared)
                        continue;

                if (pos->np->parent != client->dev.parent->of_node)
                        continue;

                dev_info(&client->dev, "clearing %s@0x%02x interrupts\n",
                         pos->id->compatible, pos->i2c_msg.addr);

                ret = i2c_transfer(client->adapter, &pos->i2c_msg, 1);
                if (ret != 1)
                        dev_err(&client->dev, "i2c error %d\n", ret);
        }

        mon = ioread32(irqc + IRQC_MONITOR);
        if (mon & REGULATOR_IRQ_MASK)
                goto remove;

        return 0;

remove:
        dev_info(dev, "IRQ2 is not asserted, removing quirk\n");

        list_for_each_entry_safe(pos, tmp, &quirk_list, list) {
                list_del(&pos->list);
                of_node_put(pos->np);
                kfree(pos);
        }

        done = true;
        iounmap(irqc);
        return 0;
}

static struct notifier_block regulator_quirk_nb = {
        .notifier_call = regulator_quirk_notify
};

static int __init rcar_gen2_regulator_quirk(void)
{
        struct regulator_quirk *quirk, *pos, *tmp;
        struct of_phandle_args *argsa, *argsb;
        const struct of_device_id *id;
        struct device_node *np;
        u32 mon, addr;
        int ret;

        if (!of_machine_is_compatible("renesas,koelsch") &&
            !of_machine_is_compatible("renesas,lager") &&
            !of_machine_is_compatible("renesas,porter") &&
            !of_machine_is_compatible("renesas,stout") &&
            !of_machine_is_compatible("renesas,gose"))
                return -ENODEV;

        for_each_matching_node_and_match(np, rcar_gen2_quirk_match, &id) {
                if (!of_device_is_available(np)) {
                        of_node_put(np);
                        break;
                }

                ret = of_property_read_u32(np, "reg", &addr);
                if (ret)        /* Skip invalid entry and continue */
                        continue;

                quirk = kzalloc_obj(*quirk);
                if (!quirk) {
                        ret = -ENOMEM;
                        of_node_put(np);
                        goto err_mem;
                }

                argsa = &quirk->irq_args;
                memcpy(&quirk->i2c_msg, id->data, sizeof(quirk->i2c_msg));

                quirk->id = id;
                quirk->np = of_node_get(np);
                quirk->i2c_msg.addr = addr;

                ret = of_irq_parse_one(np, 0, argsa);
                if (ret) {      /* Skip invalid entry and continue */
                        of_node_put(np);
                        kfree(quirk);
                        continue;
                }

                list_for_each_entry(pos, &quirk_list, list) {
                        argsb = &pos->irq_args;

                        if (argsa->args_count != argsb->args_count)
                                continue;

                        ret = memcmp(argsa->args, argsb->args,
                                     argsa->args_count *
                                     sizeof(argsa->args[0]));
                        if (!ret) {
                                pos->shared = true;
                                quirk->shared = true;
                        }
                }

                list_add_tail(&quirk->list, &quirk_list);
        }

        irqc = ioremap(IRQC_BASE, PAGE_SIZE);
        if (!irqc) {
                ret = -ENOMEM;
                goto err_mem;
        }

        mon = ioread32(irqc + IRQC_MONITOR);
        if (mon & REGULATOR_IRQ_MASK) {
                pr_debug("%s: IRQ2 is not asserted, not installing quirk\n",
                         __func__);
                ret = 0;
                goto err_free;
        }

        pr_info("IRQ2 is asserted, installing regulator quirk\n");

        bus_register_notifier(&i2c_bus_type, &regulator_quirk_nb);
        return 0;

err_free:
        iounmap(irqc);
err_mem:
        list_for_each_entry_safe(pos, tmp, &quirk_list, list) {
                list_del(&pos->list);
                of_node_put(pos->np);
                kfree(pos);
        }

        return ret;
}

arch_initcall(rcar_gen2_regulator_quirk);