René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 1 | /* |
| 2 | * LTC2952 (PowerPath) driver |
| 3 | * |
| 4 | * Copyright (C) 2014, Xsens Technologies BV <info@xsens.com> |
| 5 | * Maintainer: René Moll <linux@r-moll.nl> |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU General Public License |
| 9 | * as published by the Free Software Foundation; either version 2 |
| 10 | * of the License, or (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * ---------------------------------------- |
| 18 | * - Description |
| 19 | * ---------------------------------------- |
| 20 | * |
| 21 | * This driver is to be used with an external PowerPath Controller (LTC2952). |
| 22 | * Its function is to determine when a external shut down is triggered |
| 23 | * and react by properly shutting down the system. |
| 24 | * |
| 25 | * This driver expects a device tree with a ltc2952 entry for pin mapping. |
| 26 | * |
| 27 | * ---------------------------------------- |
| 28 | * - GPIO |
| 29 | * ---------------------------------------- |
| 30 | * |
| 31 | * The following GPIOs are used: |
| 32 | * - trigger (input) |
| 33 | * A level change indicates the shut-down trigger. If it's state reverts |
| 34 | * within the time-out defined by trigger_delay, the shut down is not |
| 35 | * executed. |
| 36 | * |
| 37 | * - watchdog (output) |
| 38 | * Once a shut down is triggered, the driver will toggle this signal, |
| 39 | * with an internal (wde_interval) to stall the hardware shut down. |
| 40 | * |
| 41 | * - kill (output) |
| 42 | * The last action during shut down is triggering this signalling, such |
| 43 | * that the PowerPath Control will power down the hardware. |
| 44 | * |
| 45 | * ---------------------------------------- |
| 46 | * - Interrupts |
| 47 | * ---------------------------------------- |
| 48 | * |
| 49 | * The driver requires a non-shared, edge-triggered interrupt on the trigger |
| 50 | * GPIO. |
| 51 | * |
| 52 | */ |
| 53 | |
| 54 | #include <linux/kernel.h> |
| 55 | #include <linux/init.h> |
| 56 | #include <linux/interrupt.h> |
| 57 | #include <linux/device.h> |
| 58 | #include <linux/platform_device.h> |
| 59 | #include <linux/ktime.h> |
| 60 | #include <linux/slab.h> |
| 61 | #include <linux/kmod.h> |
| 62 | #include <linux/module.h> |
| 63 | #include <linux/gpio/consumer.h> |
| 64 | #include <linux/reboot.h> |
| 65 | |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 66 | struct ltc2952_poweroff { |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 67 | struct hrtimer timer_trigger; |
| 68 | struct hrtimer timer_wde; |
| 69 | |
| 70 | ktime_t trigger_delay; |
| 71 | ktime_t wde_interval; |
| 72 | |
| 73 | struct device *dev; |
| 74 | |
Frans Klaver | f66472d | 2015-01-14 09:15:36 +0100 | [diff] [blame] | 75 | struct gpio_desc *gpio_trigger; |
| 76 | struct gpio_desc *gpio_watchdog; |
| 77 | struct gpio_desc *gpio_kill; |
Frans Klaver | 818ca4c | 2015-01-14 09:15:39 +0100 | [diff] [blame] | 78 | |
| 79 | bool kernel_panic; |
| 80 | struct notifier_block panic_notifier; |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 81 | }; |
| 82 | |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 83 | #define to_ltc2952(p, m) container_of(p, struct ltc2952_poweroff, m) |
| 84 | |
| 85 | /* |
| 86 | * This global variable is only needed for pm_power_off. We should |
| 87 | * remove it entirely once we don't need the global state anymore. |
| 88 | */ |
| 89 | static struct ltc2952_poweroff *ltc2952_data; |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 90 | |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 91 | /** |
| 92 | * ltc2952_poweroff_timer_wde - Timer callback |
| 93 | * Toggles the watchdog reset signal each wde_interval |
| 94 | * |
| 95 | * @timer: corresponding timer |
| 96 | * |
| 97 | * Returns HRTIMER_RESTART for an infinite loop which will only stop when the |
