RMII, GPR1[21] and devicetree?

woutervh — Mon, 06 Mar 2017 08:35:20 GMT

For our design, we use an external clock source for the RMII interface. So I have to configure GPR1[21] bit to zero to pick the external clock as a clock source. This works by changing mach-imx6q.c:

* If enet_ref from ANATOP/CCM is the PTP clock source, we need to
* set bit IOMUXC_GPR1[21]. Or the PTP clock must be from pad
* (external OSC), and we need to clear the bit.
*/
gpr = syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");
if (!IS_ERR(gpr))
regmap_update_bits(gpr, IOMUXC_GPR1,
IMX6Q_GPR1_ENET_CLK_SEL_MASK,
0 /*IMX6Q_GPR1_ENET_CLK_SEL_ANATOP*/);

But if possible, I prefer not to patch the kernel itself by something like that...
Is there another possibility to do this via devicetree?

I already found patch [PATCH] ARM: imx6q: support ptp and rmii clock from pad

However, that's already rather old, and already mostly in the kernel. (I wonder why not completely)

Anybody knows?

Re: RMII, GPR1[21] and devicetree?

igorpadykov — Tue, 07 Mar 2017 00:08:00 GMT

Hi Wouter

on nxp bsps described on below link seems there is no device tree GPR1[21] settings.

i.MX 6 / i.MX 7 Series Software and Development Tool|NXP

Description of fec driver (drivers/net/ethernet/freescale/fec_main.c)

can be found in Chapter 43 Fast Ethernet Controller (FEC) Driver attached Linux Manual.

Documentation/devicetree/bindings/..fsl-fec.txt

linux-imx.git - i.MX Linux Kernel

Best regards
igor
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

topic Re: RMII, GPR1[21] and devicetree? in i.MX Processors

RMII, GPR1[21] and devicetree?

Re: RMII, GPR1[21] and devicetree?