156 lines
3.7 KiB
C
156 lines
3.7 KiB
C
/*
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* Generic heartbeat driver for regular LED banks
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*
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* Copyright (C) 2007 - 2010 Paul Mundt
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*
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* Most SH reference boards include a number of individual LEDs that can
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* be independently controlled (either via a pre-defined hardware
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* function or via the LED class, if desired -- the hardware tends to
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* encapsulate some of the same "triggers" that the LED class supports,
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* so there's not too much value in it).
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*
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* Additionally, most of these boards also have a LED bank that we've
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* traditionally used for strobing the load average. This use case is
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* handled by this driver, rather than giving each LED bit position its
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* own struct device.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/sched.h>
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#include <linux/sched/loadavg.h>
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#include <linux/timer.h>
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#include <linux/io.h>
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#include <linux/slab.h>
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#include <asm/heartbeat.h>
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#define DRV_NAME "heartbeat"
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#define DRV_VERSION "0.1.2"
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static unsigned char default_bit_pos[] = { 0, 1, 2, 3, 4, 5, 6, 7 };
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static inline void heartbeat_toggle_bit(struct heartbeat_data *hd,
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unsigned bit, unsigned int inverted)
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{
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unsigned int new;
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new = (1 << hd->bit_pos[bit]);
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if (inverted)
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new = ~new;
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new &= hd->mask;
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switch (hd->regsize) {
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case 32:
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new |= ioread32(hd->base) & ~hd->mask;
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iowrite32(new, hd->base);
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break;
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case 16:
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new |= ioread16(hd->base) & ~hd->mask;
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iowrite16(new, hd->base);
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break;
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default:
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new |= ioread8(hd->base) & ~hd->mask;
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iowrite8(new, hd->base);
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break;
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}
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}
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static void heartbeat_timer(struct timer_list *t)
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{
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struct heartbeat_data *hd = from_timer(hd, t, timer);
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static unsigned bit = 0, up = 1;
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heartbeat_toggle_bit(hd, bit, hd->flags & HEARTBEAT_INVERTED);
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bit += up;
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if ((bit == 0) || (bit == (hd->nr_bits)-1))
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up = -up;
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mod_timer(&hd->timer, jiffies + (110 - ((300 << FSHIFT) /
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((avenrun[0] / 5) + (3 << FSHIFT)))));
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}
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static int heartbeat_drv_probe(struct platform_device *pdev)
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{
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struct resource *res;
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struct heartbeat_data *hd;
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int i;
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if (unlikely(pdev->num_resources != 1)) {
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dev_err(&pdev->dev, "invalid number of resources\n");
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return -EINVAL;
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}
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (unlikely(res == NULL)) {
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dev_err(&pdev->dev, "invalid resource\n");
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return -EINVAL;
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}
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if (pdev->dev.platform_data) {
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hd = pdev->dev.platform_data;
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} else {
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hd = kzalloc(sizeof(struct heartbeat_data), GFP_KERNEL);
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if (unlikely(!hd))
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return -ENOMEM;
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}
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hd->base = ioremap_nocache(res->start, resource_size(res));
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if (unlikely(!hd->base)) {
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dev_err(&pdev->dev, "ioremap failed\n");
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if (!pdev->dev.platform_data)
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kfree(hd);
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return -ENXIO;
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}
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if (!hd->nr_bits) {
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hd->bit_pos = default_bit_pos;
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hd->nr_bits = ARRAY_SIZE(default_bit_pos);
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}
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hd->mask = 0;
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for (i = 0; i < hd->nr_bits; i++)
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hd->mask |= (1 << hd->bit_pos[i]);
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if (!hd->regsize) {
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switch (res->flags & IORESOURCE_MEM_TYPE_MASK) {
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case IORESOURCE_MEM_32BIT:
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hd->regsize = 32;
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break;
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case IORESOURCE_MEM_16BIT:
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hd->regsize = 16;
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break;
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case IORESOURCE_MEM_8BIT:
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default:
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hd->regsize = 8;
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break;
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}
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}
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timer_setup(&hd->timer, heartbeat_timer, 0);
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platform_set_drvdata(pdev, hd);
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return mod_timer(&hd->timer, jiffies + 1);
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}
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static struct platform_driver heartbeat_driver = {
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.probe = heartbeat_drv_probe,
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.driver = {
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.name = DRV_NAME,
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.suppress_bind_attrs = true,
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},
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};
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static int __init heartbeat_init(void)
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{
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printk(KERN_NOTICE DRV_NAME ": version %s loaded\n", DRV_VERSION);
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return platform_driver_register(&heartbeat_driver);
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}
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device_initcall(heartbeat_init);
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