273 lines
7.1 KiB
C
273 lines
7.1 KiB
C
/*
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* drivers/char/watchdog/pnx4008_wdt.c
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*
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* Watchdog driver for PNX4008 board
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*
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* Authors: Dmitry Chigirev <source@mvista.com>,
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* Vitaly Wool <vitalywool@gmail.com>
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* Based on sa1100 driver,
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* Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
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*
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* 2005-2006 (c) MontaVista Software, Inc.
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*
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* (C) 2012 Wolfram Sang, Pengutronix
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*
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* This file is licensed under the terms of the GNU General Public License
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* version 2. This program is licensed "as is" without any warranty of any
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* kind, whether express or implied.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/watchdog.h>
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#include <linux/platform_device.h>
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#include <linux/clk.h>
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#include <linux/spinlock.h>
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#include <linux/io.h>
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#include <linux/slab.h>
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#include <linux/err.h>
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#include <linux/of.h>
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#include <linux/delay.h>
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#include <linux/reboot.h>
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#include <mach/hardware.h>
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/* WatchDog Timer - Chapter 23 Page 207 */
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#define DEFAULT_HEARTBEAT 19
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#define MAX_HEARTBEAT 60
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/* Watchdog timer register set definition */
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#define WDTIM_INT(p) ((p) + 0x0)
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#define WDTIM_CTRL(p) ((p) + 0x4)
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#define WDTIM_COUNTER(p) ((p) + 0x8)
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#define WDTIM_MCTRL(p) ((p) + 0xC)
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#define WDTIM_MATCH0(p) ((p) + 0x10)
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#define WDTIM_EMR(p) ((p) + 0x14)
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#define WDTIM_PULSE(p) ((p) + 0x18)
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#define WDTIM_RES(p) ((p) + 0x1C)
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/* WDTIM_INT bit definitions */
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#define MATCH_INT 1
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/* WDTIM_CTRL bit definitions */
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#define COUNT_ENAB 1
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#define RESET_COUNT (1 << 1)
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#define DEBUG_EN (1 << 2)
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/* WDTIM_MCTRL bit definitions */
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#define MR0_INT 1
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#undef RESET_COUNT0
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#define RESET_COUNT0 (1 << 2)
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#define STOP_COUNT0 (1 << 2)
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#define M_RES1 (1 << 3)
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#define M_RES2 (1 << 4)
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#define RESFRC1 (1 << 5)
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#define RESFRC2 (1 << 6)
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/* WDTIM_EMR bit definitions */
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#define EXT_MATCH0 1
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#define MATCH_OUTPUT_HIGH (2 << 4) /*a MATCH_CTRL setting */
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/* WDTIM_RES bit definitions */
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#define WDOG_RESET 1 /* read only */
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#define WDOG_COUNTER_RATE 13000000 /*the counter clock is 13 MHz fixed */
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static bool nowayout = WATCHDOG_NOWAYOUT;
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static unsigned int heartbeat = DEFAULT_HEARTBEAT;
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static DEFINE_SPINLOCK(io_lock);
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static void __iomem *wdt_base;
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static struct clk *wdt_clk;
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static int pnx4008_wdt_start(struct watchdog_device *wdd)
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{
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spin_lock(&io_lock);
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/* stop counter, initiate counter reset */
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writel(RESET_COUNT, WDTIM_CTRL(wdt_base));
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/*wait for reset to complete. 100% guarantee event */
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while (readl(WDTIM_COUNTER(wdt_base)))
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cpu_relax();
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/* internal and external reset, stop after that */
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writel(M_RES2 | STOP_COUNT0 | RESET_COUNT0, WDTIM_MCTRL(wdt_base));
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/* configure match output */
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writel(MATCH_OUTPUT_HIGH, WDTIM_EMR(wdt_base));
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/* clear interrupt, just in case */
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writel(MATCH_INT, WDTIM_INT(wdt_base));
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/* the longest pulse period 65541/(13*10^6) seconds ~ 5 ms. */
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writel(0xFFFF, WDTIM_PULSE(wdt_base));
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writel(wdd->timeout * WDOG_COUNTER_RATE, WDTIM_MATCH0(wdt_base));
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/*enable counter, stop when debugger active */
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writel(COUNT_ENAB | DEBUG_EN, WDTIM_CTRL(wdt_base));
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spin_unlock(&io_lock);
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return 0;
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}
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static int pnx4008_wdt_stop(struct watchdog_device *wdd)
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{
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spin_lock(&io_lock);
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writel(0, WDTIM_CTRL(wdt_base)); /*stop counter */
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spin_unlock(&io_lock);
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return 0;
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}
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static int pnx4008_wdt_set_timeout(struct watchdog_device *wdd,
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unsigned int new_timeout)
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{
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wdd->timeout = new_timeout;
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return 0;
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}
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static int pnx4008_restart_handler(struct watchdog_device *wdd,
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unsigned long mode, void *cmd)
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{
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const char *boot_cmd = cmd;
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/*
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* Verify if a "cmd" passed from the userspace program rebooting
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* the system; if available, handle it.
