drivers/rtc/rtc-as3722: add RTC driver

The ams AS3722 is a compact system PMU suitable for mobile phones, tablets
etc.

Add a driver to support accessing the RTC found on the ams AS3722 PMIC
using RTC framework.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Florian Lobmaier <florian.lobmaier@ams.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 286 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 4f48b9a26aa0..15f166a470a7 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -153,6 +153,16 @@ config RTC_DRV_88PM80X
           This driver can also be built as a module. If so, the module
           will be called rtc-88pm80x.
 
+config RTC_DRV_AS3722
+        tristate "ams AS3722 RTC driver"
+        depends on MFD_AS3722
+        help
+          If you say yes here you get support for the RTC of ams AS3722 PMIC
+          chips.
+
+          This driver can also be built as a module. If so, the module
+          will be called rtc-as3722.
+
 config RTC_DRV_DS1307
         tristate "Dallas/Maxim DS1307/37/38/39/40, ST M41T00, EPSON RX-8025"
         help
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 9312e7965365..27b4bd884066 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_RTC_DRV_88PM860X)  += rtc-88pm860x.o
 obj-$(CONFIG_RTC_DRV_88PM80X)   += rtc-88pm80x.o
 obj-$(CONFIG_RTC_DRV_AB3100)    += rtc-ab3100.o
 obj-$(CONFIG_RTC_DRV_AB8500)    += rtc-ab8500.o
+obj-$(CONFIG_RTC_DRV_AS3722)    += rtc-as3722.o
 obj-$(CONFIG_RTC_DRV_AT32AP700X)+= rtc-at32ap700x.o
 obj-$(CONFIG_RTC_DRV_AT91RM9200)+= rtc-at91rm9200.o
 obj-$(CONFIG_RTC_DRV_AT91SAM9)  += rtc-at91sam9.o
diff --git a/drivers/rtc/rtc-as3722.c b/drivers/rtc/rtc-as3722.c
new file mode 100644
index 000000000000..9cfa8170a2d6
--- /dev/null
+++ b/drivers/rtc/rtc-as3722.c
@@ -0,0 +1,275 @@
+/*
+ * rtc-as3722.c - Real Time Clock driver for ams AS3722 PMICs
+ *
+ * Copyright (C) 2013 ams AG
+ * Copyright (c) 2013, NVIDIA Corporation. All rights reserved.
+ *
+ * Author: Florian Lobmaier <florian.lobmaier@ams.com>
+ * Author: Laxman Dewangan <ldewangan@nvidia.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/bcd.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/ioctl.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mfd/as3722.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/time.h>
+
+#define AS3722_RTC_START_YEAR     2000
+struct as3722_rtc {
+        struct rtc_device       *rtc;
+        struct device           *dev;
+        struct as3722           *as3722;
+        int                     alarm_irq;
+        bool                    irq_enable;
+};
+
+static void as3722_time_to_reg(u8 *rbuff, struct rtc_time *tm)
+{
+        rbuff[0] = bin2bcd(tm->tm_sec);
+        rbuff[1] = bin2bcd(tm->tm_min);
+        rbuff[2] = bin2bcd(tm->tm_hour);
+        rbuff[3] = bin2bcd(tm->tm_mday);
+        rbuff[4] = bin2bcd(tm->tm_mon);
+        rbuff[5] = bin2bcd(tm->tm_year - (AS3722_RTC_START_YEAR - 1900));
+}
+
+static void as3722_reg_to_time(u8 *rbuff, struct rtc_time *tm)
+{
+        tm->tm_sec = bcd2bin(rbuff[0] & 0x7F);
+        tm->tm_min = bcd2bin(rbuff[1] & 0x7F);
+        tm->tm_hour = bcd2bin(rbuff[2] & 0x3F);
+        tm->tm_mday = bcd2bin(rbuff[3] & 0x3F);
+        tm->tm_mon = bcd2bin(rbuff[4] & 0x1F);
+        tm->tm_year = (AS3722_RTC_START_YEAR - 1900) + bcd2bin(rbuff[5] & 0x7F);
+        return;
+}
+
+static int as3722_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+        struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
