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Message-Id: <1336672352-23191-1-git-send-email-marcus.folkesson@gmail.com>
Date: Thu, 10 May 2012 19:52:32 +0200
From: Marcus Folkesson <marcus.folkesson@...il.com>
To: Sekhar Nori <nsekhar@...com>, Kevin Hilman <khilman@...com>,
Russell King <linux@....linux.org.uk>,
Nicolas Pitre <nicolas.pitre@...aro.org>,
Catalin Marinas <catalin.marinas@....com>,
Marcus Folkesson <marcus.folkesson@...il.com>,
linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH] ARM: davinci: turn off DDR PHY when entering deep sleep
Deepsleep is the most power saving state on the davinci-platform.
The DDR PHY consumes about 25mW and should be turned off in this low
power state.
Signed-off-by: Marcus Folkesson <marcus.folkesson@...il.com>
---
arch/arm/mach-davinci/include/mach/memory.h | 2 ++
arch/arm/mach-davinci/sleep.S | 10 ++++++++++
2 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/arch/arm/mach-davinci/include/mach/memory.h b/arch/arm/mach-davinci/include/mach/memory.h
index 7873194..1b1b8ac 100644
--- a/arch/arm/mach-davinci/include/mach/memory.h
+++ b/arch/arm/mach-davinci/include/mach/memory.h
@@ -36,6 +36,8 @@
#define DDR2_MCLKSTOPEN_BIT BIT(30)
#define DDR2_LPMODEN_BIT BIT(31)
+#define DDR2_DRPHYC1R_OFFSET 0xe4
+#define DDR_PWRDNEN_BIT BIT(6)
/*
* Increase size of DMA-consistent memory region
*/
diff --git a/arch/arm/mach-davinci/sleep.S b/arch/arm/mach-davinci/sleep.S
index 5f1e045..30713b2 100644
--- a/arch/arm/mach-davinci/sleep.S
+++ b/arch/arm/mach-davinci/sleep.S
@@ -57,6 +57,11 @@ ENTRY(davinci_cpu_suspend)
ldmia r0, {r0-r4}
+ /* Turn PHY off */
+ ldr ip, [r0, #DDR2_DRPHYC1R_OFFSET]
+ orr ip, ip, #DDR_PWRDNEN_BIT
+ str ip, [r0, #DDR2_DRPHYC1R_OFFSET]
+
/*
* Switch DDR to self-refresh mode.
*/
@@ -171,6 +176,11 @@ ENTRY(davinci_cpu_suspend)
bic ip, ip, #DDR2_LPMODEN_BIT
str ip, [r0, #DDR2_SDRCR_OFFSET]
+ /* Turn PHY on */
+ ldr ip, [r0, #DDR2_DRPHYC1R_OFFSET]
+ bic ip, ip, #DDR_PWRDNEN_BIT
+ str ip, [r0, #DDR2_DRPHYC1R_OFFSET]
+
/* Restore registers and return */
ldmfd sp!, {r0-r12, pc}
--
1.7.5.4
--
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