[PATCH 0/3] rtc: twl: update TWL RTC driver

[PATCH 0/3] rtc: twl: update TWL RTC driver

[Venu Byravarasu]

From: Venu Byravarasu <vbyravarasu@nvidia.com>

Observed minor issues with TWL RTC driver.
Hence tried fixing them with below 3 patches.

Venu Byravarasu (3):
  rtc: twl: Enable RTC irrespective of its prior state
  rtc: twl: Simplify RTC interrupt clearing
  rtc: twl: Return correct RTC event from ISR

 drivers/rtc/rtc-twl.c |   20 ++++++--------------
 1 files changed, 6 insertions(+), 14 deletions(-)

[PATCH 1/3] rtc: twl: Enable RTC irrespective of its prior state

[Venu Byravarasu]

From: Venu Byravarasu <vbyravarasu@nvidia.com>

As part of probe, before enabling RTC, RTC_CTRL register is read
to check if it is already running. If RTC is used by kernel alone,
then this read is not required. Even if RTC was enabled already by
boot loader, setting STOP_RTC bit again should not harm.
Hence removed unwanted read operation.

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
---
 drivers/rtc/rtc-twl.c |   12 ++----------
 1 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/drivers/rtc/rtc-twl.c b/drivers/rtc/rtc-twl.c
index 20687d5..61ae1b7 100644
--- a/drivers/rtc/rtc-twl.c
+++ b/drivers/rtc/rtc-twl.c
@@ -449,19 +449,11 @@ static int __devinit twl_rtc_probe(struct platform_device *pdev)
 			REG_INT_MSK_STS_A);
 	}
 
-	/* Check RTC module status, Enable if it is off */
-	ret = twl_rtc_read_u8(&rd_reg, REG_RTC_CTRL_REG);
+	dev_info(&pdev->dev, "Enabling TWL-RTC\n");
+	ret = twl_rtc_write_u8(BIT_RTC_CTRL_REG_STOP_RTC_M, REG_RTC_CTRL_REG);
 	if (ret < 0)
 		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 out1;
-	}
-
 	/* init cached IRQ enable bits */
 	ret = twl_rtc_read_u8(&rtc_irq_bits, REG_RTC_INTERRUPTS_REG);
 	if (ret < 0)
-- 
1.7.1.1

[PATCH 2/3] rtc: twl: Simplify RTC interrupt clearing

[Venu Byravarasu]

From: Venu Byravarasu <vbyravarasu@nvidia.com>

For clearing RTC interrupt, programming ALARM bit only is
sufficient, as all other bits are any way not affected by
writing 0 to them.

Hence removed unwanted OR operation.

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
---
 drivers/rtc/rtc-twl.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/rtc/rtc-twl.c b/drivers/rtc/rtc-twl.c
index 61ae1b7..1c85443 100644
--- a/drivers/rtc/rtc-twl.c
+++ b/drivers/rtc/rtc-twl.c
@@ -376,7 +376,7 @@ static irqreturn_t twl_rtc_interrupt(int irq, void *rtc)
 	else
 		events |= RTC_IRQF | RTC_UF;
 
-	res = twl_rtc_write_u8(rd_reg | BIT_RTC_STATUS_REG_ALARM_M,
+	res = twl_rtc_write_u8(BIT_RTC_STATUS_REG_ALARM_M,
 				   REG_RTC_STATUS_REG);
 	if (res)
 		goto out;
-- 
1.7.1.1

[PATCH 3/3] rtc: twl: Return correct RTC event from ISR

[Venu Byravarasu]

From: Venu Byravarasu <vbyravarasu@nvidia.com>

Following changes are made as part of this change:
1. As TWL RTC supports periodic interrupt, the correct event
should be RTC_PF instead of RTC_UF.
2. No need to initialize variable "events" to 0 & then OR it
with the event values. Hence fixing it.

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
---
 drivers/rtc/rtc-twl.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/rtc/rtc-twl.c b/drivers/rtc/rtc-twl.c
index 1c85443..a0236a0 100644
--- a/drivers/rtc/rtc-twl.c
+++ b/drivers/rtc/rtc-twl.c
@@ -357,7 +357,7 @@ out:
 
 static irqreturn_t twl_rtc_interrupt(int irq, void *rtc)
 {
-	unsigned long events = 0;
+	unsigned long events;
 	int ret = IRQ_NONE;
 	int res;
 	u8 rd_reg;
@@ -372,9 +372,9 @@ static irqreturn_t twl_rtc_interrupt(int irq, void *rtc)
 	 * by reading RTS_INTERRUPTS_REGISTER[IT_TIMER,IT_ALARM]
 	 */
 	if (rd_reg & BIT_RTC_STATUS_REG_ALARM_M)
-		events |= RTC_IRQF | RTC_AF;
+		events = RTC_IRQF | RTC_AF;
 	else
-		events |= RTC_IRQF | RTC_UF;
+		events = RTC_IRQF | RTC_PF;
 
 	res = twl_rtc_write_u8(BIT_RTC_STATUS_REG_ALARM_M,
 				   REG_RTC_STATUS_REG);
-- 
1.7.1.1