Change in coreboot[master]: mb/google/guybrush: Switch eSPI to 16 MHz

[Martin Roth (Code Review)]

Martin Roth has submitted this change. ( https://review.coreboot.org/c/coreboot/+/51953 )

Change subject: mb/google/guybrush: Switch eSPI to 16 MHz
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mb/google/guybrush: Switch eSPI to 16 MHz

It looks like we are having SI issues on eSPI at 33 MHz. Switching to 16
MHz makes everything a lot more stable.

BUG=b:183524609
TEST=Boot to OS and run `ectool version` 1000 times and see no problems.
Before with 33 MHz there was an error every few cycles.
declare -i i=0; while ectool version; do i+=1; echo "$i"; sleep .11; done; echo "Finished: $i"

Signed-off-by: Raul E Rangel 
Change-Id: I6ab515629703a157c1d1ac6adcf5cf379e80f8ee
Reviewed-on: https://review.coreboot.org/c/coreboot/+/51953
Tested-by: build bot (Jenkins) 
Reviewed-by: Felix Held 
Reviewed-by: Mathew King 
Reviewed-by: Rob Barnes 
---
M src/mainboard/google/guybrush/variants/baseboard/devicetree.cb
1 file changed, 1 insertion(+), 1 deletion(-)

Approvals:
  build bot (Jenkins): Verified
  Felix Held: Looks good to me, approved
  Mathew King: Looks good to me, approved
  Rob Barnes: Looks good to me, approved

diff --git a/src/mainboard/google/guybrush/variants/baseboard/devicetree.cb b/src/mainboard/google/guybrush/variants/baseboard/devicetree.cb
index 4d57b52..b90ea0b 100644
--- a/src/mainboard/google/guybrush/variants/baseboard/devicetree.cb
+++ b/src/mainboard/google/guybrush/variants/baseboard/devicetree.cb
@@ -27,7 +27,7 @@
    	},

.io_mode = ESPI_IO_MODE_QUAD,
-		.op_freq_mhz = ESPI_OP_FREQ_33_MHZ,
+		.op_freq_mhz = ESPI_OP_FREQ_16_MHZ,
    	.crc_check_enable = 1,
    	.dedicated_alert_pin = 1,
    	.periph_ch_en = 1,