ec/starlabs/merlin: Add support for enabling fast charge

The Lite Mk IV's can enable fast charging, with support up to 100W
via USB-C PD 3.0.

The default for this is disabled, as it can reduce battery life
span. This patch adds the option to enable fast charging, by
writing 0x01 to 0x18 in the EC space.

Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Change-Id: Ie01eb59d3f41b242190973fd9c58b1494320c12a
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66298
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/ec/starlabs/merlin/Kconfig

@@ -50,6 +50,13 @@ config EC_STARLABS_FAN
 	help
 	  Select if the mainboard has a fan.
 
+config EC_STARLABS_FAST_CHARGE
+	bool
+	default n
+	depends on EC_STARLABS_NUVOTON
+	help
+	  Select if the mainboard supports fast charging.
+
 config EC_STARLABS_MAX_CHARGE
 	bool
 	default n

src/ec/starlabs/merlin/ec.h

@@ -71,6 +71,10 @@
 #define CHARGE_80		0xbb
 #define CHARGE_60		0xaa
 
+/* Fast Charge Setting */
+#define CHARGE_RATE_NORMAL	0x00
+#define CHARGE_RATE_FAST	0x01
+
 /* Fan Mode Setting */
 #define FAN_NORMAL		0x00
 #define FAN_AGGRESSIVE		0xbb

src/ec/starlabs/merlin/nuvoton.c

@@ -136,6 +136,27 @@ static void merlin_init(struct device *dev)
 						 max_charge,
 						 ARRAY_SIZE(max_charge)));
 
+	/*
+	 * Fast Charge
+	 *
+	 * Setting:	fast_charge
+	 *
+	 * Values:	Normal, Fast
+	 * Default:	Normal
+	 *
+	 */
+	const uint8_t fast_charge[] = {
+		CHARGE_RATE_NORMAL,
+		CHARGE_RATE_FAST
+	};
+
+	if (CONFIG(EC_STARLABS_FAST_CHARGE))
+		ec_write(ECRAM_FAST_CHARGE,
+			get_ec_value_from_option("fast_charge",
+						 0,
+						 fast_charge,
+						 ARRAY_SIZE(fast_charge)));
+
 	/*
 	 * Fan Mode
 	 *

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

@@ -22,5 +22,6 @@
 #define ECRAM_FN_CTRL_REVERSE	0x2d
 #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)
 
 #endif

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

@@ -1,5 +1,8 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <assert.h>
+#include <stdint.h>
+
 /*
  * EC communication interface for ITE Embedded Controller
  */
@@ -19,5 +22,6 @@
 #define ECRAM_FN_CTRL_REVERSE	0x22
 #define ECRAM_MAX_CHARGE	0x23
 #define ECRAM_FAN_MODE		0x24
+#define ECRAM_FAST_CHARGE	dead_code_t(uint8_t)
 
 #endif

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

@@ -1,5 +1,8 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <assert.h>
+#include <stdint.h>
+
 /*
  * EC communication interface for ITE Embedded Controller
  */
@@ -19,5 +22,6 @@
 #define ECRAM_KBL_STATE		0x18
 #define ECRAM_KBL_BRIGHTNESS	0x19
 #define ECRAM_FN_LOCK_STATE	0x2c
+#define ECRAM_FAST_CHARGE	dead_code_t(uint8_t)
 
 #endif

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

@@ -22,5 +22,6 @@
 #define ECRAM_FN_CTRL_REVERSE	0x2d
 #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)
 
 #endif

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

@@ -22,5 +22,6 @@
 #define ECRAM_FN_CTRL_REVERSE	0x13
 #define ECRAM_MAX_CHARGE	dead_code_t(uint8_t)
 #define ECRAM_FAN_MODE		dead_code_t(uint8_t)
+#define ECRAM_FAST_CHARGE       0x18
 
 #endif

src/ec/starlabs/merlin/variants/glkr/emem.asl

@@ -26,6 +26,7 @@ Field (ECF2, ByteAcc, Lock, Preserve)
 	FLKE, 8,	// Function Lock State
 	KLSE, 8,	// Keyboard Backlight State
 	KLBE, 8,	// Keyboard Backlight Brightness
+	FSCH, 8,	// Fast Charge
 
 	Offset(0x20),
 	RCMD, 8,	// Send EC command

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

@@ -22,5 +22,6 @@
 #define ECRAM_FAN_MODE		0x42
 #define ECRAM_FN_CTRL_REVERSE	0x43
 #define ECRAM_MAX_CHARGE	dead_code_t(uint8_t)
+#define ECRAM_FAST_CHARGE	dead_code_t(uint8_t)
 
 #endif

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

@@ -19,5 +19,6 @@
 #define ECRAM_KBL_TIMEOUT	0x35
 #define ECRAM_FAN_MODE		0x50
 #define ECRAM_MAX_CHARGE	0x51
+#define ECRAM_FAST_CHARGE       0x52
 
 #endif

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

@@ -1,5 +1,8 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <assert.h>
+#include <stdint.h>
+
 /*
  * EC communication interface for ITE Embedded Controller
  */
@@ -19,5 +22,6 @@
 #define ECRAM_FN_CTRL_REVERSE	0x17
 #define ECRAM_MAX_CHARGE	0x1a
 #define ECRAM_FAN_MODE		0x1b
+#define ECRAM_FAST_CHARGE	dead_code_t(uint8_t)
 
 #endif