Re: [PATCH v4 2/6] platform: arm64: add Lenovo Yoga C630 WOS EC driver

[Bryan O'Donoghue <bryan.odonoghue@linaro.org>]

On 28/05/2024 21:44, Dmitry Baryshkov wrote:
> Lenovo Yoga C630 WOS is a laptop using Snapdragon 850 SoC. Like many
> laptops it uses embedded controller (EC) to perform various platform

an embedded controller

> operations, including, but not limited, to Type-C port control or power
> supply handlng.
> 
> Add the driver for the EC, that creates devices for UCSI and power
> supply devices.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
>   drivers/platform/arm64/Kconfig                 |  14 ++
>   drivers/platform/arm64/Makefile                |   1 +
>   drivers/platform/arm64/lenovo-yoga-c630.c      | 279 +++++++++++++++++++++++++
>   include/linux/platform_data/lenovo-yoga-c630.h |  42 ++++
>   4 files changed, 336 insertions(+)
> 
> diff --git a/drivers/platform/arm64/Kconfig b/drivers/platform/arm64/Kconfig
> index 8fdca0f8e909..8c103b3150d1 100644
> --- a/drivers/platform/arm64/Kconfig
> +++ b/drivers/platform/arm64/Kconfig
> @@ -32,4 +32,18 @@ config EC_ACER_ASPIRE1
>   	  laptop where this information is not properly exposed via the
>   	  standard ACPI devices.
>   
> +config EC_LENOVO_YOGA_C630
> +	tristate "Lenovo Yoga C630 Embedded Controller driver"
> +	depends on I2C
> +	help
> +	  Driver for the Embedded Controller in the Qualcomm Snapdragon-based
> +	  Lenovo Yoga C630, which provides battery and power adapter
> +	  information.
> +
> +	  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.
> +
>   endif # ARM64_PLATFORM_DEVICES
> diff --git a/drivers/platform/arm64/Makefile b/drivers/platform/arm64/Makefile
> index 4fcc9855579b..b2ae9114fdd8 100644
> --- a/drivers/platform/arm64/Makefile
> +++ b/drivers/platform/arm64/Makefile
> @@ -6,3 +6,4 @@
>   #
>   
>   obj-$(CONFIG_EC_ACER_ASPIRE1)	+= acer-aspire1-ec.o
> +obj-$(CONFIG_EC_LENOVO_YOGA_C630) += lenovo-yoga-c630.o
> diff --git a/drivers/platform/arm64/lenovo-yoga-c630.c b/drivers/platform/arm64/lenovo-yoga-c630.c
> new file mode 100644
> index 000000000000..3d1d5acde807
> --- /dev/null
> +++ b/drivers/platform/arm64/lenovo-yoga-c630.c
> @@ -0,0 +1,279 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2022-2024, Linaro Ltd
> + * Authors:
> + *    Bjorn Andersson
> + *    Dmitry Baryshkov
> + */
> +#include <linux/auxiliary_bus.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/notifier.h>
> +#include <linux/platform_data/lenovo-yoga-c630.h>
> +
> +#define LENOVO_EC_RESPONSE_REG		0x01
> +#define LENOVO_EC_REQUEST_REG		0x02
> +
> +#define LENOVO_EC_UCSI_WRITE		0x20
> +#define LENOVO_EC_UCSI_READ		0x21
> +
> +#define LENOVO_EC_READ_REG		0xb0
> +#define LENOVO_EC_REQUEST_NEXT_EVENT	0x84
> +
> +struct yoga_c630_ec {
> +	struct i2c_client *client;
> +	struct mutex lock;
> +	struct blocking_notifier_head notifier_list;
> +};
> +
> +static int yoga_c630_ec_request(struct yoga_c630_ec *ec, u8 *req, size_t req_len,
> +				u8 *resp, size_t resp_len)
> +{
> +	int ret;
> +
> +	WARN_ON(!mutex_is_locked(&ec->lock));
> +
> +	ret = i2c_smbus_write_i2c_block_data(ec->client, LENOVO_EC_REQUEST_REG,
> +					     req_len, req);
> +	if (ret < 0)
> +		return ret;
> +
> +	return i2c_smbus_read_i2c_block_data(ec->client, LENOVO_EC_RESPONSE_REG,
> +					     resp_len, resp);
> +}
> +
> +int yoga_c630_ec_read8(struct yoga_c630_ec *ec, u8 addr)
> +{
> +	u8 req[2] = { LENOVO_EC_READ_REG, };
> +	int ret;
> +	u8 val;
> +
> +	mutex_lock(&ec->lock);
> +	req[1] = addr;
> +	ret = yoga_c630_ec_request(ec, req, sizeof(req), &val, 1);
> +	mutex_unlock(&ec->lock);
> +
> +	return ret < 0 ? ret : val;
> +}
> +EXPORT_SYMBOL_GPL(yoga_c630_ec_read8);
> +
> +int yoga_c630_ec_read16(struct yoga_c630_ec *ec, u8 addr)
> +{
> +	u8 req[2] = { LENOVO_EC_READ_REG, };
> +	int ret;
> +	u8 msb;
> +	u8 lsb;
> +
> +	mutex_lock(&ec->lock);
> +
> +	req[1] = addr;
> +	ret = yoga_c630_ec_request(ec, req, sizeof(req), &lsb, 1);
> +	if (ret < 0)
> +		goto out;
> +
> +	req[1] = addr + 1;
> +	ret = yoga_c630_ec_request(ec, req, sizeof(req), &msb, 1);
> +
> +out:
> +	mutex_unlock(&ec->lock);
> +
> +	return ret < 0 ? ret : msb << 8 | lsb;
> +}
> +EXPORT_SYMBOL_GPL(yoga_c630_ec_read16);
> +
> +u16 yoga_c630_ec_ucsi_get_version(struct yoga_c630_ec *ec)
> +{
> +	u8 req[3] = { 0xb3, 0xf2, 0x20};

