// SPDX-License-Identifier: GPL-2.0
/*
 * Generic heartbeat driver for regular LED banks
 *
 * Copyright (C) 2007 - 2010  Paul Mundt
 *
 * Most SH reference boards include a number of individual LEDs that can
 * be independently controlled (either via a pre-defined hardware
 * function or via the LED class, if desired -- the hardware tends to
 * encapsulate some of the same "triggers" that the LED class supports,
 * so there's not too much value in it).
 *
 * Additionally, most of these boards also have a LED bank that we've
 * traditionally used for strobing the load average. This use case is
 * handled by this driver, rather than giving each LED bit position its
 * own struct device.
 */
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
#include <linux/sched/loadavg.h>
#include <linux/timer.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <asm/heartbeat.h>

#define DRV_NAME "heartbeat"
#define DRV_VERSION "0.1.2"

static unsigned char default_bit_pos[] = { 0, 1, 2, 3, 4, 5, 6, 7 };

static inline void heartbeat_toggle_bit(struct heartbeat_data *hd,
                                        unsigned bit, unsigned int inverted)
{
        unsigned int new;

        new = (1 << hd->bit_pos[bit]);
        if (inverted)
                new = ~new;

        new &= hd->mask;

        switch (hd->regsize) {
        case 32:
                new |= ioread32(hd->base) & ~hd->mask;
                iowrite32(new, hd->base);
                break;
        case 16:
                new |= ioread16(hd->base) & ~hd->mask;
                iowrite16(new, hd->base);
                break;
        default:
                new |= ioread8(hd->base) & ~hd->mask;
                iowrite8(new, hd->base);
                break;
        }
}

static void heartbeat_timer(struct timer_list *t)
{
        struct heartbeat_data *hd = timer_container_of(hd, t, timer);
        static unsigned bit = 0, up = 1;

        heartbeat_toggle_bit(hd, bit, hd->flags & HEARTBEAT_INVERTED);

        bit += up;
        if ((bit == 0) || (bit == (hd->nr_bits)-1))
                up = -up;

        mod_timer(&hd->timer, jiffies + (110 - ((300 << FSHIFT) /
                        ((avenrun[0] / 5) + (3 << FSHIFT)))));
}

static int heartbeat_drv_probe(struct platform_device *pdev)
{
        struct resource *res;
        struct heartbeat_data *hd;
        int i;

        if (unlikely(pdev->num_resources != 1)) {
                dev_err(&pdev->dev, "invalid number of resources\n");
                return -EINVAL;
        }

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (unlikely(res == NULL)) {
                dev_err(&pdev->dev, "invalid resource\n");
                return -EINVAL;
        }

        if (pdev->dev.platform_data) {
                hd = pdev->dev.platform_data;
        } else {
                hd = kzalloc_obj(struct heartbeat_data);
                if (unlikely(!hd))
                        return -ENOMEM;
        }

        hd->base = ioremap(res->start, resource_size(res));
        if (unlikely(!hd->base)) {
                dev_err(&pdev->dev, "ioremap failed\n");

                if (!pdev->dev.platform_data)
                        kfree(hd);

                return -ENXIO;
        }

        if (!hd->nr_bits) {
                hd->bit_pos = default_bit_pos;
                hd->nr_bits = ARRAY_SIZE(default_bit_pos);
        }

        hd->mask = 0;
        for (i = 0; i < hd->nr_bits; i++)
                hd->mask |= (1 << hd->bit_pos[i]);

        if (!hd->regsize) {
                switch (res->flags & IORESOURCE_MEM_TYPE_MASK) {
                case IORESOURCE_MEM_32BIT:
                        hd->regsize = 32;
                        break;
                case IORESOURCE_MEM_16BIT:
                        hd->regsize = 16;
                        break;
                case IORESOURCE_MEM_8BIT:
                default:
                        hd->regsize = 8;
                        break;
                }
        }

        timer_setup(&hd->timer, heartbeat_timer, 0);
        platform_set_drvdata(pdev, hd);

        return mod_timer(&hd->timer, jiffies + 1);
}

static struct platform_driver heartbeat_driver = {
        .probe          = heartbeat_drv_probe,
        .driver         = {
                .name                   = DRV_NAME,
                .suppress_bind_attrs    = true,
        },
};

static int __init heartbeat_init(void)
{
        printk(KERN_NOTICE DRV_NAME ": version %s loaded\n", DRV_VERSION);
        return platform_driver_register(&heartbeat_driver);
}
device_initcall(heartbeat_init);