linux-stable/drivers/rtc/rtc-ds1374.c
Uwe Kleine-König ed5c2f5fd1 i2c: Make remove callback return void
The value returned by an i2c driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Reviewed-by: Jeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: Benjamin Mugnier <benjamin.mugnier@foss.st.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Crt Mori <cmo@melexis.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Marek Behún <kabel@kernel.org> # for leds-turris-omnia
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Machata <petrm@nvidia.com> # for mlxsw
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com> # for surface3_power
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> # for bmc150-accel-i2c + kxcjk-1013
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> # for media/* + staging/media/*
Acked-by: Miguel Ojeda <ojeda@kernel.org> # for auxdisplay/ht16k33 + auxdisplay/lcd2s
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com> # for versaclock5
Reviewed-by: Ajay Gupta <ajayg@nvidia.com> # for ucsi_ccg
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for iio
Acked-by: Peter Rosin <peda@axentia.se> # for i2c-mux-*, max9860
Acked-by: Adrien Grassein <adrien.grassein@gmail.com> # for lontium-lt8912b
Reviewed-by: Jean Delvare <jdelvare@suse.de> # for hwmon, i2c-core and i2c/muxes
Acked-by: Corey Minyard <cminyard@mvista.com> # for IPMI
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com> # for drivers/power
Acked-by: Krzysztof Hałasa <khalasa@piap.pl>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
2022-08-16 12:46:26 +02:00

584 lines
14 KiB
C

// 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", 0 },
{ }
};
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_new = 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");