Date:   Tue, 14 Mar 2017 17:02:24 +0000
From:   Lee Jones <lee.jones@...aro.org>
To:     Enric Balletbo i Serra <enric.balletbo@...labora.com>
Cc:     MyungJoo Ham <myungjoo.ham@...sung.com>,
        Rob Herring <robh+dt@...nel.org>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        Benson Leung <bleung@...omium.org>
Subject: Re: [PATCH v2 1/2] extcon: cros-ec: Add extcon-cros-ec driver to
 support display out.

On Wed, 01 Mar 2017, Enric Balletbo i Serra wrote:

> From: Benson Leung <bleung@...omium.org>
> 
> This is the driver for the USB Type C cable detection mechanism
> built into the ChromeOS Embedded Controller on systems that
> have USB Type-C ports.
> 
> At present, this allows for the presence of display out, but in
> future, it may also be used to notify host and device type cables
> and the presence of power.
> 
> Signed-off-by: Benson Leung <bleung@...omium.org>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
> ---
> Changes since v1:
>  Requested by Chanwoo Choi
>  - Rename files changing _ for -
>  - Remove the unneeded blank line on bottom of header.
>  - Remove kobject.h and cros_ec_commands.h includes.
>  - Remove the debug message as is not necessary.
>  - Use the tab for indentation instead of space for if sentence.
>  - Define each variable on different lines when the variables should be
>    initialized.
>  - Remove EXTCON_USB and EXTCON_USB_HOST as are not really used for now.
>  - Add one blank line to split out between state and property setting.
>  - Add the author information (header and module)
> 
>  Enric Balletbo
>  - As Rob suggested to rename the compatible name to something indicating that
>    is USB Type C related I also renamed the file names, extcon-cros-ec ->
>    extcon-usbc-cros-ec, I think it's more clear.
> 
>  drivers/extcon/Kconfig               |   7 +
>  drivers/extcon/Makefile              |   1 +
>  drivers/extcon/extcon-usbc-cros-ec.c | 415 +++++++++++++++++++++++++++++++++++

>  include/linux/mfd/cros_ec_commands.h |  75 +++++++

Acked-by: Lee Jones <lee.jones@...aro.org>

>  4 files changed, 498 insertions(+)
>  create mode 100644 drivers/extcon/extcon-usbc-cros-ec.c
> 
> diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
> index 96bbae5..9e67e68 100644
> --- a/drivers/extcon/Kconfig
> +++ b/drivers/extcon/Kconfig
> @@ -142,4 +142,11 @@ config EXTCON_USB_GPIO
>  	  Say Y here to enable GPIO based USB cable detection extcon support.
>  	  Used typically if GPIO is used for USB ID pin detection.
>  
> +config EXTCON_USBC_CROS_EC
> +	tristate "ChromeOS Embedded Controller EXTCON support"
> +	depends on MFD_CROS_EC
> +	help
> +	  Say Y here to enable USB Type C cable detection extcon support when
> +	  using Chrome OS EC based USB Type-C ports.
