[2/5] platform: arm64: add Huawei Matebook E Go (sc8280xp) EC driver

There are 3 variants, Huawei released first 2 at the same time.
Huawei Matebook E Go LTE(sc8180x), codename should be gaokun2.
Huawei Matebook E Go(sc8280xp@3.0GHz), codename is gaokun3.
Huawei Matebook E Go 2023(sc8280xp@2.69GHz).

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 yet.

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

- 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 the driver for the EC, that creates devices for UCSI, wmi and power
supply devices.

Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
---
 drivers/platform/arm64/Kconfig                |  19 +
 drivers/platform/arm64/Makefile               |   2 +
 drivers/platform/arm64/huawei-gaokun-ec.c     | 598 ++++++++++++++++++
 drivers/platform/arm64/huawei-gaokun-wmi.c    | 283 +++++++++
 .../linux/platform_data/huawei-gaokun-ec.h    |  90 +++
 5 files changed, 992 insertions(+)
 create mode 100644 drivers/platform/arm64/huawei-gaokun-ec.c
 create mode 100644 drivers/platform/arm64/huawei-gaokun-wmi.c
 create mode 100644 include/linux/platform_data/huawei-gaokun-ec.h

On 27/12/2024 17:13, Pengyu Luo wrote:
> There are 3 variants, Huawei released first 2 at the same time.

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

> Huawei Matebook E Go LTE(sc8180x), codename should be gaokun2.
> Huawei Matebook E Go(sc8280xp@3.0GHz), codename is gaokun3.

Choose either "codename should be" or "codename is"

> Huawei Matebook E Go 2023(sc8280xp@2.69GHz).

Maybe say here "codename unknown"

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

"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 the driver for the EC, that creates devices for UCSI, wmi and power
> supply devices.

I'm a terrible man for the "," dropped all about the place but you're 
going too mad with the commans there ->

"Add a driver for the EC which creates devices for UCSI, WMI and power 
supply devices"

> 
> Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
> ---
>   drivers/platform/arm64/Kconfig                |  19 +
>   drivers/platform/arm64/Makefile               |   2 +
>   drivers/platform/arm64/huawei-gaokun-ec.c     | 598 ++++++++++++++++++
>   drivers/platform/arm64/huawei-gaokun-wmi.c    | 283 +++++++++
>   .../linux/platform_data/huawei-gaokun-ec.h    |  90 +++
>   5 files changed, 992 insertions(+)
>   create mode 100644 drivers/platform/arm64/huawei-gaokun-ec.c
>   create mode 100644 drivers/platform/arm64/huawei-gaokun-wmi.c
>   create mode 100644 include/linux/platform_data/huawei-gaokun-ec.h
> 
> diff --git a/drivers/platform/arm64/Kconfig b/drivers/platform/arm64/Kconfig
> index f88395ea3..eb7fbacf0 100644
> --- a/drivers/platform/arm64/Kconfig
> +++ b/drivers/platform/arm64/Kconfig
> @@ -33,6 +33,25 @@ config EC_ACER_ASPIRE1
>   	  laptop where this information is not properly exposed via the
>   	  standard ACPI devices.
>   
> +config EC_HUAWEI_GAOKUN
> +	tristate "Huawei Matebook E Go (sc8280xp) Embedded Controller driver"

Krzysztof already mentioned this but the "sc8280xp" is questionable, you 
should probably drop mention of qcom and sc8280xp from your compat and 
tristate here.

> +	depends on ARCH_QCOM || COMPILE_TEST
> +	depends on I2C
> +	depends on DRM
> +	depends on POWER_SUPPLY
> +	depends on INPUT
> +	help
> +	  Say Y here to enable the EC driver for Huawei Matebook E Go 2in1
> +	  tablet. The driver handles battery(information, charge control) and
> +	  USB Type-C DP HPD events as well as some misc functions like the lid
> +	  sensor and temperature sensors, etc.
> +
> +	  This driver provides battery and AC status support for the mentioned
> +	  laptop where this information is not properly exposed via the
> +	  standard ACPI devices.
> +
> +	  Say M or Y here to include this support.

OTOH the help text is where you could mention the sc8280xp class of 
laptops/tablets.

