Lenovo Yoga C630 WOS is a laptop using Snapdragon 850 SoC. Like many
laptops it uses an embedded controller (EC) to perform various platform
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.

Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
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      | 283 +++++++++++++++++++++++++
 include/linux/platform_data/lenovo-yoga-c630.h |  43 ++++
 4 files changed, 341 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..ffad8c443a13
--- /dev/null
+++ b/drivers/platform/arm64/lenovo-yoga-c630.c
@@ -0,0 +1,283 @@
+// 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/device.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/irqreturn.h>
+#include <linux/lockdep.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/notifier.h>
+#include <linux/slab.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;
+
+	lockdep_assert_held(&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;
+
+	scoped_guard(mutex, &ec->lock) {
+		req[1] = addr;
+		ret = yoga_c630_ec_request(ec, req, sizeof(req), &val, 1);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 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;
+
+	scoped_guard(mutex, &ec->lock) {
+		req[1] = addr;
+		ret = yoga_c630_ec_request(ec, req, sizeof(req), &lsb, 1);
+		if (ret < 0)
+			return ret;
+
+		req[1] = addr + 1;
+		ret = yoga_c630_ec_request(ec, req, sizeof(req), &msb, 1);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 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};
+	int ret;
+	u8 msb;
+	u8 lsb;
+
+	scoped_guard(mutex, &ec->lock) {
+		ret = yoga_c630_ec_request(ec, req, sizeof(req), &lsb, 1);
+		if (ret < 0)
+			return ret;
+
+		req[2] = 0x21;
+		ret = yoga_c630_ec_request(ec, req, sizeof(req), &msb, 1);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 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_thread_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;
+
+	blocking_notifier_call_chain(&ec->notifier_list, event, ec);
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * yoga_c630_ec_register_notify - Register a notifier callback for EC events.
+ * @ec: Yoga C630 EC
+ * @nb: Notifier block pointer to register
+ *
+ * Return: 0 on success or negative error code.
+ */
+int yoga_c630_ec_register_notify(struct yoga_c630_ec *ec, struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&ec->notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(yoga_c630_ec_register_notify);
+
+/**
+ * yoga_c630_ec_unregister_notify - Unregister notifier callback for EC events.
+ * @ec: Yoga C630 EC
+ * @nb: Notifier block pointer to unregister
+ *
+ * Unregister a notifier callback that was previously registered with
+ * yoga_c630_ec_register_notify().
+ */
+void yoga_c630_ec_unregister_notify(struct yoga_c630_ec *ec, struct notifier_block *nb)
+{
+	blocking_notifier_chain_unregister(&ec->notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(yoga_c630_ec_unregister_notify);
+
+static void yoga_c630_aux_release(struct device *dev)
+{
+	struct auxiliary_device *adev = to_auxiliary_dev(dev);
+
+	kfree(adev);
+}
+
+static void yoga_c630_aux_remove(void *data)
+{
+	struct auxiliary_device *adev = data;
+
+	auxiliary_device_delete(adev);
+	auxiliary_device_uninit(adev);
+}
+
