Subject: Re: [PATCH net-next 5/6] net: stmmac: rk: use rk_encode_wm16() for clock selection

From: "Russell King (Oracle)" <[email-masked]>
Date: Wed, 4 Feb 2026 22:26:21 +0000

On Wed, Feb 04, 2026 at 11:03:51PM +0100, Heiko Stübner wrote:
> Am Mittwoch, 4. Februar 2026, 10:14:38 Mitteleuropäische Normalzeit schrieb Russell King (Oracle):
> > Use rk_encode_wm16() for RMII clock gating control, and also for the
> > io_clksel bit used to select the transmit clock between CRU-derived
> > and IO-derived clock sources.
> > 
> > Both of these were configured via the "set_clock_selection" method in
> > the SoC specific operations, but there is no requirement to change the
> > io_clksel except when enabling clocks.
> > 
> > It is also possible that we don't need to ungate the RMII clock if we
> > are operating in RGMII mode, but this commit makes no change there.
> > 
> > Split up the configuration of these as separate functions, and remove
> > the set_clock_selection() method. Since these clocking bits are in the
> > same register that we call the "speed" register, move the logic for
> > writing that register into rk_write_speed_grf_reg().
> > 
> > Signed-off-by: Russell King (Oracle) <[email-masked]>
> > ---
> >  .../net/ethernet/stmicro/stmmac/dwmac-rk.c    | 174 ++++++++----------
> >  1 file changed, 75 insertions(+), 99 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> > index 4099cbc5d0de..ed9adac70f0a 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> > @@ -27,8 +27,17 @@
> >  struct rk_priv_data;
> >  
> >  struct rk_clock_fields {
> > +	/* io_clksel_cru_mask - io_clksel bit in clock GRF register which,
> > +	 * when set, selects the tx clock from CRU.
> > +	 */
> > +	u16 io_clksel_cru_mask;
> > +	/* io_clksel_io_mask - io_clksel bit in clock GRF register which,
> > +	 * when set, selects the tx clock from IO.
> > +	 */
> 
> nit: comment stile does not seem to follow the kernel coding style
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/coding-style.rst#n622

netdev has historically had this style which is separate from the rest
of the kernel. The file already uses this comment style, so it is
entirely correct to keep to the style which already exists in this
file, rather than mixing styles and turning it into a mess.

> Reviewed-by: Heiko Stuebner <[email-masked]>
> Tested-by: Heiko Stuebner <[email-masked]> #px30,rk3328,rk3568,rk3588

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