Niilo Minkkinen <[email protected]> writes: > On Wed, 2009-06-24 at 02:27 +0200, ext Kevin Hilman wrote: >> 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 <[email protected]> >> >> Tested-by: Mike Chan <[email protected]> >> Signed-off-by: Kevin Hilman <[email protected]> >> --- >> 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); > > Do you think, this is safe to do w/o waiting reset to be finished > like : ? > > + omap_writel( SOFTRST, OTG_SYSCONFIG ); /* acquire RESET */ > + start = jiffies; > + timeout = start + msecs_to_jiffies(10); /* max 10 ms */ > + while (!time_after(jiffies, timeout)) /* wait until RESET OK */ > + if ( omap_readl(OTG_SYSSTATUS) & RESETDONE ) > + break;
I thought about waiting for reset, but I decided that it wasn't necessary to wait since I wasn't going to write any other values after. Why hold up the boot process when nothing else will be writing? Kevin > SOFTRST & RESETDONE already defined in omap2430.h > >> + >> + clk_disable(iclk); >> + clk_put(iclk); >> } >> >> #ifdef CONFIG_USB_MUSB_SOC -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