> +
>   config EC_LENOVO_YOGA_C630
>   	tristate "Lenovo Yoga C630 Embedded Controller driver"
>   	depends on ARCH_QCOM || COMPILE_TEST
> diff --git a/drivers/platform/arm64/Makefile b/drivers/platform/arm64/Makefile
> index b2ae9114f..ed32ad6c0 100644
> --- a/drivers/platform/arm64/Makefile
> +++ b/drivers/platform/arm64/Makefile
> @@ -6,4 +6,6 @@
>   #
>   
>   obj-$(CONFIG_EC_ACER_ASPIRE1)	+= acer-aspire1-ec.o
> +obj-$(CONFIG_EC_HUAWEI_GAOKUN)	+= huawei-gaokun-ec.o
> +obj-$(CONFIG_EC_HUAWEI_GAOKUN)	+= huawei-gaokun-wmi.o
>   obj-$(CONFIG_EC_LENOVO_YOGA_C630) += lenovo-yoga-c630.o
> diff --git a/drivers/platform/arm64/huawei-gaokun-ec.c b/drivers/platform/arm64/huawei-gaokun-ec.c
> new file mode 100644
> index 000000000..c1c657f7b
> --- /dev/null
> +++ b/drivers/platform/arm64/huawei-gaokun-ec.c
> @@ -0,0 +1,598 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * huawei-gaokun-ec - An EC driver for HUAWEI Matebook E Go (sc8280xp)
> + *
> + * reference: drivers/platform/arm64/acer-aspire1-ec.c
> + *            drivers/platform/arm64/lenovo-yoga-c630.c
> + *
> + * Copyright (C) 2024 Pengyu Luo <mitltlatltl@gmail.com>
> + */
> +
> +#include <linux/auxiliary_bus.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/i2c.h>
> +#include <linux/input.h>
> +#include <linux/notifier.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/version.h>
> +
> +#include <linux/platform_data/huawei-gaokun-ec.h>
> +
> +#define EC_EVENT		0x06
> +
> +/* Also can be found in ACPI specification 12.3 */
> +#define EC_READ			0x80
> +#define EC_WRITE		0x81

Is this odd indentation ?

> +#define EC_BURST		0x82
> +#define EC_QUERY		0x84
> +
> +
> +#define EC_EVENT_LID		0x81
> +
> +#define EC_LID_STATE		0x80
> +#define EC_LID_OPEN		BIT(1)
> +
> +#define UCSI_REG_SIZE		7
> +
> +/* for tx, command sequences are arranged as
> + * {master_cmd, slave_cmd, data_len, data_seq}
> + */
> +#define REQ_HDR_SIZE		3
> +#define INPUT_SIZE_OFFSET	2
> +#define INPUT_DATA_OFFSET	3
> +
> +/* for rx, data sequences are arranged as
> + * {status, data_len(unreliable), data_seq}
> + */
> +#define RESP_HDR_SIZE		2
> +#define DATA_OFFSET		2
> +
> +
> +struct gaokun_ec {
> +	struct i2c_client *client;
> +	struct mutex lock;
> +	struct blocking_notifier_head notifier_list;
> +	struct input_dev *idev;
> +	bool suspended;
> +};
> +
> +static int gaokun_ec_request(struct gaokun_ec *ec, const u8 *req,
> +			     size_t resp_len, u8 *resp)
> +{
> +	struct i2c_client *client = ec->client;
> +	struct i2c_msg msgs[2] = {
> +		{
> +			.addr = client->addr,
> +			.flags = client->flags,
> +			.len = req[INPUT_SIZE_OFFSET] + REQ_HDR_SIZE,
> +			.buf = req,
> +		}, {
> +			.addr = client->addr,
> +			.flags = client->flags | I2C_M_RD,
> +			.len = resp_len,
> +			.buf = resp,
> +		},
> +	};
> +
> +	mutex_lock(&ec->lock);
> +
> +	i2c_transfer(client->adapter, msgs, 2);
