1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Watchdog device driver for DA9062 and DA9061 PMICs
4 * Copyright (C) 2015  Dialog Semiconductor Ltd.
5 *
6 */
7
8#include <linux/kernel.h>
9#include <linux/module.h>
10#include <linux/watchdog.h>
11#include <linux/platform_device.h>
12#include <linux/uaccess.h>
13#include <linux/slab.h>
14#include <linux/i2c.h>
15#include <linux/delay.h>
16#include <linux/jiffies.h>
17#include <linux/mfd/da9062/registers.h>
18#include <linux/mfd/da9062/core.h>
19#include <linux/property.h>
20#include <linux/regmap.h>
21#include <linux/of.h>
22
23static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
24#define DA9062_TWDSCALE_DISABLE		0
25#define DA9062_TWDSCALE_MIN		1
26#define DA9062_TWDSCALE_MAX		(ARRAY_SIZE(wdt_timeout) - 1)
27#define DA9062_WDT_MIN_TIMEOUT		wdt_timeout[DA9062_TWDSCALE_MIN]
28#define DA9062_WDT_MAX_TIMEOUT		wdt_timeout[DA9062_TWDSCALE_MAX]
29#define DA9062_WDG_DEFAULT_TIMEOUT	wdt_timeout[DA9062_TWDSCALE_MAX-1]
30#define DA9062_RESET_PROTECTION_MS	300
31
32struct da9062_watchdog {
33	struct da9062 *hw;
34	struct watchdog_device wdtdev;
35	bool use_sw_pm;
36};
37
38static unsigned int da9062_wdt_read_timeout(struct da9062_watchdog *wdt)
39{
40	unsigned int val;
41
42	regmap_read(wdt->hw->regmap, DA9062AA_CONTROL_D, &val);
43
44	return wdt_timeout[val & DA9062AA_TWDSCALE_MASK];
45}
46
47static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs)
48{
49	unsigned int i;
50
51	for (i = DA9062_TWDSCALE_MIN; i <= DA9062_TWDSCALE_MAX; i++) {
52		if (wdt_timeout[i] >= secs)
53			return i;
54	}
55
56	return DA9062_TWDSCALE_MAX;
57}
58
59static int da9062_reset_watchdog_timer(struct da9062_watchdog *wdt)
60{
61	return regmap_update_bits(wdt->hw->regmap, DA9062AA_CONTROL_F,
62				  DA9062AA_WATCHDOG_MASK,
63				  DA9062AA_WATCHDOG_MASK);
64}
65
66static int da9062_wdt_update_timeout_register(struct da9062_watchdog *wdt,
67					      unsigned int regval)
68{
69	struct da9062 *chip = wdt->hw;
70
71	regmap_update_bits(chip->regmap,
72				  DA9062AA_CONTROL_D,
73				  DA9062AA_TWDSCALE_MASK,
74				  DA9062_TWDSCALE_DISABLE);
75
76	usleep_range(150, 300);
77
78	return regmap_update_bits(chip->regmap,
79				  DA9062AA_CONTROL_D,
80				  DA9062AA_TWDSCALE_MASK,
81				  regval);
82}
83
84static int da9062_wdt_start(struct watchdog_device *wdd)
85{
86	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
87	unsigned int selector;
88	int ret;
89
90	selector = da9062_wdt_timeout_to_sel(wdt->wdtdev.timeout);
91	ret = da9062_wdt_update_timeout_register(wdt, selector);
92	if (ret)
93		dev_err(wdt->hw->dev, "Watchdog failed to start (err = %d)\n",
94			ret);
95
96	return ret;
97}
98
99static int da9062_wdt_stop(struct watchdog_device *wdd)
100{
101	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
102	int ret;
103
104	ret = regmap_update_bits(wdt->hw->regmap,
105				 DA9062AA_CONTROL_D,
106				 DA9062AA_TWDSCALE_MASK,
107				 DA9062_TWDSCALE_DISABLE);
108	if (ret)
109		dev_err(wdt->hw->dev, "Watchdog failed to stop (err = %d)\n",
110			ret);
111
112	return ret;
113}
114
115static int da9062_wdt_ping(struct watchdog_device *wdd)
116{
117	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
118	int ret;
119
120	/*
121	 * Prevent pings from occurring late in system poweroff/reboot sequence
122	 * and possibly locking out restart handler from accessing i2c bus.
123	 */
124	if (system_state > SYSTEM_RUNNING)
125		return 0;
126
127	ret = da9062_reset_watchdog_timer(wdt);
128	if (ret)
129		dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
130			ret);
131
132	return ret;
133}
134
135static int da9062_wdt_set_timeout(struct watchdog_device *wdd,
136				  unsigned int timeout)
137{
138	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
139	unsigned int selector;
140	int ret;
141
142	selector = da9062_wdt_timeout_to_sel(timeout);
143	ret = da9062_wdt_update_timeout_register(wdt, selector);
144	if (ret)
145		dev_err(wdt->hw->dev, "Failed to set watchdog timeout (err = %d)\n",
146			ret);
147	else
148		wdd->timeout = wdt_timeout[selector];
149
150	return ret;
151}
152
153static int da9062_wdt_restart(struct watchdog_device *wdd, unsigned long action,
154			      void *data)
155{
156	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
157	struct i2c_client *client = to_i2c_client(wdt->hw->dev);
158	union i2c_smbus_data msg;
159	int ret;
160
161	/*
162	 * Don't use regmap because it is not atomic safe. Additionally, use
163	 * unlocked flavor of i2c_smbus_xfer to avoid scenario where i2c bus
164	 * might be previously locked by some process unable to release the
165	 * lock due to interrupts already being disabled at this late stage.
