rtc: Add MAX8998 rtc driver

This adds support for the RTC provided by the Maxim 8998 chip. This
driver was tested on a GONI board by using the rtc-test application from
the Documentation/rtc.txt.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 300 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-max8998.c b/drivers/rtc/rtc-max8998.c
new file mode 100644
index 000000000000..f22dee35f330
--- /dev/null
+++ b/drivers/rtc/rtc-max8998.c
@@ -0,0 +1,300 @@
+/*
+ * RTC driver for Maxim MAX8998
+ *
+ * Copyright (C) 2010 Samsung Electronics Co.Ltd
+ * Author: Minkyu Kang <mk7.kang@samsung.com>
+ * Author: Joonyoung Shim <jy0922.shim@samsung.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.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/bcd.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/max8998.h>
+#include <linux/mfd/max8998-private.h>
+
+#define MAX8998_RTC_SEC                 0x00
+#define MAX8998_RTC_MIN                 0x01
+#define MAX8998_RTC_HOUR                0x02
+#define MAX8998_RTC_WEEKDAY             0x03
+#define MAX8998_RTC_DATE                0x04
+#define MAX8998_RTC_MONTH               0x05
+#define MAX8998_RTC_YEAR1               0x06
+#define MAX8998_RTC_YEAR2               0x07
+#define MAX8998_ALARM0_SEC              0x08
+#define MAX8998_ALARM0_MIN              0x09
+#define MAX8998_ALARM0_HOUR             0x0a
+#define MAX8998_ALARM0_WEEKDAY          0x0b
+#define MAX8998_ALARM0_DATE             0x0c
+#define MAX8998_ALARM0_MONTH            0x0d
+#define MAX8998_ALARM0_YEAR1            0x0e
+#define MAX8998_ALARM0_YEAR2            0x0f
+#define MAX8998_ALARM1_SEC              0x10
+#define MAX8998_ALARM1_MIN              0x11
+#define MAX8998_ALARM1_HOUR             0x12
+#define MAX8998_ALARM1_WEEKDAY          0x13
+#define MAX8998_ALARM1_DATE             0x14
+#define MAX8998_ALARM1_MONTH            0x15
+#define MAX8998_ALARM1_YEAR1            0x16
+#define MAX8998_ALARM1_YEAR2            0x17
+#define MAX8998_ALARM0_CONF             0x18
+#define MAX8998_ALARM1_CONF             0x19
+#define MAX8998_RTC_STATUS              0x1a
+#define MAX8998_WTSR_SMPL_CNTL          0x1b
+#define MAX8998_TEST                    0x1f
+
+#define HOUR_12                         (1 << 7)
+#define HOUR_PM                         (1 << 5)
+#define ALARM0_STATUS                   (1 << 1)
+#define ALARM1_STATUS                   (1 << 2)
+
+enum {
+        RTC_SEC = 0,
+        RTC_MIN,
+        RTC_HOUR,
+        RTC_WEEKDAY,
+        RTC_DATE,
+        RTC_MONTH,
+        RTC_YEAR1,
+        RTC_YEAR2,
+};
+
+struct max8998_rtc_info {
+        struct device           *dev;
+        struct max8998_dev      *max8998;
+        struct i2c_client       *rtc;
+        struct rtc_device       *rtc_dev;
+        int irq;
+};
+
+static void max8998_data_to_tm(u8 *data, struct rtc_time *tm)
+{
+        tm->tm_sec = bcd2bin(data[RTC_SEC]);
+        tm->tm_min = bcd2bin(data[RTC_MIN]);
+        if (data[RTC_HOUR] & HOUR_12) {
+                tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x1f);
+                if (data[RTC_HOUR] & HOUR_PM)
+                        tm->tm_hour += 12;
+        } else
+                tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f);
+
+        tm->tm_wday = data[RTC_WEEKDAY] & 0x07;
+        tm->tm_mday = bcd2bin(data[RTC_DATE]);
+        tm->tm_mon = bcd2bin(data[RTC_MONTH]);
+        tm->tm_year = bcd2bin(data[RTC_YEAR1]) + bcd2bin(data[RTC_YEAR2]) * 100;
+        tm->tm_year -= 1900;
+}
+
+static void max8998_tm_to_data(struct rtc_time *tm, u8 *data)
+{
+        data[RTC_SEC] = bin2bcd(tm->tm_sec);
+        data[RTC_MIN] = bin2bcd(tm->tm_min);
+        data[RTC_HOUR] = bin2bcd(tm->tm_hour);
+        data[RTC_WEEKDAY] = tm->tm_wday;
+        data[RTC_DATE] = bin2bcd(tm->tm_mday);
+        data[RTC_MONTH] = bin2bcd(tm->tm_mon);
+        data[RTC_YEAR1] = bin2bcd(tm->tm_year % 100);
+        data[RTC_YEAR2] = bin2bcd((tm->tm_year + 1900) / 100);
+}
+
+static int max8998_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+        struct max8998_rtc_info *info = dev_get_drvdata(dev);
+        u8 data[8];
+        int ret;
+
+        ret = max8998_bulk_read(info->rtc, MAX8998_RTC_SEC, 8, data);
+        if (ret < 0)
+                return ret;
+
+        max8998_data_to_tm(data, tm);
+
+        return rtc_valid_tm(tm);
+}
+
+static int max8998_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+        struct max8998_rtc_info *info = dev_get_drvdata(dev);
+        u8 data[8];
+
+        max8998_tm_to_data(tm, data);
+
+        return max8998_bulk_write(info->rtc, MAX8998_RTC_SEC, 8, data);
+}
+
+static int max8998_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+        struct max8998_rtc_info *info = dev_get_drvdata(dev);
