[PATCH v2 2/4] rtc: mediatek: add driver for RTC on MT7622 SoC

sean.wang-NuS5LvNUpcJWk0Htik3J/w
2017-10-17T09:40:33Z

From: Sean Wang <sean.wang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>

This patch introduces the driver for the RTC on MT7622 SoC.

Signed-off-by: Sean Wang <sean.wang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
---
drivers/rtc/Kconfig | 10 ++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-mt7622.c | 418 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 429 insertions(+)
create mode 100644 drivers/rtc/rtc-mt7622.c

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index e0e58f3..4226295 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1705,6 +1705,16 @@ config RTC_DRV_MOXART
This driver can also be built as a module. If so, the module
will be called rtc-moxart

+config RTC_DRV_MEDIATEK
+ tristate "MediaTek SoC based RTC"
+ depends on ARCH_MEDIATEK || COMPILE_TEST
+ help
+ This enables support for the real time clock built in the MediaTek
+ SoCs.
+
+ This drive can also be built as a module. If so, the module
+ will be called rtc-mediatek.
+
config RTC_DRV_MT6397
tristate "Mediatek Real Time Clock driver"
depends on MFD_MT6397 || (COMPILE_TEST && IRQ_DOMAIN)
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 7230014..593a02c 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -101,6 +101,7 @@ obj-$(CONFIG_RTC_DRV_MOXART) += rtc-moxart.o
obj-$(CONFIG_RTC_DRV_MPC5121) += rtc-mpc5121.o
obj-$(CONFIG_RTC_DRV_VRTC) += rtc-mrst.o
obj-$(CONFIG_RTC_DRV_MSM6242) += rtc-msm6242.o
+obj-$(CONFIG_RTC_DRV_MEDIATEK) += rtc-mt7622.o
obj-$(CONFIG_RTC_DRV_MT6397) += rtc-mt6397.o
obj-$(CONFIG_RTC_DRV_MV) += rtc-mv.o
obj-$(CONFIG_RTC_DRV_MXC) += rtc-mxc.o
diff --git a/drivers/rtc/rtc-mt7622.c b/drivers/rtc/rtc-mt7622.c
new file mode 100644
index 0000000..1f00494
--- /dev/null
+++ b/drivers/rtc/rtc-mt7622.c
@@ -0,0 +1,418 @@
+/*
+ * Driver for MediaTek SoC based RTC
+ *
+ * Copyright (C) 2017 Sean Wang <sean.wang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
+ *
+ * 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/clk.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+
+#define MTK_RTC_DEV KBUILD_MODNAME
+
+#define MTK_RTC_PWRCHK1 0x4
+#define RTC_PWRCHK1_MAGIC 0xc6
+
+#define MTK_RTC_PWRCHK2 0x8
+#define RTC_PWRCHK2_MAGIC 0x9a
+
+#define MTK_RTC_KEY 0xc
+#define RTC_KEY_MAGIC 0x59
+
+#define MTK_RTC_PROT1 0x10
+#define RTC_PROT1_MAGIC 0xa3
+
+#define MTK_RTC_PROT2 0x14
+#define RTC_PROT2_MAGIC 0x57
+
+#define MTK_RTC_PROT3 0x18
+#define RTC_PROT3_MAGIC 0x67
+
+#define MTK_RTC_PROT4 0x1c
+#define RTC_PROT4_MAGIC 0xd2
+
+#define MTK_RTC_CTL 0x20
+#define RTC_RC_STOP BIT(0)
+
+#define MTK_RTC_DEBNCE 0x2c
+#define RTC_DEBNCE_MASK GENMASK(2, 0)
+
+#define MTK_RTC_INT 0x30
+#define RTC_INT_AL_STA BIT(4)
+
+/* Ranges from 0x40 to 0x78 provide RTC time setup for year, month,
+ * day of month, day of week, hour, minute and second.