> +	usleep_range(2000, 2500);

What is this sleep about and why are you doing it inside of a critical 
section ?

> +
> +	mutex_unlock(&ec->lock);
> +
> +	return *resp;
> +}
> +
> +/* -------------------------------------------------------------------------- */
> +/* Common API */
> +
> +/**
> + * gaokun_ec_read - read from EC
> + * @ec: The gaokun_ec
> + * @req: The sequence to request
> + * @resp_len: The size to read
> + * @resp: Where the data are read to
> + *
> + * This function is used to read data after writing a magic sequence to EC.
> + * All EC operations dependent on this functions.

depend on this

> + *
> + * Huawei uses magic sequences everywhere to complete various functions, all
> + * these sequences are passed to ECCD(a ACPI method which is quiet similar
> + * to gaokun_ec_request), there is no good abstraction to generalize these
> + * sequences, so just wrap it for now. Almost all magic sequences are kept
> + * in this file.
> + */
> +int gaokun_ec_read(struct gaokun_ec *ec, const u8 *req,
> +		   size_t resp_len, u8 *resp)
> +{
> +	return gaokun_ec_request(ec, req, resp_len, resp);
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_read);
> +
> +/**
> + * gaokun_ec_write - write to EC
> + * @ec: The gaokun_ec
> + * @req: The sequence to request
> + *
> + * This function has no big difference from gaokun_ec_read. When caller care
> + * only write status and no actual data are returnd, then use it.
> + */
> +int gaokun_ec_write(struct gaokun_ec *ec, u8 *req)
> +{
> +	u8 resp[RESP_HDR_SIZE];
> +
> +	return gaokun_ec_request(ec, req, sizeof(resp), resp);
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_write);
> +
> +int gaokun_ec_read_byte(struct gaokun_ec *ec, u8 *req, u8 *byte)
> +{
> +	int ret;
> +	u8 resp[RESP_HDR_SIZE + sizeof(*byte)];
> +
> +	ret = gaokun_ec_read(ec, req, sizeof(resp), resp);
> +	*byte = resp[DATA_OFFSET];
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_read_byte);
> +
> +int gaokun_ec_register_notify(struct gaokun_ec *ec, struct notifier_block *nb)
> +{
> +	return blocking_notifier_chain_register(&ec->notifier_list, nb);
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_register_notify);
> +
> +void gaokun_ec_unregister_notify(struct gaokun_ec *ec, struct notifier_block *nb)
> +{
> +	blocking_notifier_chain_unregister(&ec->notifier_list, nb);
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_unregister_notify);
> +
> +/* -------------------------------------------------------------------------- */
> +/* API For PSY */
> +
> +int gaokun_ec_psy_multi_read(struct gaokun_ec *ec, u8 reg,
> +			     size_t resp_len, u8 *resp)
> +{
> +	int i, ret;
> +	u8 _resp[RESP_HDR_SIZE + 1];
> +	u8 req[REQ_HDR_SIZE + 1] = {0x02, EC_READ, 1, };

Instead of constructing your packet inline like this, suggest a 
dedicated function to construct a request packet.

