f6072896e3
This implements stricter and more compliant knightrider strobing in the heartbeat handler. While there still seems to be some debate as to whether the double 0 is "more" correct or not, this updated version appears to have general consensus. Fixes a long-term "bug". Signed-off-by: Takashi YOSHII <takashi.yoshii.ze@hitachi.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
126 lines
3.1 KiB
C
126 lines
3.1 KiB
C
/*
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* Generic heartbeat driver for regular LED banks
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*
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* Copyright (C) 2007 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/module.h>
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#include <linux/platform_device.h>
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#include <linux/sched.h>
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#include <linux/timer.h>
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#include <linux/io.h>
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#define DRV_NAME "heartbeat"
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#define DRV_VERSION "0.1.0"
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struct heartbeat_data {
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void __iomem *base;
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unsigned char bit_pos[8];
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struct timer_list timer;
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};
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static void heartbeat_timer(unsigned long data)
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{
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struct heartbeat_data *hd = (struct heartbeat_data *)data;
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static unsigned bit = 0, up = 1;
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ctrl_outw(1 << hd->bit_pos[bit], (unsigned long)hd->base);
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bit += up;
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if ((bit == 0) || (bit == ARRAY_SIZE(hd->bit_pos)-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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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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hd = kmalloc(sizeof(struct heartbeat_data), GFP_KERNEL);
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if (unlikely(!hd))
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return -ENOMEM;
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if (pdev->dev.platform_data) {
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memcpy(hd->bit_pos, pdev->dev.platform_data,
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ARRAY_SIZE(hd->bit_pos));
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} else {
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int i;
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for (i = 0; i < ARRAY_SIZE(hd->bit_pos); i++)
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hd->bit_pos[i] = i;
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}
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hd->base = (void __iomem *)res->start;
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setup_timer(&hd->timer, heartbeat_timer, (unsigned long)hd);
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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 int heartbeat_drv_remove(struct platform_device *pdev)
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{
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struct heartbeat_data *hd = platform_get_drvdata(pdev);
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del_timer_sync(&hd->timer);
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platform_set_drvdata(pdev, NULL);
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kfree(hd);
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return 0;
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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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.remove = heartbeat_drv_remove,
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.driver = {
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.name = DRV_NAME,
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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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static void __exit heartbeat_exit(void)
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{
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platform_driver_unregister(&heartbeat_driver);
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}
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module_init(heartbeat_init);
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module_exit(heartbeat_exit);
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MODULE_VERSION(DRV_VERSION);
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MODULE_AUTHOR("Paul Mundt");
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MODULE_LICENSE("GPLv2");
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