From: Sean Wang <[email protected]> The power device is responsible for externally down or up the power of the remote MediaTek SoC through the tiny circuit BBPU inside PMIC RTC.
Though it's a part of RTC device, it would be better to be a standalone driver than to be a part of existent RTC driver so as to let us make concentration on works about power-controlling topic and to obtain improvements while the subsystem power/reset constantly growing. Currently, the most basic functionality supported is to just power off the system by writing to a special bit field in BBPU register after the system has reached pm_poweroff. Signed-off-by: Sean Wang <[email protected]> --- drivers/power/reset/Kconfig | 10 ++++ drivers/power/reset/Makefile | 1 + drivers/power/reset/mt6323-poweroff.c | 97 +++++++++++++++++++++++++++++++++++ include/linux/mfd/mt6397/rtc.h | 1 + 4 files changed, 109 insertions(+) create mode 100644 drivers/power/reset/mt6323-poweroff.c diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig index df58fc8..7b49d71 100644 --- a/drivers/power/reset/Kconfig +++ b/drivers/power/reset/Kconfig @@ -128,6 +128,16 @@ config POWER_RESET_LTC2952 This driver supports an external powerdown trigger and board power down via the LTC2952. Bindings are made in the device tree. +config POWER_RESET_MT6323 + bool "MediaTek MT6323 power-off driver" + depends on MFD_MT6397 + help + The power-off driver is responsible for externally shutdown down + the power of a remote MediaTek SoC MT6323 is connected to through + controlling a tiny circuit BBPU inside MT6323 RTC. + + Say Y if you have a board where MT6323 could be found. + config POWER_RESET_QNAP bool "QNAP power-off driver" depends on OF_GPIO && PLAT_ORION diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile index 7778c74..8836172 100644 --- a/drivers/power/reset/Makefile +++ b/drivers/power/reset/Makefile @@ -11,6 +11,7 @@ obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o obj-$(CONFIG_POWER_RESET_GPIO_RESTART) += gpio-restart.o obj-$(CONFIG_POWER_RESET_HISI) += hisi-reboot.o obj-$(CONFIG_POWER_RESET_MSM) += msm-poweroff.o +obj-$(CONFIG_POWER_RESET_MT6323) += mt6323-poweroff.o obj-$(CONFIG_POWER_RESET_OCELOT_RESET) += ocelot-reset.o obj-$(CONFIG_POWER_RESET_PIIX4_POWEROFF) += piix4-poweroff.o obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o diff --git a/drivers/power/reset/mt6323-poweroff.c b/drivers/power/reset/mt6323-poweroff.c new file mode 100644 index 0000000..c195766 --- /dev/null +++ b/drivers/power/reset/mt6323-poweroff.c @@ -0,0 +1,97 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Power off through MediaTek PMIC + * + * Copyright (C) 2018 MediaTek Inc. + * + * Author: Sean Wang <[email protected]> + * + */ + +#include <linux/err.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/mfd/mt6397/core.h> +#include <linux/mfd/mt6397/rtc.h> + +struct mt6323_pwrc { + struct device *dev; + struct regmap *regmap; + u32 base; +}; + +static struct mt6323_pwrc *mt_pwrc; + +static void mt6323_do_pwroff(void) +{ + struct mt6323_pwrc *pwrc = mt_pwrc; + unsigned int val; + int ret; + + regmap_write(pwrc->regmap, pwrc->base + RTC_BBPU, RTC_BBPU_KEY); + regmap_write(pwrc->regmap, pwrc->base + RTC_WRTGR, 1); + + ret = regmap_read_poll_timeout(pwrc->regmap, + pwrc->base + RTC_BBPU, val, + !(val & RTC_BBPU_CBUSY), + MTK_RTC_POLL_DELAY_US, + MTK_RTC_POLL_TIMEOUT); + if (ret) + dev_err(pwrc->dev, "failed to write BBPU: %d\n", ret); + + /* Wait some time until system down, otherwise, notice with a warn */ + mdelay(1000); + + WARN_ONCE(1, "Unable to power off system\n"); +} + +static int mt6323_pwrc_probe(struct platform_device *pdev) +{ + struct mt6397_chip *mt6397_chip = dev_get_drvdata(pdev->dev.parent); + struct mt6323_pwrc *pwrc; + struct resource *res; + + pwrc = devm_kzalloc(&pdev->dev, sizeof(*pwrc), GFP_KERNEL); + if (!pwrc) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + pwrc->base = res->start; + pwrc->regmap = mt6397_chip->regmap; + pwrc->dev = &pdev->dev; + mt_pwrc = pwrc; + + pm_power_off = &mt6323_do_pwroff; + + return 0; +} + +static int mt6323_pwrc_remove(struct platform_device *pdev) +{ + if (pm_power_off == &mt6323_do_pwroff) + pm_power_off = NULL; + + return 0; +} + +static const struct of_device_id mt6323_pwrc_dt_match[] = { + { .compatible = "mediatek,mt6323-pwrc" }, + {}, +}; +MODULE_DEVICE_TABLE(of, mt6323_pwrc_dt_match); + +static struct platform_driver mt6323_pwrc_driver = { + .probe = mt6323_pwrc_probe, + .remove = mt6323_pwrc_remove, + .driver = { + .name = "mt6323-pwrc", + .of_match_table = mt6323_pwrc_dt_match, + }, +}; + +module_platform_driver(mt6323_pwrc_driver); + +MODULE_DESCRIPTION("Poweroff driver for MT6323 PMIC"); +MODULE_AUTHOR("Sean Wang <[email protected]>"); +MODULE_LICENSE("GPL v2"); diff --git a/include/linux/mfd/mt6397/rtc.h b/include/linux/mfd/mt6397/rtc.h index 480977c..ac932c9 100644 --- a/include/linux/mfd/mt6397/rtc.h +++ b/include/linux/mfd/mt6397/rtc.h @@ -16,6 +16,7 @@ #define RTC_BBPU 0x0000 #define RTC_BBPU_CBUSY BIT(6) +#define RTC_BBPU_KEY (0x43 << 8) #define RTC_WRTGR 0x003c -- 2.7.4
