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Subject[PATCH] rtc: add MAX8907 RTC driver
Date
From: Stephen Warren <swarren@nvidia.com>

The MAX8907 is an I2C-based power-management IC containing voltage
regulators, a reset controller, a real-time clock, and a touch-screen
controller.

The driver is based on an original by or fixed by:
* Tom Cherry <tcherry@nvidia.com>
* Prashant Gaikwad <pgaikwad@nvidia.com>
* Joseph Yoon <tyoon@nvidia.com>

During upstreaming, I (swarren):
* Converted to regmap.
* Fixed handling of RTC_HOUR register containing 12.
* Fixed handling of RTC_WEEKDAY register.
* General cleanup.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
drivers/rtc/Kconfig | 10 ++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-max8907.c | 245 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 256 insertions(+), 0 deletions(-)
create mode 100644 drivers/rtc/rtc-max8907.c
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index fabc99a..c84f960 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -203,6 +203,16 @@ config RTC_DRV_MAX6900
This driver can also be built as a module. If so, the module
will be called rtc-max6900.

+config RTC_DRV_MAX8907
+ tristate "Maxim MAX8907"
+ depends on MFD_MAX8907
+ help
+ If you say yes here you will get support for the
+ RTC of Maxim MAX8907 PMIC.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-max8907.
+
config RTC_DRV_MAX8925
tristate "Maxim MAX8925"
depends on MFD_MAX8925
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 0d5b2b6..a0b4fbe 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -64,6 +64,7 @@ obj-$(CONFIG_RTC_DRV_M48T59) += rtc-m48t59.o
obj-$(CONFIG_RTC_DRV_M48T86) += rtc-m48t86.o
obj-$(CONFIG_RTC_DRV_MXC) += rtc-mxc.o
obj-$(CONFIG_RTC_DRV_MAX6900) += rtc-max6900.o
+obj-$(CONFIG_RTC_DRV_MAX8907) += rtc-max8907.o
obj-$(CONFIG_RTC_DRV_MAX8925) += rtc-max8925.o
obj-$(CONFIG_RTC_DRV_MAX8998) += rtc-max8998.o
obj-$(CONFIG_RTC_DRV_MAX6902) += rtc-max6902.o
diff --git a/drivers/rtc/rtc-max8907.c b/drivers/rtc/rtc-max8907.c
new file mode 100644
index 0000000..4880374
--- /dev/null
+++ b/drivers/rtc/rtc-max8907.c
@@ -0,0 +1,245 @@
+/*
+ * RTC driver for Maxim MAX8907
+ *
+ * Copyright (c) 2011-2012, NVIDIA Corporation.
+ *
+ * Based on drivers/rtc/rtc-max8925.c,
+ * Copyright (C) 2009-2010 Marvell International Ltd.
+ *
+ * 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.
+ */
+
+#include <linux/bcd.h>
+#include <linux/i2c.h>
+#include <linux/mfd/max8907.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/rtc.h>
+#include <linux/slab.h>
+
+enum {
+ RTC_SEC = 0,
+ RTC_MIN,
+ RTC_HOUR,
+ RTC_WEEKDAY,
+ RTC_DATE,
+ RTC_MONTH,
+ RTC_YEAR1,
+ RTC_YEAR2,
+};
+
+#define TIME_NUM 8
+#define ALARM_1SEC (1 << 7)
+#define HOUR_12 (1 << 7)
+#define HOUR_AM_PM (1 << 5)
+#define ALARM0_IRQ (1 << 3)
+#define ALARM1_IRQ (1 << 2)
+#define ALARM0_STATUS (1 << 2)
+#define ALARM1_STATUS (1 << 1)
+
+struct max8907_rtc {
+ struct max8907 *max8907;
+ struct regmap *regmap;
+ struct rtc_device *rtc_dev;
+ int irq;
+};
+
+static irqreturn_t max8907_irq_handler(int irq, void *data)
+{
+ struct max8907_rtc *rtc = data;
+
+ regmap_update_bits(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0x7f, 0);
+
+ rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
+
+ return IRQ_HANDLED;
+}
+
+static void regs_to_tm(u8 *regs, struct rtc_time *tm)
+{
+ tm->tm_year = bcd2bin(regs[RTC_YEAR2]) * 100 +
+ bcd2bin(regs[RTC_YEAR1]) - 1900;
+ tm->tm_mon = bcd2bin(regs[RTC_MONTH] & 0x1f) - 1;
+ tm->tm_mday = bcd2bin(regs[RTC_DATE] & 0x3f);
+ tm->tm_wday = (regs[RTC_WEEKDAY] & 0x07) - 1;
+ if (regs[RTC_HOUR] & HOUR_12) {
+ tm->tm_hour = bcd2bin(regs[RTC_HOUR] & 0x01f);
+ if (tm->tm_hour == 12)
+ tm->tm_hour = 0;
+ if (regs[RTC_HOUR] & HOUR_AM_PM)
+ tm->tm_hour += 12;
+ } else {
+ tm->tm_hour = bcd2bin(regs[RTC_HOUR] & 0x03f);
+ }
+ tm->tm_min = bcd2bin(regs[RTC_MIN] & 0x7f);
+ tm->tm_sec = bcd2bin(regs[RTC_SEC] & 0x7f);
+}
+
