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  */
sc27xx_poweroff_shutdown(void)31 static void sc27xx_poweroff_shutdown(void)
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 struct syscore_ops poweroff_syscore_ops = {
44 	.shutdown = sc27xx_poweroff_shutdown,
45 };
46 
sc27xx_poweroff_do_poweroff(void)47 static void sc27xx_poweroff_do_poweroff(void)
48 {
49 	/* Disable the external subsys connection's power firstly */
50 	regmap_write(regmap, SC27XX_SLP_CTRL, SC27XX_LDO_XTL_EN);
51 
52 	regmap_write(regmap, SC27XX_PWR_PD_HW, SC27XX_PWR_OFF_EN);
53 }
54 
sc27xx_poweroff_probe(struct platform_device * pdev)55 static int sc27xx_poweroff_probe(struct platform_device *pdev)
56 {
57 	if (regmap)
58 		return -EINVAL;
59 
60 	regmap = dev_get_regmap(pdev->dev.parent, NULL);
61 	if (!regmap)
62 		return -ENODEV;
63 
64 	pm_power_off = sc27xx_poweroff_do_poweroff;
65 	register_syscore_ops(&poweroff_syscore_ops);
66 	return 0;
67 }
68 
69 static struct platform_driver sc27xx_poweroff_driver = {
70 	.probe = sc27xx_poweroff_probe,
71 	.driver = {
72 		.name = "sc27xx-poweroff",
73 	},
74 };
75 module_platform_driver(sc27xx_poweroff_driver);
76 
77 MODULE_DESCRIPTION("Power off driver for SC27XX PMIC Device");
78 MODULE_AUTHOR("Baolin Wang <baolin.wang@unisoc.com>");
79 MODULE_LICENSE("GPL v2");
80