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/module.h> 10 #include <linux/platform_device.h> 11 #include <linux/pm.h> 12 #include <linux/regmap.h> 13 #include <linux/syscore_ops.h> 14 15 #define SC27XX_PWR_PD_HW 0xc2c 16 #define SC27XX_PWR_OFF_EN BIT(0) 17 #define SC27XX_SLP_CTRL 0xdf0 18 #define SC27XX_LDO_XTL_EN BIT(3) 19 20 static struct regmap *regmap; 21 22 /* 23 * On Spreadtrum platform, we need power off system through external SC27xx 24 * series PMICs, and it is one similar SPI bus mapped by regmap to access PMIC, 25 * which is not fast io access. 26 * 27 * So before stopping other cores, we need release other cores' resource by 28 * taking cpus down to avoid racing regmap or spi mutex lock when poweroff 29 * system through PMIC. 30 */ 31 static void sc27xx_poweroff_shutdown(void *data) 32 { 33 #ifdef CONFIG_HOTPLUG_CPU 34 int cpu; 35 36 for_each_online_cpu(cpu) { 37 if (cpu != smp_processor_id()) 38 remove_cpu(cpu); 39 } 40 #endif 41 } 42 43 static const struct syscore_ops poweroff_syscore_ops = { 44 .shutdown = sc27xx_poweroff_shutdown, 45 }; 46 47 static struct syscore poweroff_syscore = { 48 .ops = &poweroff_syscore_ops, 49 }; 50 51 static void sc27xx_poweroff_do_poweroff(void) 52 { 53 /* Disable the external subsys connection's power firstly */ 54 regmap_write(regmap, SC27XX_SLP_CTRL, SC27XX_LDO_XTL_EN); 55 56 regmap_write(regmap, SC27XX_PWR_PD_HW, SC27XX_PWR_OFF_EN); 57 } 58 59 static int sc27xx_poweroff_probe(struct platform_device *pdev) 60 { 61 if (regmap) 62 return -EINVAL; 63 64 regmap = dev_get_regmap(pdev->dev.parent, NULL); 65 if (!regmap) 66 return -ENODEV; 67 68 pm_power_off = sc27xx_poweroff_do_poweroff; 69 register_syscore(&poweroff_syscore); 70 return 0; 71 } 72 73 static struct platform_driver sc27xx_poweroff_driver = { 74 .probe = sc27xx_poweroff_probe, 75 .driver = { 76 .name = "sc27xx-poweroff", 77 }, 78 }; 79 module_platform_driver(sc27xx_poweroff_driver); 80 81 MODULE_DESCRIPTION("Power off driver for SC27XX PMIC Device"); 82 MODULE_AUTHOR("Baolin Wang <baolin.wang@unisoc.com>"); 83 MODULE_LICENSE("GPL v2"); 84