You have a define above for the read_reg and write_reg commands, could 
you not define 0xb3 as LENOVO_EC_GET_VERSION ?

All of the other commands here seem to have a named define.

> +	int ret;
> +	u8 msb;
> +	u8 lsb;
> +
> +	mutex_lock(&ec->lock);
> +	ret = yoga_c630_ec_request(ec, req, sizeof(req), &lsb, 1);
> +	if (ret < 0)
> +		goto out;
> +
> +	req[2]++;

why not set reg[2] = 0x21;

also is req[2] some kind of address ?

> +	ret = yoga_c630_ec_request(ec, req, sizeof(req), &msb, 1);
> +
> +out:
> +	mutex_unlock(&ec->lock);
> +
> +	return ret < 0 ? ret : msb << 8 | lsb;
> +}
> +EXPORT_SYMBOL_GPL(yoga_c630_ec_ucsi_get_version);
> +
> +int yoga_c630_ec_ucsi_write(struct yoga_c630_ec *ec,
> +			    const u8 req[YOGA_C630_UCSI_WRITE_SIZE])
> +{
> +	int ret;
> +
> +	mutex_lock(&ec->lock);
> +	ret = i2c_smbus_write_i2c_block_data(ec->client, LENOVO_EC_UCSI_WRITE,
> +					     YOGA_C630_UCSI_WRITE_SIZE, req);
> +	mutex_unlock(&ec->lock);
> +
> +	return ret < 0 ? ret : 0;
> +}
> +EXPORT_SYMBOL_GPL(yoga_c630_ec_ucsi_write);
> +
> +int yoga_c630_ec_ucsi_read(struct yoga_c630_ec *ec,
> +			   u8 resp[YOGA_C630_UCSI_READ_SIZE])
> +{
> +	int ret;
> +
> +	mutex_lock(&ec->lock);
> +	ret = i2c_smbus_read_i2c_block_data(ec->client, LENOVO_EC_UCSI_READ,
> +					    YOGA_C630_UCSI_READ_SIZE, resp);
> +	mutex_unlock(&ec->lock);
> +
> +	return ret < 0 ? ret : 0;
> +}
> +EXPORT_SYMBOL_GPL(yoga_c630_ec_ucsi_read);
> +
> +static irqreturn_t yoga_c630_ec_intr(int irq, void *data)
> +{
> +	u8 req[] = { LENOVO_EC_REQUEST_NEXT_EVENT };
> +	struct yoga_c630_ec *ec = data;
> +	u8 event;
> +	int ret;
> +
> +	mutex_lock(&ec->lock);
> +	ret = yoga_c630_ec_request(ec, req, sizeof(req), &event, 1);
> +	mutex_unlock(&ec->lock);
> +	if (ret < 0)
> +		return IRQ_HANDLED;
> +
> +	pr_info("NOTIFY %x\n", event);

why not dev_info() ?

---
bod