Re: [PATCH 3/5] usb: typec: ucsi: add Huawei Matebook E Go (sc8280xp) ucsi driver

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

On 27/12/2024 17:13, Pengyu Luo wrote:
> The Huawei Matebook E Go (sc8280xp) tablet provides implements UCSI
> interface in the onboard EC. Add the glue driver to interface the
> platform's UCSI implementation.
> 
> Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
> ---
>   drivers/usb/typec/ucsi/Kconfig              |   9 +
>   drivers/usb/typec/ucsi/Makefile             |   1 +
>   drivers/usb/typec/ucsi/ucsi_huawei_gaokun.c | 481 ++++++++++++++++++++
>   3 files changed, 491 insertions(+)
>   create mode 100644 drivers/usb/typec/ucsi/ucsi_huawei_gaokun.c
> 
> diff --git a/drivers/usb/typec/ucsi/Kconfig b/drivers/usb/typec/ucsi/Kconfig
> index 680e1b87b..0d0f07488 100644
> --- a/drivers/usb/typec/ucsi/Kconfig
> +++ b/drivers/usb/typec/ucsi/Kconfig
> @@ -78,4 +78,13 @@ config UCSI_LENOVO_YOGA_C630
>   	  To compile the driver as a module, choose M here: the module will be
>   	  called ucsi_yoga_c630.
>   
> +config UCSI_HUAWEI_GAOKUN
> +	tristate "UCSI Interface Driver for Huawei Matebook E Go (sc8280xp)"
> +	depends on EC_HUAWEI_GAOKUN
> +	help
> +	  This driver enables UCSI support on the Huawei Matebook E Go tablet.
> +
> +	  To compile the driver as a module, choose M here: the module will be
> +	  called ucsi_huawei_gaokun.
> +
>   endif
> diff --git a/drivers/usb/typec/ucsi/Makefile b/drivers/usb/typec/ucsi/Makefile
> index aed41d238..0b400122b 100644
> --- a/drivers/usb/typec/ucsi/Makefile
> +++ b/drivers/usb/typec/ucsi/Makefile
> @@ -22,3 +22,4 @@ 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
> +obj-$(CONFIG_UCSI_HUAWEI_GAOKUN)	+= ucsi_huawei_gaokun.o
> diff --git a/drivers/usb/typec/ucsi/ucsi_huawei_gaokun.c b/drivers/usb/typec/ucsi/ucsi_huawei_gaokun.c
> new file mode 100644
> index 000000000..84ed0407d
> --- /dev/null
> +++ b/drivers/usb/typec/ucsi/ucsi_huawei_gaokun.c
> @@ -0,0 +1,481 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * ucsi-huawei-gaokun - A UCSI driver for HUAWEI Matebook E Go (sc8280xp)
> + *
> + * reference: drivers/usb/typec/ucsi/ucsi_yoga_c630.c
> + *            drivers/usb/typec/ucsi/ucsi_glink.c
> + *            drivers/soc/qcom/pmic_glink_altmode.c
> + *
> + * Copyright (C) 2024 Pengyu Luo <mitltlatltl@gmail.com>
> + */
> +
> +#include <linux/auxiliary_bus.h>
> +#include <linux/bitops.h>
> +#include <linux/completion.h>
> +#include <linux/container_of.h>
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/notifier.h>
> +#include <linux/of.h>
> +#include <linux/string.h>
> +#include <linux/workqueue_types.h>
> +
> +#include <linux/usb/pd_vdo.h>
> +#include <drm/bridge/aux-bridge.h

Is there a reason you don't have strict include alphanumeric ordering here ?

>
> +
> +#include "ucsi.h"
> +#include <linux/platform_data/huawei-gaokun-ec.h>
> +
> +
> +#define EC_EVENT_UCSI	0x21
> +#define EC_EVENT_USB	0x22
> +
> +#define GAOKUN_CCX_MASK		GENMASK(1, 0)
> +#define GAOKUN_MUX_MASK		GENMASK(3, 2)
> +
> +#define GAOKUN_DPAM_MASK	GENMASK(3, 0)
> +#define GAOKUN_HPD_STATE_MASK	BIT(4)
> +#define GAOKUN_HPD_IRQ_MASK	BIT(5)
> +
> +#define CCX_TO_ORI(ccx) (++ccx % 3)

Why do you increment the value of the enum ?
Seems strange.

