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46#include <linux/kernel.h>
47#include <linux/init.h>
48#include <linux/interrupt.h>
49#include <linux/device.h>
50#include <linux/platform_device.h>
51#include <linux/ktime.h>
52#include <linux/slab.h>
53#include <linux/kmod.h>
54#include <linux/module.h>
55#include <linux/panic_notifier.h>
56#include <linux/mod_devicetable.h>
57#include <linux/gpio/consumer.h>
58#include <linux/reboot.h>
59#include <linux/property.h>
60
61struct ltc2952_poweroff {
62 struct hrtimer timer_trigger;
63 struct hrtimer timer_wde;
64
65 ktime_t trigger_delay;
66 ktime_t wde_interval;
67
68 struct device *dev;
69
70 struct gpio_desc *gpio_trigger;
71 struct gpio_desc *gpio_watchdog;
72 struct gpio_desc *gpio_kill;
73
74 bool kernel_panic;
75 struct notifier_block panic_notifier;
76};
77
78#define to_ltc2952(p, m) container_of(p, struct ltc2952_poweroff, m)
79
80
81
82
83
84static struct ltc2952_poweroff *ltc2952_data;
85
86
87
88
89
90
91
92
93
94
95static enum hrtimer_restart ltc2952_poweroff_timer_wde(struct hrtimer *timer)
96{
97 ktime_t now;
98 int state;
99 struct ltc2952_poweroff *data = to_ltc2952(timer, timer_wde);
100
101 if (data->kernel_panic)
102 return HRTIMER_NORESTART;
103
104 state = gpiod_get_value(data->gpio_watchdog);
105 gpiod_set_value(data->gpio_watchdog, !state);
106
107 now = hrtimer_cb_get_time(timer);
108 hrtimer_forward(timer, now, data->wde_interval);
109
110 return HRTIMER_RESTART;
111}
112
113static void ltc2952_poweroff_start_wde(struct ltc2952_poweroff *data)
114{
115 hrtimer_start(&data->timer_wde, data->wde_interval, HRTIMER_MODE_REL);
116}
117
118static enum hrtimer_restart
119ltc2952_poweroff_timer_trigger(struct hrtimer *timer)
120{
121 struct ltc2952_poweroff *data = to_ltc2952(timer, timer_trigger);
122
123 ltc2952_poweroff_start_wde(data);
124 dev_info(data->dev, "executing shutdown\n");
125 orderly_poweroff(true);
126
127 return HRTIMER_NORESTART;
128}
129
130
131
132
133
134
135
136
137
138
139static irqreturn_t ltc2952_poweroff_handler(int irq, void *dev_id)
140{
141 struct ltc2952_poweroff *data = dev_id;
142
143 if (data->kernel_panic || hrtimer_active(&data->timer_wde)) {
144
145 return IRQ_HANDLED;
146 }
147
148 if (gpiod_get_value(data->gpio_trigger)) {
149 hrtimer_start(&data->timer_trigger, data->trigger_delay,
150 HRTIMER_MODE_REL);
151 } else {
152 hrtimer_cancel(&data->timer_trigger);
153 }
154 return IRQ_HANDLED;
155}
156
157static void ltc2952_poweroff_kill(void)
158{
159 gpiod_set_value(ltc2952_data->gpio_kill, 1);
160}
161
162static void ltc2952_poweroff_default(struct ltc2952_poweroff *data)
163{
164 data->wde_interval = 300L * 1E6L;
165 data->trigger_delay = ktime_set(2, 500L*1E6L);
166
167 hrtimer_init(&data->timer_trigger, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
168 data->timer_trigger.function = ltc2952_poweroff_timer_trigger;
169
170 hrtimer_init(&data->timer_wde, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
171 data->timer_wde.function = ltc2952_poweroff_timer_wde;
172}
173
174static int ltc2952_poweroff_init(struct platform_device *pdev)
175{
176 int ret;
177 u32 trigger_delay_ms;
178 struct ltc2952_poweroff *data = platform_get_drvdata(pdev);
179
180 ltc2952_poweroff_default(data);
181
182 if (!device_property_read_u32(&pdev->dev, "trigger-delay-ms",
183 &trigger_delay_ms)) {
184 data->trigger_delay = ktime_set(trigger_delay_ms / MSEC_PER_SEC,