+        struct as3722 *as3722 = as3722_rtc->as3722;
+        u8 as_time_array[6];
+        int ret;
+
+        ret = as3722_block_read(as3722, AS3722_RTC_SECOND_REG,
+                        6, as_time_array);
+        if (ret < 0) {
+                dev_err(dev, "RTC_SECOND reg block read failed %d\n", ret);
+                return ret;
+        }
+        as3722_reg_to_time(as_time_array, tm);
+        return 0;
+}
+
+static int as3722_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+        struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
+        struct as3722 *as3722 = as3722_rtc->as3722;
+        u8 as_time_array[6];
+        int ret;
+
+        if (tm->tm_year < (AS3722_RTC_START_YEAR - 1900))
+                return -EINVAL;
+
+        as3722_time_to_reg(as_time_array, tm);
+        ret = as3722_block_write(as3722, AS3722_RTC_SECOND_REG, 6,
+                        as_time_array);
+        if (ret < 0)
+                dev_err(dev, "RTC_SECOND reg block write failed %d\n", ret);
+        return ret;
+}
+
+static int as3722_rtc_alarm_irq_enable(struct device *dev,
+                unsigned int enabled)
+{
+        struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
+
+        if (enabled && !as3722_rtc->irq_enable) {
+                enable_irq(as3722_rtc->alarm_irq);
+                as3722_rtc->irq_enable = true;
+        } else if (!enabled && as3722_rtc->irq_enable)  {
+                disable_irq(as3722_rtc->alarm_irq);
+                as3722_rtc->irq_enable = false;
+        }
+        return 0;
+}
+
+static int as3722_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+        struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
+        struct as3722 *as3722 = as3722_rtc->as3722;
+        u8 as_time_array[6];
+        int ret;
+
+        ret = as3722_block_read(as3722, AS3722_RTC_ALARM_SECOND_REG, 6,
+                        as_time_array);
+        if (ret < 0) {
+                dev_err(dev, "RTC_ALARM_SECOND block read failed %d\n", ret);
+                return ret;
+        }
+
+        as3722_reg_to_time(as_time_array, &alrm->time);
+        return 0;
+}
+
+static int as3722_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+        struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
+        struct as3722 *as3722 = as3722_rtc->as3722;
+        u8 as_time_array[6];
+        int ret;
+
+        if (alrm->time.tm_year < (AS3722_RTC_START_YEAR - 1900))
+                return -EINVAL;
+
+        ret = as3722_rtc_alarm_irq_enable(dev, 0);
+        if (ret < 0) {
+                dev_err(dev, "Disable RTC alarm failed\n");
+                return ret;
+        }
+
+        as3722_time_to_reg(as_time_array, &alrm->time);
+        ret = as3722_block_write(as3722, AS3722_RTC_ALARM_SECOND_REG, 6,
+                        as_time_array);
+        if (ret < 0) {
+                dev_err(dev, "RTC_ALARM_SECOND block write failed %d\n", ret);
+                return ret;
+        }
+
+        if (alrm->enabled)
+                ret = as3722_rtc_alarm_irq_enable(dev, alrm->enabled);
+        return ret;
+}
+
+static irqreturn_t as3722_alarm_irq(int irq, void *data)
+{
+        struct as3722_rtc *as3722_rtc = data;
+
+        rtc_update_irq(as3722_rtc->rtc, 1, RTC_IRQF | RTC_AF);
+        return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops as3722_rtc_ops = {
+        .read_time = as3722_rtc_read_time,
+        .set_time = as3722_rtc_set_time,