> +
> +#define GET_IDX(updt) (ffs(updt) - 1)
> +
> +/* Configuration Channel Extension */
> +enum gaokun_ucsi_ccx {
> +	USBC_CCX_NORMAL,
> +	USBC_CCX_REVERSE,
> +	USBC_CCX_NONE,
> +};
> +
> +enum gaokun_ucsi_mux {
> +	USBC_MUX_NONE,
> +	USBC_MUX_USB_2L,
> +	USBC_MUX_DP_4L,
> +	USBC_MUX_USB_DP,
> +};
> +
> +struct gaokun_ucsi_reg {
> +	u8 port_num;
> +	u8 port_updt;
> +	u8 port_data[4];
> +	u8 checksum;
> +	u8 reserved;
> +} __packed;
> +
> +struct gaokun_ucsi_port {
> +	struct completion usb_ack;
> +	spinlock_t lock;
> +
> +	struct gaokun_ucsi *ucsi;
> +	struct auxiliary_device *bridge;
> +
> +	int idx;
> +	enum gaokun_ucsi_ccx ccx;
> +	enum gaokun_ucsi_mux mux;
> +	u8 mode;
> +	u16 svid;
> +	u8 hpd_state;
> +	u8 hpd_irq;
> +};
> +
> +struct gaokun_ucsi {
> +	struct gaokun_ec *ec;
> +	struct ucsi *ucsi;
> +	struct gaokun_ucsi_port *ports;
> +	struct device *dev;
> +	struct work_struct work;
> +	struct notifier_block nb;
> +	u16 version;
> +	u8 port_num;
> +};
> +
> +/* -------------------------------------------------------------------------- */
> +/* For UCSI */
> +
> +static int gaokun_ucsi_read_version(struct ucsi *ucsi, u16 *version)
> +{
> +	struct gaokun_ucsi *uec = ucsi_get_drvdata(ucsi);
> +
> +	*version = uec->version;
> +
> +	return 0;
> +}
> +
> +static int gaokun_ucsi_read_cci(struct ucsi *ucsi, u32 *cci)
> +{
> +	struct gaokun_ucsi *uec = ucsi_get_drvdata(ucsi);
> +	u8 buf[GAOKUN_UCSI_READ_SIZE];
> +	int ret;
> +
> +	ret = gaokun_ec_ucsi_read(uec->ec, buf);
> +	if (ret)
> +		return ret;
> +
> +	memcpy(cci, buf, sizeof(*cci));
> +
> +	return 0;
> +}
> +
> +static int gaokun_ucsi_read_message_in(struct ucsi *ucsi,
> +				       void *val, size_t val_len)
> +{
> +	struct gaokun_ucsi *uec = ucsi_get_drvdata(ucsi);
> +	u8 buf[GAOKUN_UCSI_READ_SIZE];
> +	int ret;
> +
> +	ret = gaokun_ec_ucsi_read(uec->ec, buf);
> +	if (ret)
> +		return ret;
> +
> +	memcpy(val, buf + GAOKUN_UCSI_CCI_SIZE,
> +	       min(val_len, GAOKUN_UCSI_DATA_SIZE));
> +
> +	return 0;
> +}
> +
> +static int gaokun_ucsi_async_control(struct ucsi *ucsi, u64 command)
> +{
> +	struct gaokun_ucsi *uec = ucsi_get_drvdata(ucsi);
> +	u8 buf[GAOKUN_UCSI_WRITE_SIZE] = {};
> +
> +	memcpy(buf, &command, sizeof(command));
> +
> +	return gaokun_ec_ucsi_write(uec->ec, buf);
> +}
> +
> +static void gaokun_ucsi_update_connector(struct ucsi_connector *con)
