[S] Change in coreboot[main]: ec/google/chromeec: Add option to control reading long battery strings

[Subrata Banik (Code Review)]

Subrata Banik has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/84352?usp=email )

Change subject: ec/google/chromeec: Add option to control reading long battery strings
......................................................................

ec/google/chromeec: Add option to control reading long battery strings

Older ChromeOS devices (pre-CR50) do not support reading long battery
strings. This commit adds a Kconfig option,
EC_GOOGLE_CHROMEEC_READ_BATTERY_LONG_STRING, to enable or disable this
feature.

This allows devices with TPM_GOOGLE (CR50/TI50) to read and display
long battery strings, while older devices like google/link, wolf, samus,
and chell will continue to display only the first 8 characters.

This change ensures compatibility with older devices while enabling
the display of complete battery information on newer platforms.

BUG=b:366338622
TEST=Verified on google/tivviks_ufs:
     * Long battery string is displayed when
       EC_GOOGLE_CHROMEEC_READ_BATTERY_LONG_STRING is enabled.
     * Short battery string is displayed when
       EC_GOOGLE_CHROMEEC_READ_BATTERY_LONG_STRING=n.

Change-Id: I7859809278b7e926bbe8beb1a0a9e12c7e6c220d
Signed-off-by: Subrata Banik 
---
M src/ec/google/chromeec/Kconfig
M src/ec/google/chromeec/acpi/battery.asl
2 files changed, 19 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/52/84352/1

diff --git a/src/ec/google/chromeec/Kconfig b/src/ec/google/chromeec/Kconfig
index 7a8777f..f0418ff 100644
--- a/src/ec/google/chromeec/Kconfig
+++ b/src/ec/google/chromeec/Kconfig
@@ -152,6 +152,21 @@
    help
      Put the fan in auto mode at boot.

+config EC_GOOGLE_CHROMEEC_READ_BATTERY_LONG_STRING
+	depends on TPM_GOOGLE
+	bool
+	default y
+	help
+	  The Chrome EC currently supports two ways to read battery strings on
+	  ACPI platforms:
+
+	  * Read up to 8 bytes from EC shared memory BMFG, BMOD, ...
+	  * Send a EC_CMD_BATTERY_GET_STATIC host command and read longer strings as a response.
+
+	  Select this config to support readout of longer battery strings.
+
+	  If unsure, say N.
+
 endif # EC_GOOGLE_CHROMEEC

source "src/ec/google/chromeec/*/Kconfig"
diff --git a/src/ec/google/chromeec/acpi/battery.asl b/src/ec/google/chromeec/acpi/battery.asl
index f5047cb..30fe0fc 100644
--- a/src/ec/google/chromeec/acpi/battery.asl
+++ b/src/ec/google/chromeec/acpi/battery.asl
@@ -54,9 +54,12 @@
    Return (Local0)
 }

+#if CONFIG(EC_GOOGLE_CHROMEEC_READ_BATTERY_LONG_STRING)
 // Cached flag for BSRF FIFO readout support from EC.
 Name(BRSS, 0xff)
-
+#else
+Name(BRSS, 0x0)
+#endif
 // Read extended battery strings from the selected battery.
 //   Arg0 = string index
 //