1ec66096bSMichael Klein // SPDX-License-Identifier: GPL-2.0-only 2ec66096bSMichael Klein /* 3ec66096bSMichael Klein * Force-disables a regulator to power down a device 4ec66096bSMichael Klein * 5ec66096bSMichael Klein * Michael Klein <michael@fossekall.de> 6ec66096bSMichael Klein * 7ec66096bSMichael Klein * Copyright (C) 2020 Michael Klein 8ec66096bSMichael Klein * 9ec66096bSMichael Klein * Based on the gpio-poweroff driver. 10ec66096bSMichael Klein */ 11ec66096bSMichael Klein #include <linux/delay.h> 12ec66096bSMichael Klein #include <linux/module.h> 13ec66096bSMichael Klein #include <linux/of.h> 14ec66096bSMichael Klein #include <linux/platform_device.h> 15ec66096bSMichael Klein #include <linux/pm.h> 16ec66096bSMichael Klein #include <linux/regulator/consumer.h> 17ec66096bSMichael Klein 18ec66096bSMichael Klein #define TIMEOUT_MS 3000 19ec66096bSMichael Klein 20ec66096bSMichael Klein /* 21ec66096bSMichael Klein * Hold configuration here, cannot be more than one instance of the driver 22ec66096bSMichael Klein * since pm_power_off itself is global. 23ec66096bSMichael Klein */ 24ec66096bSMichael Klein static struct regulator *cpu_regulator; 25ec66096bSMichael Klein 26ec66096bSMichael Klein static void regulator_poweroff_do_poweroff(void) 27ec66096bSMichael Klein { 28ec66096bSMichael Klein if (cpu_regulator && regulator_is_enabled(cpu_regulator)) 29ec66096bSMichael Klein regulator_force_disable(cpu_regulator); 30ec66096bSMichael Klein 31ec66096bSMichael Klein /* give it some time */ 32ec66096bSMichael Klein mdelay(TIMEOUT_MS); 33ec66096bSMichael Klein 34ec66096bSMichael Klein WARN_ON(1); 35ec66096bSMichael Klein } 36ec66096bSMichael Klein 37ec66096bSMichael Klein static int regulator_poweroff_probe(struct platform_device *pdev) 38ec66096bSMichael Klein { 39ec66096bSMichael Klein /* If a pm_power_off function has already been added, leave it alone */ 40ec66096bSMichael Klein if (pm_power_off != NULL) { 41ec66096bSMichael Klein dev_err(&pdev->dev, 42ec66096bSMichael Klein "%s: pm_power_off function already registered\n", 43ec66096bSMichael Klein __func__); 44ec66096bSMichael Klein return -EBUSY; 45ec66096bSMichael Klein } 46ec66096bSMichael Klein 47ec66096bSMichael Klein cpu_regulator = devm_regulator_get(&pdev->dev, "cpu"); 48ec66096bSMichael Klein if (IS_ERR(cpu_regulator)) 49ec66096bSMichael Klein return PTR_ERR(cpu_regulator); 50ec66096bSMichael Klein 51ec66096bSMichael Klein pm_power_off = ®ulator_poweroff_do_poweroff; 52ec66096bSMichael Klein return 0; 53ec66096bSMichael Klein } 54ec66096bSMichael Klein 55ec66096bSMichael Klein static int regulator_poweroff_remove(__maybe_unused struct platform_device *pdev) 56ec66096bSMichael Klein { 57ec66096bSMichael Klein if (pm_power_off == ®ulator_poweroff_do_poweroff) 58ec66096bSMichael Klein pm_power_off = NULL; 59ec66096bSMichael Klein 60ec66096bSMichael Klein return 0; 61ec66096bSMichael Klein } 62ec66096bSMichael Klein 63ec66096bSMichael Klein static const struct of_device_id of_regulator_poweroff_match[] = { 64ec66096bSMichael Klein { .compatible = "regulator-poweroff", }, 65ec66096bSMichael Klein {}, 66ec66096bSMichael Klein }; 67*4465b3a6SZou Wei MODULE_DEVICE_TABLE(of, of_regulator_poweroff_match); 68ec66096bSMichael Klein 69ec66096bSMichael Klein static struct platform_driver regulator_poweroff_driver = { 70ec66096bSMichael Klein .probe = regulator_poweroff_probe, 71ec66096bSMichael Klein .remove = regulator_poweroff_remove, 72ec66096bSMichael Klein .driver = { 73ec66096bSMichael Klein .name = "poweroff-regulator", 74ec66096bSMichael Klein .of_match_table = of_regulator_poweroff_match, 75ec66096bSMichael Klein }, 76ec66096bSMichael Klein }; 77ec66096bSMichael Klein 78ec66096bSMichael Klein module_platform_driver(regulator_poweroff_driver); 79ec66096bSMichael Klein 80ec66096bSMichael Klein MODULE_AUTHOR("Michael Klein <michael@fossekall.de>"); 81ec66096bSMichael Klein MODULE_DESCRIPTION("Regulator poweroff driver"); 82ec66096bSMichael Klein MODULE_LICENSE("GPL v2"); 83ec66096bSMichael Klein MODULE_ALIAS("platform:poweroff-regulator"); 84