Initial import

1 files changed, 724 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-ds1374.c b/drivers/rtc/rtc-ds1374.c
new file mode 100644
index 000000000..167783fa7
--- /dev/null
+++ b/drivers/rtc/rtc-ds1374.c
@@ -0,0 +1,724 @@
+/*
+ * RTC client/driver for the Maxim/Dallas DS1374 Real-Time Clock over I2C
+ *
+ * Based on code by Randy Vinson <rvinson@mvista.com>,
+ * which was based on the m41t00.c by Mark Greer <mgreer@mvista.com>.
+ *
+ * Copyright (C) 2014 Rose Technology
+ * Copyright (C) 2006-2007 Freescale Semiconductor
+ *
+ * 2005 (c) MontaVista Software, Inc. This file is licensed under
+ * the terms of the GNU General Public License version 2. This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ */
+/*
+ * It would be more efficient to use i2c msgs/i2c_transfer directly but, as
+ * recommened in .../Documentation/i2c/writing-clients section
+ * "Sending and receiving", using SMBus level communication is preferred.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+#include <linux/workqueue.h>
+#include <linux/slab.h>
+#include <linux/pm.h>
+#ifdef CONFIG_RTC_DRV_DS1374_WDT
+#include <linux/fs.h>
+#include <linux/ioctl.h>
+#include <linux/miscdevice.h>
+#include <linux/reboot.h>
+#include <linux/watchdog.h>
+#endif
+
+#define DS1374_REG_TOD0		0x00 /* Time of Day */
+#define DS1374_REG_TOD1		0x01
+#define DS1374_REG_TOD2		0x02
+#define DS1374_REG_TOD3		0x03
+#define DS1374_REG_WDALM0	0x04 /* Watchdog/Alarm */
+#define DS1374_REG_WDALM1	0x05
+#define DS1374_REG_WDALM2	0x06
+#define DS1374_REG_CR		0x07 /* Control */
+#define DS1374_REG_CR_AIE	0x01 /* Alarm Int. Enable */
+#define DS1374_REG_CR_WDALM	0x20 /* 1=Watchdog, 0=Alarm */
+#define DS1374_REG_CR_WACE	0x40 /* WD/Alarm counter enable */
+#define DS1374_REG_SR		0x08 /* Status */
+#define DS1374_REG_SR_OSF	0x80 /* Oscillator Stop Flag */
+#define DS1374_REG_SR_AF	0x01 /* Alarm Flag */
+#define DS1374_REG_TCR		0x09 /* Trickle Charge */
+
+static const struct i2c_device_id ds1374_id[] = {
+	{ "ds1374", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ds1374_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id ds1374_of_match[] = {
+	{ .compatible = "dallas,ds1374" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ds1374_of_match);
+#endif
+
+struct ds1374 {
+	struct i2c_client *client;
+	struct rtc_device *rtc;
+	struct work_struct work;
+
+	/* The mutex protects alarm operations, and prevents a race
+	 * between the enable_irq() in the workqueue and the free_irq()
+	 * in the remove function.
+	 */
+	struct mutex mutex;
+	int exiting;
+};
+
+static struct i2c_driver ds1374_driver;
+
+static int ds1374_read_rtc(struct i2c_client *client, u32 *time,
+			   int reg, int nbytes)
+{
+	u8 buf[4];
+	int ret;
+	int i;
+
+	if (nbytes > 4) {
+		WARN_ON(1);
+		return -EINVAL;
+	}
+
+	ret = i2c_smbus_read_i2c_block_data(client, reg, nbytes, buf);
+
+	if (ret < 0)
+		return ret;
+	if (ret < nbytes)
+		return -EIO;
+
+	for (i = nbytes - 1, *time = 0; i >= 0; i--)
+		*time = (*time << 8) | buf[i];
+
+	return 0;
+}
+
+static int ds1374_write_rtc(struct i2c_client *client, u32 time,
+			    int reg, int nbytes)
+{
+	u8 buf[4];
+	int i;
+
+	if (nbytes > 4) {
+		WARN_ON(1);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < nbytes; i++) {
+		buf[i] = time & 0xff;
+		time >>= 8;
+	}
+
+	return i2c_smbus_write_i2c_block_data(client, reg, nbytes, buf);
+}
+
+static int ds1374_check_rtc_status(struct i2c_client *client)
+{
+	int ret = 0;
+	int control, stat;
+
+	stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
+	if (stat < 0)
+		return stat;
+
+	if (stat & DS1374_REG_SR_OSF)
+		dev_warn(&client->dev,
+			 "oscillator discontinuity flagged, time unreliable\n");
+
+	stat &= ~(DS1374_REG_SR_OSF | DS1374_REG_SR_AF);
+
+	ret = i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
+	if (ret < 0)
+		return ret;
+
+	/* If the alarm is pending, clear it before requesting
+	 * the interrupt, so an interrupt event isn't reported
+	 * before everything is initialized.