For example 1 @ INPUT_SIZE_OFFSET => the size of data a dedicated 
function will make the "stuffing" of the request frame more obvious to 
readers and make the construction of packets less error prone.

> +
> +	for (i = 0; i < resp_len; ++i) {
> +		req[INPUT_DATA_OFFSET] = reg++;
> +		ret = gaokun_ec_read(ec, req, sizeof(_resp), _resp);
> +		if (ret)
> +			return -EIO;
> +		resp[i] = _resp[DATA_OFFSET];
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_psy_multi_read);
> +
> +/* -------------------------------------------------------------------------- */
> +/* API For WMI */
> +
> +/* Battery charging threshold */
> +int gaokun_ec_wmi_get_threshold(struct gaokun_ec *ec, u8 *value, int ind)
> +{
> +	/* GBTT */
> +	return gaokun_ec_read_byte(ec, (u8 []){0x02, 0x69, 1, ind}, value);
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_wmi_get_threshold);
> +
> +int gaokun_ec_wmi_set_threshold(struct gaokun_ec *ec, u8 start, u8 end)
> +{
> +	/* SBTT */
> +	int ret;
> +	u8 req[REQ_HDR_SIZE + 2] = {0x02, 0x68, 2, 3, 0x5a};
> +
> +	ret = gaokun_ec_write(ec, req);
> +	if (ret)
> +		return -EIO;
> +
> +	if (start == 0 && end == 0)
> +		return -EINVAL;
> +
> +	if (start >= 0 && start <= end && end <= 100) {

if start >= 0

is redundant no ? start is a u8 it can _only_ be >= 0 ..


> +		req[INPUT_DATA_OFFSET] = 1;
> +		req[INPUT_DATA_OFFSET + 1] = start;
> +		ret = gaokun_ec_write(ec, req);
> +		if (ret)
> +			return -EIO;
> +
> +		req[INPUT_DATA_OFFSET] = 2;
> +		req[INPUT_DATA_OFFSET + 1] = end;

again a function to construct a packet gets you out of the business of 
inlining and "just knowing" which offset is which within any give 
function which indexes an array.

> +		ret = gaokun_ec_write(ec, req);
> +	} else {
> +		return -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_wmi_set_threshold);
> +
> +/* Smart charge param */
> +int gaokun_ec_wmi_get_smart_charge_param(struct gaokun_ec *ec, u8 *value)
> +{
> +	/* GBAC */
> +	return gaokun_ec_read_byte(ec, (u8 []){0x02, 0xE6, 0}, value);
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_wmi_get_smart_charge_param);
> +
> +int gaokun_ec_wmi_set_smart_charge_param(struct gaokun_ec *ec, u8 value)
> +{
> +	/* SBAC */
> +	if (value < 0 || value > 2)

value < 0 can never be true

> +		return -EINVAL;
> +
> +	return gaokun_ec_write(ec, (u8 []){0x02, 0xE5, 1, value});
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_wmi_set_smart_charge_param);
> +
> +/* Smart charge */
> +int gaokun_ec_wmi_get_smart_charge(struct gaokun_ec *ec,
> +				   u8 data[GAOKUN_SMART_CHARGE_DATA_SIZE])
> +{
> +	/* GBCM */
> +	u8 req[REQ_HDR_SIZE] = {0x02, 0xE4, 0};
> +	u8 resp[RESP_HDR_SIZE + 4];
> +	int ret;
> +
> +	ret = gaokun_ec_read(ec, req, sizeof(resp), resp);
> +	if (ret)
> +		return -EIO;
> +
> +	data[0] = resp[DATA_OFFSET];
> +	data[1] = resp[DATA_OFFSET + 1];
> +	data[2] = resp[DATA_OFFSET + 2];
> +	data[3] = resp[DATA_OFFSET + 3];
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_wmi_get_smart_charge);
> +
> +int gaokun_ec_wmi_set_smart_charge(struct gaokun_ec *ec,
> +				   u8 data[GAOKUN_SMART_CHARGE_DATA_SIZE])
> +{
> +	/* SBCM */
> +	u8 req[REQ_HDR_SIZE + GAOKUN_SMART_CHARGE_DATA_SIZE] = {0x02, 0XE3, 4,};
> +
> +	if (!(data[2] >= 0 && data[2] <= data[3] && data[3] <= 100))
> +		return -EINVAL;

Repeat of the clause above which was checking u8 >= 0 for the same 
values in the rest of the clause - including checking <= 100.

