Messages in this thread | | | Date | Thu, 21 Jan 2021 10:41:26 +0100 | From | Michael Walle <> | Subject | Re: [PATCH] net: macb: ignore tx_clk if MII is used |
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Hi Claudiu,
Am 2021-01-21 10:19, schrieb Claudiu.Beznea@microchip.com: > On 20.01.2021 21:43, Michael Walle wrote: >> EXTERNAL EMAIL: Do not click links or open attachments unless you know >> the content is safe >> >> If the MII interface is used, the PHY is the clock master, thus don't >> set the clock rate. On Zynq-7000, this will prevent the following >> warning: >> macb e000b000.ethernet eth0: unable to generate target frequency: >> 25000000 Hz >> > > Since in this case the PHY provides the TX clock and it provides the > proper > rate based on link speed, the MACB driver should not handle the > bp->tx_clk > at all (MACB driver uses this clock only for setting the proper rate on > it > based on link speed). So, I believe the proper fix would be to not pass > the > tx_clk at all in device tree. This clock is optional for MACB driver.
Thanks for looking into this.
I had the same thought. But shouldn't the driver handle this case gracefully? I mean it does know that the clock isn't needed at all. Ususually that clock is defined in a device tree include. So you'd have to redefine that node in an actual board file which means duplicating the other clocks.
-michael
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