+static int yoga_c630_aux_init(struct device *parent, const char *name,
+			      struct yoga_c630_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 = yoga_c630_aux_release;
+	adev->dev.platform_data = ec;
+
+	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, yoga_c630_aux_remove, adev);
+}
+
+static int yoga_c630_ec_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct yoga_c630_ec *ec;
+	int ret;
+
+	ec = devm_kzalloc(dev, sizeof(*ec), GFP_KERNEL);
+	if (!ec)
+		return -ENOMEM;
+
+	mutex_init(&ec->lock);
+	ec->client = client;
+	BLOCKING_INIT_NOTIFIER_HEAD(&ec->notifier_list);
+
+	ret = devm_request_threaded_irq(dev, client->irq,
+					NULL, yoga_c630_ec_thread_intr,
+					IRQF_ONESHOT, "yoga_c630_ec", ec);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "unable to request irq\n");
+
+	ret = yoga_c630_aux_init(dev, YOGA_C630_DEV_PSY, ec);
+	if (ret)
+		return ret;
+
+	return yoga_c630_aux_init(dev, YOGA_C630_DEV_UCSI, ec);
+}
+
+
+static const struct of_device_id yoga_c630_ec_of_match[] = {
+	{ .compatible = "lenovo,yoga-c630-ec" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, yoga_c630_ec_of_match);
+
+static const struct i2c_device_id yoga_c630_ec_i2c_id_table[] = {
+	{ "yoga-c630-ec", },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, yoga_c630_ec_i2c_id_table);
+
+static struct i2c_driver yoga_c630_ec_i2c_driver = {
+	.driver = {
+		.name = "yoga-c630-ec",
+		.of_match_table = yoga_c630_ec_of_match
+	},
+	.probe = yoga_c630_ec_probe,
+	.id_table = yoga_c630_ec_i2c_id_table,
+};
+module_i2c_driver(yoga_c630_ec_i2c_driver);
+
+MODULE_DESCRIPTION("Lenovo Yoga C630 Embedded Controller");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/platform_data/lenovo-yoga-c630.h b/include/linux/platform_data/lenovo-yoga-c630.h
new file mode 100644
index 000000000000..5571dd65ce08
--- /dev/null
+++ b/include/linux/platform_data/lenovo-yoga-c630.h
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2024, Linaro Ltd
+ * Authors:
+ *    Bjorn Andersson
+ *    Dmitry Baryshkov
+ */
+
+#ifndef _LENOVO_YOGA_C630_DATA_H
+#define _LENOVO_YOGA_C630_DATA_H
+
+struct yoga_c630_ec;
+struct notifier_block;
+
+#define YOGA_C630_MOD_NAME	"lenovo_yoga_c630"
+
+#define YOGA_C630_DEV_UCSI	"ucsi"
+#define YOGA_C630_DEV_PSY	"psy"
+
+int yoga_c630_ec_read8(struct yoga_c630_ec *ec, u8 addr);
+int yoga_c630_ec_read16(struct yoga_c630_ec *ec, u8 addr);
+
+int yoga_c630_ec_register_notify(struct yoga_c630_ec *ec, struct notifier_block *nb);
+void yoga_c630_ec_unregister_notify(struct yoga_c630_ec *ec, struct notifier_block *nb);
+
+#define YOGA_C630_UCSI_WRITE_SIZE	8
+#define YOGA_C630_UCSI_CCI_SIZE		4
+#define YOGA_C630_UCSI_DATA_SIZE	16
+#define YOGA_C630_UCSI_READ_SIZE	(YOGA_C630_UCSI_CCI_SIZE + YOGA_C630_UCSI_DATA_SIZE)
+u16 yoga_c630_ec_ucsi_get_version(struct yoga_c630_ec *ec);
+int yoga_c630_ec_ucsi_write(struct yoga_c630_ec *ec,
+			    const u8 req[YOGA_C630_UCSI_WRITE_SIZE]);
+int yoga_c630_ec_ucsi_read(struct yoga_c630_ec *ec,
+			   u8 resp[YOGA_C630_UCSI_READ_SIZE]);
+
+#define LENOVO_EC_EVENT_USB		0x20
+#define LENOVO_EC_EVENT_UCSI		0x21
+#define LENOVO_EC_EVENT_HPD		0x22
+#define LENOVO_EC_EVENT_BAT_STATUS	0x24
+#define LENOVO_EC_EVENT_BAT_INFO	0x25
+#define LENOVO_EC_EVENT_BAT_ADPT_STATUS	0x37
+
+#endif