+	 */
+
+	control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
+	if (control < 0)
+		return control;
+
+	control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
+	return i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
+}
+
+static int ds1374_read_time(struct device *dev, struct rtc_time *time)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	u32 itime;
+	int ret;
+
+	ret = ds1374_read_rtc(client, &itime, DS1374_REG_TOD0, 4);
+	if (!ret)
+		rtc_time_to_tm(itime, time);
+
+	return ret;
+}
+
+static int ds1374_set_time(struct device *dev, struct rtc_time *time)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	unsigned long itime;
+
+	rtc_tm_to_time(time, &itime);
+	return ds1374_write_rtc(client, itime, DS1374_REG_TOD0, 4);
+}
+
+#ifndef CONFIG_RTC_DRV_DS1374_WDT
+/* The ds1374 has a decrementer for an alarm, rather than a comparator.
+ * If the time of day is changed, then the alarm will need to be
+ * reset.
+ */
+static int ds1374_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ds1374 *ds1374 = i2c_get_clientdata(client);
+	u32 now, cur_alarm;
+	int cr, sr;
+	int ret = 0;
+
+	if (client->irq <= 0)
+		return -EINVAL;
+
+	mutex_lock(&ds1374->mutex);
+
+	cr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
+	if (ret < 0)
+		goto out;
+
+	sr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
+	if (ret < 0)
+		goto out;
+
+	ret = ds1374_read_rtc(client, &now, DS1374_REG_TOD0, 4);
+	if (ret)
+		goto out;
+
+	ret = ds1374_read_rtc(client, &cur_alarm, DS1374_REG_WDALM0, 3);
+	if (ret)
+		goto out;
+
+	rtc_time_to_tm(now + cur_alarm, &alarm->time);
+	alarm->enabled = !!(cr & DS1374_REG_CR_WACE);
+	alarm->pending = !!(sr & DS1374_REG_SR_AF);
+
+out:
+	mutex_unlock(&ds1374->mutex);
+	return ret;
+}
+
+static int ds1374_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ds1374 *ds1374 = i2c_get_clientdata(client);
+	struct rtc_time now;
+	unsigned long new_alarm, itime;
+	int cr;
+	int ret = 0;
+
+	if (client->irq <= 0)
+		return -EINVAL;
+
+	ret = ds1374_read_time(dev, &now);
+	if (ret < 0)
+		return ret;
+
+	rtc_tm_to_time(&alarm->time, &new_alarm);
+	rtc_tm_to_time(&now, &itime);
+
+	/* This can happen due to races, in addition to dates that are
+	 * truly in the past.  To avoid requiring the caller to check for
+	 * races, dates in the past are assumed to be in the recent past
+	 * (i.e. not something that we'd rather the caller know about via
+	 * an error), and the alarm is set to go off as soon as possible.