> +{
> +	struct gaokun_ucsi *uec = ucsi_get_drvdata(con->ucsi);
> +
> +	if (con->num > uec->port_num)
> +		return;
> +
> +	con->typec_cap.orientation_aware = true;
> +}
> +
> +static void gaokun_set_orientation(struct ucsi_connector *con,
> +				   struct gaokun_ucsi_port *port)
> +{
> +	enum gaokun_ucsi_ccx ccx;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&port->lock, flags);
> +	ccx = port->ccx;
> +	spin_unlock_irqrestore(&port->lock, flags);
> +
> +	typec_set_orientation(con->port, CCX_TO_ORI(ccx));
> +}
> +
> +static void gaokun_ucsi_connector_status(struct ucsi_connector *con)
> +{
> +	struct gaokun_ucsi *uec = ucsi_get_drvdata(con->ucsi);
> +	int idx;
> +
> +	idx = con->num - 1;
> +	if (con->num > uec->port_num) {
> +		dev_warn(uec->ucsi->dev, "set orientation out of range: con%d\n", idx);
> +		return;
> +	}
> +
> +	gaokun_set_orientation(con, &uec->ports[idx]);
> +}
> +
> +const struct ucsi_operations gaokun_ucsi_ops = {
> +	.read_version = gaokun_ucsi_read_version,
> +	.read_cci = gaokun_ucsi_read_cci,
> +	.read_message_in = gaokun_ucsi_read_message_in,
> +	.sync_control = ucsi_sync_control_common,
> +	.async_control = gaokun_ucsi_async_control,
> +	.update_connector = gaokun_ucsi_update_connector,
> +	.connector_status = gaokun_ucsi_connector_status,
> +};
> +
> +/* -------------------------------------------------------------------------- */
> +/* For Altmode */
> +
> +static void gaokun_ucsi_port_update(struct gaokun_ucsi_port *port,
> +				    const u8 *port_data)
> +{
> +	unsigned long flags;
> +	u8 dcc, ddi;
> +	int offset = port->idx * 2; /* every port has 2 Bytes data */
> +
> +	dcc = port_data[offset];
> +	ddi = port_data[offset + 1];
> +
> +	spin_lock_irqsave(&port->lock, flags);
> +
> +	port->ccx = FIELD_GET(GAOKUN_CCX_MASK, dcc);
> +	port->mux = FIELD_GET(GAOKUN_MUX_MASK, dcc);
> +	port->mode = FIELD_GET(GAOKUN_DPAM_MASK, ddi);
> +	port->hpd_state = FIELD_GET(GAOKUN_HPD_STATE_MASK, ddi);
> +	port->hpd_irq = FIELD_GET(GAOKUN_HPD_IRQ_MASK, ddi);
> +
> +	switch (port->mux) {
> +	case USBC_MUX_NONE:
> +		port->svid = 0;
> +		break;
> +	case USBC_MUX_USB_2L:
> +		port->svid = USB_SID_PD;
> +		break;
> +	case USBC_MUX_DP_4L:
> +	case USBC_MUX_USB_DP:
> +		port->svid = USB_SID_DISPLAYPORT;
> +		if (port->ccx == USBC_CCX_REVERSE)
> +			port->mode -= 6;

