[openwrt/staging/mkresin.git] / target / linux / mediatek / patches-4.14 / 0138-rtc-mediatek-add-driver-for-RTC-on-MT7622-SoC.patch

From 4cf0b74c175cb5cb751e449223c0baafc2f98499 Mon Sep 17 00:00:00 2001
From: Sean Wang <sean.wang@mediatek.com>
Date: Mon, 23 Oct 2017 15:16:45 +0800
Subject: [PATCH 138/224] rtc: mediatek: add driver for RTC on MT7622 SoC

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

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Reviewed-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
---
 drivers/rtc/Kconfig      |  10 ++
 drivers/rtc/Makefile     |   1 +
 drivers/rtc/rtc-mt7622.c | 422 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 433 insertions(+)
 create mode 100644 drivers/rtc/rtc-mt7622.c

--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1715,6 +1715,16 @@ config RTC_DRV_MT6397
 
          If you want to use Mediatek(R) RTC interface, select Y or M here.
 
+config RTC_DRV_MT7622
+       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-mt7622.
+
 config RTC_DRV_XGENE
        tristate "APM X-Gene RTC"
        depends on HAS_IOMEM
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -103,6 +103,7 @@ obj-$(CONFIG_RTC_DRV_MPC5121)       += rtc-mpc
 obj-$(CONFIG_RTC_DRV_VRTC)     += rtc-mrst.o
 obj-$(CONFIG_RTC_DRV_MSM6242)  += rtc-msm6242.o
 obj-$(CONFIG_RTC_DRV_MT6397)   += rtc-mt6397.o
+obj-$(CONFIG_RTC_DRV_MT7622)   += rtc-mt7622.o
 obj-$(CONFIG_RTC_DRV_MV)       += rtc-mv.o
 obj-$(CONFIG_RTC_DRV_MXC)      += rtc-mxc.o
 obj-$(CONFIG_RTC_DRV_NUC900)   += rtc-nuc900.o
--- /dev/null
+++ b/drivers/rtc/rtc-mt7622.c
@@ -0,0 +1,422 @@
+/*
+ * Driver for MediaTek SoC based RTC
+ *
+ * Copyright (C) 2017 Sean Wang <sean.wang@mediatek.com>
+ *
+ * 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)
+
+/*
+ * The offset is used in the translation for the year between in struct
+ * rtc_time and in hardware register MTK_RTC_TREG(x,MTK_YEA)
+ */
+#define MTK_RTC_TM_YR_OFFSET   100
+
+/*
+ * The lowest value for the valid tm_year. RTC hardware would take incorrectly
+ * tm_year 100 as not a leap year and thus it is also required being excluded
+ * from the valid options.
+ */
+#define MTK_RTC_TM_YR_L                (MTK_RTC_TM_YR_OFFSET + 1)
+
+/*
+ * The most year the RTC can hold is 99 and the next to 99 in year register
+ * would be wraparound to 0, for MT7622.
+ */
+#define MTK_RTC_HW_YR_LIMIT    99
+
+/* The highest value for the valid tm_year */
+#define MTK_RTC_TM_YR_H                (MTK_RTC_TM_YR_OFFSET + MTK_RTC_HW_YR_LIMIT)
+
+/* Simple macro helps to check whether the hardware supports the tm_year */
+#define MTK_RTC_TM_YR_VALID(_y)        ((_y) >= MTK_RTC_TM_YR_L && \
+                                (_y) <= MTK_RTC_TM_YR_H)
+
+/* Types of the function the RTC provides are time counter and alarm. */
+enum {
+       MTK_TC,
+       MTK_AL,
+};
+
+/* 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;
+};
+
+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. Note that MTK_SEC must
+        * be read first. In this way, it guarantees the others remain not
+        * changed when the results for two MTK_SEC consecutive reads are same.
+        */
+       do {
+               sec = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC));
+               min = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN));
+               hour = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU));
+               wday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW));
+               mday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM));
+               mon = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MON));
+               year = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA));
+       } 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 queries */
+       tm->tm_year = year + MTK_RTC_TM_YR_OFFSET;
+}
+
+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_OFFSET;
+
+       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);
+
+       if (!MTK_RTC_TM_YR_VALID(tm->tm_year))
+               return -EINVAL;
+
+       /* 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;
+
+       if (!MTK_RTC_TM_YR_VALID(alrm_tm->tm_year))
+               return -EINVAL;
+
+       /*
+        * 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@mediatek.com>");
+MODULE_LICENSE("GPL");