+	 */
+	if (time_before_eq(new_alarm, itime))
+		new_alarm = 1;
+	else
+		new_alarm -= itime;
+
+	mutex_lock(&ds1374->mutex);
+
+	ret = cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
+	if (ret < 0)
+		goto out;
+
+	/* Disable any existing alarm before setting the new one
+	 * (or lack thereof). */
+	cr &= ~DS1374_REG_CR_WACE;
+
+	ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
+	if (ret < 0)
+		goto out;
+
+	ret = ds1374_write_rtc(client, new_alarm, DS1374_REG_WDALM0, 3);
+	if (ret)
+		goto out;
+
+	if (alarm->enabled) {
+		cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
+		cr &= ~DS1374_REG_CR_WDALM;
+
+		ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
+	}
+
+out:
+	mutex_unlock(&ds1374->mutex);
+	return ret;
+}
+#endif
+
+static irqreturn_t ds1374_irq(int irq, void *dev_id)
+{
+	struct i2c_client *client = dev_id;
+	struct ds1374 *ds1374 = i2c_get_clientdata(client);
+
+	disable_irq_nosync(irq);
+	schedule_work(&ds1374->work);
+	return IRQ_HANDLED;
+}
+
+static void ds1374_work(struct work_struct *work)
+{
+	struct ds1374 *ds1374 = container_of(work, struct ds1374, work);
+	struct i2c_client *client = ds1374->client;
+	int stat, control;
+
+	mutex_lock(&ds1374->mutex);
+
+	stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
+	if (stat < 0)
+		goto unlock;
+
+	if (stat & DS1374_REG_SR_AF) {
+		stat &= ~DS1374_REG_SR_AF;
+		i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
+
+		control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
+		if (control < 0)
+			goto out;
+
+		control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
+		i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
+
+		rtc_update_irq(ds1374->rtc, 1, RTC_AF | RTC_IRQF);
+	}
+
+out:
+	if (!ds1374->exiting)
+		enable_irq(client->irq);
+unlock:
+	mutex_unlock(&ds1374->mutex);
+}
+
+#ifndef CONFIG_RTC_DRV_DS1374_WDT
+static int ds1374_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ds1374 *ds1374 = i2c_get_clientdata(client);
+	int ret;
+
+	mutex_lock(&ds1374->mutex);
+
+	ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
+	if (ret < 0)
+		goto out;
+
+	if (enabled) {
+		ret |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
+		ret &= ~DS1374_REG_CR_WDALM;
+	} else {
+		ret &= ~DS1374_REG_CR_WACE;
+	}
+	ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret);
+
+out:
+	mutex_unlock(&ds1374->mutex);
+	return ret;
+}
+#endif
+
+static const struct rtc_class_ops ds1374_rtc_ops = {
+	.read_time = ds1374_read_time,
+	.set_time = ds1374_set_time,
+#ifndef CONFIG_RTC_DRV_DS1374_WDT
+	.read_alarm = ds1374_read_alarm,
+	.set_alarm = ds1374_set_alarm,
+	.alarm_irq_enable = ds1374_alarm_irq_enable,
+#endif
+};
+
+#ifdef CONFIG_RTC_DRV_DS1374_WDT
+/*
+ *****************************************************************************
+ *
+ * Watchdog Driver
+ *
+ *****************************************************************************
+ */
+static struct i2c_client *save_client;
+/* Default margin */
+#define WD_TIMO 131762
+
+#define DRV_NAME "DS1374 Watchdog"
+
+static int wdt_margin = WD_TIMO;
+static unsigned long wdt_is_open;
+module_param(wdt_margin, int, 0);
+MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 32s)");
+
+static const struct watchdog_info ds1374_wdt_info = {
+	.identity       = "DS1374 WTD",
+	.options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
+						WDIOF_MAGICCLOSE,
+};
+
+static int ds1374_wdt_settimeout(unsigned int timeout)
+{
+	int ret = -ENOIOCTLCMD;
+	int cr;
+
+	ret = cr = i2c_smbus_read_byte_data(save_client, DS1374_REG_CR);
+	if (ret < 0)
+		goto out;
+
+	/* Disable any existing watchdog/alarm before setting the new one */
+	cr &= ~DS1374_REG_CR_WACE;
+
+	ret = i2c_smbus_write_byte_data(save_client, DS1374_REG_CR, cr);
+	if (ret < 0)
+		goto out;
+
+	/* Set new watchdog time */
+	ret = ds1374_write_rtc(save_client, timeout, DS1374_REG_WDALM0, 3);
+	if (ret) {
+		pr_info("couldn't set new watchdog time\n");
+		goto out;
+	}
+
+	/* Enable watchdog timer */
+	cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_WDALM;
+	cr &= ~DS1374_REG_CR_AIE;
+
+	ret = i2c_smbus_write_byte_data(save_client, DS1374_REG_CR, cr);
+	if (ret < 0)
+		goto out;
+
+	return 0;
+out:
+	return ret;
+}
+
+
+/*
+ * Reload the watchdog timer.  (ie, pat the watchdog)
+ */
+static void ds1374_wdt_ping(void)
+{
+	u32 val;
+	int ret = 0;
+
+	ret = ds1374_read_rtc(save_client, &val, DS1374_REG_WDALM0, 3);
+	if (ret)
+		pr_info("WD TICK FAIL!!!!!!!!!! %i\n", ret);
+}
+
+static void ds1374_wdt_disable(void)
+{
+	int ret = -ENOIOCTLCMD;
+	int cr;
+
+	cr = i2c_smbus_read_byte_data(save_client, DS1374_REG_CR);
+	/* Disable watchdog timer */
+	cr &= ~DS1374_REG_CR_WACE;
+
+	ret = i2c_smbus_write_byte_data(save_client, DS1374_REG_CR, cr);
+}
+
+/*
+ * Watchdog device is opened, and watchdog starts running.