why minus six ?
needs a comment.

> +		break;
> +	default:
> +		break;
> +	}
> +
> +	spin_unlock_irqrestore(&port->lock, flags);
> +}
> +
> +static int gaokun_ucsi_refresh(struct gaokun_ucsi *uec)
> +{
> +	struct gaokun_ucsi_reg ureg;
> +	int ret, idx;
> +
> +	ret = gaokun_ec_ucsi_get_reg(uec->ec, (u8 *)&ureg);
> +	if (ret)
> +		return -EIO;
> +
> +	uec->port_num = ureg.port_num;
> +	idx = GET_IDX(ureg.port_updt);
> +
> +	if (idx >= 0 && idx < ureg.port_num)
> +		gaokun_ucsi_port_update(&uec->ports[idx], ureg.port_data);

Since you are checking the validity of the index, you should -EINVAL if 
the index is out of range.

> +
> +	return idx;
> +}
> +
> +static void gaokun_ucsi_handle_altmode(struct gaokun_ucsi_port *port)
> +{
> +	struct gaokun_ucsi *uec = port->ucsi;
> +	int idx = port->idx;
> +
> +	if (idx >= uec->ucsi->cap.num_connectors || !uec->ucsi->connector) {
> +		dev_warn(uec->ucsi->dev, "altmode port out of range: %d\n", idx);
> +		return;
> +	}
> +
> +	/* UCSI callback .connector_status() have set orientation */
> +	if (port->bridge)
> +		drm_aux_hpd_bridge_notify(&port->bridge->dev,
> +					  port->hpd_state ?
> +					  connector_status_connected :
> +					  connector_status_disconnected);
> +
> +	gaokun_ec_ucsi_pan_ack(uec->ec, port->idx);
> +}
> +
> +static void gaokun_ucsi_altmode_notify_ind(struct gaokun_ucsi *uec)
> +{
> +	int idx;
> +
> +	idx = gaokun_ucsi_refresh(uec);
> +	if (idx < 0)
> +		gaokun_ec_ucsi_pan_ack(uec->ec, idx);
> +	else
> +		gaokun_ucsi_handle_altmode(&uec->ports[idx]);
> +}
> +
> +/*
> + * USB event is necessary for enabling altmode, the event should follow
> + * UCSI event, if not after timeout(this notify may be disabled somehow),
> + * then force to enable altmode.
> + */
> +static void gaokun_ucsi_handle_no_usb_event(struct gaokun_ucsi *uec, int idx)
> +{
> +	struct gaokun_ucsi_port *port;
> +
> +	port = &uec->ports[idx];
> +	if (!wait_for_completion_timeout(&port->usb_ack, 2 * HZ)) {
> +		dev_warn(uec->dev, "No USB EVENT, triggered by UCSI EVENT");
> +		gaokun_ucsi_altmode_notify_ind(uec);
> +	}
> +}
> +
> +static int gaokun_ucsi_notify(struct notifier_block *nb,
> +			      unsigned long action, void *data)
> +{
> +	u32 cci;
> +	struct gaokun_ucsi *uec = container_of(nb, struct gaokun_ucsi, nb);
> +
> +	switch (action) {
> +	case EC_EVENT_USB:
> +		gaokun_ucsi_altmode_notify_ind(uec);
> +		return NOTIFY_OK;
> +
> +	case EC_EVENT_UCSI:
> +		uec->ucsi->ops->read_cci(uec->ucsi, &cci);
> +		ucsi_notify_common(uec->ucsi, cci);
> +		if (UCSI_CCI_CONNECTOR(cci))
> +			gaokun_ucsi_handle_no_usb_event(uec, UCSI_CCI_CONNECTOR(cci) - 1);
> +
> +		return NOTIFY_OK;
> +
> +	default:
> +		return NOTIFY_DONE;
> +	}
> +}
> +
> +static int gaokun_ucsi_get_port_num(struct gaokun_ucsi *uec)
> +{
> +	struct gaokun_ucsi_reg ureg;
> +	int ret;
> +
> +	ret = gaokun_ec_ucsi_get_reg(uec->ec, (u8 *)&ureg);
> +
> +	return ret ? 0 : ureg.port_num;
> +}
> +
> +static int gaokun_ucsi_ports_init(struct gaokun_ucsi *uec)
> +{
> +	u32 port;
> +	int i, ret, port_num;
> +	struct device *dev = uec->dev;
> +	struct gaokun_ucsi_port *ucsi_port;
> +	struct fwnode_handle *fwnode;
> +
> +	port_num = gaokun_ucsi_get_port_num(uec);
> +	uec->port_num = port_num;
> +
> +	uec->ports = devm_kzalloc(dev, port_num * sizeof(*(uec->ports)),
> +				  GFP_KERNEL);
> +	if (!uec->ports)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < port_num; ++i) {
> +		ucsi_port = &uec->ports[i];
> +		ucsi_port->ccx = USBC_CCX_NONE;
> +		ucsi_port->idx = i;
> +		ucsi_port->ucsi = uec;
> +		init_completion(&ucsi_port->usb_ack);
> +		spin_lock_init(&ucsi_port->lock);
> +	}
> +
> +	device_for_each_child_node(dev, fwnode) {
> +		ret = fwnode_property_read_u32(fwnode, "reg", &port);
> +		if (ret < 0) {
> +			dev_err(dev, "missing reg property of %pOFn\n", fwnode);
> +			fwnode_handle_put(fwnode);
> +			return ret;
> +		}
> +
> +		if (port >= port_num) {
> +			dev_warn(dev, "invalid connector number %d, ignoring\n", port);
> +			continue;
> +		}
> +
> +		ucsi_port = &uec->ports[port];
> +		ucsi_port->bridge = devm_drm_dp_hpd_bridge_alloc(dev, to_of_node(fwnode));
> +		if (IS_ERR(ucsi_port->bridge)) {
> +			fwnode_handle_put(fwnode);
> +			return PTR_ERR(ucsi_port->bridge);
> +		}
> +	}
> +
> +	for (i = 0; i < port_num; i++) {
> +		if (!uec->ports[i].bridge)
> +			continue;
> +
> +		ret = devm_drm_dp_hpd_bridge_add(dev, uec->ports[i].bridge);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static void gaokun_ucsi_register_worker(struct work_struct *work)
> +{
> +	struct gaokun_ucsi *uec;
> +	struct ucsi *ucsi;
> +	int ret;
> +
> +	uec = container_of(work, struct gaokun_ucsi, work);
> +	ucsi = uec->ucsi;
> +
> +	ucsi->quirks = UCSI_NO_PARTNER_PDOS | UCSI_DELAY_DEVICE_PDOS;
> +
> +	ssleep(3); /* EC can't handle UCSI properly in the early stage */

