--- /dev/null
+/*
+ * Motorola CPCAP PMIC RTC driver
+ *
+ * Based on cpcap-regulator.c from Motorola Linux kernel tree
+ * Copyright (C) 2009 Motorola, Inc.
+ *
+ * Rewritten for mainline kernel
+ * - use DT
+ * - use regmap
+ * - use standard interrupt framework
+ * - use managed device resources
+ * - remove custom "secure clock daemon" helpers
+ *
+ * Copyright (C) 2017 Sebastian Reichel <sre@kernel.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/err.h>
+#include <linux/regmap.h>
+#include <linux/mfd/motorola-cpcap.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+
+#define SECS_PER_DAY 86400
+#define DAY_MASK 0x7FFF
+#define TOD1_MASK 0x00FF
+#define TOD2_MASK 0x01FF
+
+struct cpcap_time {
+ int day;
+ int tod1;
+ int tod2;
+};
+
+struct cpcap_rtc {
+ struct regmap *regmap;
+ struct rtc_device *rtc_dev;
+ u16 vendor;
+ int alarm_irq;
+ bool alarm_enabled;
+ int update_irq;
+ bool update_enabled;
+};
+
+static void cpcap2rtc_time(struct rtc_time *rtc, struct cpcap_time *cpcap)
+{
+ unsigned long int tod;
+ unsigned long int time;
+
+ tod = (cpcap->tod1 & TOD1_MASK) | ((cpcap->tod2 & TOD2_MASK) << 8);
+ time = tod + ((cpcap->day & DAY_MASK) * SECS_PER_DAY);
+
+ rtc_time_to_tm(time, rtc);
+}
+
+static void rtc2cpcap_time(struct cpcap_time *cpcap, struct rtc_time *rtc)
+{
+ unsigned long time;
+
+ rtc_tm_to_time(rtc, &time);
+
+ cpcap->day = time / SECS_PER_DAY;
+ time %= SECS_PER_DAY;
+ cpcap->tod2 = (time >> 8) & TOD2_MASK;
+ cpcap->tod1 = time & TOD1_MASK;
+}
+
+static int cpcap_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct cpcap_rtc *rtc = dev_get_drvdata(dev);
+
+ if (rtc->alarm_enabled == enabled)
+ return 0;
+
+ if (enabled)
+ enable_irq(rtc->alarm_irq);
+ else
+ disable_irq(rtc->alarm_irq);
+
+ rtc->alarm_enabled = !!enabled;
+
+ return 0;
+}
+
+static int cpcap_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct cpcap_rtc *rtc;
+ struct cpcap_time cpcap_tm;
+ int temp_tod2;
+ int ret;
+
+ rtc = dev_get_drvdata(dev);
+
+ ret = regmap_read(rtc->regmap, CPCAP_REG_TOD2, &temp_tod2);
+ ret |= regmap_read(rtc->regmap, CPCAP_REG_DAY, &cpcap_tm.day);
+ ret |= regmap_read(rtc->regmap, CPCAP_REG_TOD1, &cpcap_tm.tod1);
+ ret |= regmap_read(rtc->regmap, CPCAP_REG_TOD2, &cpcap_tm.tod2);
+
+ if (temp_tod2 > cpcap_tm.tod2)
+ ret |= regmap_read(rtc->regmap, CPCAP_REG_DAY, &cpcap_tm.day);
+
+ if (ret) {
+ dev_err(dev, "Failed to read time\n");
+ return -EIO;
+ }
+
+ cpcap2rtc_time(tm, &cpcap_tm);
+
+ return rtc_valid_tm(tm);
+}
+
+static int cpcap_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct cpcap_rtc *rtc;
+ struct cpcap_time cpcap_tm;
+ int ret = 0;
+
+ rtc = dev_get_drvdata(dev);
+
+ rtc2cpcap_time(&cpcap_tm, tm);
+
+ if (rtc->alarm_enabled)
+ disable_irq(rtc->alarm_irq);
+ if (rtc->update_enabled)
+ disable_irq(rtc->update_irq);
+
+ if (rtc->vendor == CPCAP_VENDOR_ST) {
+ /* The TOD1 and TOD2 registers MUST be written in this order
+ * for the change to properly set.
+ */
+ ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD1,
+ TOD1_MASK, cpcap_tm.tod1);
+ ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD2,
+ TOD2_MASK, cpcap_tm.tod2);
+ ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_DAY,
+ DAY_MASK, cpcap_tm.day);
+ } else {
+ /* Clearing the upper lower 8 bits of the TOD guarantees that
+ * the upper half of TOD (TOD2) will not increment for 0xFF RTC
+ * ticks (255 seconds). During this time we can safely write
+ * to DAY, TOD2, then TOD1 (in that order) and expect RTC to be
+ * synchronized to the exact time requested upon the final write
+ * to TOD1.
