[coreboot-gerrit] Change in ...coreboot[master]: board/kukui: Support ADC value for NC

[Julius Werner (Code Review)]

Julius Werner has submitted this change and it was merged. ( https://review.coreboot.org/c/coreboot/+/32353 )

Change subject: board/kukui: Support ADC value for NC
......................................................................

board/kukui: Support ADC value for NC

When the components like LCM ID are not installed (i.e., NC), ADC will
return some value with much larger variation from standard value (out of
the tolerance we set). To support that, we should check tolerance only
on non-NC voltages.

Also improve the error messages so we can see the ADC raw values
instead of simple assertion error (which makes debugging more difficult
since we have to build another firmware image just to print the values).

BUG=None
TEST=Booted on Kukui and got correct SKU ID for NC LCMID.
BRANCH=None

Change-Id: I8d00956e0e3b48ddbcaa505dd3ade24720c3b4ad
Signed-off-by: Hung-Te Lin 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32353
Reviewed-by: Julius Werner 
Reviewed-by: You-Cheng Syu 
Tested-by: build bot (Jenkins) 
---
M src/mainboard/google/kukui/boardid.c
1 file changed, 7 insertions(+), 1 deletion(-)

Approvals:
  build bot (Jenkins): Verified
  Julius Werner: Looks good to me, approved
  You-Cheng Syu: Looks good to me, but someone else must approve

diff --git a/src/mainboard/google/kukui/boardid.c b/src/mainboard/google/kukui/boardid.c
index b9f1ba2..71f051f 100644
--- a/src/mainboard/google/kukui/boardid.c
+++ b/src/mainboard/google/kukui/boardid.c
@@ -15,6 +15,7 @@

#include <assert.h>
 #include <boardid.h>
+#include <console/console.h>
 #include <soc/auxadc.h>
 #include <ec/google/chromeec/ec.h>
 #include <stddef.h>
@@ -82,8 +83,13 @@
    	if (value < (voltages[id] + voltages[id + 1]) / 2)
    		break;

+	/* The last level is NC and may be larger than standard tolerance. */
    const int tolerance = 10000; /* 10,000 uV */
-	assert(ABS(value - voltages[id]) < tolerance);
+	if (id < ADC_LEVELS - 1 && ABS(value - voltages[id]) > tolerance) {
+		printk(BIOS_ERR, "ADC channel %u value out of range: %d\n",
+		       channel, value);
+		assert(0);
+	}

return id;
 }