platform: arm64: add Huawei Matebook E Go EC driver

There are three variants of which Huawei released the first two
simultaneously.

Huawei Matebook E Go LTE(sc8180x), codename seems to be gaokun2.
Huawei Matebook E Go(sc8280xp@3.0GHz), codename must be gaokun3. (see [1])
Huawei Matebook E Go 2023(sc8280xp@2.69GHz), codename should be also gaokun3.

Adding support for the latter two variants for now, this driver should
also work for the sc8180x variant according to acpi table files, but I
don't have the device to test yet.

Different from other Qualcomm Snapdragon sc8280xp based machines, the
Huawei Matebook E Go uses an embedded controller while others use
a system called PMIC GLink. This embedded controller can be used to
perform a set of various functions, including, but not limited to:

- Battery and charger monitoring;
- Charge control and smart charge;
- Fn_lock settings;
- Tablet lid status;
- Temperature sensors;
- USB Type-C notifications (ports orientation,  DP alt mode HPD);
- USB Type-C PD (according to observation, up to 48w).

Add a driver for the EC which creates devices for UCSI and power supply
devices.

This driver is inspired by the following drivers:
        drivers/platform/arm64/acer-aspire1-ec.c
        drivers/platform/arm64/lenovo-yoga-c630.c
        drivers/platform/x86/huawei-wmi.c

Also thanks for reviewers' working. They have made this patch improve
a lot.

[1] https://bugzilla.kernel.org/show_bug.cgi?id=219645

Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20250214180656.28599-3-mitltlatltl@gmail.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

1 files changed, 79 insertions, 0 deletions

diff --git a/include/linux/platform_data/huawei-gaokun-ec.h b/include/linux/platform_data/huawei-gaokun-ec.h
new file mode 100644
index 000000000000..faa15d315128
--- /dev/null
+++ b/include/linux/platform_data/huawei-gaokun-ec.h
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Huawei Matebook E Go Embedded Controller
+ *
+ * Copyright (C) 2024-2025 Pengyu Luo <mitltlatltl@gmail.com>
+ */
+
+#ifndef __HUAWEI_GAOKUN_EC_H__
+#define __HUAWEI_GAOKUN_EC_H__
+
+#define GAOKUN_UCSI_CCI_SIZE	4
+#define GAOKUN_UCSI_MSGI_SIZE	16
+#define GAOKUN_UCSI_READ_SIZE	(GAOKUN_UCSI_CCI_SIZE + GAOKUN_UCSI_MSGI_SIZE)
+#define GAOKUN_UCSI_WRITE_SIZE	24 /* 8B CTRL, 16B MSGO */
+
+#define GAOKUN_UCSI_NO_PORT_UPDATE	(-1)
+
+#define GAOKUN_SMART_CHARGE_DATA_SIZE	4 /* mode, delay, start, end */
+
+/* -------------------------------------------------------------------------- */
+
+struct gaokun_ec;
+struct gaokun_ucsi_reg;
+struct notifier_block;
+
+#define GAOKUN_MOD_NAME			"huawei_gaokun_ec"
+#define GAOKUN_DEV_PSY			"psy"
+#define GAOKUN_DEV_UCSI			"ucsi"
+
+/* -------------------------------------------------------------------------- */
+/* Common API */
+
+int gaokun_ec_register_notify(struct gaokun_ec *ec,
+			      struct notifier_block *nb);
+void gaokun_ec_unregister_notify(struct gaokun_ec *ec,
+				 struct notifier_block *nb);
+
+int gaokun_ec_read(struct gaokun_ec *ec, const u8 *req,
+		   size_t resp_len, u8 *resp);
+int gaokun_ec_write(struct gaokun_ec *ec, const u8 *req);
+int gaokun_ec_read_byte(struct gaokun_ec *ec, const u8 *req, u8 *byte);
+
+/* -------------------------------------------------------------------------- */
+/* API for PSY */
+
+int gaokun_ec_psy_multi_read(struct gaokun_ec *ec, u8 reg,
+			     size_t resp_len, u8 *resp);
+
+static inline int gaokun_ec_psy_read_byte(struct gaokun_ec *ec,
+					  u8 reg, u8 *byte)
+{
+	return gaokun_ec_psy_multi_read(ec, reg, sizeof(*byte), byte);
+}
+
+static inline int gaokun_ec_psy_read_word(struct gaokun_ec *ec,
+					  u8 reg, u16 *word)
+{
+	return gaokun_ec_psy_multi_read(ec, reg, sizeof(*word), (u8 *)word);
+}
+
+int gaokun_ec_psy_get_smart_charge(struct gaokun_ec *ec,
+				   u8 resp[GAOKUN_SMART_CHARGE_DATA_SIZE]);
+int gaokun_ec_psy_set_smart_charge(struct gaokun_ec *ec,
+				   const u8 req[GAOKUN_SMART_CHARGE_DATA_SIZE]);
+
+int gaokun_ec_psy_get_smart_charge_enable(struct gaokun_ec *ec, bool *on);
+int gaokun_ec_psy_set_smart_charge_enable(struct gaokun_ec *ec, bool on);
+
+/* -------------------------------------------------------------------------- */
+/* API for UCSI */
+
+int gaokun_ec_ucsi_read(struct gaokun_ec *ec, u8 resp[GAOKUN_UCSI_READ_SIZE]);
+int gaokun_ec_ucsi_write(struct gaokun_ec *ec,
+			 const u8 req[GAOKUN_UCSI_WRITE_SIZE]);
+
+int gaokun_ec_ucsi_get_reg(struct gaokun_ec *ec, struct gaokun_ucsi_reg *ureg);
+int gaokun_ec_ucsi_pan_ack(struct gaokun_ec *ec, int port_id);
+
+#endif /* __HUAWEI_GAOKUN_EC_H__ */