ec/starlabs/merlin: Add support for setting the charging speed

Allow boards that use the merlin EC to configure the charging speed,
as all versions of the merlin EC support this.

All coreboot does it write a value to the EC RAM and the EC will
handle the rest.

Change-Id: I46faa540530c5bd7f5473021561380213158152e
Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/84633
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>

src/ec/starlabs/merlin/Kconfig

@@ -64,6 +64,12 @@ config EC_STARLABS_MAX_CHARGE
 	help
 	  Select if the mainboard supports limiting the maximum charge of the battery.
 
+config EC_STARLABS_CHARGING_SPEED
+	bool "Enable setting the charging speed"
+	depends on EC_STARLABS_MERLIN
+	help
+	  Select if the mainboard supports configuring the charging speed.
+
 config EC_STARLABS_MERLIN
 	bool "Use open-source Merlin EC Firmware"
 	default n

src/ec/starlabs/merlin/ec.h

@@ -98,6 +98,11 @@
 #define KBL_DISABLED		0x00
 #define KBL_ENABLED		0xdd
 
+/* Charging Speed */
+#define SPEED_1_0C		0x00
+#define SPEED_0_5C		0x01
+#define SPEED_0_2C		0x02
+
 uint16_t ec_get_version(void);
 
 #endif

src/ec/starlabs/merlin/ite.c

@@ -69,6 +69,7 @@ static void merlin_init(struct device *dev)
 	 * trackpad_state
 	 * kbl_brightness
 	 * kbl_state
+	 * charging_speed
 	 */
 
 	/*
@@ -240,6 +241,28 @@ static void merlin_init(struct device *dev)
 	 */
 
 	ec_write(ECRAM_KBL_STATE, KBL_ENABLED);
+
+	/*
+	 * Charging Speed
+	 *
+	 * Setting:	charging_speed
+	 *
+	 * Values:	1.0C, 0.5C, 0.2C
+	 * Default:	0.5C
+	 *
+	 */
+	const uint8_t charging_speed[] = {
+		SPEED_1_0C,
+		SPEED_0_5C,
+		SPEED_0_2C
+	};
+
+	if (CONFIG(EC_STARLABS_CHARGING_SPEED))
+		ec_write(ECRAM_CHARGING_SPEED,
+			get_ec_value_from_option("charging_speed",
+				SPEED_0_5C,
+				charging_speed,
+				ARRAY_SIZE(charging_speed)));
 }
 
 static struct device_operations ops = {

src/ec/starlabs/merlin/variants/apl/ecdefs.h

@@ -20,5 +20,6 @@
 #define ECRAM_MAX_CHARGE	dead_code_t(uint8_t)
 #define ECRAM_FAN_MODE		dead_code_t(uint8_t)
 #define ECRAM_FAST_CHARGE	dead_code_t(uint8_t)
+#define ECRAM_CHARGING_SPEED	dead_code_t(uint8_t)
 
 #endif

src/ec/starlabs/merlin/variants/cezanne/ecdefs.h

@@ -23,5 +23,6 @@
 #define ECRAM_KBL_BRIGHTNESS	0x36
 #define ECRAM_FN_LOCK_STATE	0x70
 #define ECRAM_FAST_CHARGE	dead_code_t(uint8_t)
+#define ECRAM_CHARGING_SPEED	dead_code_t(uint8_t)
 
 #endif

src/ec/starlabs/merlin/variants/glk/ecdefs.h

@@ -20,5 +20,6 @@
 #define ECRAM_MAX_CHARGE	dead_code_t(uint8_t)
 #define ECRAM_FAN_MODE		dead_code_t(uint8_t)
 #define ECRAM_FAST_CHARGE	dead_code_t(uint8_t)
+#define ECRAM_CHARGING_SPEED	dead_code_t(uint8_t)
 
 #endif

src/ec/starlabs/merlin/variants/glkr/ecdefs.h

@@ -23,5 +23,6 @@
 #define ECRAM_MAX_CHARGE	dead_code_t(uint8_t)
 #define ECRAM_FAN_MODE		dead_code_t(uint8_t)
 #define ECRAM_FAST_CHARGE       0x18
+#define ECRAM_CHARGING_SPEED	dead_code_t(uint8_t)
 
 #endif

src/ec/starlabs/merlin/variants/kbl/ecdefs.h

@@ -20,5 +20,6 @@
 #define ECRAM_FN_CTRL_REVERSE	0x43
 #define ECRAM_MAX_CHARGE	dead_code_t(uint8_t)
 #define ECRAM_FAST_CHARGE	dead_code_t(uint8_t)
+#define ECRAM_CHARGING_SPEED	dead_code_t(uint8_t)
 
 #endif

src/ec/starlabs/merlin/variants/merlin/ecdefs.h

@@ -20,5 +20,6 @@
 #define ECRAM_MAX_CHARGE	0x1a
 #define ECRAM_FAN_MODE		0x1b
 #define ECRAM_FAST_CHARGE	dead_code_t(uint8_t)
+#define ECRAM_CHARGING_SPEED	0x1d
 
 #endif