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Message-Id: <1478183365-23708-3-git-send-email-narmstrong@baylibre.com>
Date: Thu, 3 Nov 2016 15:29:24 +0100
From: Neil Armstrong <narmstrong@...libre.com>
To: khilman@...libre.com, carlo@...one.org, a.zummo@...ertech.it,
alexandre.belloni@...e-electrons.com
Cc: Neil Armstrong <narmstrong@...libre.com>,
rtc-linux@...glegroups.com, linux-amlogic@...ts.infradead.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [RFC PATCH 2/3] 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@...libre.com>
---
drivers/rtc/Kconfig | 10 +++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-meson-vrtc.c | 164 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 175 insertions(+)
create mode 100644 drivers/rtc/rtc-meson-vrtc.c
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index e859d14..d0f65fb 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -351,6 +351,16 @@ 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
+ 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 RK808/RK818 RTC"
depends on MFD_RK808
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 1ac694a..feb83ad 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -92,6 +92,7 @@ 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_MOXART) += rtc-moxart.o
diff --git a/drivers/rtc/rtc-meson-vrtc.c b/drivers/rtc/rtc-meson-vrtc.c
new file mode 100644
index 0000000..34c45bd
--- /dev/null
+++ b/drivers/rtc/rtc-meson-vrtc.c
@@ -0,0 +1,164 @@
+/*
+ * drivers/rtc/rtc-meson-vrtc.c
+ *
+ * Copyright (C) 2016 BayLibre, SAS
+ * Author: Neil Armstrong <narmstrong@...libre.com>
+ * Copyright (C) 2015 Amlogic, Inc. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/pm_wakeup.h>
+#include <linux/time64.h>
+
+struct meson_vrtc_data {
+ struct platform_device *pdev;
+ void __iomem *io_alarm;
+ struct rtc_device *rtc;
+ unsigned long alarm_time;
+};
+
+static int meson_vrtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ unsigned long local_time;
+ struct timeval time;
+
+ do_gettimeofday(&time);
+ local_time = time.tv_sec - (sys_tz.tz_minuteswest * 60);
+ rtc_time_to_tm(local_time, tm);
+
+ return 0;
+}
+
+static void meson_vrtc_set_wakeup_time(struct meson_vrtc_data *vrtc,
+ unsigned long time)
+{
+ writel_relaxed(time, vrtc->io_alarm);
+
+ dev_dbg(&vrtc->pdev->dev, "set_wakeup_time: %lu\n", time);
+}
+
+static int meson_vrtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+ struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);
+ struct timeval time;
+ unsigned long local_time;
+ unsigned long alarm_secs;
+ int ret;
+
+ if (alarm->enabled) {
+ ret = rtc_tm_to_time(&alarm->time, &alarm_secs);
+ if (ret)
+ return ret;
+
+ do_gettimeofday(&time);
+ local_time = time.tv_sec - (sys_tz.tz_minuteswest * 60);
+
+ vrtc->alarm_time = alarm_secs;
+
+ if (alarm_secs >= local_time) {
+ alarm_secs = alarm_secs - local_time;
+
+ meson_vrtc_set_wakeup_time(vrtc, alarm_secs);
+
+ pr_debug("system will wakeup %lus later\n", alarm_secs);
+ }
+ } else {
+ vrtc->alarm_time = 0;
+ meson_vrtc_set_wakeup_time(vrtc, 0);
+ }
+
+ return 0;
+}
+
+static int meson_vrtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+ struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);
+
+ if (!vrtc->alarm_time) {
+ alm->enabled = true;
+
+ rtc_time_to_tm(vrtc->alarm_time, &alm->time);
+ }
+
+ return 0;
+}
+
+static const struct rtc_class_ops meson_vrtc_ops = {
+ .read_time = meson_vrtc_read_time,
+ .set_alarm = meson_vrtc_set_alarm,
+ .read_alarm = meson_vrtc_read_alarm,
+};
+
+static int meson_vrtc_probe(struct platform_device *pdev)
+{
+ struct meson_vrtc_data *vrtc;
+ struct resource *res;
+
+ vrtc = devm_kzalloc(&pdev->dev, sizeof(*vrtc), GFP_KERNEL);
+ if (!vrtc)
+ return -ENOMEM;
+
+ vrtc->pdev = pdev;
+
+ /* Alarm registers */
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ vrtc->io_alarm = devm_ioremap_resource(&pdev->dev, res);
+ 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_device_register(&pdev->dev, "meson-vrtc",
+ &meson_vrtc_ops, THIS_MODULE);
+ if (IS_ERR(vrtc->rtc))
+ return PTR_ERR(vrtc->rtc);
+
+ return 0;
+}
+
+int meson_vrtc_resume(struct platform_device *pdev)
+{
+ struct meson_vrtc_data *vrtc = platform_get_drvdata(pdev);
+
+ meson_vrtc_set_wakeup_time(vrtc, 0);
+
+ return 0;
+}
+
+static const struct of_device_id meson_vrtc_dt_match[] = {
+ { .compatible = "amlogic,meson-vrtc"},
+ {},
+};
+MODULE_DEVICE_TABLE(of, meson_vrtc_dt_match);
+
+struct platform_driver meson_vrtc_driver = {
+ .driver = {
+ .name = "meson-vrtc",
+ .of_match_table = meson_vrtc_dt_match,
+ },
+ .probe = meson_vrtc_probe,
+ .resume = meson_vrtc_resume,
+};
+
+module_platform_driver(meson_vrtc_driver);
+
+MODULE_DESCRIPTION("Amlogic Virtual Wakeup RTC Timer driver");
+MODULE_LICENSE("GPL");
--
1.9.1
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