From 222dedcdc09247126d39364a614ff2019789f52a Mon Sep 17 00:00:00 2001 From: Dom Cobley Date: Fri, 7 Jul 2023 20:00:45 +0100 Subject: [PATCH] rtc: rtc-rpi: Add simple RTC driver for Raspberry Pi This supports setting and reading the real time clock and supports wakeup alarms. To support wake up alarms you want this bootloader config: POWER_OFF_ON_HALT=1 WAKE_ON_GPIO=0 You can test with: echo +600 | sudo tee /sys/class/rtc/rtc0/wakealarm sudo halt That will halt (in an almost no power state), then wake and restart after 10 minutes. Signed-off-by: Dom Cobley --- drivers/rtc/Kconfig | 11 +++ drivers/rtc/Makefile | 1 + drivers/rtc/rtc-rpi.c | 177 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 189 insertions(+) create mode 100644 drivers/rtc/rtc-rpi.c --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -223,6 +223,17 @@ config RTC_DRV_AC100 This driver can also be built as a module. If so, the module will be called rtc-ac100. +config RTC_DRV_RPI + tristate "Raspberry Pi RTC" + depends on ARCH_BRCMSTB || COMPILE_TEST + default ARCH_BRCMSTB + help + If you say yes here you get support for the RTC found on + Raspberry Pi devices. + + This driver can also be built as a module. If so, the module + will be called rtc-rpi. + config RTC_DRV_BRCMSTB tristate "Broadcom STB wake-timer" depends on ARCH_BRCMSTB || BMIPS_GENERIC || COMPILE_TEST --- a/drivers/rtc/Makefile +++ b/drivers/rtc/Makefile @@ -140,6 +140,7 @@ obj-$(CONFIG_RTC_DRV_RC5T583) += rtc-rc5 obj-$(CONFIG_RTC_DRV_RC5T619) += rtc-rc5t619.o obj-$(CONFIG_RTC_DRV_RK808) += rtc-rk808.o obj-$(CONFIG_RTC_DRV_RP5C01) += rtc-rp5c01.o +obj-$(CONFIG_RTC_DRV_RPI) += rtc-rpi.o obj-$(CONFIG_RTC_DRV_RS5C313) += rtc-rs5c313.o obj-$(CONFIG_RTC_DRV_RS5C348) += rtc-rs5c348.o obj-$(CONFIG_RTC_DRV_RS5C372) += rtc-rs5c372.o --- /dev/null +++ b/drivers/rtc/rtc-rpi.c @@ -0,0 +1,177 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause +/** + * rtc-rpi.c + * + * RTC driver using firmware mailbox + * Supports battery backed RTC and wake alarms + * + * Based on rtc-meson-vrtc by Neil Armstrong + * + * Copyright (c) 2023, Raspberry Pi Ltd. + */ + +#include +#include +#include +#include +#include + +struct rpi_rtc_data { + struct rtc_device *rtc; + struct rpi_firmware *fw; +}; + +#define RPI_FIRMWARE_GET_RTC_REG 0x00030087 +#define RPI_FIRMWARE_SET_RTC_REG 0x00038087 +enum {RTC_TIME, RTC_ALARM, RTC_ALARM_PENDING, RTC_ALARM_ENABLE}; + +static int rpi_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct rpi_rtc_data *vrtc = dev_get_drvdata(dev); + u32 data[2] = {RTC_TIME}; + int err; + + err = rpi_firmware_property(vrtc->fw, RPI_FIRMWARE_GET_RTC_REG, + &data, sizeof(data)); + rtc_time64_to_tm(data[1], tm); + return err; +} + +static int rpi_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct rpi_rtc_data *vrtc = dev_get_drvdata(dev); + u32 data[2] = {RTC_TIME, rtc_tm_to_time64(tm)}; + + return rpi_firmware_property(vrtc->fw, RPI_FIRMWARE_SET_RTC_REG, + &data, sizeof(data)); +} + +static int rpi_rtc_alarm_irq_is_enabled(struct device *dev, unsigned char *enabled) +{ + struct rpi_rtc_data *vrtc = dev_get_drvdata(dev); + u32 