| 98 | * machine actually shuts down |
| 99 | */ |
| 100 | static enum hrtimer_restart ltc2952_poweroff_timer_wde(struct hrtimer *timer) |
| 101 | { |
| 102 | ktime_t now; |
| 103 | int state; |
| 104 | unsigned long overruns; |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 105 | struct ltc2952_poweroff *data = to_ltc2952(timer, timer_wde); |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 106 | |
Frans Klaver | 818ca4c | 2015-01-14 09:15:39 +0100 | [diff] [blame] | 107 | if (data->kernel_panic) |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 108 | return HRTIMER_NORESTART; |
| 109 | |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 110 | state = gpiod_get_value(data->gpio_watchdog); |
| 111 | gpiod_set_value(data->gpio_watchdog, !state); |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 112 | |
| 113 | now = hrtimer_cb_get_time(timer); |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 114 | overruns = hrtimer_forward(timer, now, data->wde_interval); |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 115 | |
| 116 | return HRTIMER_RESTART; |
| 117 | } |
| 118 | |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 119 | static enum hrtimer_restart |
| 120 | ltc2952_poweroff_timer_trigger(struct hrtimer *timer) |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 121 | { |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 122 | struct ltc2952_poweroff *data = to_ltc2952(timer, timer_trigger); |
| 123 | int ret = hrtimer_start(&data->timer_wde, |
| 124 | data->wde_interval, HRTIMER_MODE_REL); |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 125 | |
| 126 | if (ret) { |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 127 | dev_err(data->dev, "unable to start the timer\n"); |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 128 | /* |
| 129 | * The device will not toggle the watchdog reset, |
| 130 | * thus shut down is only safe if the PowerPath controller |
| 131 | * has a long enough time-off before triggering a hardware |
| 132 | * power-off. |
| 133 | * |
| 134 | * Only sending a warning as the system will power-off anyway |
| 135 | */ |
| 136 | } |
| 137 | |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 138 | dev_info(data->dev, "executing shutdown\n"); |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 139 | |
| 140 | orderly_poweroff(true); |
| 141 | |
| 142 | return HRTIMER_NORESTART; |
| 143 | } |
| 144 | |
| 145 | /** |
| 146 | * ltc2952_poweroff_handler - Interrupt handler |
| 147 | * Triggered each time the trigger signal changes state and (de)activates a |
| 148 | * time-out (timer_trigger). Once the time-out is actually reached the shut |
| 149 | * down is executed. |
| 150 | * |
| 151 | * @irq: IRQ number |
| 152 | * @dev_id: pointer to the main data structure |
| 153 | */ |
| 154 | static irqreturn_t ltc2952_poweroff_handler(int irq, void *dev_id) |
| 155 | { |
| 156 | int ret; |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 157 | struct ltc2952_poweroff *data = dev_id; |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 158 | |
Frans Klaver | 818ca4c | 2015-01-14 09:15:39 +0100 | [diff] [blame] | 159 | if (data->kernel_panic) |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 160 | goto irq_ok; |
| 161 | |
| 162 | if (hrtimer_active(&data->timer_wde)) { |
| 163 | /* shutdown is already triggered, nothing to do any more */ |
| 164 | goto irq_ok; |
| 165 | } |
| 166 | |
| 167 | if (!hrtimer_active(&data->timer_trigger)) { |
| 168 | ret = hrtimer_start(&data->timer_trigger, data->trigger_delay, |
| 169 | HRTIMER_MODE_REL); |
| 170 | |
| 171 | if (ret) |
| 172 | dev_err(data->dev, "unable to start the wait timer\n"); |
| 173 | } else { |
| 174 | ret = hrtimer_cancel(&data->timer_trigger); |
| 175 | /* omitting return value check, timer should have been valid */ |
