projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| ec66096b MK |
1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | /* | |
| 3 | * Force-disables a regulator to power down a device | |
| 4 | * | |
| 5 | * Michael Klein <michael@fossekall.de> | |
| 6 | * | |
| 7 | * Copyright (C) 2020 Michael Klein | |
| 8 | * | |
| 9 | * Based on the gpio-poweroff driver. | |
| 10 | */ | |
| 11 | #include <linux/delay.h> | |
| 12 | #include <linux/module.h> | |
| 13 | #include <linux/of.h> | |
| 14 | #include <linux/platform_device.h> | |
| 15 | #include <linux/pm.h> | |
| 16 | #include <linux/regulator/consumer.h> | |
| 17 | ||
| 18 | #define TIMEOUT_MS 3000 | |
| 19 | ||
| 20 | /* | |
| 21 | * Hold configuration here, cannot be more than one instance of the driver | |
| 22 | * since pm_power_off itself is global. | |
| 23 | */ | |
| 24 | static struct regulator *cpu_regulator; | |
| 25 | ||
| 26 | static void regulator_poweroff_do_poweroff(void) | |
| 27 | { | |
| 28 | if (cpu_regulator && regulator_is_enabled(cpu_regulator)) | |
| 29 | regulator_force_disable(cpu_regulator); | |
| 30 | ||
| 31 | /* give it some time */ | |
| 32 | mdelay(TIMEOUT_MS); | |
| 33 | ||
| 34 | WARN_ON(1); | |
| 35 | } | |
| 36 | ||
| 37 | static int regulator_poweroff_probe(struct platform_device *pdev) | |
| 38 | { | |
| 39 | /* If a pm_power_off function has already been added, leave it alone */ | |
| 40 | if (pm_power_off != NULL) { | |
| 41 | dev_err(&pdev->dev, | |
| 42 | "%s: pm_power_off function already registered\n", | |
| 43 | __func__); | |
| 44 | return -EBUSY; | |
| 45 | } | |
| 46 | ||
| 47 | cpu_regulator = devm_regulator_get(&pdev->dev, "cpu"); | |
| 48 | if (IS_ERR(cpu_regulator)) | |
| 49 | return PTR_ERR(cpu_regulator); | |
| 50 | ||
| 51 | pm_power_off = ®ulator_poweroff_do_poweroff; | |
| 52 | return 0; | |
| 53 | } | |
| 54 | ||
| 55 | static int regulator_poweroff_remove(__maybe_unused struct platform_device *pdev) | |
| 56 | { | |
| 57 | if (pm_power_off == ®ulator_poweroff_do_poweroff) | |
| 58 | pm_power_off = NULL; | |
| 59 | ||
| 60 | return 0; | |
| 61 | } | |
| 62 | ||
| 63 | static const struct of_device_id of_regulator_poweroff_match[] = { | |
| 64 | { .compatible = "regulator-poweroff", }, | |
| 65 | {}, | |
| 66 | }; | |
| 67 | ||
| 68 | static struct platform_driver regulator_poweroff_driver = { | |
| 69 | .probe = regulator_poweroff_probe, | |
| 70 | .remove = regulator_poweroff_remove, | |
| 71 | .driver = { | |
| 72 | .name = "poweroff-regulator", | |
| 73 | .of_match_table = of_regulator_poweroff_match, | |
| 74 | }, | |
| 75 | }; | |
| 76 | ||
| 77 | module_platform_driver(regulator_poweroff_driver); | |
| 78 | ||
| 79 | MODULE_AUTHOR("Michael Klein <michael@fossekall.de>"); | |
| 80 | MODULE_DESCRIPTION("Regulator poweroff driver"); | |
| 81 | MODULE_LICENSE("GPL v2"); | |
| 82 | MODULE_ALIAS("platform:poweroff-regulator"); |