> +
>  endif
> diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile
> index 237ac3f..e4422949 100644
> --- a/drivers/extcon/Makefile
> +++ b/drivers/extcon/Makefile
> @@ -19,3 +19,4 @@ obj-$(CONFIG_EXTCON_QCOM_SPMI_MISC) += extcon-qcom-spmi-misc.o
>  obj-$(CONFIG_EXTCON_RT8973A)	+= extcon-rt8973a.o
>  obj-$(CONFIG_EXTCON_SM5502)	+= extcon-sm5502.o
>  obj-$(CONFIG_EXTCON_USB_GPIO)	+= extcon-usb-gpio.o
> +obj-$(CONFIG_EXTCON_USBC_CROS_EC) += extcon-usbc-cros-ec.o
> diff --git a/drivers/extcon/extcon-usbc-cros-ec.c b/drivers/extcon/extcon-usbc-cros-ec.c
> new file mode 100644
> index 0000000..e759ed4
> --- /dev/null
> +++ b/drivers/extcon/extcon-usbc-cros-ec.c
> @@ -0,0 +1,415 @@
> +/**
> + * drivers/extcon/extcon-usbc-cros-ec - ChromeOS Embedded Controller extcon
> + *
> + * Copyright (C) 2017 Google, Inc
> + * Author: Benson Leung <bleung@...omium.org>
> + *
> + * This software is licensed under the terms of the GNU General Public
> + * License version 2, as published by the Free Software Foundation, and
> + * may be copied, distributed, and modified under those terms.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/extcon.h>
> +#include <linux/kernel.h>
> +#include <linux/mfd/cros_ec.h>
> +#include <linux/module.h>
> +#include <linux/notifier.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/sched.h>
> +
> +struct cros_ec_extcon_info {
> +	struct device *dev;
> +	struct extcon_dev *edev;
> +
> +	int port_id;
> +
> +	struct cros_ec_device *ec;
> +
> +	struct notifier_block notifier;
> +
> +	bool dp; /* DisplayPort enabled */
> +	bool mux; /* SuperSpeed (usb3) enabled */
> +	unsigned int power_type;
> +};
> +
> +static const unsigned int usb_type_c_cable[] = {
> +	EXTCON_DISP_DP,
> +	EXTCON_NONE,
> +};
> +
> +/**
> + * cros_ec_pd_command() - Send a command to the EC.
> + * @info: pointer to struct cros_ec_extcon_info
> + * @command: EC command
> + * @version: EC command version
> + * @outdata: EC command output data
> + * @outsize: Size of outdata
> + * @indata: EC command input data
> + * @insize: Size of indata
> + *
> + * Return: 0 on success, <0 on failure.
> + */
> +static int cros_ec_pd_command(struct cros_ec_extcon_info *info,
> +			      unsigned int command,
> +			      unsigned int version,
> +			      void *outdata,
> +			      unsigned int outsize,
> +			      void *indata,
> +			      unsigned int insize)
> +{
> +	struct cros_ec_command *msg;
> +	int ret;
> +
> +	msg = kzalloc(sizeof(*msg) + max(outsize, insize), GFP_KERNEL);
> +
> +	msg->version = version;
> +	msg->command = command;
> +	msg->outsize = outsize;
> +	msg->insize = insize;
> +
> +	if (outsize)
> +		memcpy(msg->data, outdata, outsize);
> +
> +	ret = cros_ec_cmd_xfer_status(info->ec, msg);
> +	if (ret >= 0 && insize)
> +		memcpy(indata, msg->data, insize);
> +
> +	kfree(msg);
> +	return ret;
> +}
> +
> +/**
> + * cros_ec_usb_get_power_type() - Get power type info about PD device attached
> + * to given port.
> + * @info: pointer to struct cros_ec_extcon_info
> + *
> + * Return: power type on success, <0 on failure.
> + */
> +static int cros_ec_usb_get_power_type(struct cros_ec_extcon_info *info)
> +{
> +	struct ec_params_usb_pd_power_info req;
> +	struct ec_response_usb_pd_power_info resp;
> +	int ret;
> +
> +	req.port = info->port_id;
> +	ret = cros_ec_pd_command(info, EC_CMD_USB_PD_POWER_INFO, 0,
> +				 &req, sizeof(req), &resp, sizeof(resp));
> +	if (ret < 0)
> +		return ret;
> +
> +	return resp.type;
> +}
> +
> +/**
> + * cros_ec_usb_get_pd_mux_state() - Get PD mux state for given port.
> + * @info: pointer to struct cros_ec_extcon_info
> + *
> + * Return: PD mux state on success, <0 on failure.
