diff options
Diffstat (limited to 'drivers/rtc/rtc-ds1374.c')
| -rw-r--r-- | drivers/rtc/rtc-ds1374.c | 724 |
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"); |