-- 
2.39.2

On Fri, 7 Jun 2024, Dmitry Baryshkov wrote:

> Lenovo Yoga C630 WOS is a laptop using Snapdragon 850 SoC. Like many
> laptops it uses an embedded controller (EC) to perform various platform
> 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.
> 
> Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
> 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      | 283 +++++++++++++++++++++++++
>  include/linux/platform_data/lenovo-yoga-c630.h |  43 ++++
>  4 files changed, 341 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..ffad8c443a13
> --- /dev/null
> +++ b/drivers/platform/arm64/lenovo-yoga-c630.c

> +int yoga_c630_ec_read8(struct yoga_c630_ec *ec, u8 addr)
> +{
> +	u8 req[2] = { LENOVO_EC_READ_REG, };
> +	int ret;
> +	u8 val;
> +
> +	scoped_guard(mutex, &ec->lock) {
> +		req[1] = addr;
> +		ret = yoga_c630_ec_request(ec, req, sizeof(req), &val, 1);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return val;

For simple cases like this which don't do logic after the unlock, guard() 
would be enough (I don't mind scoped_guard() myself though).

> +}
> +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;

addr + 1 could overflow below so it would be good the return -EINVAL if 
0xff addr is given as a parameter.

> +	scoped_guard(mutex, &ec->lock) {
> +		req[1] = addr;
> +		ret = yoga_c630_ec_request(ec, req, sizeof(req), &lsb, 1);
> +		if (ret < 0)
> +			return ret;
> +
> +		req[1] = addr + 1;
> +		ret = yoga_c630_ec_request(ec, req, sizeof(req), &msb, 1);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 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};
> +	int ret;
> +	u8 msb;
> +	u8 lsb;
> +
> +	scoped_guard(mutex, &ec->lock) {
> +		ret = yoga_c630_ec_request(ec, req, sizeof(req), &lsb, 1);
> +		if (ret < 0)
> +			return ret;
> +
> +		req[2] = 0x21;

Could you name 0x20 with a define and use it above and with + 1 here?

> +		ret = yoga_c630_ec_request(ec, req, sizeof(req), &msb, 1);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return msb << 8 | lsb;
> +}
> +EXPORT_SYMBOL_GPL(yoga_c630_ec_ucsi_get_version);

> diff --git a/include/linux/platform_data/lenovo-yoga-c630.h b/include/linux/platform_data/lenovo-yoga-c630.h
> new file mode 100644
> index 000000000000..5571dd65ce08
> --- /dev/null
> +++ b/include/linux/platform_data/lenovo-yoga-c630.h
> @@ -0,0 +1,43 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2022-2024, Linaro Ltd
> + * Authors:
> + *    Bjorn Andersson
> + *    Dmitry Baryshkov
> + */
> +
> +#ifndef _LENOVO_YOGA_C630_DATA_H
> +#define _LENOVO_YOGA_C630_DATA_H
> +
> +struct yoga_c630_ec;
> +struct notifier_block;
> +
> +#define YOGA_C630_MOD_NAME	"lenovo_yoga_c630"
> +
> +#define YOGA_C630_DEV_UCSI	"ucsi"
> +#define YOGA_C630_DEV_PSY	"psy"
> +
> +int yoga_c630_ec_read8(struct yoga_c630_ec *ec, u8 addr);
> +int yoga_c630_ec_read16(struct yoga_c630_ec *ec, u8 addr);
> +
> +int yoga_c630_ec_register_notify(struct yoga_c630_ec *ec, struct notifier_block *nb);
> +void yoga_c630_ec_unregister_notify(struct yoga_c630_ec *ec, struct notifier_block *nb);
> +
> +#define YOGA_C630_UCSI_WRITE_SIZE	8
> +#define YOGA_C630_UCSI_CCI_SIZE		4
> +#define YOGA_C630_UCSI_DATA_SIZE	16
> +#define YOGA_C630_UCSI_READ_SIZE	(YOGA_C630_UCSI_CCI_SIZE + YOGA_C630_UCSI_DATA_SIZE)

Add newline here.

> +u16 yoga_c630_ec_ucsi_get_version(struct yoga_c630_ec *ec);
> +int yoga_c630_ec_ucsi_write(struct yoga_c630_ec *ec,
> +			    const u8 req[YOGA_C630_UCSI_WRITE_SIZE]);
> +int yoga_c630_ec_ucsi_read(struct yoga_c630_ec *ec,
> +			   u8 resp[YOGA_C630_UCSI_READ_SIZE]);
> +
> +#define LENOVO_EC_EVENT_USB		0x20
> +#define LENOVO_EC_EVENT_UCSI		0x21
> +#define LENOVO_EC_EVENT_HPD		0x22
> +#define LENOVO_EC_EVENT_BAT_STATUS	0x24
> +#define LENOVO_EC_EVENT_BAT_INFO	0x25
> +#define LENOVO_EC_EVENT_BAT_ADPT_STATUS	0x37
> +
> +#endif
> 
> 

-- 
 i.