[PATCH v5 3/6] usb: typec: ucsi: add Lenovo Yoga C630 glue driver

[Dmitry Baryshkov]

The Lenovo Yoga C630 WOS laptop provides implements UCSI interface in
the onboard EC. Add glue driver to interface the platform's UCSI
implementation.

Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
---
 drivers/usb/typec/ucsi/Kconfig          |   9 ++
 drivers/usb/typec/ucsi/Makefile         |   1 +
 drivers/usb/typec/ucsi/ucsi_yoga_c630.c | 202 ++++++++++++++++++++++++++++++++
 3 files changed, 212 insertions(+)

diff --git a/drivers/usb/typec/ucsi/Kconfig b/drivers/usb/typec/ucsi/Kconfig
index bdcb1764cfae..680e1b87b152 100644
--- a/drivers/usb/typec/ucsi/Kconfig
+++ b/drivers/usb/typec/ucsi/Kconfig
@@ -69,4 +69,13 @@ config UCSI_PMIC_GLINK
 	  To compile the driver as a module, choose M here: the module will be
 	  called ucsi_glink.
 
+config UCSI_LENOVO_YOGA_C630
+	tristate "UCSI Interface Driver for Lenovo Yoga C630"
+	depends on EC_LENOVO_YOGA_C630
+	help
+	  This driver enables UCSI support on the Lenovo Yoga C630 laptop.
+
+	  To compile the driver as a module, choose M here: the module will be
+	  called ucsi_yoga_c630.
+
 endif
diff --git a/drivers/usb/typec/ucsi/Makefile b/drivers/usb/typec/ucsi/Makefile
index b4679f94696b..aed41d23887b 100644
--- a/drivers/usb/typec/ucsi/Makefile
+++ b/drivers/usb/typec/ucsi/Makefile
@@ -21,3 +21,4 @@ obj-$(CONFIG_UCSI_ACPI)			+= ucsi_acpi.o
 obj-$(CONFIG_UCSI_CCG)			+= ucsi_ccg.o
 obj-$(CONFIG_UCSI_STM32G0)		+= ucsi_stm32g0.o
 obj-$(CONFIG_UCSI_PMIC_GLINK)		+= ucsi_glink.o
+obj-$(CONFIG_UCSI_LENOVO_YOGA_C630)	+= ucsi_yoga_c630.o
diff --git a/drivers/usb/typec/ucsi/ucsi_yoga_c630.c b/drivers/usb/typec/ucsi/ucsi_yoga_c630.c
new file mode 100644
index 000000000000..194b49291f28
--- /dev/null
+++ b/drivers/usb/typec/ucsi/ucsi_yoga_c630.c
@@ -0,0 +1,202 @@
+// 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/bitops.h>
+#include <linux/completion.h>
+#include <linux/container_of.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/string.h>
+#include <linux/platform_data/lenovo-yoga-c630.h>
+
+#include "ucsi.h"
+
+struct yoga_c630_ucsi {
+	struct yoga_c630_ec *ec;
+	struct ucsi *ucsi;
+	struct notifier_block nb;
+	struct completion complete;
+	unsigned long flags;
+#define UCSI_C630_COMMAND_PENDING	0
+#define UCSI_C630_ACK_PENDING		1
+	u16 version;
+};
+
+static int yoga_c630_ucsi_read(struct ucsi *ucsi, unsigned int offset,
+			       void *val, size_t val_len)
+{
+	struct yoga_c630_ucsi *uec = ucsi_get_drvdata(ucsi);
+	u8 buf[YOGA_C630_UCSI_READ_SIZE];
+	int ret;
+
+	ret = yoga_c630_ec_ucsi_read(uec->ec, buf);
+	if (ret)
+		return ret;
+
+	if (offset == UCSI_VERSION) {
+		memcpy(val, &uec->version, min(val_len, sizeof(uec->version)));
+		return 0;
+	}
+
+	if (offset == UCSI_CCI)
+		memcpy(val, buf, min(val_len, YOGA_C630_UCSI_CCI_SIZE));
+	else if (offset == UCSI_MESSAGE_IN)
+		memcpy(val, buf + YOGA_C630_UCSI_CCI_SIZE,
+		       min(val_len, YOGA_C630_UCSI_DATA_SIZE));
+	else
+		return -EINVAL;
+
+	return 0;
+}
+
+static int yoga_c630_ucsi_async_write(struct ucsi *ucsi, unsigned int offset,
+				      const void *val, size_t val_len)
+{
+	struct yoga_c630_ucsi *uec = ucsi_get_drvdata(ucsi);
+
+	if (offset != UCSI_CONTROL ||
+	    val_len != YOGA_C630_UCSI_WRITE_SIZE)
+		return -EINVAL;
+
+	return yoga_c630_ec_ucsi_write(uec->ec, val);
+}
+
+static int yoga_c630_ucsi_sync_write(struct ucsi *ucsi, unsigned int offset,