Certainly a candidate for functional decomposition, inline function or a 
define.

> +
> +	memcpy(req + INPUT_DATA_OFFSET, data, GAOKUN_SMART_CHARGE_DATA_SIZE);
> +
> +	return gaokun_ec_write(ec, req);
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_wmi_set_smart_charge);
> +
> +/* Fn lock */
> +int gaokun_ec_wmi_get_fn_lock(struct gaokun_ec *ec, u8 *on)
> +{
> +	/* GFRS */
> +	int ret;
> +	u8 val;
> +	u8 req[REQ_HDR_SIZE] = {0x02, 0x6B, 0};

Reverse Christmas tree

u8 req[REQ_HDR_SIZE];
int ret;
u8 val;

Not required but nice to look at.

> +
> +	ret = gaokun_ec_read_byte(ec, req, &val);
> +	if (val == 0x55)
> +		*on = 0;
> +	else if (val == 0x5A)
> +		*on = 1;
> +	else
> +		return -EIO;
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_wmi_get_fn_lock);
> +
> +int gaokun_ec_wmi_set_fn_lock(struct gaokun_ec *ec, u8 on)
> +{
> +	/* SFRS */
> +	u8 req[REQ_HDR_SIZE + 1] = {0x02, 0x6C, 1,};
> +
> +	if (on == 0)
> +		req[INPUT_DATA_OFFSET] = 0x55;
> +	else if (on == 1)
> +		req[INPUT_DATA_OFFSET] = 0x5A;
> +	else
> +		return -EINVAL;

Why not use a bool for on ?

> +
> +	return gaokun_ec_write(ec, req);
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_wmi_set_fn_lock);
> +
> +/* Thermal Zone */
> +/* Range from 0 to 0x2C, partial valid */
> +static const u8 temp_reg[] = {0x05, 0x07, 0x08, 0x0E, 0x0F, 0x12, 0x15, 0x1E,
> +			      0x1F, 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26,
> +			      0x27, 0x28, 0x29, 0x2A};
> +
> +int gaokun_ec_wmi_get_temp(struct gaokun_ec *ec, s16 temp[GAOKUN_TZ_REG_NUM])

int gaokun_ec_wmi_get_temp(struct gaokun_ec *ec, s16 *temp, size_t 
temp_reg_num)


> +{
> +	/* GTMP */
> +	u8 req[REQ_HDR_SIZE] = {0x02, 0x61, 1,};
> +	u8 resp[RESP_HDR_SIZE + sizeof(s16)];
> +	int ret, i = 0;
> +
> +	while (i < GAOKUN_TZ_REG_NUM) {
while (i < temp_reg_num)

> +		req[INPUT_DATA_OFFSET] = temp_reg[i];
> +		ret = gaokun_ec_read(ec, req, sizeof(resp), resp);
> +		if (ret)
> +			return -EIO;
> +		temp[i++] = *(s16 *)(resp + DATA_OFFSET);

What's the point of the casting here ?

memcpy(temp, resp, sizeof(s16));
temp++;

> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_wmi_get_temp);
> +
> +/* -------------------------------------------------------------------------- */
> +/* API For UCSI */
> +
> +int gaokun_ec_ucsi_read(struct gaokun_ec *ec,
> +			u8 resp[GAOKUN_UCSI_READ_SIZE])
> +{
> +	u8 req[REQ_HDR_SIZE] = {0x3, 0xD5, 0};
> +	u8 _resp[RESP_HDR_SIZE + GAOKUN_UCSI_READ_SIZE];
> +	int ret;
> +
> +	ret = gaokun_ec_read(ec, req, sizeof(_resp), _resp);
> +	if (ret)
> +		return ret;
> +
> +	memcpy(resp, _resp + DATA_OFFSET, GAOKUN_UCSI_READ_SIZE);
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_ucsi_read);
> +
> +int gaokun_ec_ucsi_write(struct gaokun_ec *ec,
> +			 const u8 req[GAOKUN_UCSI_WRITE_SIZE])
> +{
> +	u8 _req[REQ_HDR_SIZE + GAOKUN_UCSI_WRITE_SIZE];
> +
> +	_req[0] = 0x03;
> +	_req[1] = 0xD4;
> +	_req[INPUT_SIZE_OFFSET] = GAOKUN_UCSI_WRITE_SIZE;
> +	memcpy(_req + INPUT_DATA_OFFSET, req, GAOKUN_UCSI_WRITE_SIZE);
> +
> +	return gaokun_ec_write(ec, _req);
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_ucsi_write);
> +
> +int gaokun_ec_ucsi_get_reg(struct gaokun_ec *ec, u8 *ureg)
> +{
> +	u8 req[REQ_HDR_SIZE] = {0x03, 0xD3, 0};
> +	u8 _resp[RESP_HDR_SIZE + UCSI_REG_SIZE];
> +	int ret;
> +
> +	ret = gaokun_ec_read(ec, req, sizeof(_resp), _resp);
> +	if (ret)
> +		return ret;
> +
> +	memcpy(ureg, _resp + DATA_OFFSET, UCSI_REG_SIZE);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_ucsi_get_reg);
> +
> +int gaokun_ec_ucsi_pan_ack(struct gaokun_ec *ec, int port_id)
> +{
> +	u8 req[REQ_HDR_SIZE + 1] = {0x03, 0xD2, 1, 0};
> +
> +	if (port_id >= 0)
> +		req[INPUT_DATA_OFFSET] = 1 << port_id;
> +
> +	return gaokun_ec_write(ec, req);
> +}
> +EXPORT_SYMBOL_GPL(gaokun_ec_ucsi_pan_ack);
> +
> +/* -------------------------------------------------------------------------- */
> +/* Modern Standby */
> +
> +static int gaokun_ec_suspend(struct device *dev)
> +{
> +	struct gaokun_ec *ec = dev_get_drvdata(dev);
> +	u8 req[REQ_HDR_SIZE + 1] = {0x02, 0xB2, 1, 0xDB};
> +	int ret;
> +
> +	if (ec->suspended)
> +		return 0;
> +
> +	ret = gaokun_ec_write(ec, req);
> +
> +	if (ret)
> +		return ret;
> +
> +	ec->suspended = true;
> +
> +	return 0;
> +}
> +
> +static int gaokun_ec_resume(struct device *dev)
> +{
> +	struct gaokun_ec *ec = dev_get_drvdata(dev);
> +	u8 req[REQ_HDR_SIZE + 1] = {0x02, 0xB2, 1, 0xEB};
> +	int ret;
> +	int i;
> +
> +	if (!ec->suspended)
> +		return 0;
> +
> +	for (i = 0; i < 3; i++) {
> +		ret = gaokun_ec_write(ec, req);
> +		if (ret == 0)
> +			break;
> +
> +		msleep(100);
> +	};

