Baruch Siach | 336694a | 2015-03-31 09:14:59 +0300 | [diff] [blame] | 1 | /* |
| 2 | * Watchdog driver for Conexant Digicolor |
| 3 | * |
| 4 | * Copyright (C) 2015 Paradox Innovation Ltd. |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify it |
| 7 | * under the terms of the GNU General Public License as published by the |
| 8 | * Free Software Foundation; either version 2 of the License, or (at your |
| 9 | * option) any later version. |
| 10 | */ |
| 11 | |
| 12 | #include <linux/types.h> |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/io.h> |
| 15 | #include <linux/delay.h> |
| 16 | #include <linux/clk.h> |
| 17 | #include <linux/watchdog.h> |
Baruch Siach | 336694a | 2015-03-31 09:14:59 +0300 | [diff] [blame] | 18 | #include <linux/platform_device.h> |
| 19 | #include <linux/of_address.h> |
| 20 | |
| 21 | #define TIMER_A_CONTROL 0 |
| 22 | #define TIMER_A_COUNT 4 |
| 23 | |
| 24 | #define TIMER_A_ENABLE_COUNT BIT(0) |
| 25 | #define TIMER_A_ENABLE_WATCHDOG BIT(1) |
| 26 | |
| 27 | struct dc_wdt { |
| 28 | void __iomem *base; |
| 29 | struct clk *clk; |
Baruch Siach | 336694a | 2015-03-31 09:14:59 +0300 | [diff] [blame] | 30 | spinlock_t lock; |
| 31 | }; |
| 32 | |
| 33 | static unsigned timeout; |
| 34 | module_param(timeout, uint, 0); |
| 35 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds"); |
| 36 | |
| 37 | static void dc_wdt_set(struct dc_wdt *wdt, u32 ticks) |
| 38 | { |
| 39 | unsigned long flags; |
| 40 | |
| 41 | spin_lock_irqsave(&wdt->lock, flags); |
| 42 | |
| 43 | writel_relaxed(0, wdt->base + TIMER_A_CONTROL); |
| 44 | writel_relaxed(ticks, wdt->base + TIMER_A_COUNT); |
| 45 | writel_relaxed(TIMER_A_ENABLE_COUNT | TIMER_A_ENABLE_WATCHDOG, |
| 46 | wdt->base + TIMER_A_CONTROL); |
| 47 | |
| 48 | spin_unlock_irqrestore(&wdt->lock, flags); |
| 49 | } |
| 50 | |
Guenter Roeck | 4d8b229 | 2016-02-26 17:32:49 -0800 | [diff] [blame] | 51 | static int dc_wdt_restart(struct watchdog_device *wdog, unsigned long action, |
| 52 | void *data) |
Baruch Siach | 336694a | 2015-03-31 09:14:59 +0300 | [diff] [blame] | 53 | { |
Damien Riegel | d3b0818 | 2015-11-16 12:28:02 -0500 | [diff] [blame] | 54 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); |
Baruch Siach | 336694a | 2015-03-31 09:14:59 +0300 | [diff] [blame] | 55 | |
| 56 | dc_wdt_set(wdt, 1); |
| 57 | /* wait for reset to assert... */ |
| 58 | mdelay(500); |
| 59 | |
Damien Riegel | d3b0818 | 2015-11-16 12:28:02 -0500 | [diff] [blame] | 60 | return 0; |
Baruch Siach | 336694a | 2015-03-31 09:14:59 +0300 | [diff] [blame] | 61 | } |
| 62 | |
| 63 | static int dc_wdt_start(struct watchdog_device *wdog) |
| 64 | { |
| 65 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); |
| 66 | |
| 67 | dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk)); |
| 68 | |
| 69 | return 0; |
| 70 | } |
| 71 | |
| 72 | static int dc_wdt_stop(struct watchdog_device *wdog) |
| 73 | { |
| 74 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); |
| 75 | |
| 76 | writel_relaxed(0, wdt->base + TIMER_A_CONTROL); |
| 77 | |
| 78 | return 0; |
| 79 | } |
| 80 | |
| 81 | static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t) |
| 82 | { |
| 83 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); |
| 84 | |
| 85 | dc_wdt_set(wdt, t * clk_get_rate(wdt->clk)); |
| 86 | wdog->timeout = t; |
| 87 | |
| 88 | return 0; |
| 89 | } |
| 90 | |
| 91 | static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog) |
| 92 | { |
| 93 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); |
| 94 | uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT); |
| 95 | |
| 96 | return count / clk_get_rate(wdt->clk); |
| 97 | } |
| 98 | |
| 99 | static struct watchdog_ops dc_wdt_ops = { |
| 100 | .owner = THIS_MODULE, |