+ */
+#define MTK_RTC_TREG(_t, _f) (0x40 + (0x4 * (_f)) + ((_t) * 0x20))
+
+#define MTK_RTC_AL_CTL 0x7c
+#define RTC_AL_EN BIT(0)
+#define RTC_AL_ALL GENMASK(7, 0)
+
+#define MTK_RTC_TM_YR_L 100
+
+/* The maximum years the RTC can support is 99, For MT7622 */
+#define MTK_RTC_HW_YR_LIMIT 100
+
+/* Types of the function the RTC provides are time counter and alarm. */
+enum {
+ MTK_TC,
+ MTK_AL,
+ MTK_TYPE_MAX,
+};
+
+/* Indexes are used for the pointer to relevant registers in MTK_RTC_TREG */
+enum {
+ MTK_YEA,
+ MTK_MON,
+ MTK_DOM,
+ MTK_DOW,
+ MTK_HOU,
+ MTK_MIN,
+ MTK_SEC
+};
+
+struct mtk_rtc {
+ struct rtc_device *rtc;
+ void __iomem *base;
+ int irq;
+ struct clk *clk;
+ u32 yr_base[MTK_TYPE_MAX];
+};
+
+static void mtk_w32(struct mtk_rtc *rtc, u32 reg, u32 val)
+{
+ writel_relaxed(val, rtc->base + reg);
+}
+
+static u32 mtk_r32(struct mtk_rtc *rtc, u32 reg)
+{
+ return readl_relaxed(rtc->base + reg);
+}
+
+static void mtk_rmw(struct mtk_rtc *rtc, u32 reg, u32 mask, u32 set)
+{
+ u32 val;
+
+ val = mtk_r32(rtc, reg);
+ val &= ~mask;
+ val |= set;
+ mtk_w32(rtc, reg, val);
+}
+
+static void mtk_set(struct mtk_rtc *rtc, u32 reg, u32 val)
+{
+ mtk_rmw(rtc, reg, 0, val);
+}
+
+static void mtk_clr(struct mtk_rtc *rtc, u32 reg, u32 val)
+{
+ mtk_rmw(rtc, reg, val, 0);
+}
+
+static void mtk_rtc_hw_init(struct mtk_rtc *hw)
+{
+ /* The setup of the init sequence is for allowing RTC got to work */
+ mtk_w32(hw, MTK_RTC_PWRCHK1, RTC_PWRCHK1_MAGIC);
+ mtk_w32(hw, MTK_RTC_PWRCHK2, RTC_PWRCHK2_MAGIC);
+ mtk_w32(hw, MTK_RTC_KEY, RTC_KEY_MAGIC);
+ mtk_w32(hw, MTK_RTC_PROT1, RTC_PROT1_MAGIC);
+ mtk_w32(hw, MTK_RTC_PROT2, RTC_PROT2_MAGIC);
+ mtk_w32(hw, MTK_RTC_PROT3, RTC_PROT3_MAGIC);
+ mtk_w32(hw, MTK_RTC_PROT4, RTC_PROT4_MAGIC);
+ mtk_rmw(hw, MTK_RTC_DEBNCE, RTC_DEBNCE_MASK, 0);
+ mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP);
+}
+
+static void mtk_rtc_get_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm,
+ int time_alarm)
+{
+ u32 year, mon, mday, wday, hour, min, sec;
+
+ /*
+ * Read again until the field of the second is not changed which
+ * ensures all fields in the consistent state.