> + */
> +static int cros_ec_usb_get_pd_mux_state(struct cros_ec_extcon_info *info)
> +{
> +	struct ec_params_usb_pd_mux_info req;
> +	struct ec_response_usb_pd_mux_info resp;
> +	int ret;
> +
> +	req.port = info->port_id;
> +	ret = cros_ec_pd_command(info, EC_CMD_USB_PD_MUX_INFO, 0,
> +				 &req, sizeof(req),
> +				 &resp, sizeof(resp));
> +	if (ret < 0)
> +		return ret;
> +
> +	return resp.flags;
> +}
> +
> +/**
> + * cros_ec_usb_get_role() - Get role info about possible PD device attached to a
> + * given port.
> + * @info: pointer to struct cros_ec_extcon_info
> + * @polarity: pointer to cable polarity (return value)
> + *
> + * Return: role info on success, -ENOTCONN if no cable is connected, <0 on
> + * failure.
> + */
> +static int cros_ec_usb_get_role(struct cros_ec_extcon_info *info,
> +				bool *polarity)
> +{
> +	struct ec_params_usb_pd_control pd_control;
> +	struct ec_response_usb_pd_control_v1 resp;
> +	int ret;
> +
> +	pd_control.port = info->port_id;
> +	pd_control.role = USB_PD_CTRL_ROLE_NO_CHANGE;
> +	pd_control.mux = USB_PD_CTRL_MUX_NO_CHANGE;
> +	ret = cros_ec_pd_command(info, EC_CMD_USB_PD_CONTROL, 1,
> +				 &pd_control, sizeof(pd_control),
> +				 &resp, sizeof(resp));
> +	if (ret < 0)
> +		return ret;
> +
> +	if (!(resp.enabled & PD_CTRL_RESP_ENABLED_CONNECTED))
> +		return -ENOTCONN;
> +
> +	*polarity = resp.polarity;
> +
> +	return resp.role;
> +}
> +
> +/**
> + * cros_ec_pd_get_num_ports() - Get number of EC charge ports.
> + * @info: pointer to struct cros_ec_extcon_info
> + *
> + * Return: number of ports on success, <0 on failure.
> + */
> +static int cros_ec_pd_get_num_ports(struct cros_ec_extcon_info *info)
> +{
> +	struct ec_response_usb_pd_ports resp;
> +	int ret;
> +
> +	ret = cros_ec_pd_command(info, EC_CMD_USB_PD_PORTS,
> +				 0, NULL, 0, &resp, sizeof(resp));
> +	if (ret < 0)
> +		return ret;
> +
> +	return resp.num_ports;
> +}
> +
> +static int extcon_cros_ec_detect_cable(struct cros_ec_extcon_info *info,
> +				       bool force)
> +{
> +	struct device *dev = info->dev;
> +	int role, power_type;
> +	bool polarity = false;
> +	bool dp = false;
> +	bool mux = false;
> +	bool hpd = false;
> +
> +	power_type = cros_ec_usb_get_power_type(info);
> +	if (power_type < 0) {
> +		dev_err(dev, "failed getting power type err = %d\n",
> +			power_type);
> +		return power_type;
> +	}
> +
> +	role = cros_ec_usb_get_role(info, &polarity);
> +	if (role < 0) {
> +		if (role != -ENOTCONN) {
> +			dev_err(dev, "failed getting role err = %d\n", role);
> +			return role;
> +		}
> +	} else {
> +		int pd_mux_state;
> +
> +		pd_mux_state = cros_ec_usb_get_pd_mux_state(info);
> +		if (pd_mux_state < 0)
> +			pd_mux_state = USB_PD_MUX_USB_ENABLED;
> +
> +		dp = pd_mux_state & USB_PD_MUX_DP_ENABLED;
> +		mux = pd_mux_state & USB_PD_MUX_USB_ENABLED;
> +		hpd = pd_mux_state & USB_PD_MUX_HPD_IRQ;
> +	}
> +
> +	if (force || info->dp != dp || info->mux != mux ||
> +		info->power_type != power_type) {
> +
> +		info->dp = dp;
> +		info->mux = mux;
> +		info->power_type = power_type;
> +
> +		extcon_set_state(info->edev, EXTCON_DISP_DP, dp);
> +
> +		extcon_set_property(info->edev, EXTCON_DISP_DP,
> +				    EXTCON_PROP_USB_TYPEC_POLARITY,