+        .read_alarm = as3722_rtc_read_alarm,
+        .set_alarm = as3722_rtc_set_alarm,
+        .alarm_irq_enable = as3722_rtc_alarm_irq_enable,
+};
+
+static int as3722_rtc_probe(struct platform_device *pdev)
+{
+        struct as3722 *as3722 = dev_get_drvdata(pdev->dev.parent);
+        struct as3722_rtc *as3722_rtc;
+        int ret;
+
+        as3722_rtc = devm_kzalloc(&pdev->dev, sizeof(*as3722_rtc), GFP_KERNEL);
+        if (!as3722_rtc)
+                return -ENOMEM;
+
+        as3722_rtc->as3722 = as3722;
+        as3722_rtc->dev = &pdev->dev;
+        platform_set_drvdata(pdev, as3722_rtc);
+
+        /* Enable the RTC to make sure it is running. */
+        ret = as3722_update_bits(as3722, AS3722_RTC_CONTROL_REG,
+                        AS3722_RTC_ON | AS3722_RTC_ALARM_WAKEUP_EN,
+                        AS3722_RTC_ON | AS3722_RTC_ALARM_WAKEUP_EN);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "RTC_CONTROL reg write failed: %d\n", ret);
+                return ret;
+        }
+
+        device_init_wakeup(&pdev->dev, 1);
+
+        as3722_rtc->rtc = rtc_device_register("as3722", &pdev->dev,
+                                &as3722_rtc_ops, THIS_MODULE);
+        if (IS_ERR(as3722_rtc->rtc)) {
+                ret = PTR_ERR(as3722_rtc->rtc);
+                dev_err(&pdev->dev, "RTC register failed: %d\n", ret);
+                return ret;
+        }
+
+        as3722_rtc->alarm_irq = platform_get_irq(pdev, 0);
+        dev_info(&pdev->dev, "RTC interrupt %d\n", as3722_rtc->alarm_irq);
+
+        ret = request_threaded_irq(as3722_rtc->alarm_irq, NULL,
+                        as3722_alarm_irq, IRQF_ONESHOT | IRQF_EARLY_RESUME,
+                        "rtc-alarm", as3722_rtc);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
+                                as3722_rtc->alarm_irq, ret);
+                goto scrub;
+        }
+        disable_irq(as3722_rtc->alarm_irq);
+        return 0;
+scrub:
+        rtc_device_unregister(as3722_rtc->rtc);
+        return ret;
+}
+
+static int as3722_rtc_remove(struct platform_device *pdev)
+{
+        struct as3722_rtc *as3722_rtc = platform_get_drvdata(pdev);
+
+        free_irq(as3722_rtc->alarm_irq, as3722_rtc);
+        rtc_device_unregister(as3722_rtc->rtc);
+        return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int as3722_rtc_suspend(struct device *dev)
+{
+        struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
+
+        if (device_may_wakeup(dev))
+                enable_irq_wake(as3722_rtc->alarm_irq);
+
+        return 0;
+}
+
+static int as3722_rtc_resume(struct device *dev)
+{
+        struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
+
+        if (device_may_wakeup(dev))
+                disable_irq_wake(as3722_rtc->alarm_irq);
+        return 0;
+}
+#endif
+
+static const struct dev_pm_ops as3722_rtc_pm_ops = {
+        SET_SYSTEM_SLEEP_PM_OPS(as3722_rtc_suspend, as3722_rtc_resume)
+};
+
+static struct platform_driver as3722_rtc_driver = {
+        .probe = as3722_rtc_probe,
+        .remove = as3722_rtc_remove,
+        .driver = {
+                .name = "as3722-rtc",
+                .pm = &as3722_rtc_pm_ops,
+        },
+};
+module_platform_driver(as3722_rtc_driver);
+
+MODULE_DESCRIPTION("RTC driver for AS3722 PMICs");
+MODULE_ALIAS("platform:as3722-rtc");
+MODULE_AUTHOR("Florian Lobmaier <florian.lobmaier@ams.com>");
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
+MODULE_LICENSE("GPL");