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SubjectRe: [PATCH] ARM: OMAP4: clock: Initialize USB DPLL
On 03/21/2013 03:48 PM, Roger Quadros wrote:
> If the bootloader doesn't configure USB DPLL (e.g. in u-boot,
> disable CONFIG_USB_EHCI_OMAP), then we get all sorts of problems
> like
> - division by zero errors at boot [1]
> - USB DPLL fails to enter locked state
> - USB EHCI Host is non functional
> - Device can't enter OFF mode
>
> Initializing the USB DPLL fixes all these issues.
>
> [1]
>
> [ 0.000000] clock: dpll_usb_ck failed transition to 'locked'
> [ 0.000000] Division by zero in kernel.
> [ 0.000000] [<c001b00c>] (unwind_backtrace+0x0/0xf0) from [<c02b2378>] (Ldiv0+0x8/0x10)
> [ 0.000000] [<c02b2378>] (Ldiv0+0x8/0x10) from [<c041cf3c>] (clk_divider_set_rate+0x10/0x124)
> [ 0.000000] [<c041cf3c>] (clk_divider_set_rate+0x10/0x124) from [<c041bfc4>] (clk_change_rate+0x3c/0xb4)
> [ 0.000000] [<c041bfc4>] (clk_change_rate+0x3c/0xb4) from [<c041c028>] (clk_change_rate+0xa0/0xb4)
>
> Signed-off-by: Roger Quadros <rogerq@ti.com>
> ---
> arch/arm/mach-omap2/cclock44xx_data.c | 19 +++++++++++++++++++
> 1 files changed, 19 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/cclock44xx_data.c b/arch/arm/mach-omap2/cclock44xx_data.c
> index bfc46c1..6127bb9 100644
> --- a/arch/arm/mach-omap2/cclock44xx_data.c
> +++ b/arch/arm/mach-omap2/cclock44xx_data.c
> @@ -53,6 +53,12 @@
> */
> #define OMAP4_DPLL_ABE_DEFFREQ 98304000
>
> +/*
> + * OMAP4450 TRM Rev X, section "3.6.3.9.5 DPLL_USB Preferred Settings"

4460 actually.

cheers,
-roger


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