185 (trigger_delay_ms % MSEC_PER_SEC) * NSEC_PER_MSEC);
186 }
187
188 data->gpio_watchdog = devm_gpiod_get(&pdev->dev, "watchdog",
189 GPIOD_OUT_LOW);
190 if (IS_ERR(data->gpio_watchdog)) {
191 ret = PTR_ERR(data->gpio_watchdog);
192 dev_err(&pdev->dev, "unable to claim gpio \"watchdog\"\n");
193 return ret;
194 }
195
196 data->gpio_kill = devm_gpiod_get(&pdev->dev, "kill", GPIOD_OUT_LOW);
197 if (IS_ERR(data->gpio_kill)) {
198 ret = PTR_ERR(data->gpio_kill);
199 dev_err(&pdev->dev, "unable to claim gpio \"kill\"\n");
200 return ret;
201 }
202
203 data->gpio_trigger = devm_gpiod_get_optional(&pdev->dev, "trigger",
204 GPIOD_IN);
205 if (IS_ERR(data->gpio_trigger)) {
206
207
208
209
210
211 dev_err(&pdev->dev, "unable to claim gpio \"trigger\"\n");
212 data->gpio_trigger = NULL;
213 }
214
215 if (devm_request_irq(&pdev->dev, gpiod_to_irq(data->gpio_trigger),
216 ltc2952_poweroff_handler,
217 (IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING),
218 "ltc2952-poweroff",
219 data)) {
220
221
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231
232
233
234
235 if (data->gpio_trigger) {
236 dev_warn(&pdev->dev,
237 "unable to configure the trigger interrupt\n");
238 devm_gpiod_put(&pdev->dev, data->gpio_trigger);
239 data->gpio_trigger = NULL;
240 }
241 dev_info(&pdev->dev,
242 "power down trigger input will not be used\n");
243 ltc2952_poweroff_start_wde(data);
244 }
245
246 return 0;
247}
248
249static int ltc2952_poweroff_notify_panic(struct notifier_block *nb,
250 unsigned long code, void *unused)
251{
252 struct ltc2952_poweroff *data = to_ltc2952(nb, panic_notifier);
253
254 data->kernel_panic = true;
255 return NOTIFY_DONE;
256}
257
258static int ltc2952_poweroff_probe(struct platform_device *pdev)
259{
260 int ret;
261 struct ltc2952_poweroff *data;
262
263 if (pm_power_off) {
264 dev_err(&pdev->dev, "pm_power_off already registered");
265 return -EBUSY;
266 }
267
268 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
269 if (!data)
270 return -ENOMEM;
271
272 data->dev = &pdev->dev;
273 platform_set_drvdata(pdev, data);
274
275 ret = ltc2952_poweroff_init(pdev);
276 if (ret)
277 return ret;
278
279
280 ltc2952_data = data;
281 pm_power_off = ltc2952_poweroff_kill;
282
283 data->panic_notifier.notifier_call = ltc2952_poweroff_notify_panic;
284 atomic_notifier_chain_register(&panic_notifier_list,
285 &data->panic_notifier);
286 dev_info(&pdev->dev, "probe successful\n");
287
288 return 0;
289}
290
291static int ltc2952_poweroff_remove(struct platform_device *pdev)
292{
293 struct ltc2952_poweroff *data = platform_get_drvdata(pdev);
294
295 pm_power_off = NULL;
296 hrtimer_cancel(&data->timer_trigger);
297 hrtimer_cancel(&data->timer_wde);
298 atomic_notifier_chain_unregister(&panic_notifier_list,
299 &data->panic_notifier);
300 return 0;
301}
302
303static const struct of_device_id of_ltc2952_poweroff_match[] = {
304 { .compatible = "lltc,ltc2952"},
305 {},
306};
307MODULE_DEVICE_TABLE(of, of_ltc2952_poweroff_match);
308
309static struct platform_driver ltc2952_poweroff_driver = {
310 .probe = ltc2952_poweroff_probe,
311 .remove = ltc2952_poweroff_remove,
312 .driver = {
313 .name = "ltc2952-poweroff",
314 .of_match_table = of_ltc2952_poweroff_match,
315 },
316};
317
318module_platform_driver(ltc2952_poweroff_driver);
319
320MODULE_AUTHOR("René Moll <rene.moll@xsens.com>");
321MODULE_DESCRIPTION("LTC PowerPath power-off driver");
322MODULE_LICENSE("GPL v2");
323