From 806a0fc320ad8f6c391b6e4a4d872af0ffc17fbc Mon Sep 17 00:00:00 2001
From: Todd Poynor <toddpoynor@google.com>
Date: Wed, 27 Jul 2011 07:07:21 +0000
Subject: [PATCH 10/14] rtc: twl: Fix registration vs. init order

Only register as an RTC device after the hardware has been
successfully initialized.  The RTC class driver will call
back to this driver to read a pending alarm, and other
drivers watching for new devices on the RTC class may
read the RTC time upon registration.  Such access might
occur while the RTC is stopped, prior to clearing
pending alarms, etc.

The new ordering also avoids leaving the platform
device drvdata set to an unregistered struct rtc_device *
on probe errors.

Signed-off-by: Todd Poynor <toddpoynor@google.com>
---
 drivers/rtc/rtc-twl.c |   52 ++++++++++++++++++++++--------------------------
 1 files changed, 24 insertions(+), 28 deletions(-)

diff --git a/drivers/rtc/rtc-twl.c b/drivers/rtc/rtc-twl.c
index 3fee95e..a64494e 100644
--- a/drivers/rtc/rtc-twl.c
+++ b/drivers/rtc/rtc-twl.c
@@ -420,24 +420,12 @@ static struct rtc_class_ops twl_rtc_ops = {
 static int __devinit twl_rtc_probe(struct platform_device *pdev)
 {
 	struct rtc_device *rtc;
-	int ret = 0;
+	int ret = -EINVAL;
 	int irq = platform_get_irq(pdev, 0);
 	u8 rd_reg;
 
 	if (irq <= 0)
-		return -EINVAL;
-
-	rtc = rtc_device_register(pdev->name,
-				  &pdev->dev, &twl_rtc_ops, THIS_MODULE);
-	if (IS_ERR(rtc)) {
-		ret = PTR_ERR(rtc);
-		dev_err(&pdev->dev, "can't register RTC device, err %ld\n",
-			PTR_ERR(rtc));
-		goto out0;
-
-	}
-
-	platform_set_drvdata(pdev, rtc);
+		goto out1;
 
 	ret = twl_rtc_read_u8(&rd_reg, REG_RTC_STATUS_REG);
 	if (ret < 0)
@@ -454,14 +442,6 @@ static int __devinit twl_rtc_probe(struct platform_device *pdev)
 	if (ret < 0)
 		goto out1;
 
-	ret = request_threaded_irq(irq, NULL, twl_rtc_interrupt,
-				   IRQF_TRIGGER_RISING,
-				   dev_name(&rtc->dev), rtc);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "IRQ is not free.\n");
-		goto out1;
-	}
-
 	if (twl_class_is_6030()) {
 		twl6030_interrupt_unmask(TWL6030_RTC_INT_MASK,
 			REG_INT_MSK_LINE_A);
@@ -472,28 +452,44 @@ static int __devinit twl_rtc_probe(struct platform_device *pdev)
 	/* Check RTC module status, Enable if it is off */
 	ret = twl_rtc_read_u8(&rd_reg, REG_RTC_CTRL_REG);
 	if (ret < 0)
-		goto out2;
+		goto out1;
 
 	if (!(rd_reg & BIT_RTC_CTRL_REG_STOP_RTC_M)) {
 		dev_info(&pdev->dev, "Enabling TWL-RTC.\n");
 		rd_reg = BIT_RTC_CTRL_REG_STOP_RTC_M;
 		ret = twl_rtc_write_u8(rd_reg, REG_RTC_CTRL_REG);
 		if (ret < 0)
-			goto out2;
+			goto out1;
 	}
 
 	/* init cached IRQ enable bits */
 	ret = twl_rtc_read_u8(&rtc_irq_bits, REG_RTC_INTERRUPTS_REG);
 	if (ret < 0)
+		goto out1;
+
+	rtc = rtc_device_register(pdev->name,
+				  &pdev->dev, &twl_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rtc)) {
+		ret = PTR_ERR(rtc);
+		dev_err(&pdev->dev, "can't register RTC device, err %ld\n",
+			PTR_ERR(rtc));
+		goto out1;
+	}
+
+	ret = request_threaded_irq(irq, NULL, twl_rtc_interrupt,
+				   IRQF_TRIGGER_RISING,
+				   dev_name(&rtc->dev), rtc);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "IRQ is not free.\n");
 		goto out2;
+	}
 
-	return ret;
+	platform_set_drvdata(pdev, rtc);
+	return 0;
 
 out2:
-	free_irq(irq, rtc);
-out1:
 	rtc_device_unregister(rtc);
-out0:
+out1:
 	return ret;
 }
 
-- 
1.6.6.1