+ */
+ do {
+ year = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA));
+ mon = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MON));
+ wday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW));
+ mday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM));
+ hour = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU));
+ min = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN));
+ sec = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC));
+ } while (sec != mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC)));
+
+ tm->tm_sec = sec;
+ tm->tm_min = min;
+ tm->tm_hour = hour;
+ tm->tm_wday = wday;
+ tm->tm_mday = mday;
+ tm->tm_mon = mon - 1;
+
+ /* Rebase to the absolute year which userspace requires */
+ tm->tm_year = year + MTK_RTC_TM_YR_L + hw->yr_base[time_alarm];
+}
+
+static void mtk_rtc_set_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm,
+ int time_alarm)
+{
+ u32 year;
+
+ /* Rebase to the relative year which RTC hardware requires */
+ year = tm->tm_year - MTK_RTC_TM_YR_L - hw->yr_base[time_alarm];
+
+ mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA), year);
+ mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MON), tm->tm_mon + 1);
+ mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW), tm->tm_wday);
+ mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM), tm->tm_mday);
+ mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU), tm->tm_hour);
+ mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN), tm->tm_min);
+ mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC), tm->tm_sec);
+}
+
+static irqreturn_t mtk_rtc_alarmirq(int irq, void *id)
+{
+ struct mtk_rtc *hw = (struct mtk_rtc *)id;
+ u32 irq_sta;
+
+ irq_sta = mtk_r32(hw, MTK_RTC_INT);
+ if (irq_sta & RTC_INT_AL_STA) {
+ /* Stop alarm also implicitly disables the alarm interrupt */
+ mtk_w32(hw, MTK_RTC_AL_CTL, 0);
+ rtc_update_irq(hw->rtc, 1, RTC_IRQF | RTC_AF);
+
+ /* Ack alarm interrupt status */
+ mtk_w32(hw, MTK_RTC_INT, RTC_INT_AL_STA);
+ return IRQ_HANDLED;
+ }
+
+ return IRQ_NONE;
+}
+
+static int mtk_rtc_gettime(struct device *dev, struct rtc_time *tm)
+{
+ struct mtk_rtc *hw = dev_get_drvdata(dev);
+
+ mtk_rtc_get_alarm_or_time(hw, tm, MTK_TC);
+
+ return rtc_valid_tm(tm);
+}
+
+static int mtk_rtc_settime(struct device *dev, struct rtc_time *tm)
+{
+ struct mtk_rtc *hw = dev_get_drvdata(dev);
+
+ /* Epoch == 1900, and the driver assumes that tm->tm_year has to be
+ * at least MTK_RTC_TM_YR_L.
+ */
+ if (tm->tm_year < MTK_RTC_TM_YR_L)
+ return -EINVAL;
+
+ /* Keep yr_base used to calculate the calculate year when userspace
+ * queries and extend the maximum year the RTC can count.
+ */
+ hw->yr_base[MTK_TC] = tm->tm_year - MTK_RTC_TM_YR_L -
+ (tm->tm_year % MTK_RTC_HW_YR_LIMIT);
+
+ /* Stop time counter before setting a new one*/
+ mtk_set(hw, MTK_RTC_CTL, RTC_RC_STOP);
+
+ mtk_rtc_set_alarm_or_time(hw, tm, MTK_TC);
+
+ /* Restart the time counter */
+ mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP);
+
+ return 0;
+}
+
+static int mtk_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
+{
+ struct mtk_rtc *hw = dev_get_drvdata(dev);
+ struct rtc_time *alrm_tm = &wkalrm->time;
+
+ mtk_rtc_get_alarm_or_time(hw, alrm_tm, MTK_AL);
+
+ wkalrm->enabled = !!(mtk_r32(hw, MTK_RTC_AL_CTL) & RTC_AL_EN);
+ wkalrm->pending = !!(mtk_r32(hw, MTK_RTC_INT) & RTC_INT_AL_STA);
+
+ return 0;
+}
+
+static int mtk_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
+{
+ struct mtk_rtc *hw = dev_get_drvdata(dev);
+ struct rtc_time *alrm_tm = &wkalrm->time;
+
+ /* Epoch == 1900, and the driver assumes that alrm_tm->tm_year has to
+ * be at least MTK_RTC_TM_YR_L.
+ */
+ if (alrm_tm->tm_year < MTK_RTC_TM_YR_L)
+ return -EINVAL;
+
+ /* Keep yr_base used to calculate the calculate year when userspace
+ * queries and extend the maximum time the alarm can support.
+ */
+ hw->yr_base[MTK_AL] = alrm_tm->tm_year - MTK_RTC_TM_YR_L -
+ (alrm_tm->tm_year % MTK_RTC_HW_YR_LIMIT);
+
+ /*
+ * Stop the alarm also implicitly including disables interrupt before
+ * setting a new one.
+ */
+ mtk_clr(hw, MTK_RTC_AL_CTL, RTC_AL_EN);
+
+ /*
+ * Avoid contention between mtk_rtc_setalarm and IRQ handler so that
+ * disabling the interrupt and awaiting for pending IRQ handler to
+ * complete.