166	 */
167	msg.byte = DA9062AA_SHUTDOWN_MASK;
168	ret = __i2c_smbus_xfer(client->adapter, client->addr, client->flags,
169			       I2C_SMBUS_WRITE, DA9062AA_CONTROL_F,
170			       I2C_SMBUS_BYTE_DATA, &msg);
171
172	if (ret < 0)
173		dev_alert(wdt->hw->dev, "Failed to shutdown (err = %d)\n",
174			  ret);
175
176	/* wait for reset to assert... */
177	mdelay(500);
178
179	return ret;
180}
181
182static const struct watchdog_info da9062_watchdog_info = {
183	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
184	.identity = "DA9062 WDT",
185};
186
187static const struct watchdog_ops da9062_watchdog_ops = {
188	.owner = THIS_MODULE,
189	.start = da9062_wdt_start,
190	.stop = da9062_wdt_stop,
191	.ping = da9062_wdt_ping,
192	.set_timeout = da9062_wdt_set_timeout,
193	.restart = da9062_wdt_restart,
194};
195
196static const struct of_device_id da9062_compatible_id_table[] = {
197	{ .compatible = "dlg,da9062-watchdog", },
198	{ },
199};
200
201MODULE_DEVICE_TABLE(of, da9062_compatible_id_table);
202
203static int da9062_wdt_probe(struct platform_device *pdev)
204{
205	struct device *dev = &pdev->dev;
206	unsigned int timeout;
207	struct da9062 *chip;
208	struct da9062_watchdog *wdt;
209
210	chip = dev_get_drvdata(dev->parent);
211	if (!chip)
212		return -EINVAL;
213
214	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
215	if (!wdt)
216		return -ENOMEM;
217
218	wdt->use_sw_pm = device_property_present(dev, "dlg,use-sw-pm");
219
220	wdt->hw = chip;
221
222	wdt->wdtdev.info = &da9062_watchdog_info;
223	wdt->wdtdev.ops = &da9062_watchdog_ops;
224	wdt->wdtdev.min_timeout = DA9062_WDT_MIN_TIMEOUT;
225	wdt->wdtdev.max_timeout = DA9062_WDT_MAX_TIMEOUT;
226	wdt->wdtdev.min_hw_heartbeat_ms = DA9062_RESET_PROTECTION_MS;
227	wdt->wdtdev.timeout = DA9062_WDG_DEFAULT_TIMEOUT;
228	wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
229	wdt->wdtdev.parent = dev;
230
231	watchdog_set_restart_priority(&wdt->wdtdev, 128);
232
233	watchdog_set_drvdata(&wdt->wdtdev, wdt);
234	dev_set_drvdata(dev, &wdt->wdtdev);
235
236	timeout = da9062_wdt_read_timeout(wdt);
237	if (timeout)
238		wdt->wdtdev.timeout = timeout;
239
240	/* Set timeout from DT value if available */
241	watchdog_init_timeout(&wdt->wdtdev, 0, dev);
242
243	if (timeout) {
244		da9062_wdt_set_timeout(&wdt->wdtdev, wdt->wdtdev.timeout);
245		set_bit(WDOG_HW_RUNNING, &wdt->wdtdev.status);
246	}
247
248	return devm_watchdog_register_device(dev, &wdt->wdtdev);
249}
250
251static int __maybe_unused da9062_wdt_suspend(struct device *dev)
252{
253	struct watchdog_device *wdd = dev_get_drvdata(dev);
254	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
255
256	if (!wdt->use_sw_pm)
257		return 0;
258
259	if (watchdog_active(wdd))
260		return da9062_wdt_stop(wdd);
261
262	return 0;
263}
264
265static int __maybe_unused da9062_wdt_resume(struct device *dev)
266{
267	struct watchdog_device *wdd = dev_get_drvdata(dev);
268	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
269
270	if (!wdt->use_sw_pm)
271		return 0;
272
273	if (watchdog_active(wdd))
274		return da9062_wdt_start(wdd);
275
276	return 0;
277}
278
279static SIMPLE_DEV_PM_OPS(da9062_wdt_pm_ops,
280			 da9062_wdt_suspend, da9062_wdt_resume);
281
282static struct platform_driver da9062_wdt_driver = {
283	.probe = da9062_wdt_probe,
284	.driver = {
285		.name = "da9062-watchdog",
286		.pm = &da9062_wdt_pm_ops,
287		.of_match_table = da9062_compatible_id_table,
288	},
289};
290module_platform_driver(da9062_wdt_driver);
291
292MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>");
293MODULE_DESCRIPTION("WDT device driver for Dialog DA9062 and DA9061");
294MODULE_LICENSE("GPL");
295MODULE_ALIAS("platform:da9062-watchdog");
296