+static void tm_to_regs(struct rtc_time *tm, u8 *regs)
+{
+ u8 high, low;
+
+ high = (tm->tm_year + 1900) / 100;
+ low = tm->tm_year % 100;
+ regs[RTC_YEAR2] = bin2bcd(high);
+ regs[RTC_YEAR1] = bin2bcd(low);
+ regs[RTC_MONTH] = bin2bcd(tm->tm_mon + 1);
+ regs[RTC_DATE] = bin2bcd(tm->tm_mday);
+ regs[RTC_WEEKDAY] = tm->tm_wday + 1;
+ regs[RTC_HOUR] = bin2bcd(tm->tm_hour);
+ regs[RTC_MIN] = bin2bcd(tm->tm_min);
+ regs[RTC_SEC] = bin2bcd(tm->tm_sec);
+}
+
+static int max8907_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct max8907_rtc *rtc = dev_get_drvdata(dev);
+ u8 regs[TIME_NUM];
+ int ret;
+
+ ret = regmap_bulk_read(rtc->regmap, MAX8907_REG_RTC_SEC, regs,
+ TIME_NUM);
+ if (ret < 0)
+ return ret;
+
+ regs_to_tm(regs, tm);
+
+ return 0;
+}
+
+static int max8907_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct max8907_rtc *rtc = dev_get_drvdata(dev);
+ u8 regs[TIME_NUM];
+
+ tm_to_regs(tm, regs);
+
+ return regmap_bulk_write(rtc->regmap, MAX8907_REG_RTC_SEC, regs,
+ TIME_NUM);
+}
+
+static int max8907_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct max8907_rtc *rtc = dev_get_drvdata(dev);
+ u8 regs[TIME_NUM];
+ unsigned int val;
+ int ret;
+
+ ret = regmap_bulk_read(rtc->regmap, MAX8907_REG_ALARM0_SEC, regs,
+ TIME_NUM);
+ if (ret < 0)
+ return ret;
+
+ regs_to_tm(regs, &alrm->time);
+
+ ret = regmap_read(rtc->regmap, MAX8907_REG_ALARM0_CNTL, &val);
+ if (ret < 0)
+ return ret;
+
+ alrm->enabled = !!(val & 0x7f);
+
+ return 0;
+}
+
+static int max8907_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct max8907_rtc *rtc = dev_get_drvdata(dev);
+ u8 regs[TIME_NUM];
+ int ret;
+
+ tm_to_regs(&alrm->time, regs);
+
+ /* Disable alarm while we update the target time */
+ ret = regmap_update_bits(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0x7f, 0);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_bulk_write(rtc->regmap, MAX8907_REG_ALARM0_SEC, regs,
+ TIME_NUM);
+ if (ret < 0)
+ return ret;
+
+ if (alrm->enabled)
+ ret = regmap_update_bits(rtc->regmap, MAX8907_REG_ALARM0_CNTL,
+ 0x7f, 0x7f);
+
+ return ret;
+}
+
+static const struct rtc_class_ops max8907_rtc_ops = {
+ .read_time = max8907_rtc_read_time,
+ .set_time = max8907_rtc_set_time,
+ .read_alarm = max8907_rtc_read_alarm,
+ .set_alarm = max8907_rtc_set_alarm,
+};
+
+static int __devinit max8907_rtc_probe(struct platform_device *pdev)
+{
+ struct max8907 *max8907 = dev_get_drvdata(pdev->dev.parent);
+ struct max8907_rtc *rtc;
+ int ret;
+
+ rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
+ if (!rtc)
+ return -ENOMEM;
+ platform_set_drvdata(pdev, rtc);
+
+ rtc->max8907 = max8907;
+ rtc->regmap = max8907->regmap_rtc;
+
+ rtc->rtc_dev = rtc_device_register("max8907-rtc", &pdev->dev,
+ &max8907_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc->rtc_dev)) {
+ ret = PTR_ERR(rtc->rtc_dev);
+ dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
+ return ret;
+ }
+
+ rtc->irq = regmap_irq_get_virq(max8907->irqc_rtc,
+ MAX8907_IRQ_RTC_ALARM0);
+ if (rtc->irq < 0) {
+ ret = rtc->irq;
+ goto err_unregister;
+ }
+
+ ret = request_threaded_irq(rtc->irq, NULL, max8907_irq_handler,
+ IRQF_ONESHOT, "max8907-alarm0", rtc);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to request IRQ%d: %d\n",
+ rtc->irq, ret);
+ goto err_unregister;
+ }
+
+ return 0;
+
+err_unregister:
+ rtc_device_unregister(rtc->rtc_dev);
+ return ret;
+}
+
+static int __devexit max8907_rtc_remove(struct platform_device *pdev)
+{
+ struct max8907_rtc *rtc = platform_get_drvdata(pdev);
+
+ free_irq(rtc->irq, rtc);
+ rtc_device_unregister(rtc->rtc_dev);
+
+ return 0;
+}
+
+static struct platform_driver max8907_rtc_driver = {
+ .driver = {
+ .name = "max8907-rtc",
+ .owner = THIS_MODULE,
+ },
+ .probe = max8907_rtc_probe,
+ .remove = __devexit_p(max8907_rtc_remove),
+};
+module_platform_driver(max8907_rtc_driver);
+
+MODULE_DESCRIPTION("Maxim MAX8907 RTC driver");
+MODULE_LICENSE("GPL v2");
+
--
1.7.0.4


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