--- /dev/null
+/*
+ * 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");
Code Review / kvmfornfv.git / blobdiff