mirror of
https://github.com/adulau/aha.git
synced 2024-12-28 19:56:18 +00:00
rtc: RTC class driver for the ds1374
This patch adds an RTC class driver for the Maxim/Dallas 1374 RTC chip, based on drivers/i2c/chips/ds1374.c. It supports alarm functionality. Signed-off-by: Scott Wood <scottwood@freescale.com> Acked-by: Alessandro Zummo <a.zummo@towertech.it> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Scott Wood
Linus Torvalds
parent
c018664c51
commit
bf4994d781
3 changed files with 461 additions and 0 deletions
|
|
@ -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
|
||||
|
|
|
|||
|
|
@ -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
|
||||
|
|
|
|||
449
drivers/rtc/rtc-ds1374.c
Normal file
449
drivers/rtc/rtc-ds1374.c
Normal file
|
|
@ -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");
|
||||
Loading…
Reference in a new issue