LXR linux/drivers/power/reset/sc27xx-poweroff.c

   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
  17static 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 */
  28static 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
  37static struct syscore_ops poweroff_syscore_ops = {
  38        .shutdown = sc27xx_poweroff_shutdown,
  39};
  40
  41static void sc27xx_poweroff_do_poweroff(void)
  42{
  43        regmap_write(regmap, SC27XX_PWR_PD_HW, SC27XX_PWR_OFF_EN);
  44}
  45
  46static 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
  60static struct platform_driver sc27xx_poweroff_driver = {
  61        .probe = sc27xx_poweroff_probe,
  62        .driver = {
  63                .name = "sc27xx-poweroff",
  64        },
  65};
  66builtin_platform_driver(sc27xx_poweroff_driver);
  67