mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-05 18:14:07 +08:00
0abc920116
Factor out some boilerplate code for i2c driver registration into module_i2c_driver. Signed-off-by: Axel Lin <axel.lin@gmail.com> Cc: Piotr Ziecik <kosmo@semihalf.com> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Scott Wood <scottwood@freescale.com> Cc: Srikanth Srinivasan <srikanth.srinivasan@freescale.com> Cc: Mike Rapoport <mike@compulab.co.il> Cc: Sergey Lapin <slapin@ossfans.org> Cc: Roman Fietze <roman.fietze@telemotive.de> Cc: Herbert Valerio Riedel <hvr@gnu.org> Cc: Alexander Bigga <ab@mycable.de> Cc: Dale Farnsworth <dale@farnsworth.org> Cc: Gregory Hermant <gregory.hermant@calao-systems.com> Cc: Wolfgang Grandegger <wg@grandegger.com> Cc: Martyn Welch <martyn.welch@ge.com> Cc: Byron Bradley <byron.bbradley@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
454 lines
11 KiB
C
454 lines
11 KiB
C
/*
|
|
* 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>
|
|
#include <linux/slab.h>
|
|
#include <linux/pm.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 */
|
|
|
|
static const struct i2c_device_id ds1374_id[] = {
|
|
{ "ds1374", 0 },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(i2c, ds1374_id);
|
|
|
|
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);
|
|
|
|
/* 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;
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
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,
|
|
.alarm_irq_enable = ds1374_alarm_irq_enable,
|
|
};
|
|
|
|
static int ds1374_probe(struct i2c_client *client,
|
|
const struct i2c_device_id *id)
|
|
{
|
|
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;
|
|
}
|
|
|
|
device_set_wakeup_capable(&client->dev, 1);
|
|
}
|
|
|
|
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:
|
|
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);
|
|
cancel_work_sync(&ds1374->work);
|
|
}
|
|
|
|
rtc_device_unregister(ds1374->rtc);
|
|
kfree(ds1374);
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_PM
|
|
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;
|
|
}
|
|
|
|
static SIMPLE_DEV_PM_OPS(ds1374_pm, ds1374_suspend, ds1374_resume);
|
|
|
|
#define DS1374_PM (&ds1374_pm)
|
|
#else
|
|
#define DS1374_PM NULL
|
|
#endif
|
|
|
|
static struct i2c_driver ds1374_driver = {
|
|
.driver = {
|
|
.name = "rtc-ds1374",
|
|
.owner = THIS_MODULE,
|
|
.pm = DS1374_PM,
|
|
},
|
|
.probe = ds1374_probe,
|
|
.remove = __devexit_p(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");
|