+ */
+ ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD1,
+ TOD1_MASK, 0);
+ ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_DAY,
+ DAY_MASK, cpcap_tm.day);
+ ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD2,
+ TOD2_MASK, cpcap_tm.tod2);
+ ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD1,
+ TOD1_MASK, cpcap_tm.tod1);
+ }
+
+ if (rtc->update_enabled)
+ enable_irq(rtc->update_irq);
+ if (rtc->alarm_enabled)
+ enable_irq(rtc->alarm_irq);
+
+ return ret;
+}
+
+static int cpcap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct cpcap_rtc *rtc;
+ struct cpcap_time cpcap_tm;
+ int ret;
+
+ rtc = dev_get_drvdata(dev);
+
+ alrm->enabled = rtc->alarm_enabled;
+
+ ret = regmap_read(rtc->regmap, CPCAP_REG_DAYA, &cpcap_tm.day);
+ ret |= regmap_read(rtc->regmap, CPCAP_REG_TODA2, &cpcap_tm.tod2);
+ ret |= regmap_read(rtc->regmap, CPCAP_REG_TODA1, &cpcap_tm.tod1);
+
+ if (ret) {
+ dev_err(dev, "Failed to read time\n");
+ return -EIO;
+ }
+
+ cpcap2rtc_time(&alrm->time, &cpcap_tm);
+ return rtc_valid_tm(&alrm->time);
+}
+
+static int cpcap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct cpcap_rtc *rtc;
+ struct cpcap_time cpcap_tm;
+ int ret;
+
+ rtc = dev_get_drvdata(dev);
+
+ rtc2cpcap_time(&cpcap_tm, &alrm->time);
+
+ if (rtc->alarm_enabled)
+ disable_irq(rtc->alarm_irq);
+
+ ret = regmap_update_bits(rtc->regmap, CPCAP_REG_DAYA, DAY_MASK,
+ cpcap_tm.day);
+ ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TODA2, TOD2_MASK,
+ cpcap_tm.tod2);
+ ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TODA1, TOD1_MASK,
+ cpcap_tm.tod1);
+
+ if (!ret) {
+ enable_irq(rtc->alarm_irq);
+ rtc->alarm_enabled = true;
+ }
+
+ return ret;
+}
+
+static const struct rtc_class_ops cpcap_rtc_ops = {
+ .read_time = cpcap_rtc_read_time,
+ .set_time = cpcap_rtc_set_time,
+ .read_alarm = cpcap_rtc_read_alarm,
+ .set_alarm = cpcap_rtc_set_alarm,
+ .alarm_irq_enable = cpcap_rtc_alarm_irq_enable,
+};
+
+static irqreturn_t cpcap_rtc_alarm_irq(int irq, void *data)
+{
+ struct cpcap_rtc *rtc = data;
+
+ rtc_update_irq(rtc->rtc_dev, 1, RTC_AF | RTC_IRQF);
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t cpcap_rtc_update_irq(int irq, void *data)
+{
+ struct cpcap_rtc *rtc = data;
+
+ rtc_update_irq(rtc->rtc_dev, 1, RTC_UF | RTC_IRQF);
+ return IRQ_HANDLED;
+}
+
+static int cpcap_rtc_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct cpcap_rtc *rtc;
+ int err;
+
+ rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);
+ if (!rtc)
+ return -ENOMEM;
+
+ rtc->regmap = dev_get_regmap(dev->parent, NULL);
+ if (!rtc->regmap)
+ return -ENODEV;
+
+ platform_set_drvdata(pdev, rtc);
+ rtc->rtc_dev = devm_rtc_device_register(dev, "cpcap_rtc",
+ &cpcap_rtc_ops, THIS_MODULE);
+
+ if (IS_ERR(rtc->rtc_dev)) {
+ kfree(rtc);
+ return PTR_ERR(rtc->rtc_dev);
+ }
+
+ err = cpcap_get_vendor(dev, rtc->regmap, &rtc->vendor);
+ if (err)
+ return err;
+
+ rtc->alarm_irq = platform_get_irq(pdev, 0);
+ err = devm_request_threaded_irq(dev, rtc->alarm_irq, NULL,
+ cpcap_rtc_alarm_irq, IRQ_NONE,
+ "rtc_alarm", rtc);
+ if (err) {
+ dev_err(dev, "Could not request alarm irq: %d\n", err);
+ return err;
+ }
+ disable_irq(rtc->alarm_irq);
+
+ /* Stock Android uses the 1 Hz interrupt for "secure clock daemon",
+ * which is not supported by the mainline kernel. The mainline kernel
+ * does not use the irq at the moment, but we explicitly request and
+ * disable it, so that its masked and does not wake up the processor
+ * every second.
+ */
+ rtc->update_irq = platform_get_irq(pdev, 1);
+ err = devm_request_threaded_irq(dev, rtc->update_irq, NULL,
+ cpcap_rtc_update_irq, IRQ_NONE,
+ "rtc_1hz", rtc);
+ if (err) {
+ dev_err(dev, "Could not request update irq: %d\n", err);
+ return err;
+ }
+ disable_irq(rtc->update_irq);
+
+ err = device_init_wakeup(dev, 1);
+ if (err) {
+ dev_err(dev, "wakeup initialization failed (%d)\n", err);
+ /* ignore error and continue without wakeup support */
+ }
+
+ return 0;
+}
+
+static const struct of_device_id cpcap_rtc_of_match[] = {
+ { .compatible = "motorola,cpcap-rtc", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, cpcap_rtc_of_match);
+
+static struct platform_driver cpcap_rtc_driver = {
+ .probe = cpcap_rtc_probe,
+ .driver = {
+ .name = "cpcap-rtc",
+ .of_match_table = cpcap_rtc_of_match,
+ },
+};
+
+module_platform_driver(cpcap_rtc_driver);
+
+MODULE_ALIAS("platform:cpcap-rtc");
+MODULE_DESCRIPTION("CPCAP RTC driver");
+MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
+MODULE_LICENSE("GPL");
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