> +				    (union extcon_property_value)(int)polarity);
> +		extcon_set_property(info->edev, EXTCON_DISP_DP,
> +				    EXTCON_PROP_USB_SS,
> +				    (union extcon_property_value)(int)mux);
> +		extcon_set_property(info->edev, EXTCON_DISP_DP,
> +				    EXTCON_PROP_DISP_HPD,
> +				    (union extcon_property_value)(int)hpd);
> +
> +		extcon_sync(info->edev, EXTCON_DISP_DP);
> +
> +	} else if (hpd) {
> +		extcon_set_property(info->edev, EXTCON_DISP_DP,
> +				    EXTCON_PROP_DISP_HPD,
> +				    (union extcon_property_value)(int)hpd);
> +		extcon_sync(info->edev, EXTCON_DISP_DP);
> +	}
> +
> +	return 0;
> +}
> +
> +static int extcon_cros_ec_event(struct notifier_block *nb,
> +				unsigned long queued_during_suspend,
> +				void *_notify)
> +{
> +	struct cros_ec_extcon_info *info;
> +	struct cros_ec_device *ec;
> +	u32 host_event;
> +
> +	info = container_of(nb, struct cros_ec_extcon_info, notifier);
> +	ec = info->ec;
> +
> +	host_event = cros_ec_get_host_event(ec);
> +	if (host_event & (EC_HOST_EVENT_MASK(EC_HOST_EVENT_PD_MCU) |
> +			  EC_HOST_EVENT_MASK(EC_HOST_EVENT_USB_MUX))) {
> +		extcon_cros_ec_detect_cable(info, false);
> +		return NOTIFY_OK;
> +	}
> +
> +	return NOTIFY_DONE;
> +}
> +
> +static int extcon_cros_ec_probe(struct platform_device *pdev)
> +{
> +	struct cros_ec_extcon_info *info;
> +	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	int numports, ret;
> +
> +	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
> +	if (!info)
> +		return -ENOMEM;
> +
> +	info->dev = dev;
> +	info->ec = ec;
> +
> +	if (np) {
> +		u32 port;
> +
> +		ret = of_property_read_u32(np, "google,usb-port-id", &port);
> +		if (ret < 0) {
> +			dev_err(dev, "Missing google,usb-port-id property\n");
> +			return ret;
> +		}
> +		info->port_id = port;
> +	} else {
> +		info->port_id = pdev->id;
> +	}
> +
> +	numports = cros_ec_pd_get_num_ports(info);
> +	if (numports < 0) {
> +		dev_err(dev, "failed getting number of ports! ret = %d\n",
> +			numports);
> +		return numports;
> +	}
> +
> +	if (info->port_id >= numports) {
> +		dev_err(dev, "This system only supports %d ports\n", numports);
> +		return -ENODEV;
> +	}
> +
> +	info->edev = devm_extcon_dev_allocate(dev, usb_type_c_cable);
> +	if (IS_ERR(info->edev)) {
> +		dev_err(dev, "failed to allocate extcon device\n");
> +		return -ENOMEM;
> +	}
> +
> +	ret = devm_extcon_dev_register(dev, info->edev);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to register extcon device\n");
> +		return ret;
> +	}
> +
> +	extcon_set_property_capability(info->edev, EXTCON_DISP_DP,
> +				       EXTCON_PROP_USB_TYPEC_POLARITY);
> +	extcon_set_property_capability(info->edev, EXTCON_DISP_DP,
> +				       EXTCON_PROP_USB_SS);
> +	extcon_set_property_capability(info->edev, EXTCON_DISP_DP,
> +				       EXTCON_PROP_DISP_HPD);
> +
> +	platform_set_drvdata(pdev, info);
> +
> +	/* Get PD events from the EC */
> +	info->notifier.notifier_call = extcon_cros_ec_event;
> +	ret = blocking_notifier_chain_register(&info->ec->event_notifier,
> +					       &info->notifier);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to register notifier\n");
> +		return ret;
> +	}
> +
> +	/* Perform initial detection */
