[PATCHv5 3/6] ARM: OMAP4 PM: Add IO Daisychain support

[Paul Walmsley]

Hi

On Tue, 6 Mar 2012, Tero Kristo wrote:

> From: Rajendra Nayak <rnayak at ti.com>
> 
> IO daisychain is a mechanism that allows individual IO pads to generate
> wakeup events on their own based on a switch of an input signal level.
> This allows the hardware module behind the pad to be powered down, but
> still have device level capability to detect IO events, and once this
> happens the module can be powered back up to resume IO. See section
> 3.9.4 in OMAP4430 Public TRM for details.
> 
> Signed-off-by: Rajendra Nayak <rnayak at ti.com>
> Signed-off-by: Vishwanath BS <vishwanath.bs at ti.com>
> Signed-off-by: Tero Kristo <t-kristo at ti.com>

Here's an updated version of this patch.  Please let me know if you think 
we should remove the poll on the WUCLKOUT line to conform with the change 
that Tero made to the OMAP3 version.


- Paul

From: Rajendra Nayak <rnayak at ti.com>
Date: Fri, 2 Mar 2012 17:17:52 +0200
Subject: [PATCH 3/6] ARM: OMAP4: PRM: Add IO Daisychain support

IO daisychain is a mechanism that allows individual IO pads to generate
wakeup events on their own based on a switch of an input signal level.
This allows the hardware module behind the pad to be powered down, but
still have device level capability to detect IO events, and once this
happens the module can be powered back up to resume IO. See section
3.9.4 in OMAP4430 Public TRM for details.

Signed-off-by: Rajendra Nayak <rnayak at ti.com>
Signed-off-by: Vishwanath BS <vishwanath.bs at ti.com>
Signed-off-by: Tero Kristo <t-kristo at ti.com>
[paul at pwsan.com: removed MAX_IOPAD_LATCH_TIME declaration; renamed
 omap4_trigger_io_chain() to conform to other PRM function names;
 added kerneldoc]
Signed-off-by: Paul Walmsley <paul at pwsan.com>
---
 arch/arm/mach-omap2/prm44xx.c |   48 +++++++++++++++++++++++++++++++++++++++++
 arch/arm/mach-omap2/prm44xx.h |    2 +
 2 files changed, 50 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-omap2/prm44xx.c b/arch/arm/mach-omap2/prm44xx.c
index a1d6154..5868a12 100644
--- a/arch/arm/mach-omap2/prm44xx.c
+++ b/arch/arm/mach-omap2/prm44xx.c
@@ -231,6 +231,54 @@ void omap44xx_prm_restore_irqen(u32 *saved_mask)
 				 OMAP4_PRM_IRQENABLE_MPU_2_OFFSET);
 }
 
+/**
+ * omap44xx_prm_reconfigure_io_chain - clear latches and reconfigure I/O chain
+ *
+ * Clear any previously-latched I/O wakeup events and ensure that the
+ * I/O wakeup gates are aligned with the current mux settings.  Works
+ * by asserting WUCLKIN, waiting for WUCLKOUT to be asserted, and then
+ * deasserting WUCLKIN and waiting for WUCLKOUT to be deasserted.
+ * No return value. XXX Are the final two steps necessary?
+ */
+void omap44xx_prm_reconfigure_io_chain(void)
+{
+	int i = 0;
+
+	/* Enable GLOBAL_WUEN */
+	if (!(omap4_prm_read_inst_reg(OMAP4430_PRM_DEVICE_INST,
+		OMAP4_PRM_IO_PMCTRL_OFFSET) & OMAP4430_GLOBAL_WUEN_MASK))
+		omap4_prm_rmw_inst_reg_bits(OMAP4430_GLOBAL_WUEN_MASK,
+			OMAP4430_GLOBAL_WUEN_MASK, OMAP4430_PRM_DEVICE_INST,
+			OMAP4_PRM_IO_PMCTRL_OFFSET);
+
+	/* Trigger WUCLKIN enable */
+	omap4_prm_rmw_inst_reg_bits(OMAP4430_WUCLK_CTRL_MASK,
+			OMAP4430_WUCLK_CTRL_MASK, OMAP4430_PRM_DEVICE_INST,
+			OMAP4_PRM_IO_PMCTRL_OFFSET);
+	omap_test_timeout(
+		(((omap4_prm_read_inst_reg(OMAP4430_PRM_DEVICE_INST,
+			OMAP4_PRM_IO_PMCTRL_OFFSET) &
+			OMAP4430_WUCLK_STATUS_MASK) >>
+			OMAP4430_WUCLK_STATUS_SHIFT) == 1),
+		MAX_IOPAD_LATCH_TIME, i);
+	if (i == MAX_IOPAD_LATCH_TIME)
+		pr_warn("PRM: I/O chain clock line assertion timed out\n");
+
+	/* Trigger WUCLKIN disable */
+	omap4_prm_rmw_inst_reg_bits(OMAP4430_WUCLK_CTRL_MASK, 0x0,
+			OMAP4430_PRM_DEVICE_INST, OMAP4_PRM_IO_PMCTRL_OFFSET);
+	omap_test_timeout(
+		(((omap4_prm_read_inst_reg(OMAP4430_PRM_DEVICE_INST,
+			OMAP4_PRM_IO_PMCTRL_OFFSET) &
+			OMAP4430_WUCLK_STATUS_MASK) >>
+			OMAP4430_WUCLK_STATUS_SHIFT) == 0),
+		MAX_IOPAD_LATCH_TIME, i);
+	if (i == MAX_IOPAD_LATCH_TIME)
+		pr_warn("PRM: I/O chain clock line deassertion timed out\n");
+
+	return;
+}
+
 static int __init omap4xxx_prcm_init(void)
 {
 	if (cpu_is_omap44xx())
diff --git a/arch/arm/mach-omap2/prm44xx.h b/arch/arm/mach-omap2/prm44xx.h
index 7978092..ee72ae6 100644
--- a/arch/arm/mach-omap2/prm44xx.h
+++ b/arch/arm/mach-omap2/prm44xx.h
@@ -763,6 +763,8 @@ extern u32 omap4_prm_vcvp_read(u8 offset);
 extern void omap4_prm_vcvp_write(u32 val, u8 offset);
 extern u32 omap4_prm_vcvp_rmw(u32 mask, u32 bits, u8 offset);
 
+extern void omap44xx_prm_reconfigure_io_chain(void);
+
 /* PRM interrupt-related functions */
 extern void omap44xx_prm_read_pending_irqs(unsigned long *events);
 extern void omap44xx_prm_ocp_barrier(void);
-- 
1.7.9.1