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linux/drivers/rtc/rtc-ds1374.c
Uwe Kleine-König a47d377e22 rtc: Drop explicit initialization of struct i2c_device_id::driver_data to 0 
These drivers don't use the driver_data member of struct i2c_device_id,
so don't explicitly initialize this member.

This prepares putting driver_data in an anonymous union which requires
either no initialization or named designators. But it's also a nice
cleanup on its own.

While add it, also remove a comma after the sentinel entry in
rtc-hym8563.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20240515194336.58342-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2024-07-07 00:40:29 +02:00

585 lines
14 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
/*
* 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
* Copyright (c) 2005 MontaVista Software, Inc.
*/
/*
* It would be more efficient to use i2c msgs/i2c_transfer directly but, as
* recommended in .../Documentation/i2c/writing-clients.rst 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_WDSTR 0x08 /* 1=INT, 0=RST */
#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" },
{ }
};
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;
#ifdef CONFIG_RTC_DRV_DS1374_WDT
struct watchdog_device wdt;
#endif
/* 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 (WARN_ON(nbytes > 4))
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_time64_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_time64(time);
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_time64_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;
new_alarm = rtc_tm_to_time64(&alarm->time);
itime = rtc_tm_to_time64(&now);
/* 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
*
*****************************************************************************
*/
/* Default margin */
#define TIMER_MARGIN_DEFAULT 32
#define TIMER_MARGIN_MIN 1
#define TIMER_MARGIN_MAX 4095 /* 24-bit value */
static int wdt_margin;
module_param(wdt_margin, int, 0);
MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 32s)");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default ="
__MODULE_STRING(WATCHDOG_NOWAYOUT)")");
static const struct watchdog_info ds1374_wdt_info = {
.identity = "DS1374 Watchdog",
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
};
static int ds1374_wdt_settimeout(struct watchdog_device *wdt, unsigned int timeout)
{
struct ds1374 *ds1374 = watchdog_get_drvdata(wdt);
struct i2c_client *client = ds1374->client;
int ret, cr;
wdt->timeout = timeout;
cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
if (cr < 0)
return cr;
/* Disable any existing watchdog/alarm before setting the new one */
cr &= ~DS1374_REG_CR_WACE;
ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
if (ret < 0)
return ret;
/* Set new watchdog time */
timeout = timeout * 4096;
ret = ds1374_write_rtc(client, timeout, DS1374_REG_WDALM0, 3);
if (ret)
return ret;
/* Enable watchdog timer */
cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_WDALM;
cr &= ~DS1374_REG_CR_WDSTR;/* for RST PIN */
cr &= ~DS1374_REG_CR_AIE;
ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
if (ret < 0)
return ret;
return 0;
}
/*
* Reload the watchdog timer. (ie, pat the watchdog)
*/
static int ds1374_wdt_start(struct watchdog_device *wdt)
{
struct ds1374 *ds1374 = watchdog_get_drvdata(wdt);
u32 val;
return ds1374_read_rtc(ds1374->client, &val, DS1374_REG_WDALM0, 3);
}
static int ds1374_wdt_stop(struct watchdog_device *wdt)
{
struct ds1374 *ds1374 = watchdog_get_drvdata(wdt);
struct i2c_client *client = ds1374->client;
int cr;
cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
if (cr < 0)
return cr;
/* Disable watchdog timer */
cr &= ~DS1374_REG_CR_WACE;
return i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
}
static const struct watchdog_ops ds1374_wdt_ops = {
.owner = THIS_MODULE,
.start = ds1374_wdt_start,
.stop = ds1374_wdt_stop,
.set_timeout = ds1374_wdt_settimeout,
};
#endif /*CONFIG_RTC_DRV_DS1374_WDT*/
/*
*****************************************************************************
*
* Driver Interface
*
*****************************************************************************
*/
static int ds1374_probe(struct i2c_client *client)
{
struct ds1374 *ds1374;
int ret;
ds1374 = devm_kzalloc(&client->dev, sizeof(struct ds1374), GFP_KERNEL);
if (!ds1374)
return -ENOMEM;
ds1374->rtc = devm_rtc_allocate_device(&client->dev);
if (IS_ERR(ds1374->rtc))
return PTR_ERR(ds1374->rtc);
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->ops = &ds1374_rtc_ops;
ds1374->rtc->range_max = U32_MAX;
ret = devm_rtc_register_device(ds1374->rtc);
if (ret)
return ret;
#ifdef CONFIG_RTC_DRV_DS1374_WDT
ds1374->wdt.info = &ds1374_wdt_info;
ds1374->wdt.ops = &ds1374_wdt_ops;
ds1374->wdt.timeout = TIMER_MARGIN_DEFAULT;
ds1374->wdt.min_timeout = TIMER_MARGIN_MIN;
ds1374->wdt.max_timeout = TIMER_MARGIN_MAX;
watchdog_init_timeout(&ds1374->wdt, wdt_margin, &client->dev);
watchdog_set_nowayout(&ds1374->wdt, nowayout);
watchdog_stop_on_reboot(&ds1374->wdt);
watchdog_stop_on_unregister(&ds1374->wdt);
watchdog_set_drvdata(&ds1374->wdt, ds1374);
ds1374_wdt_settimeout(&ds1374->wdt, ds1374->wdt.timeout);
ret = devm_watchdog_register_device(&client->dev, &ds1374->wdt);
if (ret)
return ret;
#endif
return 0;
}
static void 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);
devm_free_irq(&client->dev, client->irq, client);
cancel_work_sync(&ds1374->work);
}
}
#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",
.of_match_table = of_match_ptr(ds1374_of_match),
.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");
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