[PATCH 07/12] rtc: omap: silence bogus power-up reset message at probe

Johan Hovold
2014-10-09T19:12:31Z

Some legacy RTC IP revisions has a power-up reset flag in the status
register that later revisions lack.

As this flag is always read back as set on later revisions (or is
overloaded with a different flag), make sure to only clear the flag and
print the info message on legacy platforms.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/rtc/rtc-omap.c | 23 +++++++++++++++++------
1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
index 1c58920b0c88..0ef016553a97 100644
--- a/drivers/rtc/rtc-omap.c
+++ b/drivers/rtc/rtc-omap.c
@@ -118,6 +118,12 @@
*/
#define OMAP_RTC_HAS_32KCLK_EN BIT(2)

+/*
+ * Some legacy RTC IP revisions has a power-up reset flag which later
+ * revisions lack.
+ */
+#define OMAP_RTC_HAS_POWER_UP_RESET BIT(3)
+
static void __iomem *rtc_base;

#define rtc_read(addr) readb(rtc_base + (addr))
@@ -347,6 +353,7 @@ static int omap_rtc_timer;
static struct platform_device_id omap_rtc_devtype[] = {
{
.name = DRIVER_NAME,
+ .driver_data = OMAP_RTC_HAS_POWER_UP_RESET,
},
[OMAP_RTC_DATA_AM3352_IDX] = {
.name = "am3352-rtc",
@@ -376,7 +383,7 @@ static int __init omap_rtc_probe(struct platform_device *pdev)
{
struct resource *res;
struct rtc_device *rtc;
- u8 reg, new_ctrl;
+ u8 reg, mask, new_ctrl;
const struct platform_device_id *id_entry;
const struct of_device_id *of_id;

@@ -429,12 +436,16 @@ static int __init omap_rtc_probe(struct platform_device *pdev)

/* clear old status */
reg = rtc_read(OMAP_RTC_STATUS_REG);
- if (reg & (u8) OMAP_RTC_STATUS_POWER_UP) {
- dev_info(&pdev->dev, "RTC power up reset detected\n");
- rtc_write(OMAP_RTC_STATUS_POWER_UP, OMAP_RTC_STATUS_REG);
+
+ mask = OMAP_RTC_STATUS_ALARM;
+ if (id_entry->driver_data & OMAP_RTC_HAS_POWER_UP_RESET) {
+ mask |= OMAP_RTC_STATUS_POWER_UP;
+ if (reg & OMAP_RTC_STATUS_POWER_UP)
+ dev_info(&pdev->dev, "RTC power up reset detected\n");
}
- if (reg & (u8) OMAP_RTC_STATUS_ALARM)
- rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
+
+ if (reg & mask)
+ rtc_write(reg & mask, OMAP_RTC_STATUS_REG);

/* handle periodic and alarm irqs */
if (devm_request_irq(&pdev->dev, omap_rtc_timer, rtc_irq, 0,
--
2.0.4