Rather than simply setting force-idle mode on boot, do a reset of the
OTG module. This really ensures that any bootloader/bootstrap code
that leaves it active will not prevent future retention. After reset,
OTG module will be in force-idle, force-standby mode.
In addition, ensure that the iclk is enabled before attempting a write
to the module SYSCONFIG register.
Problem reported by Mike Chan <mikechan@xxxxxxxxxx>
Tested-by: Mike Chan <mikechan@xxxxxxxxxx>
Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
---
If no comments/issues, this will be applied to PM branch and
backported to pm-2.6.29.
arch/arm/mach-omap2/usb-musb.c | 21 ++++++++++++++++++---
1 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/arch/arm/mach-omap2/usb-musb.c b/arch/arm/mach-omap2/usb-musb.c
index d85296d..85731b8 100644
--- a/arch/arm/mach-omap2/usb-musb.c
+++ b/arch/arm/mach-omap2/usb-musb.c
@@ -32,12 +32,27 @@
#include <mach/usb.h>
#define OTG_SYSCONFIG (OMAP34XX_HSUSB_OTG_BASE + 0x404)
+#define OTG_SYSC_SOFTRESET BIT(1)
static void __init usb_musb_pm_init(void)
{
- /* Ensure force-idle mode for OTG controller */
- if (cpu_is_omap34xx())
- omap_writel(0, OTG_SYSCONFIG);
+ struct clk *iclk;
+
+ if (!cpu_is_omap34xx())
+ return;
+
+ iclk = clk_get(NULL, "hsotgusb_ick");
+ if (WARN_ON(!iclk))
+ return;
+
+ clk_enable(iclk);
+
+ /* Reset OTG controller. After reset, it will be in
+ * force-idle, force-standby mode. */
+ omap_writel(OTG_SYSC_SOFTRESET, OTG_SYSCONFIG);
+
+ clk_disable(iclk);
+ clk_put(iclk);
}
#ifdef CONFIG_USB_MUSB_SOC
--
1.6.3.2
--
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