rtc: ds1685: fix possible race condition

The IRQ is requested before the struct rtc is allocated and registered, but
this struct is used in the IRQ handler.

Switch to devm_rtc_allocate_device/rtc_register_device to allocate the rtc
before requesting the IRQ.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/drivers/rtc/rtc-ds1685.c b/drivers/rtc/rtc-ds1685.c
index f0f8011..e639047 100644 (file)
--- a/drivers/rtc/rtc-ds1685.c
+++ b/drivers/rtc/rtc-ds1685.c
@@ -2037,6 +2037,22 @@ ds1685_rtc_probe(struct platform_device *pdev)
        rtc->write(rtc, RTC_EXT_CTRL_4B,
                   (rtc->read(rtc, RTC_EXT_CTRL_4B) | RTC_CTRL_4B_KSE));
 
+       rtc_dev = devm_rtc_allocate_device(&pdev->dev);
+       if (IS_ERR(rtc_dev))
+               return PTR_ERR(rtc_dev);
+
+       rtc_dev->ops = &ds1685_rtc_ops;
+
+       /* Maximum periodic rate is 8192Hz (0.122070ms). */
+       rtc_dev->max_user_freq = RTC_MAX_USER_FREQ;
+
+       /* See if the platform doesn't support UIE. */
+       if (pdata->uie_unsupported)
+               rtc_dev->uie_unsupported = 1;
+       rtc->uie_unsupported = pdata->uie_unsupported;
+
+       rtc->dev = rtc_dev;
+
        /*
         * Fetch the IRQ and setup the interrupt handler.
         *
@@ -2069,32 +2085,13 @@ ds1685_rtc_probe(struct platform_device *pdev)
        /* Setup complete. */
        ds1685_rtc_switch_to_bank0(rtc);
 
-       /* Register the device as an RTC. */
-       rtc_dev = rtc_device_register(pdev->name, &pdev->dev,
-                                     &ds1685_rtc_ops, THIS_MODULE);
-
-       /* Success? */
-       if (IS_ERR(rtc_dev))
-               return PTR_ERR(rtc_dev);
-
-       /* Maximum periodic rate is 8192Hz (0.122070ms). */
-       rtc_dev->max_user_freq = RTC_MAX_USER_FREQ;
-
-       /* See if the platform doesn't support UIE. */
-       if (pdata->uie_unsupported)
-               rtc_dev->uie_unsupported = 1;
-       rtc->uie_unsupported = pdata->uie_unsupported;
-
-       rtc->dev = rtc_dev;
-
 #ifdef CONFIG_SYSFS
        ret = ds1685_rtc_sysfs_register(&pdev->dev);
        if (ret)
-               rtc_device_unregister(rtc->dev);
+               return ret;
 #endif
 
-       /* Done! */
-       return ret;
+       return rtc_register_device(rtc_dev);
 }
 
 /**
@@ -2110,8 +2107,6 @@ ds1685_rtc_remove(struct platform_device *pdev)
        ds1685_rtc_sysfs_unregister(&pdev->dev);
 #endif
 
-       rtc_device_unregister(rtc->dev);
-
        /* Read Ctrl B and clear PIE/AIE/UIE. */
        rtc->write(rtc, RTC_CTRL_B,
                   (rtc->read(rtc, RTC_CTRL_B) &