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1// SPDX-License-Identifier: GPL-2.0+2/*3 * Watchdog driver for Conexant Digicolor4 *5 * Copyright (C) 2015 Paradox Innovation Ltd.6 *7 */8 9#include <linux/types.h>10#include <linux/module.h>11#include <linux/io.h>12#include <linux/delay.h>13#include <linux/clk.h>14#include <linux/watchdog.h>15#include <linux/platform_device.h>16#include <linux/of_address.h>17 18#define TIMER_A_CONTROL 019#define TIMER_A_COUNT 420 21#define TIMER_A_ENABLE_COUNT BIT(0)22#define TIMER_A_ENABLE_WATCHDOG BIT(1)23 24struct dc_wdt {25 void __iomem *base;26 struct clk *clk;27 spinlock_t lock;28};29 30static unsigned timeout;31module_param(timeout, uint, 0);32MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");33 34static void dc_wdt_set(struct dc_wdt *wdt, u32 ticks)35{36 unsigned long flags;37 38 spin_lock_irqsave(&wdt->lock, flags);39 40 writel_relaxed(0, wdt->base + TIMER_A_CONTROL);41 writel_relaxed(ticks, wdt->base + TIMER_A_COUNT);42 writel_relaxed(TIMER_A_ENABLE_COUNT | TIMER_A_ENABLE_WATCHDOG,43 wdt->base + TIMER_A_CONTROL);44 45 spin_unlock_irqrestore(&wdt->lock, flags);46}47 48static int dc_wdt_restart(struct watchdog_device *wdog, unsigned long action,49 void *data)50{51 struct dc_wdt *wdt = watchdog_get_drvdata(wdog);52 53 dc_wdt_set(wdt, 1);54 /* wait for reset to assert... */55 mdelay(500);56 57 return 0;58}59 60static int dc_wdt_start(struct watchdog_device *wdog)61{62 struct dc_wdt *wdt = watchdog_get_drvdata(wdog);63 64 dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk));65 66 return 0;67}68 69static int dc_wdt_stop(struct watchdog_device *wdog)70{71 struct dc_wdt *wdt = watchdog_get_drvdata(wdog);72 73 writel_relaxed(0, wdt->base + TIMER_A_CONTROL);74 75 return 0;76}77 78static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)79{80 struct dc_wdt *wdt = watchdog_get_drvdata(wdog);81 82 dc_wdt_set(wdt, t * clk_get_rate(wdt->clk));83 wdog->timeout = t;84 85 return 0;86}87 88static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog)89{90 struct dc_wdt *wdt = watchdog_get_drvdata(wdog);91 uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT);92 93 return count / clk_get_rate(wdt->clk);94}95 96static const struct watchdog_ops dc_wdt_ops = {97 .owner = THIS_MODULE,98 .start = dc_wdt_start,99 .stop = dc_wdt_stop,100 .set_timeout = dc_wdt_set_timeout,101 .get_timeleft = dc_wdt_get_timeleft,102 .restart = dc_wdt_restart,103};104 105static const struct watchdog_info dc_wdt_info = {106 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE107 | WDIOF_KEEPALIVEPING,108 .identity = "Conexant Digicolor Watchdog",109};110 111static struct watchdog_device dc_wdt_wdd = {112 .info = &dc_wdt_info,113 .ops = &dc_wdt_ops,114 .min_timeout = 1,115};116 117static int dc_wdt_probe(struct platform_device *pdev)118{119 struct device *dev = &pdev->dev;120 struct dc_wdt *wdt;121 122 wdt = devm_kzalloc(dev, sizeof(struct dc_wdt), GFP_KERNEL);123 if (!wdt)124 return -ENOMEM;125 126 wdt->base = devm_platform_ioremap_resource(pdev, 0);127 if (IS_ERR(wdt->base))128 return PTR_ERR(wdt->base);129 130 wdt->clk = devm_clk_get(dev, NULL);131 if (IS_ERR(wdt->clk))132 return PTR_ERR(wdt->clk);133 dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk);134 dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout;135 dc_wdt_wdd.parent = dev;136 137 spin_lock_init(&wdt->lock);138 139 watchdog_set_drvdata(&dc_wdt_wdd, wdt);140 watchdog_set_restart_priority(&dc_wdt_wdd, 128);141 watchdog_init_timeout(&dc_wdt_wdd, timeout, dev);142 watchdog_stop_on_reboot(&dc_wdt_wdd);143 return devm_watchdog_register_device(dev, &dc_wdt_wdd);144}145 146static const struct of_device_id dc_wdt_of_match[] = {147 { .compatible = "cnxt,cx92755-wdt", },148 {},149};150MODULE_DEVICE_TABLE(of, dc_wdt_of_match);151 152static struct platform_driver dc_wdt_driver = {153 .probe = dc_wdt_probe,154 .driver = {155 .name = "digicolor-wdt",156 .of_match_table = dc_wdt_of_match,157 },158};159module_platform_driver(dc_wdt_driver);160 161MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");162MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer");163MODULE_LICENSE("GPL");164