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linux/drivers/rtc/rtc-ds1374.c
Wolfram Sang fbae3fb154 i2c: Remove all i2c_set_clientdata(client, NULL) in drivers 
I2C drivers can use the clientdata-pointer to point to private data. As I2C
devices are not really unregistered, but merely detached from their driver, it
used to be the drivers obligation to clear this pointer during remove() or a
failed probe(). As a couple of drivers forgot to do this, it was agreed that it
was cleaner if the i2c-core does this clearance when appropriate, as there is
no guarantee for the lifetime of the clientdata-pointer after remove() anyhow.
This feature was added to the core with commit
e4a7b9b04d to fix the faulty drivers.

As there is no need anymore to clear the clientdata-pointer, remove all current
occurrences in the drivers to simplify the code and prevent confusion.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Richard Purdie <rpurdie@linux.intel.com>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2010-06-03 11:33:58 +02:00

475 lines
11 KiB
C
Raw Blame History

/*
* 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>
#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_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,
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);
flush_scheduled_work();
}
rtc_device_unregister(ds1374->rtc);
kfree(ds1374);
return 0;
}
#ifdef CONFIG_PM
static int ds1374_suspend(struct i2c_client *client, pm_message_t state)
{
if (client->irq >= 0 && device_may_wakeup(&client->dev))
enable_irq_wake(client->irq);
return 0;
}
static int ds1374_resume(struct i2c_client *client)
{
if (client->irq >= 0 && device_may_wakeup(&client->dev))
disable_irq_wake(client->irq);
return 0;
}
#else
#define ds1374_suspend NULL
#define ds1374_resume NULL
#endif
static struct i2c_driver ds1374_driver = {
.driver = {
.name = "rtc-ds1374",
.owner = THIS_MODULE,
},
.probe = ds1374_probe,
.suspend = ds1374_suspend,
.resume = ds1374_resume,
.remove = __devexit_p(ds1374_remove),
.id_table = ds1374_id,
};
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");
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