Could you not schedule work for + 3 seconds instead of sleeping here - 
representing the required stall time in some sort of state machine ?

3 seconds is an incredibly long time for a computer to sleep.

> +
> +	ret = gaokun_ec_register_notify(uec->ec, &uec->nb);
> +	if (ret) {
> +		dev_err_probe(ucsi->dev, ret, "notifier register failed\n");
> +		return;
> +	}
> +
> +	ret = ucsi_register(ucsi);
> +	if (ret)
> +		dev_err_probe(ucsi->dev, ret, "ucsi register failed\n");
> +}
> +
> +static int gaokun_ucsi_register(struct gaokun_ucsi *uec)
> +{
> +	schedule_work(&uec->work);
> +
> +	return 0;
> +}
> +
> +static int gaokun_ucsi_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_ucsi *uec;
> +	int ret;
> +
> +	uec = devm_kzalloc(dev, sizeof(*uec), GFP_KERNEL);
> +	if (!uec)
> +		return -ENOMEM;
> +
> +	uec->ec = ec;
> +	uec->dev = dev;
> +	uec->version = 0x0100;
> +	uec->nb.notifier_call = gaokun_ucsi_notify;
> +
> +	INIT_WORK(&uec->work, gaokun_ucsi_register_worker);
> +
> +	ret = gaokun_ucsi_ports_init(uec);
> +	if (ret)
> +		return ret;
> +
> +	uec->ucsi = ucsi_create(dev, &gaokun_ucsi_ops);
> +	if (IS_ERR(uec->ucsi))
> +		return PTR_ERR(uec->ucsi);
> +
> +	ucsi_set_drvdata(uec->ucsi, uec);
> +	auxiliary_set_drvdata(adev, uec);
> +
> +	return gaokun_ucsi_register(uec);
> +}
> +
> +static void gaokun_ucsi_remove(struct auxiliary_device *adev)
> +{
> +	struct gaokun_ucsi *uec = auxiliary_get_drvdata(adev);
> +
> +	gaokun_ec_unregister_notify(uec->ec, &uec->nb);
> +	ucsi_unregister(uec->ucsi);
> +	ucsi_destroy(uec->ucsi);
> +}
> +
> +static const struct auxiliary_device_id gaokun_ucsi_id_table[] = {
> +	{ .name = GAOKUN_MOD_NAME "." GAOKUN_DEV_UCSI, },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(auxiliary, gaokun_ucsi_id_table);
> +
> +static struct auxiliary_driver gaokun_ucsi_driver = {
> +	.name = GAOKUN_DEV_UCSI,
> +	.id_table = gaokun_ucsi_id_table,
> +	.probe = gaokun_ucsi_probe,
> +	.remove = gaokun_ucsi_remove,
> +};
> +
> +module_auxiliary_driver(gaokun_ucsi_driver);
> +
> +MODULE_DESCRIPTION("HUAWEI Matebook E Go UCSI driver");
> +MODULE_LICENSE("GPL");