| 176 | } |
| 177 | |
| 178 | irq_ok: |
| 179 | return IRQ_HANDLED; |
| 180 | } |
| 181 | |
| 182 | static void ltc2952_poweroff_kill(void) |
| 183 | { |
Frans Klaver | f66472d | 2015-01-14 09:15:36 +0100 | [diff] [blame] | 184 | gpiod_set_value(ltc2952_data->gpio_kill, 1); |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 185 | } |
| 186 | |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 187 | static void ltc2952_poweroff_default(struct ltc2952_poweroff *data) |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 188 | { |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 189 | data->wde_interval = ktime_set(0, 300L*1E6L); |
| 190 | data->trigger_delay = ktime_set(2, 500L*1E6L); |
| 191 | |
| 192 | hrtimer_init(&data->timer_trigger, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
| 193 | data->timer_trigger.function = <c2952_poweroff_timer_trigger; |
| 194 | |
| 195 | hrtimer_init(&data->timer_wde, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
| 196 | data->timer_wde.function = <c2952_poweroff_timer_wde; |
| 197 | } |
| 198 | |
| 199 | static int ltc2952_poweroff_init(struct platform_device *pdev) |
| 200 | { |
| 201 | int ret, virq; |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 202 | struct ltc2952_poweroff *data = platform_get_drvdata(pdev); |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 203 | |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 204 | ltc2952_poweroff_default(data); |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 205 | |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 206 | data->gpio_watchdog = devm_gpiod_get(&pdev->dev, "watchdog", |
| 207 | GPIOD_OUT_LOW); |
| 208 | if (IS_ERR(data->gpio_watchdog)) { |
| 209 | ret = PTR_ERR(data->gpio_watchdog); |
Frans Klaver | f66472d | 2015-01-14 09:15:36 +0100 | [diff] [blame] | 210 | dev_err(&pdev->dev, "unable to claim gpio \"watchdog\"\n"); |
| 211 | return ret; |
| 212 | } |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 213 | |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 214 | data->gpio_kill = devm_gpiod_get(&pdev->dev, "kill", GPIOD_OUT_LOW); |
| 215 | if (IS_ERR(data->gpio_kill)) { |
| 216 | ret = PTR_ERR(data->gpio_kill); |
Frans Klaver | f66472d | 2015-01-14 09:15:36 +0100 | [diff] [blame] | 217 | dev_err(&pdev->dev, "unable to claim gpio \"kill\"\n"); |
Frans Klaver | 62113b3 | 2015-01-14 09:15:37 +0100 | [diff] [blame] | 218 | return ret; |
Frans Klaver | f66472d | 2015-01-14 09:15:36 +0100 | [diff] [blame] | 219 | } |
| 220 | |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 221 | data->gpio_trigger = devm_gpiod_get(&pdev->dev, "trigger", |
| 222 | GPIOD_IN); |
Frans Klaver | f66472d | 2015-01-14 09:15:36 +0100 | [diff] [blame] | 223 | if (IS_ERR(ltc2952_data->gpio_trigger)) { |
| 224 | ret = PTR_ERR(ltc2952_data->gpio_trigger); |
| 225 | dev_err(&pdev->dev, "unable to claim gpio \"trigger\"\n"); |
Frans Klaver | 62113b3 | 2015-01-14 09:15:37 +0100 | [diff] [blame] | 226 | return ret; |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 227 | } |
| 228 | |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 229 | virq = gpiod_to_irq(data->gpio_trigger); |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 230 | if (virq < 0) { |
| 231 | dev_err(&pdev->dev, "cannot map GPIO as interrupt"); |
Frans Klaver | 62113b3 | 2015-01-14 09:15:37 +0100 | [diff] [blame] | 232 | return ret; |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 233 | } |
| 234 | |
Frans Klaver | 07d0823 | 2015-01-14 09:15:35 +0100 | [diff] [blame] | 235 | ret = devm_request_irq(&pdev->dev, virq, |
| 236 | ltc2952_poweroff_handler, |
| 237 | (IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING), |
| 238 | "ltc2952-poweroff", |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 239 | data); |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 240 | |
