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

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

On 29/05/2024 00:56, Dmitry Baryshkov wrote:
> On Wed, May 29, 2024 at 12:51:04AM +0100, Bryan O'Donoghue wrote:
>> 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.
> 
> Because unlike other registers it is not clear what other use cases does
> 0xb3 support
> 
>>
>>> +	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;
> 
> ack
> 
>>
>> also is req[2] some kind of address ?
> 
> Unfortunately no idea. This is totally based on the AML code in DSDT. I
> have no documentation on the EC or its programming interface.
> 
>>
>>> +	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() ?
> 
> Argh, debugging code. I should drop it.
> 

Assuming you do all of that in v5

Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>