2 * Moschip MCS814x Watchdog driver
4 * Copyright (C) 2012, Florian Fainelli <florian@openwrt.org>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 #include <linux/module.h>
22 #include <linux/slab.h>
23 #include <linux/init.h>
24 #include <linux/platform_device.h>
25 #include <linux/miscdevice.h>
26 #include <linux/watchdog.h>
28 #include <linux/err.h>
29 #include <linux/clk.h>
32 #define WDT_COUNT 0x00
34 #define WDT_CTRL_EN 0x1
36 /* watchdog frequency */
37 #define WDT_MAX_VALUE (0xffffffff)
42 struct watchdog_device wdt_dev
;
46 static int mcs814x_wdt_start(struct watchdog_device
*dev
)
48 struct mcs814x_wdt
*wdt
= watchdog_get_drvdata(dev
);
51 spin_lock(&wdt
->lock
);
52 reg
= readl_relaxed(wdt
->regs
+ WDT_CTRL
);
54 writel_relaxed(reg
, wdt
->regs
+ WDT_CTRL
);
55 spin_unlock(&wdt
->lock
);
60 static int mcs814x_wdt_stop(struct watchdog_device
*dev
)
62 struct mcs814x_wdt
*wdt
= watchdog_get_drvdata(dev
);
65 spin_lock(&wdt
->lock
);
66 reg
= readl_relaxed(wdt
->regs
+ WDT_CTRL
);
68 writel_relaxed(reg
, wdt
->regs
+ WDT_CTRL
);
69 spin_unlock(&wdt
->lock
);
74 static int mcs814x_wdt_set_timeout(struct watchdog_device
*dev
,
75 unsigned int new_timeout
)
77 struct mcs814x_wdt
*wdt
= watchdog_get_drvdata(dev
);
79 spin_lock(&wdt
->lock
);
80 /* watchdog counts upward and rollover (0xfffffff -> 0)
83 writel_relaxed(WDT_MAX_VALUE
- (new_timeout
* clk_get_rate(wdt
->clk
)),
84 wdt
->regs
+ WDT_COUNT
);
85 spin_unlock(&wdt
->lock
);
90 static int mcs814x_wdt_ping(struct watchdog_device
*dev
)
92 /* restart the watchdog */
93 mcs814x_wdt_stop(dev
);
94 mcs814x_wdt_set_timeout(dev
, dev
->timeout
);
95 mcs814x_wdt_start(dev
);
100 static const struct watchdog_info mcs814x_wdt_ident
= {
101 .options
= WDIOF_CARDRESET
| WDIOF_SETTIMEOUT
|
102 WDIOF_MAGICCLOSE
| WDIOF_KEEPALIVEPING
,
103 .identity
= "MCS814x Watchdog",
106 static struct watchdog_ops mcs814x_wdt_ops
= {
107 .owner
= THIS_MODULE
,
108 .start
= mcs814x_wdt_start
,
109 .stop
= mcs814x_wdt_stop
,
110 .set_timeout
= mcs814x_wdt_set_timeout
,
111 .ping
= mcs814x_wdt_ping
,
114 static int mcs814x_wdt_probe(struct platform_device
*pdev
)
116 struct resource
*res
;
117 struct mcs814x_wdt
*wdt
;
121 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
125 clk
= clk_get(NULL
, "wdt");
126 if (IS_ERR_OR_NULL(clk
)) {
127 dev_err(&pdev
->dev
, "failed to get watchdog clock\n");
131 wdt
= kzalloc(sizeof(*wdt
), GFP_KERNEL
);
137 spin_lock_init(&wdt
->lock
);
139 wdt
->wdt_dev
.info
= &mcs814x_wdt_ident
;
140 wdt
->wdt_dev
.ops
= &mcs814x_wdt_ops
;
141 wdt
->wdt_dev
.min_timeout
= 1;
142 /* approximately 10995 secs */
143 wdt
->wdt_dev
.max_timeout
= (WDT_MAX_VALUE
/ clk_get_rate(clk
));
145 platform_set_drvdata(pdev
, wdt
);
147 /* only ioremap registers, because the register is shared */
148 wdt
->regs
= devm_ioremap(&pdev
->dev
, res
->start
, resource_size(res
));
154 watchdog_set_drvdata(&wdt
->wdt_dev
, wdt
);
156 ret
= watchdog_register_device(&wdt
->wdt_dev
);
158 dev_err(&pdev
->dev
, "cannot register watchdog: %d\n", ret
);
162 dev_info(&pdev
->dev
, "registered\n");
166 platform_set_drvdata(pdev
, NULL
);
173 static int mcs814x_wdt_remove(struct platform_device
*pdev
)
175 struct mcs814x_wdt
*wdt
= platform_get_drvdata(pdev
);
178 watchdog_unregister_device(&wdt
->wdt_dev
);
179 watchdog_set_drvdata(&wdt
->wdt_dev
, NULL
);
181 platform_set_drvdata(pdev
, NULL
);
186 static const struct of_device_id mcs814x_wdt_ids
[] = {
187 { .compatible
= "moschip,mcs814x-wdt", },
191 static struct platform_driver mcs814x_wdt_driver
= {
193 .name
= "mcs814x-wdt",
194 .owner
= THIS_MODULE
,
195 .of_match_table
= mcs814x_wdt_ids
,
197 .probe
= mcs814x_wdt_probe
,
198 .remove
= mcs814x_wdt_remove
,
201 module_platform_driver(mcs814x_wdt_driver
);
203 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
204 MODULE_DESCRIPTION("Moschip MCS814x Watchdog driver");
205 MODULE_LICENSE("GPL");
206 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR
);
207 MODULE_ALIAS("platform:mcs814x-wdt");