1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2018 Spreadtrum Communications Inc. 4 * Copyright (C) 2018 Linaro Ltd. 5 */ 6 7 #include <linux/cpu.h> 8 #include <linux/kernel.h> 9 #include <linux/platform_device.h> 10 #include <linux/pm.h> 11 #include <linux/regmap.h> 12 #include <linux/syscore_ops.h> 13 14 #define SC27XX_PWR_PD_HW 0xc2c 15 #define SC27XX_PWR_OFF_EN BIT(0) 16 17 static struct regmap *regmap; 18 19 /* 20 * On Spreadtrum platform, we need power off system through external SC27xx 21 * series PMICs, and it is one similar SPI bus mapped by regmap to access PMIC, 22 * which is not fast io access. 23 * 24 * So before stopping other cores, we need release other cores' resource by 25 * taking cpus down to avoid racing regmap or spi mutex lock when poweroff 26 * system through PMIC. 27 */ 28 static void sc27xx_poweroff_shutdown(void) 29 { 30 #ifdef CONFIG_PM_SLEEP_SMP 31 int cpu = smp_processor_id(); 32 33 freeze_secondary_cpus(cpu); 34 #endif 35 } 36 37 static struct syscore_ops poweroff_syscore_ops = { 38 .shutdown = sc27xx_poweroff_shutdown, 39 }; 40 41 static void sc27xx_poweroff_do_poweroff(void) 42 { 43 regmap_write(regmap, SC27XX_PWR_PD_HW, SC27XX_PWR_OFF_EN); 44 } 45 46 static int sc27xx_poweroff_probe(struct platform_device *pdev) 47 { 48 if (regmap) 49 return -EINVAL; 50 51 regmap = dev_get_regmap(pdev->dev.parent, NULL); 52 if (!regmap) 53 return -ENODEV; 54 55 pm_power_off = sc27xx_poweroff_do_poweroff; 56 register_syscore_ops(&poweroff_syscore_ops); 57 return 0; 58 } 59 60 static struct platform_driver sc27xx_poweroff_driver = { 61 .probe = sc27xx_poweroff_probe, 62 .driver = { 63 .name = "sc27xx-poweroff", 64 }, 65 }; 66 builtin_platform_driver(sc27xx_poweroff_driver); 67