Write three times with a 100 millisecond sleep ?

Deserves a comment at least.

> +
> +	ec->suspended = false;
> +
> +	return 0;
> +}
> +
> +static void gaokun_aux_release(struct device *dev)
> +{
> +	struct auxiliary_device *adev = to_auxiliary_dev(dev);
> +
> +	kfree(adev);
> +}
> +
> +static void gaokun_aux_remove(void *data)
> +{
> +	struct auxiliary_device *adev = data;
> +
> +	auxiliary_device_delete(adev);
> +	auxiliary_device_uninit(adev);
> +}
> +
> +static int gaokun_aux_init(struct device *parent, const char *name,
> +			   struct gaokun_ec *ec)
> +{
> +	struct auxiliary_device *adev;
> +	int ret;
> +
> +	adev = kzalloc(sizeof(*adev), GFP_KERNEL);
> +	if (!adev)
> +		return -ENOMEM;
> +
> +	adev->name = name;
> +	adev->id = 0;
> +	adev->dev.parent = parent;
> +	adev->dev.release = gaokun_aux_release;
> +	adev->dev.platform_data = ec;
> +	/* Allow aux devices to access parent's DT nodes directly */
> +	device_set_of_node_from_dev(&adev->dev, parent);
> +
> +	ret = auxiliary_device_init(adev);
> +	if (ret) {
> +		kfree(adev);
> +		return ret;
> +	}
> +
> +	ret = auxiliary_device_add(adev);
> +	if (ret) {
> +		auxiliary_device_uninit(adev);
> +		return ret;
> +	}
> +
> +	return devm_add_action_or_reset(parent, gaokun_aux_remove, adev);
> +}
> +
> +/* -------------------------------------------------------------------------- */
> +/* EC */
> +
> +static irqreturn_t gaokun_ec_irq_handler(int irq, void *data)
> +{
> +	struct gaokun_ec *ec = data;
> +	u8 req[REQ_HDR_SIZE] = {EC_EVENT, EC_QUERY, 0};
> +	u8 status, id;
> +	int ret;
> +
> +	ret = gaokun_ec_read_byte(ec, req, &id);
> +	if (ret)
> +		return IRQ_HANDLED;
> +
> +	switch (id) {
> +	case 0x0: /* No event */
> +		break;
> +
> +	case EC_EVENT_LID:
> +		gaokun_ec_psy_read_byte(ec, EC_LID_STATE, &status);
> +		status = EC_LID_OPEN & status;
> +		input_report_switch(ec->idev, SW_LID, !status);
> +		input_sync(ec->idev);
> +		break;
> +
> +	default:
> +		blocking_notifier_call_chain(&ec->notifier_list, id, ec);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int gaokun_ec_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct gaokun_ec *ec;
> +	int ret;
> +
> +	ec = devm_kzalloc(dev, sizeof(*ec), GFP_KERNEL);
> +	if (!ec)
> +		return -ENOMEM;
> +
> +	mutex_init(&ec->lock);
> +	ec->client = client;
> +	i2c_set_clientdata(client, ec);
> +	BLOCKING_INIT_NOTIFIER_HEAD(&ec->notifier_list);
> +
> +	/* Lid switch */
> +	ec->idev = devm_input_allocate_device(dev);
> +	if (!ec->idev)
> +		return -ENOMEM;
> +
> +	ec->idev->name = "LID";
> +	ec->idev->phys = "gaokun-ec/input0";
> +	input_set_capability(ec->idev, EV_SW, SW_LID);
> +
> +	ret = input_register_device(ec->idev);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to register input device\n");
> +
> +	ret = gaokun_aux_init(dev, "psy", ec);
> +	if (ret)
> +		return ret;
> +
> +	ret = gaokun_aux_init(dev, "wmi", ec);
> +	if (ret)
> +		return ret;
> +
> +	ret = gaokun_aux_init(dev, "ucsi", ec);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_request_threaded_irq(dev, client->irq, NULL,
> +					gaokun_ec_irq_handler, IRQF_ONESHOT,
> +					dev_name(dev), ec);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to request irq\n");
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id gaokun_ec_id[] = {
> +	{ "gaokun-ec", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, gaokun_ec_id);
> +
> +static const struct of_device_id gaokun_ec_of_match[] = {
> +	{ .compatible = "huawei,gaokun-ec", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, gaokun_ec_of_match);
> +
> +static const struct dev_pm_ops gaokun_ec_pm_ops = {
> +	NOIRQ_SYSTEM_SLEEP_PM_OPS(gaokun_ec_suspend, gaokun_ec_resume)
> +};
> +
> +static struct i2c_driver gaokun_ec_driver = {
> +	.driver = {
> +		.name = "gaokun-ec",
> +		.of_match_table = gaokun_ec_of_match,
> +		.pm = &gaokun_ec_pm_ops,
> +	},
> +	.probe = gaokun_ec_probe,
> +	.id_table = gaokun_ec_id,
> +};
> +module_i2c_driver(gaokun_ec_driver);
> +
> +MODULE_DESCRIPTION("HUAWEI Matebook E Go EC driver");
> +MODULE_AUTHOR("Pengyu Luo <mitltlatltl@gmail.com>");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/platform/arm64/huawei-gaokun-wmi.c b/drivers/platform/arm64/huawei-gaokun-wmi.c
> new file mode 100644
> index 000000000..793cb1659
> --- /dev/null
> +++ b/drivers/platform/arm64/huawei-gaokun-wmi.c
> @@ -0,0 +1,283 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * huawei-gaokun-wmi - A WMI driver for HUAWEI Matebook E Go (sc8280xp)
> + *
> + * reference: drivers/platform/x86/huawei-wmi.c
> + *
> + * Copyright (C) 2024 Pengyu Luo <mitltlatltl@gmail.com>
> + */
> +
> +#include <linux/auxiliary_bus.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/sysfs.h>
> +#include <linux/version.h>
> +
> +#include <linux/platform_data/huawei-gaokun-ec.h>
> +
> +struct gaokun_wmi {
> +	struct gaokun_ec *ec;
> +	struct device *dev;
> +	struct platform_device *wmi;
> +};
> +
> +/* -------------------------------------------------------------------------- */
> +/* Battery charging threshold */
> +
> +enum gaokun_wmi_threshold_ind {
> +	START	= 1,
> +	END	= 2,
> +};
> +
> +static ssize_t charge_control_thresholds_show(struct device *dev,
> +					      struct device_attribute *attr,
> +					      char *buf)
> +{
> +	int ret;
> +	u8 start, end;
> +	struct gaokun_wmi *ecwmi = dev_get_drvdata(dev);
> +
> +	ret = gaokun_ec_wmi_get_threshold(ecwmi->ec, &start, START)
> +		|| gaokun_ec_wmi_get_threshold(ecwmi->ec, &end, END);
> +	if (ret)
> +		return ret;