data[2] = {RTC_ALARM_ENABLE}; + s32 err = 0; + + err = rpi_firmware_property(vrtc->fw, RPI_FIRMWARE_GET_RTC_REG, + &data, sizeof(data)); + *enabled = data[1] & 0x1; + return err; +} + +static int rpi_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) +{ + struct rpi_rtc_data *vrtc = dev_get_drvdata(dev); + u32 data[2] = {RTC_ALARM_ENABLE, enabled}; + + return rpi_firmware_property(vrtc->fw, RPI_FIRMWARE_SET_RTC_REG, + &data, sizeof(data)); +} + +static int rpi_rtc_alarm_clear_pending(struct device *dev) +{ + struct rpi_rtc_data *vrtc = dev_get_drvdata(dev); + u32 data[2] = {RTC_ALARM_PENDING, 1}; + + return rpi_firmware_property(vrtc->fw, RPI_FIRMWARE_SET_RTC_REG, + &data, sizeof(data)); +} + +static int rpi_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct rpi_rtc_data *vrtc = dev_get_drvdata(dev); + u32 data[2] = {RTC_ALARM}; + s32 err = 0; + + err = rpi_rtc_alarm_irq_is_enabled(dev, &alarm->enabled); + if (!err) + err = rpi_firmware_property(vrtc->fw, RPI_FIRMWARE_GET_RTC_REG, + &data, sizeof(data)); + rtc_time64_to_tm(data[1], &alarm->time); + + return err; +} + +static int rpi_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct rpi_rtc_data *vrtc = dev_get_drvdata(dev); + u32 data[2] = {RTC_ALARM, rtc_tm_to_time64(&alarm->time)}; + int err; + + err = rpi_firmware_property(vrtc->fw, RPI_FIRMWARE_SET_RTC_REG, + &data, sizeof(data)); + + if (err == 0) + err = rpi_rtc_alarm_irq_enable(dev, alarm->enabled); + + return err; +} + +static const struct rtc_class_ops rpi_rtc_ops = { + .read_time = rpi_rtc_read_time, + .set_time = rpi_rtc_set_time, + .read_alarm = rpi_rtc_read_alarm, + .set_alarm = rpi_rtc_set_alarm, + .alarm_irq_enable = rpi_rtc_alarm_irq_enable, +}; + +static int rpi_rtc_probe(struct platform_device *pdev) +{ + struct rpi_rtc_data *vrtc; + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + struct device_node *fw_node; + struct rpi_firmware *fw; + int ret; + + fw_node = of_parse_phandle(np, "firmware", 0); + if (!fw_node) { + dev_err(dev, "Missing firmware node\n"); + return -ENOENT; + } + + fw = rpi_firmware_get(fw_node); + if (!fw) + return -EPROBE_DEFER; + + vrtc = devm_kzalloc(&pdev->dev, sizeof(*vrtc), GFP_KERNEL); + if (!vrtc) + return -ENOMEM; + + vrtc->fw = fw; + + device_init_wakeup(&pdev->dev, 1); + + platform_set_drvdata(pdev, vrtc); + + vrtc->rtc = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(vrtc->rtc)) + return PTR_ERR(vrtc->rtc); + + set_bit(RTC_FEATURE_ALARM_WAKEUP_ONLY, vrtc->rtc->features); + clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, vrtc->rtc->features); + + vrtc->rtc->ops = &rpi_rtc_ops; + ret = devm_rtc_register_device(vrtc->rtc); + + rpi_rtc_alarm_clear_pending(dev); + return ret; +} + +static const struct of_device_id rpi_rtc_dt_match[] = { + { .compatible = "raspberrypi,rpi-rtc"}, + {}, +}; +MODULE_DEVICE_TABLE(of, rpi_rtc_dt_match); + +static struct platform_driver rpi_rtc_driver = { + .probe = rpi_rtc_probe, + .driver = { + .name = "rpi-rtc", + .of_match_table = rpi_rtc_dt_match, + }, +}; + +module_platform_driver(rpi_rtc_driver); + +MODULE_DESCRIPTION("Raspberry Pi RTC driver"); +MODULE_LICENSE("GPL");