+ */
+ synchronize_irq(hw->irq);
+
+ mtk_rtc_set_alarm_or_time(hw, alrm_tm, MTK_AL);
+
+ /* Restart the alarm with the new setup */
+ mtk_w32(hw, MTK_RTC_AL_CTL, RTC_AL_ALL);
+
+ return 0;
+}
+
+static const struct rtc_class_ops mtk_rtc_ops = {
+ .read_time = mtk_rtc_gettime,
+ .set_time = mtk_rtc_settime,
+ .read_alarm = mtk_rtc_getalarm,
+ .set_alarm = mtk_rtc_setalarm,
+};
+
+static const struct of_device_id mtk_rtc_match[] = {
+ { .compatible = "mediatek,mt7622-rtc" },
+ { .compatible = "mediatek,soc-rtc" },
+ {},
+};
+
+static int mtk_rtc_probe(struct platform_device *pdev)
+{
+ struct mtk_rtc *hw;
+ struct resource *res;
+ int ret;
+
+ hw = devm_kzalloc(&pdev->dev, sizeof(*hw), GFP_KERNEL);
+ if (!hw)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, hw);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ hw->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(hw->base))
+ return PTR_ERR(hw->base);
+
+ hw->clk = devm_clk_get(&pdev->dev, "rtc");
+ if (IS_ERR(hw->clk)) {
+ dev_err(&pdev->dev, "No clock\n");
+ return PTR_ERR(hw->clk);
+ }
+
+ ret = clk_prepare_enable(hw->clk);
+ if (ret)
+ return ret;
+
+ hw->irq = platform_get_irq(pdev, 0);
+ if (hw->irq < 0) {
+ dev_err(&pdev->dev, "No IRQ resource\n");
+ ret = hw->irq;
+ goto err;
+ }
+
+ ret = devm_request_irq(&pdev->dev, hw->irq, mtk_rtc_alarmirq,
+ 0, dev_name(&pdev->dev), hw);
+ if (ret) {
+ dev_err(&pdev->dev, "Can't request IRQ\n");
+ goto err;
+ }
+
+ mtk_rtc_hw_init(hw);
+
+ device_init_wakeup(&pdev->dev, true);
+
+ hw->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
+ &mtk_rtc_ops, THIS_MODULE);
+ if (IS_ERR(hw->rtc)) {
+ ret = PTR_ERR(hw->rtc);
+ dev_err(&pdev->dev, "Unable to register device\n");
+ goto err;
+ }
+
+ return 0;
+err:
+ clk_disable_unprepare(hw->clk);
+
+ return ret;
+}
+
+static int mtk_rtc_remove(struct platform_device *pdev)
+{
+ struct mtk_rtc *hw = platform_get_drvdata(pdev);
+
+ clk_disable_unprepare(hw->clk);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int mtk_rtc_suspend(struct device *dev)
+{
+ struct mtk_rtc *hw = dev_get_drvdata(dev);
+
+ if (device_may_wakeup(dev))
+ enable_irq_wake(hw->irq);
+
+ return 0;
+}
+
+static int mtk_rtc_resume(struct device *dev)
+{
+ struct mtk_rtc *hw = dev_get_drvdata(dev);
+
+ if (device_may_wakeup(dev))
+ disable_irq_wake(hw->irq);
+
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(mtk_rtc_pm_ops, mtk_rtc_suspend, mtk_rtc_resume);
+
+#define MTK_RTC_PM_OPS (&mtk_rtc_pm_ops)
+#else /* CONFIG_PM */
+#define MTK_RTC_PM_OPS NULL
+#endif /* CONFIG_PM */
+
+static struct platform_driver mtk_rtc_driver = {
+ .probe = mtk_rtc_probe,
+ .remove = mtk_rtc_remove,
+ .driver = {
+ .name = MTK_RTC_DEV,
+ .of_match_table = mtk_rtc_match,
+ .pm = MTK_RTC_PM_OPS,
+ },
+};
+
+module_platform_driver(mtk_rtc_driver);
+
+MODULE_DESCRIPTION("MediaTek SoC based RTC Driver");
+MODULE_AUTHOR("Sean Wang <sean.wang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>");
+MODULE_LICENSE("GPL");
--
2.7.4