realtek: pcs: rtl838x: drop redundant reset writes

Sometimes redundancy is so obvious that one likely misses it. Trying to
bring all SerDes setup into a unified shape, one thinks twice if
something is really needed or not.

For the RTL838x case, the single writes for take/release reset were still
an outlier. Looking closer at them one can see that the same bits are all
covered already in deactivate/activate. So before, they have been put
into the desired state but those outlier writes mess with them again.

[0, 3, 0x7146/0x7106] just deals with the SOFT_RST bit that is already
covered by rtpcs_838x_sds_reset.

[0, 0, 0xc00] touches multiple bits, amongst the EN_RX/EN_TX bits
already covered in deactivate/active. Moreover, it potentially forces
other bits into a state causing broken functionality, e.g.
INV_HSI/INV_HSO which deal with the polarity. This has no effect right
no right now but might be a latent issue in the future.

Also move the reset call down to the end of the function, doing a
soft/RX reset after every configuration is done. This is likely what the
SDK also intended, and mirrors the 839x behavior.

Link: openwrt/openwrt#23746
Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>

Author: jonasjelonek

target/linux/realtek/files-6.18/drivers/net/pcs/pcs-rtl-otto.c

@@ -890,21 +890,15 @@ static int rtpcs_838x_setup_serdes(struct rtpcs_serdes *sds,
 
 	rtpcs_838x_sds_deactivate(sds);
 
-	/* take reset */
-	rtpcs_sds_write(sds, 0x0, 0x0, 0xc00);
-	rtpcs_sds_write(sds, 0x0, 0x3, 0x7146);
-
 	rtpcs_838x_sds_patch(sds, hw_mode);
-	rtpcs_838x_sds_reset(sds);
 
 	ret = rtpcs_838x_sds_set_mode(sds, hw_mode);
 	if (ret)
 		return ret;
 
 	sds->hw_mode = hw_mode;
 
-	/* release reset */
-	rtpcs_sds_write(sds, 0, 3, 0x7106);
+	rtpcs_838x_sds_reset(sds);
 
 	rtpcs_838x_sds_activate(sds);