[openwrt/openwrt] Revert "ramips: increase spi-max-frequency for ipTIME mt7620 devices"

[LEDE Commits]

mans0n pushed a commit to openwrt/openwrt.git, branch openwrt-21.02:
https://git.openwrt.org/952de38ef4fbb466c8f31b7d55516ba23955975a

commit 952de38ef4fbb466c8f31b7d55516ba23955975a
Author: Sungbo Eo <mans0n at gorani.run>
AuthorDate: Sun Feb 20 00:19:31 2022 +0900

    Revert "ramips: increase spi-max-frequency for ipTIME mt7620 devices"
    
    This reverts commit 13a185bf8acb67da4a68873e560876c0e60b1a87.
    
    There was a report that one A1004ns device fails to detect its flash
    chip correctly:
    
    [    1.470297] spi-nor spi0.0: unrecognized JEDEC id bytes: e0 10 0c 40 10 08
    [    1.484110] spi-nor: probe of spi0.0 failed with error -2
    
    It also uses a different flash chip model:
    * in my hand: Winbond W25Q128FVSIG (SOIC-8)
    * reported: Macronix MX25L12845EMI-10G (SOP-16)
    
    Reducing spi-max-frequency solved the detection failure. Hence revert.
    
    Reported-by: Koasing <koasing at gmail.com>
    Tested-by: Koasing <koasing at gmail.com>
    Signed-off-by: Sungbo Eo <mans0n at gorani.run>
    (cherry picked from commit 9968a909c248169064446ed40e66d18986d93d11)
---
 target/linux/ramips/dts/mt7620a_iptime.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/linux/ramips/dts/mt7620a_iptime.dtsi b/target/linux/ramips/dts/mt7620a_iptime.dtsi
index c7c90ca722..5a6fdacb52 100644
--- a/target/linux/ramips/dts/mt7620a_iptime.dtsi
+++ b/target/linux/ramips/dts/mt7620a_iptime.dtsi
@@ -21,7 +21,7 @@
 	flash at 0 {
 		compatible = "jedec,spi-nor";
 		reg = <0>;
-		spi-max-frequency = <50000000>;
+		spi-max-frequency = <40000000>;
 
 		partitions {
 			compatible = "fixed-partitions";