+ */
+static int ds1374_wdt_open(struct inode *inode, struct file *file)
+{
+	struct ds1374 *ds1374 = i2c_get_clientdata(save_client);
+
+	if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
+		mutex_lock(&ds1374->mutex);
+		if (test_and_set_bit(0, &wdt_is_open)) {
+			mutex_unlock(&ds1374->mutex);
+			return -EBUSY;
+		}
+		/*
+		 *      Activate
+		 */
+		wdt_is_open = 1;
+		mutex_unlock(&ds1374->mutex);
+		return nonseekable_open(inode, file);
+	}
+	return -ENODEV;
+}
+
+/*
+ * Close the watchdog device.
+ */
+static int ds1374_wdt_release(struct inode *inode, struct file *file)
+{
+	if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
+		clear_bit(0, &wdt_is_open);
+
+	return 0;
+}
+
+/*
+ * Pat the watchdog whenever device is written to.
+ */
+static ssize_t ds1374_wdt_write(struct file *file, const char __user *data,
+				size_t len, loff_t *ppos)
+{
+	if (len) {
+		ds1374_wdt_ping();
+		return 1;
+	}
+	return 0;
+}
+
+static ssize_t ds1374_wdt_read(struct file *file, char __user *data,
+				size_t len, loff_t *ppos)
+{
+	return 0;
+}
+
+/*
+ * Handle commands from user-space.
+ */
+static long ds1374_wdt_ioctl(struct file *file, unsigned int cmd,
+							unsigned long arg)
+{
+	int new_margin, options;
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		return copy_to_user((struct watchdog_info __user *)arg,
+		&ds1374_wdt_info, sizeof(ds1374_wdt_info)) ? -EFAULT : 0;
+
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		return put_user(0, (int __user *)arg);
+	case WDIOC_KEEPALIVE:
+		ds1374_wdt_ping();
+		return 0;
+	case WDIOC_SETTIMEOUT:
+		if (get_user(new_margin, (int __user *)arg))
+			return -EFAULT;
+
+		if (new_margin < 1 || new_margin > 16777216)
+			return -EINVAL;
+
+		wdt_margin = new_margin;
+		ds1374_wdt_settimeout(new_margin);
+		ds1374_wdt_ping();
+		/* fallthrough */
+	case WDIOC_GETTIMEOUT:
+		return put_user(wdt_margin, (int __user *)arg);
+	case WDIOC_SETOPTIONS:
+		if (copy_from_user(&options, (int __user *)arg, sizeof(int)))
+			return -EFAULT;
+
+		if (options & WDIOS_DISABLECARD) {
+			pr_info("disable watchdog\n");
+			ds1374_wdt_disable();
+		}
+
+		if (options & WDIOS_ENABLECARD) {
+			pr_info("enable watchdog\n");
+			ds1374_wdt_settimeout(wdt_margin);
+			ds1374_wdt_ping();
+		}
+
+		return -EINVAL;
+	}
+	return -ENOTTY;
+}
+
+static long ds1374_wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
+			unsigned long arg)
+{
+	int ret;
+	struct ds1374 *ds1374 = i2c_get_clientdata(save_client);
+
+	mutex_lock(&ds1374->mutex);
+	ret = ds1374_wdt_ioctl(file, cmd, arg);
+	mutex_unlock(&ds1374->mutex);
+
+	return ret;
+}
+
+static int ds1374_wdt_notify_sys(struct notifier_block *this,
+			unsigned long code, void *unused)
+{
+	if (code == SYS_DOWN || code == SYS_HALT)
+		/* Disable Watchdog */
+		ds1374_wdt_disable();
+	return NOTIFY_DONE;
+}
+
+static const struct file_operations ds1374_wdt_fops = {
+	.owner			= THIS_MODULE,
+	.read			= ds1374_wdt_read,
+	.unlocked_ioctl		= ds1374_wdt_unlocked_ioctl,
+	.write			= ds1374_wdt_write,
+	.open                   = ds1374_wdt_open,
+	.release                = ds1374_wdt_release,
+	.llseek			= no_llseek,