+				     const void *val, size_t val_len)
+{
+	struct yoga_c630_ucsi *uec = ucsi_get_drvdata(ucsi);
+	bool ack = UCSI_COMMAND(*(u64 *)val) == UCSI_ACK_CC_CI;
+	int ret;
+
+	if (ack)
+		set_bit(UCSI_C630_ACK_PENDING, &uec->flags);
+	else
+		set_bit(UCSI_C630_COMMAND_PENDING, &uec->flags);
+
+	reinit_completion(&uec->complete);
+
+	ret = yoga_c630_ucsi_async_write(ucsi, offset, val, val_len);
+	if (ret)
+		goto out_clear_bit;
+
+	if (!wait_for_completion_timeout(&uec->complete, 5 * HZ))
+		ret = -ETIMEDOUT;
+
+out_clear_bit:
+	if (ack)
+		clear_bit(UCSI_C630_ACK_PENDING, &uec->flags);
+	else
+		clear_bit(UCSI_C630_COMMAND_PENDING, &uec->flags);
+
+	return ret;
+}
+
+const struct ucsi_operations yoga_c630_ucsi_ops = {
+	.read = yoga_c630_ucsi_read,
+	.sync_write = yoga_c630_ucsi_sync_write,
+	.async_write = yoga_c630_ucsi_async_write,
+};
+
+static void yoga_c630_ucsi_notify_ucsi(struct yoga_c630_ucsi *uec, u32 cci)
+{
+	if (UCSI_CCI_CONNECTOR(cci))
+		ucsi_connector_change(uec->ucsi, UCSI_CCI_CONNECTOR(cci));
+
+	if (cci & UCSI_CCI_ACK_COMPLETE &&
+	    test_bit(UCSI_C630_ACK_PENDING, &uec->flags))
+		complete(&uec->complete);
+
+	if (cci & UCSI_CCI_COMMAND_COMPLETE &&
+	    test_bit(UCSI_C630_COMMAND_PENDING, &uec->flags))
+		complete(&uec->complete);
+}
+
+static int yoga_c630_ucsi_notify(struct notifier_block *nb,
+				 unsigned long action, void *data)
+{
+	struct yoga_c630_ucsi *uec = container_of(nb, struct yoga_c630_ucsi, nb);
+	u32 cci;
+	int ret;
+
+	switch (action) {
+	case LENOVO_EC_EVENT_USB:
+	case LENOVO_EC_EVENT_HPD:
+		ucsi_connector_change(uec->ucsi, 1);
+		return NOTIFY_OK;
+
+	case LENOVO_EC_EVENT_UCSI:
+		ret = uec->ucsi->ops->read(uec->ucsi, UCSI_CCI, &cci, sizeof(cci));
+		if (ret)
+			return NOTIFY_DONE;
+
+		yoga_c630_ucsi_notify_ucsi(uec, cci);
+
+		return NOTIFY_OK;
+
+	default:
+		return NOTIFY_DONE;
+	}
+}
+
+static int yoga_c630_ucsi_probe(struct auxiliary_device *adev,
+				const struct auxiliary_device_id *id)
+{
+	struct yoga_c630_ec *ec = adev->dev.platform_data;
+	struct yoga_c630_ucsi *uec;
+	int ret;
+
+	uec = devm_kzalloc(&adev->dev, sizeof(*uec), GFP_KERNEL);
+	if (!uec)
+		return -ENOMEM;
+
+	uec->ec = ec;
+	init_completion(&uec->complete);
+	uec->nb.notifier_call = yoga_c630_ucsi_notify;
+
+	uec->ucsi = ucsi_create(&adev->dev, &yoga_c630_ucsi_ops);
+	if (IS_ERR(uec->ucsi))
+		return PTR_ERR(uec->ucsi);
+
+	ucsi_set_drvdata(uec->ucsi, uec);
+
+	uec->version = yoga_c630_ec_ucsi_get_version(uec->ec);
+
+	auxiliary_set_drvdata(adev, uec);
+
+	ret = yoga_c630_ec_register_notify(ec, &uec->nb);
+	if (ret)
+		return ret;
+
+	return ucsi_register(uec->ucsi);
+}
+
+static void yoga_c630_ucsi_remove(struct auxiliary_device *adev)
+{
+	struct yoga_c630_ucsi *uec = auxiliary_get_drvdata(adev);
+
+	yoga_c630_ec_unregister_notify(uec->ec, &uec->nb);
+	ucsi_unregister(uec->ucsi);
+}
+
+static const struct auxiliary_device_id yoga_c630_ucsi_id_table[] = {
+	{ .name = YOGA_C630_MOD_NAME "." YOGA_C630_DEV_UCSI, },
+	{}
+};
+MODULE_DEVICE_TABLE(auxiliary, yoga_c630_ucsi_id_table);
+
+static struct auxiliary_driver yoga_c630_ucsi_driver = {
+	.name = YOGA_C630_DEV_UCSI,
+	.id_table = yoga_c630_ucsi_id_table,
+	.probe = yoga_c630_ucsi_probe,
+	.remove = yoga_c630_ucsi_remove,
+};
+
+module_auxiliary_driver(yoga_c630_ucsi_driver);
+
+MODULE_DESCRIPTION("Lenovo Yoga C630 UCSI");
+MODULE_LICENSE("GPL");

-- 
2.39.2