+        u8 data[8];
+        u8 val;
+        int ret;
+
+        ret = max8998_bulk_read(info->rtc, MAX8998_ALARM0_SEC, 8, data);
+        if (ret < 0)
+                return ret;
+
+        max8998_data_to_tm(data, &alrm->time);
+
+        ret = max8998_read_reg(info->rtc, MAX8998_ALARM0_CONF, &val);
+        if (ret < 0)
+                return ret;
+
+        alrm->enabled = !!val;
+
+        ret = max8998_read_reg(info->rtc, MAX8998_RTC_STATUS, &val);
+        if (ret < 0)
+                return ret;
+
+        if (val & ALARM0_STATUS)
+                alrm->pending = 1;
+        else
+                alrm->pending = 0;
+
+        return 0;
+}
+
+static int max8998_rtc_stop_alarm(struct max8998_rtc_info *info)
+{
+        return max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, 0);
+}
+
+static int max8998_rtc_start_alarm(struct max8998_rtc_info *info)
+{
+        return max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, 0x77);
+}
+
+static int max8998_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+        struct max8998_rtc_info *info = dev_get_drvdata(dev);
+        u8 data[8];
+        int ret;
+
+        max8998_tm_to_data(&alrm->time, data);
+
+        ret = max8998_rtc_stop_alarm(info);
+        if (ret < 0)
+                return ret;
+
+        ret = max8998_bulk_write(info->rtc, MAX8998_ALARM0_SEC, 8, data);
+        if (ret < 0)
+                return ret;
+
+        if (alrm->enabled)
+                return max8998_rtc_start_alarm(info);
+
+        return 0;
+}
+
+static int max8998_rtc_alarm_irq_enable(struct device *dev,
+                                        unsigned int enabled)
+{
+        struct max8998_rtc_info *info = dev_get_drvdata(dev);
+
+        if (enabled)
+                return max8998_rtc_start_alarm(info);
+        else
+                return max8998_rtc_stop_alarm(info);
+}
+
+static irqreturn_t max8998_rtc_alarm_irq(int irq, void *data)
+{
+        struct max8998_rtc_info *info = data;
+
+        rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
+
+        return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops max8998_rtc_ops = {
+        .read_time = max8998_rtc_read_time,
+        .set_time = max8998_rtc_set_time,
+        .read_alarm = max8998_rtc_read_alarm,
+        .set_alarm = max8998_rtc_set_alarm,
+        .alarm_irq_enable = max8998_rtc_alarm_irq_enable,
+};
+
+static int __devinit max8998_rtc_probe(struct platform_device *pdev)
+{
+        struct max8998_dev *max8998 = dev_get_drvdata(pdev->dev.parent);
+        struct max8998_rtc_info *info;
+        int ret;
+
+        info = kzalloc(sizeof(struct max8998_rtc_info), GFP_KERNEL);
+        if (!info)
+                return -ENOMEM;
+
+        info->dev = &pdev->dev;
+        info->max8998 = max8998;
+        info->rtc = max8998->rtc;
+        info->irq = max8998->irq_base + MAX8998_IRQ_ALARM0;
+
+        info->rtc_dev = rtc_device_register("max8998-rtc", &pdev->dev,
+                        &max8998_rtc_ops, THIS_MODULE);
+
+        if (IS_ERR(info->rtc_dev)) {
+                ret = PTR_ERR(info->rtc_dev);
+                dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
+                goto out_rtc;
+        }
+
+        platform_set_drvdata(pdev, info);
+
+        ret = request_threaded_irq(info->irq, NULL, max8998_rtc_alarm_irq, 0,
+                        "rtc-alarm0", info);
+        if (ret < 0)
+                dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
+                        info->irq, ret);
+
+        return 0;
+
+out_rtc:
+        kfree(info);
+        return ret;
+}
+
+static int __devexit max8998_rtc_remove(struct platform_device *pdev)
+{
+        struct max8998_rtc_info *info = platform_get_drvdata(pdev);
+
+        if (info) {
+                free_irq(info->irq, info);
+                rtc_device_unregister(info->rtc_dev);
+                kfree(info);
+        }
+
+        return 0;
+}
+
+static struct platform_driver max8998_rtc_driver = {
+        .driver         = {
+                .name   = "max8998-rtc",
+                .owner  = THIS_MODULE,
+        },
+        .probe          = max8998_rtc_probe,
+        .remove         = __devexit_p(max8998_rtc_remove),
+};
+
+static int __init max8998_rtc_init(void)
+{
+        return platform_driver_register(&max8998_rtc_driver);
+}
+module_init(max8998_rtc_init);
+
+static void __exit max8998_rtc_exit(void)
+{
+        platform_driver_unregister(&max8998_rtc_driver);
+}
+module_exit(max8998_rtc_exit);
+
+MODULE_AUTHOR("Minkyu Kang <mk7.kang@samsung.com>");
+MODULE_AUTHOR("Joonyoung Shim <jy0922.shim@samsung.com>");
+MODULE_DESCRIPTION("Maxim MAX8998 RTC driver");
+MODULE_LICENSE("GPL");