// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2018 Spreadtrum Communications Inc. * Copyright (C) 2018 Linaro Ltd. */ #include <linux/cpu.h> #include <linux/kernel.h> #include <linux/platform_device.h> #include <linux/pm.h> #include <linux/regmap.h> #include <linux/syscore_ops.h> #define SC27XX_PWR_PD_HW 0xc2c #define SC27XX_PWR_OFF_EN BIT(0) static struct regmap *regmap; /* * On Spreadtrum platform, we need power off system through external SC27xx * series PMICs, and it is one similar SPI bus mapped by regmap to access PMIC, * which is not fast io access. * * So before stopping other cores, we need release other cores' resource by * taking cpus down to avoid racing regmap or spi mutex lock when poweroff * system through PMIC. */ static void sc27xx_poweroff_shutdown(void) { #ifdef CONFIG_PM_SLEEP_SMP int cpu = smp_processor_id(); freeze_secondary_cpus(cpu); #endif } static struct syscore_ops poweroff_syscore_ops = { .shutdown = sc27xx_poweroff_shutdown, }; static void sc27xx_poweroff_do_poweroff(void) { regmap_write(regmap, SC27XX_PWR_PD_HW, SC27XX_PWR_OFF_EN); } static int sc27xx_poweroff_probe(struct platform_device *pdev) { if (regmap) return -EINVAL; regmap = dev_get_regmap(pdev->dev.parent, NULL); if (!regmap) return -ENODEV; pm_power_off = sc27xx_poweroff_do_poweroff; register_syscore_ops(&poweroff_syscore_ops); return 0; } static struct platform_driver sc27xx_poweroff_driver = { .probe = sc27xx_poweroff_probe, .driver = { .name = "sc27xx-poweroff", }, }; builtin_platform_driver(sc27xx_poweroff_driver);