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Subject[PATCH 03/11] rtc: introduce new registration method
Date
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>
---
drivers/rtc/class.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/rtc.h | 7 +++++
2 files changed, 91 insertions(+)

diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index 93ce88e1b1cb..58e2a05765bb 100644
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -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");
diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index d354f56e0cf5..8e4a5f44f59e 100644
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -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
--
2.11.0
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