diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/rtc/Kconfig | 11 | ||||
| -rw-r--r-- | drivers/rtc/Makefile | 1 | ||||
| -rw-r--r-- | drivers/rtc/rtc-ds1374.c | 449 |
3 files changed, 461 insertions, 0 deletions
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index ff9e35cb308..6420a90a4a9 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -139,6 +139,17 @@ config RTC_DRV_DS1307 This driver can also be built as a module. If so, the module will be called rtc-ds1307. +config RTC_DRV_DS1374 + tristate "Maxim/Dallas Semiconductor DS1374 Real Time Clock" + depends on RTC_CLASS && I2C + help + If you say yes here you get support for Dallas Semiconductor + DS1374 real-time clock chips. If an interrupt is associated + with the device, the alarm functionality is supported. + + This driver can also be built as a module. If so, the module + will be called rtc-ds1374. + config RTC_DRV_DS1672 tristate "Dallas/Maxim DS1672" help diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index d3a33aa2696..465db4dd50b 100644 --- a/drivers/rtc/Makefile +++ b/drivers/rtc/Makefile @@ -23,6 +23,7 @@ obj-$(CONFIG_RTC_DRV_BFIN) += rtc-bfin.o obj-$(CONFIG_RTC_DRV_CMOS) += rtc-cmos.o obj-$(CONFIG_RTC_DRV_DS1216) += rtc-ds1216.o obj-$(CONFIG_RTC_DRV_DS1307) += rtc-ds1307.o +obj-$(CONFIG_RTC_DRV_DS1374) += rtc-ds1374.o obj-$(CONFIG_RTC_DRV_DS1553) += rtc-ds1553.o obj-$(CONFIG_RTC_DRV_DS1672) += rtc-ds1672.o obj-$(CONFIG_RTC_DRV_DS1742) += rtc-ds1742.o diff --git a/drivers/rtc/rtc-ds1374.c b/drivers/rtc/rtc-ds1374.c new file mode 100644 index 00000000000..45bda186bef --- /dev/null +++ b/drivers/rtc/rtc-ds1374.c @@ -0,0 +1,449 @@ +/* + * 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) 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. + */ + +#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> + +#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 */ + +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); +} + +/* 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); + + new_alarm -= 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 (new_alarm <= 0) + new_alarm = 1; + + 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; +} + +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) + return; + + 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() assumes that it is called + * from IRQ-disabled context. + */ + local_irq_disable(); + rtc_update_irq(ds1374->rtc, 1, RTC_AF | RTC_IRQF); + local_irq_enable(); + } + +out: + if (!ds1374->exiting) + enable_irq(client->irq); + + mutex_unlock(&ds1374->mutex); +} + +static int ds1374_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) +{ + struct i2c_client *client = to_i2c_client(dev); + struct ds1374 *ds1374 = i2c_get_clientdata(client); + int ret = -ENOIOCTLCMD; + + mutex_lock(&ds1374->mutex); + + switch (cmd) { + case RTC_AIE_OFF: + ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR); + if (ret < 0) + goto out; + + ret &= ~DS1374_REG_CR_WACE; + + ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret); + if (ret < 0) + goto out; + + break; + + case RTC_AIE_ON: + ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR); + if (ret < 0) + goto out; + + ret |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE; + ret &= ~DS1374_REG_CR_WDALM; + + ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret); + if (ret < 0) + goto out; + + break; + } + +out: + mutex_unlock(&ds1374->mutex); + return ret; +} + +static const struct rtc_class_ops ds1374_rtc_ops = { + .read_time = ds1374_read_time, + .set_time = ds1374_set_time, + .read_alarm = ds1374_read_alarm, + .set_alarm = ds1374_set_alarm, + .ioctl = ds1374_ioctl, +}; + +static int ds1374_probe(struct i2c_client *client) +{ + struct ds1374 *ds1374; + int ret; + + ds1374 = kzalloc(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) + goto out_free; + + if (client->irq >= 0) { + ret = request_irq(client->irq, ds1374_irq, 0, + "ds1374", client); + if (ret) { + dev_err(&client->dev, "unable to request IRQ\n"); + goto out_free; + } + } + + ds1374->rtc = rtc_device_register(client->name, &client->dev, + &ds1374_rtc_ops, THIS_MODULE); + if (IS_ERR(ds1374->rtc)) { + ret = PTR_ERR(ds1374->rtc); + dev_err(&client->dev, "unable to register the class device\n"); + goto out_irq; + } + + return 0; + +out_irq: + if (client->irq >= 0) + free_irq(client->irq, client); + +out_free: + i2c_set_clientdata(client, NULL); + kfree(ds1374); + return ret; +} + +static int __devexit ds1374_remove(struct i2c_client *client) +{ + struct ds1374 *ds1374 = i2c_get_clientdata(client); + + if (client->irq >= 0) { + mutex_lock(&ds1374->mutex); + ds1374->exiting = 1; + mutex_unlock(&ds1374->mutex); + + free_irq(client->irq, client); + flush_scheduled_work(); + } + + rtc_device_unregister(ds1374->rtc); + i2c_set_clientdata(client, NULL); + kfree(ds1374); + return 0; +} + +static struct i2c_driver ds1374_driver = { + .driver = { + .name = "rtc-ds1374", + .owner = THIS_MODULE, + }, + .probe = ds1374_probe, + .remove = __devexit_p(ds1374_remove), +}; + +static int __init ds1374_init(void) +{ + return i2c_add_driver(&ds1374_driver); +} + +static void __exit ds1374_exit(void) +{ + i2c_del_driver(&ds1374_driver); +} + +module_init(ds1374_init); +module_exit(ds1374_exit); + +MODULE_AUTHOR("Scott Wood <scottwood@freescale.com>"); +MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC Driver"); +MODULE_LICENSE("GPL"); |