| 241 | if (ret) { |
| 242 | dev_err(&pdev->dev, "cannot configure an interrupt handler\n"); |
Frans Klaver | 62113b3 | 2015-01-14 09:15:37 +0100 | [diff] [blame] | 243 | return ret; |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 244 | } |
| 245 | |
| 246 | return 0; |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 247 | } |
| 248 | |
Frans Klaver | 818ca4c | 2015-01-14 09:15:39 +0100 | [diff] [blame] | 249 | static 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 | |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 258 | static int ltc2952_poweroff_probe(struct platform_device *pdev) |
| 259 | { |
| 260 | int ret; |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 261 | struct ltc2952_poweroff *data; |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 262 | |
| 263 | if (pm_power_off) { |
| 264 | dev_err(&pdev->dev, "pm_power_off already registered"); |
| 265 | return -EBUSY; |
| 266 | } |
| 267 | |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 268 | data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); |
| 269 | if (!data) |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 270 | return -ENOMEM; |
| 271 | |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 272 | data->dev = &pdev->dev; |
| 273 | platform_set_drvdata(pdev, data); |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 274 | |
| 275 | ret = ltc2952_poweroff_init(pdev); |
| 276 | if (ret) |
Frans Klaver | 0a5c6a2 | 2015-01-14 09:15:34 +0100 | [diff] [blame] | 277 | return ret; |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 278 | |
Frans Klaver | a5f67be | 2015-01-14 09:15:38 +0100 | [diff] [blame] | 279 | /* TODO: remove ltc2952_data */ |
| 280 | ltc2952_data = data; |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 281 | pm_power_off = <c2952_poweroff_kill; |
| 282 | |
Frans Klaver | 818ca4c | 2015-01-14 09:15:39 +0100 | [diff] [blame] | 283 | data->panic_notifier.notifier_call = ltc2952_poweroff_notify_panic; |
| 284 | atomic_notifier_chain_register(&panic_notifier_list, |
| 285 | &data->panic_notifier); |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 286 | dev_info(&pdev->dev, "probe successful\n"); |
| 287 | |
| 288 | return 0; |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 289 | } |
| 290 | |
| 291 | static int ltc2952_poweroff_remove(struct platform_device *pdev) |
| 292 | { |
Frans Klaver | 818ca4c | 2015-01-14 09:15:39 +0100 | [diff] [blame] | 293 | struct ltc2952_poweroff *data = platform_get_drvdata(pdev); |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 294 | |
Frans Klaver | 818ca4c | 2015-01-14 09:15:39 +0100 | [diff] [blame] | 295 | pm_power_off = NULL; |
| 296 | atomic_notifier_chain_unregister(&panic_notifier_list, |
| 297 | &data->panic_notifier); |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 298 | return 0; |
| 299 | } |
| 300 | |
| 301 | static const struct of_device_id of_ltc2952_poweroff_match[] = { |
| 302 | { .compatible = "lltc,ltc2952"}, |
| 303 | {}, |
| 304 | }; |
| 305 | MODULE_DEVICE_TABLE(of, of_ltc2952_poweroff_match); |
| 306 | |
| 307 | static struct platform_driver ltc2952_poweroff_driver = { |
| 308 | .probe = ltc2952_poweroff_probe, |
| 309 | .remove = ltc2952_poweroff_remove, |
| 310 | .driver = { |
| 311 | .name = "ltc2952-poweroff", |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 312 | .of_match_table = of_ltc2952_poweroff_match, |
| 313 | }, |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 314 | }; |
| 315 | |
Frans Klaver | 818ca4c | 2015-01-14 09:15:39 +0100 | [diff] [blame] | 316 | module_platform_driver(ltc2952_poweroff_driver); |
René Moll | 6647156 | 2014-08-08 13:12:17 +0000 | [diff] [blame] | 317 | |
| 318 | MODULE_AUTHOR("René Moll <rene.moll@xsens.com>"); |
| 319 | MODULE_DESCRIPTION("LTC PowerPath power-off driver"); |
| 320 | MODULE_LICENSE("GPL v2"); |