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