| 101 | .start = dc_wdt_start, |
| 102 | .stop = dc_wdt_stop, |
| 103 | .set_timeout = dc_wdt_set_timeout, |
| 104 | .get_timeleft = dc_wdt_get_timeleft, |
Damien Riegel | d3b0818 | 2015-11-16 12:28:02 -0500 | [diff] [blame] | 105 | .restart = dc_wdt_restart, |
Baruch Siach | 336694a | 2015-03-31 09:14:59 +0300 | [diff] [blame] | 106 | }; |
| 107 | |
| 108 | static struct watchdog_info dc_wdt_info = { |
| 109 | .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
| 110 | | WDIOF_KEEPALIVEPING, |
| 111 | .identity = "Conexant Digicolor Watchdog", |
| 112 | }; |
| 113 | |
| 114 | static struct watchdog_device dc_wdt_wdd = { |
| 115 | .info = &dc_wdt_info, |
| 116 | .ops = &dc_wdt_ops, |
| 117 | .min_timeout = 1, |
| 118 | }; |
| 119 | |
| 120 | static int dc_wdt_probe(struct platform_device *pdev) |
| 121 | { |
| 122 | struct device *dev = &pdev->dev; |
| 123 | struct device_node *np = dev->of_node; |
| 124 | struct dc_wdt *wdt; |
| 125 | int ret; |
| 126 | |
| 127 | wdt = devm_kzalloc(dev, sizeof(struct dc_wdt), GFP_KERNEL); |
| 128 | if (!wdt) |
| 129 | return -ENOMEM; |
| 130 | platform_set_drvdata(pdev, wdt); |
| 131 | |
| 132 | wdt->base = of_iomap(np, 0); |
| 133 | if (!wdt->base) { |
| 134 | dev_err(dev, "Failed to remap watchdog regs"); |
| 135 | return -ENODEV; |
| 136 | } |
| 137 | |
| 138 | wdt->clk = devm_clk_get(&pdev->dev, NULL); |
| 139 | if (IS_ERR(wdt->clk)) { |
| 140 | ret = PTR_ERR(wdt->clk); |
| 141 | goto err_iounmap; |
| 142 | } |
| 143 | dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk); |
| 144 | dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout; |
Pratyush Anand | 6551881 | 2015-08-20 14:05:01 +0530 | [diff] [blame] | 145 | dc_wdt_wdd.parent = &pdev->dev; |
Baruch Siach | 336694a | 2015-03-31 09:14:59 +0300 | [diff] [blame] | 146 | |
| 147 | spin_lock_init(&wdt->lock); |
| 148 | |
| 149 | watchdog_set_drvdata(&dc_wdt_wdd, wdt); |
Damien Riegel | d3b0818 | 2015-11-16 12:28:02 -0500 | [diff] [blame] | 150 | watchdog_set_restart_priority(&dc_wdt_wdd, 128); |
Baruch Siach | 336694a | 2015-03-31 09:14:59 +0300 | [diff] [blame] | 151 | watchdog_init_timeout(&dc_wdt_wdd, timeout, dev); |
| 152 | ret = watchdog_register_device(&dc_wdt_wdd); |
| 153 | if (ret) { |
| 154 | dev_err(dev, "Failed to register watchdog device"); |
| 155 | goto err_iounmap; |
| 156 | } |
| 157 | |
Baruch Siach | 336694a | 2015-03-31 09:14:59 +0300 | [diff] [blame] | 158 | return 0; |
| 159 | |
| 160 | err_iounmap: |
| 161 | iounmap(wdt->base); |
| 162 | return ret; |
| 163 | } |
| 164 | |
| 165 | static int dc_wdt_remove(struct platform_device *pdev) |
| 166 | { |
| 167 | struct dc_wdt *wdt = platform_get_drvdata(pdev); |
| 168 | |
Baruch Siach | 336694a | 2015-03-31 09:14:59 +0300 | [diff] [blame] | 169 | watchdog_unregister_device(&dc_wdt_wdd); |
| 170 | iounmap(wdt->base); |
| 171 | |
| 172 | return 0; |
| 173 | } |
| 174 | |
| 175 | static void dc_wdt_shutdown(struct platform_device *pdev) |
| 176 | { |
| 177 | dc_wdt_stop(&dc_wdt_wdd); |
| 178 | } |
| 179 | |
| 180 | static const struct of_device_id dc_wdt_of_match[] = { |
| 181 | { .compatible = "cnxt,cx92755-wdt", }, |
| 182 | {}, |
| 183 | }; |
| 184 | MODULE_DEVICE_TABLE(of, dc_wdt_of_match); |
| 185 | |
| 186 | static struct platform_driver dc_wdt_driver = { |
| 187 | .probe = dc_wdt_probe, |
| 188 | .remove = dc_wdt_remove, |
| 189 | .shutdown = dc_wdt_shutdown, |
| 190 | .driver = { |
| 191 | .name = "digicolor-wdt", |
| 192 | .of_match_table = dc_wdt_of_match, |
| 193 | }, |
| 194 | }; |
| 195 | module_platform_driver(dc_wdt_driver); |
| 196 | |
| 197 | MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>"); |
| 198 | MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer"); |
| 199 | MODULE_LICENSE("GPL"); |