[PATCHv5 5/6] ARM: OMAP3PLUS PM: Add IO Daisychain support via hwmod mux

[Tero Kristo]

From: Vishwanath BS <vishwanath.bs at ti.com>

IO Daisychain feature has to be triggered whenever there is a change in
device's mux configuration (See section 3.9.4 in OMAP4 Public TRM vP).

Now devices can idle independent of the powerdomain, there can be a
window where device is idled and corresponding powerdomain can be
ON/INACTIVE state. In such situations, since both module wake up is
enabled at padlevel as well as io daisychain sequence is triggered,
there will be 2 PRCM interrupts (Module async wake up via swakeup and
IO Pad interrupt). But as PRCM Interrupt handler clears the Module
Padlevel WKST bit in the first interrupt, module specific interrupt
handler will not triggered for the second time

Also look at detailed explanation given by Rajendra at
http://www.spinics.net/lists/linux-serial/msg04480.html

Signed-off-by: Vishwanath BS <vishwanath.bs at ti.com>
Signed-off-by: Tero Kristo <t-kristo at ti.com>
---
 arch/arm/mach-omap2/omap_hwmod.c |    9 +++++++--
 arch/arm/mach-omap2/pm.c         |   21 +++++++++++++++++++++
 arch/arm/mach-omap2/pm.h         |    1 +
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 5192cab..56adbfb 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -152,6 +152,7 @@
 #include "prm44xx.h"
 #include "prminst44xx.h"
 #include "mux.h"
+#include "pm.h"
 
 /* Maximum microseconds to wait for OMAP module to softreset */
 #define MAX_MODULE_SOFTRESET_WAIT	10000
@@ -1535,8 +1536,10 @@ static int _enable(struct omap_hwmod *oh)
 	/* Mux pins for device runtime if populated */
 	if (oh->mux && (!oh->mux->enabled ||
 			((oh->_state == _HWMOD_STATE_IDLE) &&
-			 oh->mux->pads_dynamic)))
+			 oh->mux->pads_dynamic))) {
 		omap_hwmod_mux(oh->mux, _HWMOD_STATE_ENABLED);
+		omap_trigger_io_chain();
+	}
 
 	_add_initiator_dep(oh, mpu_oh);
 
@@ -1622,8 +1625,10 @@ static int _idle(struct omap_hwmod *oh)
 		clkdm_hwmod_disable(oh->clkdm, oh);
 
 	/* Mux pins for device idle if populated */
-	if (oh->mux && oh->mux->pads_dynamic)
+	if (oh->mux && oh->mux->pads_dynamic) {
 		omap_hwmod_mux(oh->mux, _HWMOD_STATE_IDLE);
+		omap_trigger_io_chain();
+	}
 
 	oh->_state = _HWMOD_STATE_IDLE;
 
diff --git a/arch/arm/mach-omap2/pm.c b/arch/arm/mach-omap2/pm.c
index 1881fe9..b7ac0f4 100644
--- a/arch/arm/mach-omap2/pm.c
+++ b/arch/arm/mach-omap2/pm.c
@@ -25,8 +25,12 @@
 #include "clockdomain.h"
 #include "pm.h"
 #include "twl-common.h"
+#include "prm2xxx_3xxx.h"
+#include "prm44xx.h"
 
 static struct omap_device_pm_latency *pm_lats;
+static void (*io_chain_trigger_func) (void);
+static DEFINE_SPINLOCK(io_chain_lock);
 
 static int _init_omap_device(char *name)
 {
@@ -64,6 +68,17 @@ static void omap2_init_processor_devices(void)
 	}
 }
 
+void omap_trigger_io_chain(void)
+{
+	unsigned long flags;
+
+	if (io_chain_trigger_func) {
+		spin_lock_irqsave(&io_chain_lock, flags);
+		io_chain_trigger_func();
+		spin_unlock_irqrestore(&io_chain_lock, flags);
+	}
+}
+
 /* Types of sleep_switch used in omap_set_pwrdm_state */
 #define FORCEWAKEUP_SWITCH	0
 #define LOWPOWERSTATE_SWITCH	1
@@ -221,6 +236,12 @@ static int __init omap2_common_pm_init(void)
 		omap2_init_processor_devices();
 	omap_pm_if_init();
 
+	if (cpu_is_omap34xx() && omap3_has_io_chain_ctrl())
+		io_chain_trigger_func = omap3_trigger_io_chain;
+
+	if (cpu_is_omap44xx())
+		io_chain_trigger_func = omap4_trigger_io_chain;
+
 	return 0;
 }
 postcore_initcall(omap2_common_pm_init);
diff --git a/arch/arm/mach-omap2/pm.h b/arch/arm/mach-omap2/pm.h
index b737b11..f9dac40 100644
--- a/arch/arm/mach-omap2/pm.h
+++ b/arch/arm/mach-omap2/pm.h
@@ -22,6 +22,7 @@ extern int omap3_can_sleep(void);
 extern int omap_set_pwrdm_state(struct powerdomain *pwrdm, u32 state);
 extern int omap3_idle_init(void);
 extern int omap4_idle_init(void);
+extern void omap_trigger_io_chain(void);
 
 #if defined(CONFIG_PM_OPP)
 extern int omap3_opp_init(void);
-- 
1.7.4.1