Re: [RFC 5/5] [powerpc] Implement a p1010rdb clock source.

[Marc Kleine-Budde <mkl@pengutronix.de>]

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On 08/08/2011 01:31 PM, Robin Holt wrote:
> OK.  Dug a bit more.  The p1010 built-in clocksource seems to be the
> periphereal clock frequency which is system bus frequency divided
> by 2.  The clock source can not be changed, but the clock divider can

On arm the clock source is selected by bit 13 of CTRL:

> This bit selects the clock source to the CAN protocol interface (CPI)
> to be either the peripheral clock (driven by the PLL) or the crystal
> oscillator clock. The selected clock is the one fed to the prescaler
> to generate the SCLK (SCLK). In order to guarantee reliable
> operation, this bit must only be changed while the module is in
> disable mode. See Section 24.4.8.4, “Protocol Timing,” for more
> information.

> 0 The CAN engine clock source is the oscillator clock (24.576 MHz)
> 1 The CAN engine clock source is the bus clock (66.5 MHz)

cheers, Marc

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