diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-30 09:22:00 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-30 09:22:00 -0700 |
| commit | 034dd340b08be1f2f0477ad16131d609f9dbd53c (patch) | |
| tree | 2536f4b2d7893ccd916b5abdf3c454ad6edc03c2 /drivers/rtc/rtc-ds1374.c | |
| download | linux-stable-034dd340b08be1f2f0477ad16131d609f9dbd53c.tar.gz linux-stable-034dd340b08be1f2f0477ad16131d609f9dbd53c.zip | |
Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted
Pull tracing fixes from Steven Rostedt:
- Fix error output of boot instance creation failure
Currently if a boot instance creation fails, instead of printing out
the name of the instance that failed, it prints "(null)". That is
because it prints "cur_str" that had already been processed by
strsep(). Print the saved name instead.
While at it, print the error code of the failure.
- Fix use-after-free for same named historgrams
Histograms can be named so that they can be used in multiple events.
But if the named histogram has a variable attached, the second event
that uses the named histogram which duplicates it and needs to free
the original after duplication leaves the old variable in place and
still visible. If another histogram uses than variable, it will use
the stale one which will try to reference the freed duplicate
histogram and crash the kernel.
Free the duplicate variables along with the duplicated histogram
data.
- Check return value of kthread_run() in event self test
The events self tests uses a kthread for testing but does not check
if it succeeded in creating a kthread. If the kthread creation were
to fail, the code will still try to call kthread_stop() on the error
returned.
- Fix race between reading trace_pipe and updating subbuffer size
If a user is reading the trace_pipe file at the same time they update
the ring buffer sub-buffer size, can cause the trace_pipe read to
read stale data. Add trace_access_lock() around updating the ring
buffer sub-buffer size.
- Fix eventfs_inode on failure path in creation of the events directory
In the creation of the "events" directory, if after allocating the
eventfs_inode a failure is detected, it calls cleanup_ei() which
calls free_ei(). The free_ei() will test if eventfs_inode being freed
has no children. It is a bug if it does. But on the failure case of
the creation of the "events" directory, the children lists have not
yet been initialized and the free will trigger a warning because
list_empty() on an uninitialized list returns false.
Move the initialization into init_ei() where it makes more sense and
makes sure that a created eventfs_inode has its lists initialized
upon creation.
- Check return value of kthread_run() in ftrace direct sample code
The sample code that shows how to use the ftrace direct calls does
not test the return of kthread_run() to see if it succeeds. Return a
failure if the kthread_run() doesn't succeed.
- Clear user events state on fork in case of alloc failure
On fork, the child gets a pointer to the parent's user events state.
It makes a copy of it then updates the child's pointer to it. But if
the allocation fails, the duplication function leaves the child with
a pointer to its parent's descriptor. When the child cleans up its
data, it will free the parent's descriptor while the parent is still
using it.
In the duplication function, set the child's user_event_mm to NULL
before testing if the allocation succeeded, and when it exits it will
not free the parent's descriptor.
- Fix retry exhaustion in simple ring buffer reader swap
simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
post-decrements it only after a failed link replacement. On the final
attempt, a successful replacement leaves retry at zero, while a
failed replacement leaves it at -1.
But the check for success expects the retry value to be non-zero and
exits with an error on zero. This is the opposite result. Fix it.
- Fail nicely when the remote swap_reader_page() returns an error
Currently, if the swap_reader_page() of a remote buffer fails, it
triggers a WARN_ON_ONCE() and continues normally. Instead, have it
exit with an error and a pr_warn() print instead of a full WARNING.
* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ring-buffer: Stop remote reader update when page swap fails
tracing: Fix retry exhaustion in simple ring buffer reader swap
tracing/user_events: Clear copied tracing state before fork duplication
samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
eventfs: Initialize ei->children and ei->list in init_ei()
tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
tracing: Fix crash passing ERR_PTR to kthread_stop()
tracing: Fix use-after-free with same-name named triggers
tracing: Fix logged instance name on creation failure
Diffstat (limited to 'drivers/rtc/rtc-ds1374.c')
| -rw-r--r-- | drivers/rtc/rtc-ds1374.c | 584 |
1 files changed, 584 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ds1374.c b/drivers/rtc/rtc-ds1374.c new file mode 100644 index 000000000..8c247215d --- /dev/null +++ b/drivers/rtc/rtc-ds1374.c @@ -0,0 +1,584 @@ +// 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[] = { + { .name = "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"); |
