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