rtc: Add Amlogic Virtual Wake RTC

The Amlogic Meson GX SoCs uses a special register to store the
time in seconds to wakeup after a system suspend.

In order to be able to reuse the RTC wakealarm feature, this
driver implements a fake RTC device which uses the system time
to deduce a suspend delay.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
[khilman: rebase to v5.3-rc, rework and modernization]
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20190812232850.8016-3-khilman@kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/MAINTAINERS b/MAINTAINERS
index 783569e3c4b48752c3555e9bee6fbc87adad5117..2ae83e1acb05a73dcceaf84214f06db42ba8a5f0 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1443,6 +1443,7 @@ F:        arch/arm64/boot/dts/amlogic/
 F:     drivers/pinctrl/meson/
 F:     drivers/mmc/host/meson*
 F:     drivers/soc/amlogic/
+F:     drivers/rtc/rtc-meson*
 N:     meson
 
 ARM/Amlogic Meson SoC Sound Drivers

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 24d16030d60cd193c515aaad8aaa2b0af00600ad..59fbf8b761b9b8f64931ac7883ecce6059be4733 100644 (file)
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -373,6 +373,17 @@ config RTC_DRV_MAX77686
          This driver can also be built as a module. If so, the module
          will be called rtc-max77686.
 
+config RTC_DRV_MESON_VRTC
+       tristate "Amlogic Meson Virtual RTC"
+       depends on ARCH_MESON || COMPILE_TEST
+       default m if ARCH_MESON
+       help
+         If you say yes here you will get support for the
+         Virtual RTC of Amlogic SoCs.
+
+         This driver can also be built as a module. If so, the module
+         will be called rtc-meson-vrtc.
+
 config RTC_DRV_RK808
        tristate "Rockchip RK805/RK808/RK809/RK817/RK818 RTC"
        depends on MFD_RK808

diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 9fe0e938272c363238ebafebe4df7829f81d91da..bd87a004b346896e2aa57353610b558d836cf26e 100644 (file)
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -102,6 +102,7 @@ obj-$(CONFIG_RTC_DRV_MAX8907)       += rtc-max8907.o
 obj-$(CONFIG_RTC_DRV_MAX8925)  += rtc-max8925.o
 obj-$(CONFIG_RTC_DRV_MAX8997)  += rtc-max8997.o
 obj-$(CONFIG_RTC_DRV_MAX8998)  += rtc-max8998.o
+obj-$(CONFIG_RTC_DRV_MESON_VRTC)+= rtc-meson-vrtc.o
 obj-$(CONFIG_RTC_DRV_MC13XXX)  += rtc-mc13xxx.o
 obj-$(CONFIG_RTC_DRV_MCP795)   += rtc-mcp795.o
 obj-$(CONFIG_RTC_DRV_MESON)    += rtc-meson.o

diff --git a/drivers/rtc/rtc-meson-vrtc.c b/drivers/rtc/rtc-meson-vrtc.c
new file mode 100644 (file)
index 0000000..4621a47
--- /dev/null
+++ b/drivers/rtc/rtc-meson-vrtc.c
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 BayLibre, SAS
+ * Author: Neil Armstrong <narmstrong@baylibre.com>
+ * Copyright (C) 2015 Amlogic, Inc. All rights reserved.
+ */
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/time64.h>
+
+struct meson_vrtc_data {
+       void __iomem *io_alarm;
+       struct rtc_device *rtc;
+       unsigned long alarm_time;
+       bool enabled;
+};
+
+static int meson_vrtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+       struct timespec64 time;
+
+       dev_dbg(dev, "%s\n", __func__);
+       ktime_get_raw_ts64(&time);
+       rtc_time64_to_tm(time.tv_sec, tm);
+
+       return 0;
+}
+
+static void meson_vrtc_set_wakeup_time(struct meson_vrtc_data *vrtc,
+                                      unsigned long time)
+{
+       writel_relaxed(time, vrtc->io_alarm);
+}
+
+static int meson_vrtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+       struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);
+
+       dev_dbg(dev, "%s: alarm->enabled=%d\n", __func__, alarm->enabled);
+       if (alarm->enabled)
+               vrtc->alarm_time = rtc_tm_to_time64(&alarm->time);
+       else
+               vrtc->alarm_time = 0;
+
+       return 0;
+}
+
+static int meson_vrtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+       struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);
+
+       vrtc->enabled = enabled;
+       return 0;
+}
+
+static const struct rtc_class_ops meson_vrtc_ops = {
+       .read_time = meson_vrtc_read_time,
+       .set_alarm = meson_vrtc_set_alarm,
+       .alarm_irq_enable = meson_vrtc_alarm_irq_enable,
+};
+
+static int meson_vrtc_probe(struct platform_device *pdev)
+{
+       struct meson_vrtc_data *vrtc;
+       int ret;
+
+       vrtc = devm_kzalloc(&pdev->dev, sizeof(*vrtc), GFP_KERNEL);
+       if (!vrtc)
+               return -ENOMEM;
+
+       vrtc->io_alarm = devm_platform_ioremap_resource(pdev, 0);
+       if (IS_ERR(vrtc->io_alarm))
+               return PTR_ERR(vrtc->io_alarm);
+
+       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);
+
+       vrtc->rtc->ops = &meson_vrtc_ops;
+       ret = rtc_register_device(vrtc->rtc);
+       if (ret)
+               return ret;
+
+       return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int meson_vrtc_suspend(struct device *dev)
+{
+       struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);
+
+       dev_dbg(dev, "%s\n", __func__);
+       if (vrtc->alarm_time) {
+               unsigned long local_time;
+               long alarm_secs;
+               struct timespec64 time;
+
+               ktime_get_raw_ts64(&time);
+               local_time = time.tv_sec;
+
+               dev_dbg(dev, "alarm_time = %lus, local_time=%lus\n",
+                       vrtc->alarm_time, local_time);
+               alarm_secs = vrtc->alarm_time - local_time;
+               if (alarm_secs > 0) {
+                       meson_vrtc_set_wakeup_time(vrtc, alarm_secs);
+                       dev_dbg(dev, "system will wakeup in %lds.\n",
+                               alarm_secs);
+               } else {
+                       dev_err(dev, "alarm time already passed: %lds.\n",
+                               alarm_secs);
+               }
+       }
+
+       return 0;
+}
+
+static int meson_vrtc_resume(struct device *dev)
+{
+       struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);
+
+       dev_dbg(dev, "%s\n", __func__);
+
+       vrtc->alarm_time = 0;
+       meson_vrtc_set_wakeup_time(vrtc, 0);
+       return 0;
+}
+#endif
+static SIMPLE_DEV_PM_OPS(meson_vrtc_pm_ops,
+                        meson_vrtc_suspend, meson_vrtc_resume);
+
+static const struct of_device_id meson_vrtc_dt_match[] = {
+       { .compatible = "amlogic,meson-vrtc"},
+       {},
+};
+MODULE_DEVICE_TABLE(of, meson_vrtc_dt_match);
+
+static struct platform_driver meson_vrtc_driver = {
+       .probe = meson_vrtc_probe,
+       .driver = {
+               .name = "meson-vrtc",
+               .of_match_table = meson_vrtc_dt_match,
+               .pm = &meson_vrtc_pm_ops,
+       },
+};
+
+module_platform_driver(meson_vrtc_driver);
+
+MODULE_DESCRIPTION("Amlogic Virtual Wakeup RTC Timer driver");
+MODULE_LICENSE("GPL");