ick ouch.

Please call these two functions and evaluate their result codes 
individually.

> +
> +	return sysfs_emit(buf, "%d %d\n", start, end);
> +}
> +
> +static ssize_t charge_control_thresholds_store(struct device *dev,
> +					       struct device_attribute *attr,
> +					       const char *buf, size_t size)
> +{
> +	int ret;
> +	u8 start, end;
> +	struct gaokun_wmi *ecwmi = dev_get_drvdata(dev);
> +
> +	if (sscanf(buf, "%hhd %hhd", &start, &end) != 2)
> +		return -EINVAL;
> +
> +	ret = gaokun_ec_wmi_set_threshold(ecwmi->ec, start, end);
> +	if (ret)
> +		return ret;
> +
> +	return size;
> +}
> +
> +static DEVICE_ATTR_RW(charge_control_thresholds);
> +
> +/* -------------------------------------------------------------------------- */
> +/* Smart charge param */
> +
> +static ssize_t smart_charge_param_show(struct device *dev,
> +				       struct device_attribute *attr,
> +				       char *buf)
> +{
> +	int ret;
> +	u8 value;
> +	struct gaokun_wmi *ecwmi = dev_get_drvdata(dev);
> +
> +	ret = gaokun_ec_wmi_get_smart_charge_param(ecwmi->ec, &value);
> +	if (ret)
> +		return ret;
> +
> +	return sysfs_emit(buf, "%d\n", value);
> +}
> +
> +static ssize_t smart_charge_param_store(struct device *dev,
> +					struct device_attribute *attr,
> +					const char *buf, size_t size)
> +{
> +	int ret;
> +	u8 value;
> +	struct gaokun_wmi *ecwmi = dev_get_drvdata(dev);
> +
> +	if (kstrtou8(buf, 10, &value))
> +		return -EINVAL;
> +
> +	ret = gaokun_ec_wmi_set_smart_charge_param(ecwmi->ec, value);
> +	if (ret)
> +		return ret;
> +
> +	return size;
> +}
> +
> +static DEVICE_ATTR_RW(smart_charge_param);
> +
> +/* -------------------------------------------------------------------------- */
> +/* Smart charge */
> +
> +static ssize_t smart_charge_show(struct device *dev,
> +				 struct device_attribute *attr,
> +				 char *buf)
> +{
> +	int ret;
> +	u8 bf[GAOKUN_SMART_CHARGE_DATA_SIZE];
> +	struct gaokun_wmi *ecwmi = dev_get_drvdata(dev);
> +
> +	ret = gaokun_ec_wmi_get_smart_charge(ecwmi->ec, bf);
> +	if (ret)
> +		return ret;
> +
> +	return sysfs_emit(buf, "%d %d %d %d\n",
> +			  bf[0], bf[1], bf[2], bf[3]);
> +}
> +
> +static ssize_t smart_charge_store(struct device *dev,
> +				  struct device_attribute *attr,
> +				  const char *buf, size_t size)
> +{
> +	int ret;
> +	u8 bf[GAOKUN_SMART_CHARGE_DATA_SIZE];
> +	struct gaokun_wmi *ecwmi = dev_get_drvdata(dev);
> +
> +	if (sscanf(buf, "%hhd %hhd %hhd %hhd", bf, bf + 1, bf + 2, bf + 3) != 4)
> +		return -EINVAL;
> +
> +	ret = gaokun_ec_wmi_set_smart_charge(ecwmi->ec, bf);
> +	if (ret)
> +		return ret;
> +
> +	return size;
> +}
> +
> +static DEVICE_ATTR_RW(smart_charge);
> +
> +/* -------------------------------------------------------------------------- */
> +/* Fn lock */
> +
> +static ssize_t fn_lock_state_show(struct device *dev,
> +				  struct device_attribute *attr,
> +				  char *buf)
> +{
> +	int ret;
> +	u8 on;
> +	struct gaokun_wmi *ecwmi = dev_get_drvdata(dev);
> +
> +	ret = gaokun_ec_wmi_get_fn_lock(ecwmi->ec, &on);
> +	if (ret)
> +		return ret;
> +
> +	return sysfs_emit(buf, "%d\n", on);
> +}
> +
> +static ssize_t fn_lock_state_store(struct device *dev,
> +				   struct device_attribute *attr,
> +				   const char *buf, size_t size)
> +{
> +	int ret;
> +	u8 on;
> +	struct gaokun_wmi *ecwmi = dev_get_drvdata(dev);
> +
> +	if (kstrtou8(buf, 10, &on))
> +		return -EINVAL;
> +
> +	ret = gaokun_ec_wmi_set_fn_lock(ecwmi->ec, on);

I mentioned already you should pass on as a bool and then decide here in 
the input function if "on" as passed is a reasonable boolean state.

> +	if (ret)
> +		return ret;
> +
> +	return size;
> +}
> +
> +static DEVICE_ATTR_RW(fn_lock_state);
> +
> +/* -------------------------------------------------------------------------- */
> +/* Thermal Zone */
> +
> +static ssize_t temperature_show(struct device *dev,
> +				struct device_attribute *attr,
> +				char *buf)
> +{
> +
> +	int ret, len, i;
> +	char *ptr = buf;
> +	s16 value;
> +	s16 temp[GAOKUN_TZ_REG_NUM];
> +	struct gaokun_wmi *ecwmi = dev_get_drvdata(dev);
> +
> +	ret = gaokun_ec_wmi_get_temp(ecwmi->ec, temp);
> +	if (ret)
> +		return ret;
> +
> +	i = 0;
> +	len = 0;
> +	while (i < GAOKUN_TZ_REG_NUM) {
> +		value = temp[i++];
> +		if (value < 0) {
> +			len += sprintf(ptr + len, "-");

Have you ever seen a negative temperature value in running silicon ?
Looks suspicious to me.