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* - For details, see the 'reboot' syscall in kernel/reboot.c
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* - If the received "cmd" is not supported, use the default mode.
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*/
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if (boot_cmd) {
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if (boot_cmd[0] == 'h')
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mode = REBOOT_HARD;
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else if (boot_cmd[0] == 's')
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mode = REBOOT_SOFT;
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}
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if (mode == REBOOT_SOFT) {
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/* Force match output active */
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writel(EXT_MATCH0, WDTIM_EMR(wdt_base));
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/* Internal reset on match output (RESOUT_N not asserted) */
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writel(M_RES1, WDTIM_MCTRL(wdt_base));
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} else {
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/* Instant assert of RESETOUT_N with pulse length 1mS */
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writel(13000, WDTIM_PULSE(wdt_base));
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writel(M_RES2 | RESFRC1 | RESFRC2, WDTIM_MCTRL(wdt_base));
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}
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/* Wait for watchdog to reset system */
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mdelay(1000);
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return NOTIFY_DONE;
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}
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static const struct watchdog_info pnx4008_wdt_ident = {
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.options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
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WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
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.identity = "PNX4008 Watchdog",
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};
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static const struct watchdog_ops pnx4008_wdt_ops = {
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.owner = THIS_MODULE,
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.start = pnx4008_wdt_start,
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.stop = pnx4008_wdt_stop,
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.set_timeout = pnx4008_wdt_set_timeout,
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.restart = pnx4008_restart_handler,
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};
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static struct watchdog_device pnx4008_wdd = {
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.info = &pnx4008_wdt_ident,
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.ops = &pnx4008_wdt_ops,
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.timeout = DEFAULT_HEARTBEAT,
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.min_timeout = 1,
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.max_timeout = MAX_HEARTBEAT,
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};
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static int pnx4008_wdt_probe(struct platform_device *pdev)
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{
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struct resource *r;
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int ret = 0;
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watchdog_init_timeout(&pnx4008_wdd, heartbeat, &pdev->dev);
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r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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wdt_base = devm_ioremap_resource(&pdev->dev, r);
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if (IS_ERR(wdt_base))
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return PTR_ERR(wdt_base);
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wdt_clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(wdt_clk))
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return PTR_ERR(wdt_clk);
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ret = clk_prepare_enable(wdt_clk);
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if (ret)
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return ret;
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pnx4008_wdd.bootstatus = (readl(WDTIM_RES(wdt_base)) & WDOG_RESET) ?
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WDIOF_CARDRESET : 0;
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pnx4008_wdd.parent = &pdev->dev;
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watchdog_set_nowayout(&pnx4008_wdd, nowayout);
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watchdog_set_restart_priority(&pnx4008_wdd, 128);
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pnx4008_wdt_stop(&pnx4008_wdd); /* disable for now */
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ret = watchdog_register_device(&pnx4008_wdd);
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if (ret < 0) {
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dev_err(&pdev->dev, "cannot register watchdog device\n");
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goto disable_clk;
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}
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dev_info(&pdev->dev, "heartbeat %d sec\n", pnx4008_wdd.timeout);
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return 0;
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disable_clk:
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clk_disable_unprepare(wdt_clk);
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return ret;
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}
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static int pnx4008_wdt_remove(struct platform_device *pdev)
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{
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watchdog_unregister_device(&pnx4008_wdd);
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clk_disable_unprepare(wdt_clk);
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return 0;
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}
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#ifdef CONFIG_OF
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static const struct of_device_id pnx4008_wdt_match[] = {
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{ .compatible = "nxp,pnx4008-wdt" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, pnx4008_wdt_match);
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#endif
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static struct platform_driver platform_wdt_driver = {
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.driver = {
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.name = "pnx4008-watchdog",
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.of_match_table = of_match_ptr(pnx4008_wdt_match),
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},
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.probe = pnx4008_wdt_probe,
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.remove = pnx4008_wdt_remove,
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};
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module_platform_driver(platform_wdt_driver);
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MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
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MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
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MODULE_DESCRIPTION("PNX4008 Watchdog Driver");
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module_param(heartbeat, uint, 0);
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MODULE_PARM_DESC(heartbeat,
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"Watchdog heartbeat period in seconds from 1 to "
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__MODULE_STRING(MAX_HEARTBEAT) ", default "
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__MODULE_STRING(DEFAULT_HEARTBEAT));
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout,
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"Set to 1 to keep watchdog running after device release");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:pnx4008-watchdog");
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