+};
+
+static struct miscdevice ds1374_miscdev = {
+	.minor          = WATCHDOG_MINOR,
+	.name           = "watchdog",
+	.fops           = &ds1374_wdt_fops,
+};
+
+static struct notifier_block ds1374_wdt_notifier = {
+	.notifier_call = ds1374_wdt_notify_sys,
+};
+
+#endif /*CONFIG_RTC_DRV_DS1374_WDT*/
+/*
+ *****************************************************************************
+ *
+ *	Driver Interface
+ *
+ *****************************************************************************
+ */
+static int ds1374_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct ds1374 *ds1374;
+	int ret;
+
+	ds1374 = devm_kzalloc(&client->dev, sizeof(struct ds1374), GFP_KERNEL);
+	if (!ds1374)
+		return -ENOMEM;
+
+	ds1374->client = client;
+	i2c_set_clientdata(client, ds1374);
+
+	INIT_WORK(&ds1374->work, ds1374_work);
+	mutex_init(&ds1374->mutex);
+
+	ret = ds1374_check_rtc_status(client);
+	if (ret)
+		return ret;
+
+	if (client->irq > 0) {
+		ret = devm_request_irq(&client->dev, client->irq, ds1374_irq, 0,
+					"ds1374", client);
+		if (ret) {
+			dev_err(&client->dev, "unable to request IRQ\n");
+			return ret;
+		}
+
+		device_set_wakeup_capable(&client->dev, 1);
+	}
+
+	ds1374->rtc = devm_rtc_device_register(&client->dev, client->name,
+						&ds1374_rtc_ops, THIS_MODULE);
+	if (IS_ERR(ds1374->rtc)) {
+		dev_err(&client->dev, "unable to register the class device\n");
+		return PTR_ERR(ds1374->rtc);
+	}
+
+#ifdef CONFIG_RTC_DRV_DS1374_WDT
+	save_client = client;
+	ret = misc_register(&ds1374_miscdev);
+	if (ret)
+		return ret;
+	ret = register_reboot_notifier(&ds1374_wdt_notifier);
+	if (ret) {
+		misc_deregister(&ds1374_miscdev);
+		return ret;
+	}
+	ds1374_wdt_settimeout(131072);
+#endif
+
+	return 0;
+}
+
+static int ds1374_remove(struct i2c_client *client)
+{
+	struct ds1374 *ds1374 = i2c_get_clientdata(client);
+#ifdef CONFIG_RTC_DRV_DS1374_WDT
+	int res;
+
+	res = misc_deregister(&ds1374_miscdev);
+	if (!res)
+		ds1374_miscdev.parent = NULL;
+	unregister_reboot_notifier(&ds1374_wdt_notifier);
+#endif
+
+	if (client->irq > 0) {
+		mutex_lock(&ds1374->mutex);
+		ds1374->exiting = 1;
+		mutex_unlock(&ds1374->mutex);
+
+		devm_free_irq(&client->dev, client->irq, client);
+		cancel_work_sync(&ds1374->work);
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int ds1374_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+
+	if (client->irq >= 0 && device_may_wakeup(&client->dev))
+		enable_irq_wake(client->irq);
+	return 0;
+}
+
+static int ds1374_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+
+	if (client->irq >= 0 && device_may_wakeup(&client->dev))
+		disable_irq_wake(client->irq);
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(ds1374_pm, ds1374_suspend, ds1374_resume);
+
+static struct i2c_driver ds1374_driver = {
+	.driver = {
+		.name = "rtc-ds1374",
+		.owner = THIS_MODULE,
+		.pm = &ds1374_pm,
+	},
+	.probe = ds1374_probe,
+	.remove = ds1374_remove,
+	.id_table = ds1374_id,
+};
+
+module_i2c_driver(ds1374_driver);
+
+MODULE_AUTHOR("Scott Wood <scottwood@freescale.com>");
+MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC Driver");
+MODULE_LICENSE("GPL");