> +			value = -value;
> +		}
> +		len += sprintf(ptr + len, "%d.%d ", value / 10, value % 10);
> +	}
> +	len += sprintf(ptr + len, "\n");
> +
> +	return len;
> +}
> +
> +static DEVICE_ATTR_RO(temperature);
> +
> +static struct attribute *gaokun_wmi_features_attrs[] = {
> +	&dev_attr_charge_control_thresholds.attr,
> +	&dev_attr_smart_charge_param.attr,
> +	&dev_attr_smart_charge.attr,
> +	&dev_attr_fn_lock_state.attr,
> +	&dev_attr_temperature.attr,
> +	NULL,
> +};
> +ATTRIBUTE_GROUPS(gaokun_wmi_features);
> +
> +static int gaokun_wmi_probe(struct auxiliary_device *adev,
> +			    const struct auxiliary_device_id *id)
> +{
> +	struct gaokun_ec *ec = adev->dev.platform_data;
> +	struct device *dev = &adev->dev;
> +	struct gaokun_wmi *ecwmi;
> +
> +	ecwmi = devm_kzalloc(&adev->dev, sizeof(*ecwmi), GFP_KERNEL);
> +	if (!ecwmi)
> +		return -ENOMEM;
> +
> +	ecwmi->ec = ec;
> +	ecwmi->dev = dev;
> +
> +	auxiliary_set_drvdata(adev, ecwmi);
> +
> +	/* make it under /sys/devices/platform, convenient for sysfs I/O,
> +	 * while adev is under
> +	 * /sys/devices/platform/soc@0/ac0000.geniqup/a9c000.i2c/i2c-15/15-0038/
> +	 */
> +	ecwmi->wmi = platform_device_register_simple("gaokun-wmi", -1, NULL, 0);
> +	if (IS_ERR(ecwmi->wmi))
> +		return dev_err_probe(dev, PTR_ERR(ecwmi->wmi),
> +				     "Failed to register wmi platform device\n");
> +
> +	platform_set_drvdata(ecwmi->wmi, ecwmi);
> +
> +	return device_add_groups(&ecwmi->wmi->dev, gaokun_wmi_features_groups);
> +}
> +
> +static void gaokun_wmi_remove(struct auxiliary_device *adev)
> +{
> +	struct gaokun_wmi *ecwmi = auxiliary_get_drvdata(adev);
> +	struct platform_device *wmi = ecwmi->wmi;
> +
> +	device_remove_groups(&wmi->dev, gaokun_wmi_features_groups);
> +	platform_device_unregister(ecwmi->wmi);
> +}
> +
> +static const struct auxiliary_device_id gaokun_wmi_id_table[] = {
> +	{ .name = GAOKUN_MOD_NAME "." GAOKUN_DEV_WMI, },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(auxiliary, gaokun_wmi_id_table);
> +
> +static struct auxiliary_driver gaokun_wmi_driver = {
> +	.name = GAOKUN_DEV_WMI,
> +	.id_table = gaokun_wmi_id_table,
> +	.probe = gaokun_wmi_probe,
> +	.remove = gaokun_wmi_remove,
> +};
> +
> +module_auxiliary_driver(gaokun_wmi_driver);
> +
> +MODULE_DESCRIPTION("HUAWEI Matebook E Go WMI driver");
> +MODULE_LICENSE("GPL");
> 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 000000000..a649e9ecf
> --- /dev/null
> +++ b/include/linux/platform_data/huawei-gaokun-ec.h
> @@ -0,0 +1,90 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/* Huawei Matebook E Go (sc8280xp) Embedded Controller
> + *
> + * Copyright (C) 2024 Pengyu Luo <mitltlatltl@gmail.com>
> + *
> + */
> +
> +#ifndef __HUAWEI_GAOKUN_EC_H__
> +#define __HUAWEI_GAOKUN_EC_H__
> +
> +#define GAOKUN_UCSI_CCI_SIZE	4
> +#define GAOKUN_UCSI_DATA_SIZE	16
> +#define GAOKUN_UCSI_READ_SIZE	(GAOKUN_UCSI_CCI_SIZE + GAOKUN_UCSI_DATA_SIZE)
> +#define GAOKUN_UCSI_WRITE_SIZE	0x18
> +
> +#define GAOKUN_TZ_REG_NUM	20
> +#define GAOKUN_SMART_CHARGE_DATA_SIZE	4 /* mode, delay, start, end */
> +
> +/* -------------------------------------------------------------------------- */
> +
> +struct gaokun_ec;
> +struct notifier_block;
> +
> +#define GAOKUN_MOD_NAME			"huawei_gaokun_ec"
> +#define GAOKUN_DEV_PSY			"psy"
> +#define GAOKUN_DEV_WMI			"wmi"
> +#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, u8 *req);
> +int gaokun_ec_read_byte(struct gaokun_ec *ec, 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, 1, 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, 2, (u8 *)word);
> +}
> +
> +/* -------------------------------------------------------------------------- */
> +/* API For WMI */
> +
> +int gaokun_ec_wmi_get_threshold(struct gaokun_ec *ec, u8 *value, int ind);
> +int gaokun_ec_wmi_set_threshold(struct gaokun_ec *ec, u8 start, u8 end);
> +
> +int gaokun_ec_wmi_get_smart_charge_param(struct gaokun_ec *ec, u8 *value);
> +int gaokun_ec_wmi_set_smart_charge_param(struct gaokun_ec *ec, u8 value);
> +
> +int gaokun_ec_wmi_get_smart_charge(struct gaokun_ec *ec,
> +				   u8 data[GAOKUN_SMART_CHARGE_DATA_SIZE]);
> +int gaokun_ec_wmi_set_smart_charge(struct gaokun_ec *ec,
> +				   u8 data[GAOKUN_SMART_CHARGE_DATA_SIZE]);
> +
> +int gaokun_ec_wmi_get_fn_lock(struct gaokun_ec *ec, u8 *on);
> +int gaokun_ec_wmi_set_fn_lock(struct gaokun_ec *ec, u8 on);
> +
> +int gaokun_ec_wmi_get_temp(struct gaokun_ec *ec, s16 temp[GAOKUN_TZ_REG_NUM]);
> +
> +/* -------------------------------------------------------------------------- */
> +/* 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, u8 *ureg);
> +int gaokun_ec_ucsi_pan_ack(struct gaokun_ec *ec, int port_id);
> +
> +
> +#endif /* __HUAWEI_GAOKUN_EC_H__ */