[RFC PATCH] ARM: DRA: hwmod: RTC: Add reset function for RTC

[Lokesh Vutla]

RTC IP have kicker feature which prevents spurious writes to its registers.
In order to write into any of the RTC registers, KICK values has te be
written to KICK registers. Currently hwmod is updating the IDLEMODE in rtc
sysconfig register without writing into any kick register which is a noop.
When autoidle is allowed for rtc, interruts are not received until IDLEMODE
is set to SIDLE_SMART_WKUP.
Adding a reset function to unlock RTC registers so that IDLEMODE is
updated.

Signed-off-by: Lokesh Vutla <lokeshvutla at ti.com>
---
 arch/arm/mach-omap2/omap_hwmod.h          |  1 +
 arch/arm/mach-omap2/omap_hwmod_7xx_data.c |  1 +
 arch/arm/mach-omap2/omap_hwmod_reset.c    | 23 +++++++++++++++++++++++
 3 files changed, 25 insertions(+)

diff --git a/arch/arm/mach-omap2/omap_hwmod.h b/arch/arm/mach-omap2/omap_hwmod.h
index 512f809..3703f99 100644
--- a/arch/arm/mach-omap2/omap_hwmod.h
+++ b/arch/arm/mach-omap2/omap_hwmod.h
@@ -744,6 +744,7 @@ const char *omap_hwmod_get_main_clk(struct omap_hwmod *oh);
  */
 
 extern int omap_hwmod_aess_preprogram(struct omap_hwmod *oh);
+int omap_hwmod_rtc_unlock(struct omap_hwmod *oh);
 
 /*
  * Chip variant-specific hwmod init routines - XXX should be converted
diff --git a/arch/arm/mach-omap2/omap_hwmod_7xx_data.c b/arch/arm/mach-omap2/omap_hwmod_7xx_data.c
index 5684f11..90e1df4 100644
--- a/arch/arm/mach-omap2/omap_hwmod_7xx_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_7xx_data.c
@@ -1584,6 +1584,7 @@ static struct omap_hwmod_class_sysconfig dra7xx_rtcss_sysc = {
 static struct omap_hwmod_class dra7xx_rtcss_hwmod_class = {
 	.name	= "rtcss",
 	.sysc	= &dra7xx_rtcss_sysc,
+	.reset	= &omap_hwmod_rtc_unlock,
 };
 
 /* rtcss */
diff --git a/arch/arm/mach-omap2/omap_hwmod_reset.c b/arch/arm/mach-omap2/omap_hwmod_reset.c
index 65e186c..b825a28 100644
--- a/arch/arm/mach-omap2/omap_hwmod_reset.c
+++ b/arch/arm/mach-omap2/omap_hwmod_reset.c
@@ -30,6 +30,12 @@
 
 #include "omap_hwmod.h"
 
+#define RTC_KICK0_REG_OFFSET	0x6c
+#define RTC_KICK1_REG_OFFSET	0x70
+
+#define RTC_KICK0_VALUE		0x83E70B13
+#define RTC_KICK1_VALUE		0x95A4F1E0
+
 /**
  * omap_hwmod_aess_preprogram - enable AESS internal autogating
  * @oh: struct omap_hwmod *
@@ -51,3 +57,20 @@ int omap_hwmod_aess_preprogram(struct omap_hwmod *oh)
 
 	return 0;
 }
+
+/**
+ * omap_hwmod_rtc_unlock - Reset and unlock the Kicker mechanism.
+ * @oh: struct omap_hwmod *
+ *
+ * RTC IP have kicker feature.  This prevents spurious writes to its registers.
+ * In order to write into any of the RTC registers, KICK values has te be
+ * written in respective KICK registers. This is needed for hwmod to write into
+ * sysconfig register.
+ */
+int omap_hwmod_rtc_unlock(struct omap_hwmod *oh)
+{
+	omap_hwmod_write(RTC_KICK0_VALUE, oh, RTC_KICK0_REG_OFFSET);
+	omap_hwmod_write(RTC_KICK1_VALUE, oh, RTC_KICK1_REG_OFFSET);
+
+	return 0;
+}
-- 
1.9.1