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>

1 files changed, 84 insertions, 0 deletions

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");