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rtc: introduce new registration method 

Introduce rtc_register_device() to register an already allocated and
initialized struct rtc_device. It automatically sets up the owner and the
two steps allocation/registration will allow to remove race conditions in
the IRQ handling of some driver. It also allows to properly extend the core
without adding more arguments to rtc_device_register().

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This commit is contained in:
Alexandre Belloni 2017-07-06 11:42:00 +02:00
parent b91336df8a
commit 3068a254d5
2 changed files with 91 additions and 0 deletions
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84
drivers/rtc/class.c
View File

@ -150,6 +150,7 @@ static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume);
#define RTC_CLASS_DEV_PM_OPS NULL
#endif
/* Ensure the caller will set the id before releasing the device */
static struct rtc_device *rtc_allocate_device(void)
{
struct rtc_device *rtc;
@ -372,6 +373,89 @@ void devm_rtc_device_unregister(struct device *dev, struct rtc_device *rtc)
}
EXPORT_SYMBOL_GPL(devm_rtc_device_unregister);
static void devm_rtc_release_device(struct device *dev, void *res)
{
struct rtc_device *rtc = *(struct rtc_device **)res;
if (rtc->registered)
rtc_device_unregister(rtc);
else
put_device(&rtc->dev);
}
struct rtc_device *devm_rtc_allocate_device(struct device *dev)
{
struct rtc_device **ptr, *rtc;
int id, err;
id = rtc_device_get_id(dev);
if (id < 0)
return ERR_PTR(id);
ptr = devres_alloc(devm_rtc_release_device, sizeof(*ptr), GFP_KERNEL);
if (!ptr) {
err = -ENOMEM;
goto exit_ida;
}
rtc = rtc_allocate_device();
if (!rtc) {
err = -ENOMEM;
goto exit_devres;
}
*ptr = rtc;
devres_add(dev, ptr);
rtc->id = id;
rtc->dev.parent = dev;
dev_set_name(&rtc->dev, "rtc%d", id);
return rtc;
exit_devres:
devres_free(ptr);
exit_ida:
ida_simple_remove(&rtc_ida, id);
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(devm_rtc_allocate_device);
int __rtc_register_device(struct module *owner, struct rtc_device *rtc)
{
struct rtc_wkalrm alrm;
int err;
if (!rtc->ops)
return -EINVAL;
rtc->owner = owner;
/* Check to see if there is an ALARM already set in hw */
err = __rtc_read_alarm(rtc, &alrm);
if (!err && !rtc_valid_tm(&alrm.time))
rtc_initialize_alarm(rtc, &alrm);
rtc_dev_prepare(rtc);
err = cdev_device_add(&rtc->char_dev, &rtc->dev);
if (err)
dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n",
MAJOR(rtc->dev.devt), rtc->id);
else
dev_dbg(rtc->dev.parent, "char device (%d:%d)\n",
MAJOR(rtc->dev.devt), rtc->id);
rtc_proc_add_device(rtc);
rtc->registered = true;
dev_info(rtc->dev.parent, "registered as %s\n",
dev_name(&rtc->dev));
return 0;
}
EXPORT_SYMBOL_GPL(__rtc_register_device);
static int __init rtc_init(void)
{
rtc_class = class_create(THIS_MODULE, "rtc");

7
include/linux/rtc.h
View File

@ -142,6 +142,8 @@ struct rtc_device {
/* Some hardware can't support UIE mode */
int uie_unsupported;
bool registered;
#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
struct work_struct uie_task;
struct timer_list uie_timer;
@ -163,6 +165,8 @@ extern struct rtc_device *devm_rtc_device_register(struct device *dev,
const char *name,
const struct rtc_class_ops *ops,
struct module *owner);
struct rtc_device *devm_rtc_allocate_device(struct device *dev);
int __rtc_register_device(struct module *owner, struct rtc_device *rtc);
extern void rtc_device_unregister(struct rtc_device *rtc);
extern void devm_rtc_device_unregister(struct device *dev,
struct rtc_device *rtc);
@ -218,6 +222,9 @@ static inline bool is_leap_year(unsigned int year)
return (!(year % 4) && (year % 100)) || !(year % 400);
}
#define rtc_register_device(device) \
__rtc_register_device(THIS_MODULE, device)
#ifdef CONFIG_RTC_HCTOSYS_DEVICE
extern int rtc_hctosys_ret;
#else