> +	ret = extcon_cros_ec_detect_cable(info, true);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to detect initial cable state\n");
> +		goto unregister_notifier;
> +	}
> +
> +	return 0;
> +
> +unregister_notifier:
> +	blocking_notifier_chain_unregister(&info->ec->event_notifier,
> +					   &info->notifier);
> +	return ret;
> +}
> +
> +static int extcon_cros_ec_remove(struct platform_device *pdev)
> +{
> +	struct cros_ec_extcon_info *info = platform_get_drvdata(pdev);
> +
> +	blocking_notifier_chain_unregister(&info->ec->event_notifier,
> +					   &info->notifier);
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int extcon_cros_ec_suspend(struct device *dev)
> +{
> +	return 0;
> +}
> +
> +static int extcon_cros_ec_resume(struct device *dev)
> +{
> +	int ret;
> +	struct cros_ec_extcon_info *info = dev_get_drvdata(dev);
> +
> +	ret = extcon_cros_ec_detect_cable(info, true);
> +	if (ret < 0)
> +		dev_err(dev, "failed to detect cable state on resume\n");
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops extcon_cros_ec_dev_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(extcon_cros_ec_suspend, extcon_cros_ec_resume)
> +};
> +
> +#define DEV_PM_OPS	(&extcon_cros_ec_dev_pm_ops)
> +#else
> +#define DEV_PM_OPS	NULL
> +#endif /* CONFIG_PM_SLEEP */
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id extcon_cros_ec_of_match[] = {
> +	{ .compatible = "google,extcon-usbc-cros-ec" },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, extcon_cros_ec_of_match);
> +#endif /* CONFIG_OF */
> +
> +static struct platform_driver extcon_cros_ec_driver = {
> +	.driver = {
> +		.name  = "extcon-usbc-cros-ec",
> +		.of_match_table = of_match_ptr(extcon_cros_ec_of_match),
> +		.pm = DEV_PM_OPS,
> +	},
> +	.remove  = extcon_cros_ec_remove,
> +	.probe   = extcon_cros_ec_probe,
> +};
> +
> +module_platform_driver(extcon_cros_ec_driver);
> +
> +MODULE_DESCRIPTION("ChromeOS Embedded Controller extcon driver");
> +MODULE_AUTHOR("Benson Leung <bleung@...omium.org>");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/mfd/cros_ec_commands.h b/include/linux/mfd/cros_ec_commands.h
> index 255d14a..3ca9953 100644
> --- a/include/linux/mfd/cros_ec_commands.h
> +++ b/include/linux/mfd/cros_ec_commands.h
> @@ -285,10 +285,15 @@ enum host_event_code {
>  	EC_HOST_EVENT_HANG_DETECT = 20,
>  	/* Hang detect logic detected a hang and warm rebooted the AP */
>  	EC_HOST_EVENT_HANG_REBOOT = 21,
> +	/* PD MCU triggering host event */
> +	EC_HOST_EVENT_PD_MCU = 22,
>  
>  	/* EC RTC event occurred */
>  	EC_HOST_EVENT_RTC = 26,
>  
> +	/* EC desires to change state of host-controlled USB mux */
> +	EC_HOST_EVENT_USB_MUX = 28,
> +
>  	/*
>  	 * The high bit of the event mask is not used as a host event code.  If
>  	 * it reads back as set, then the entire event mask should be
> @@ -2873,6 +2878,76 @@ struct ec_params_usb_pd_control {
>  	uint8_t mux;
>  } __packed;
>  
> +#define PD_CTRL_RESP_ENABLED_COMMS      (1 << 0) /* Communication enabled */
> +#define PD_CTRL_RESP_ENABLED_CONNECTED  (1 << 1) /* Device connected */
> +#define PD_CTRL_RESP_ENABLED_PD_CAPABLE (1 << 2) /* Partner is PD capable */
> +
> +struct ec_response_usb_pd_control_v1 {
> +	uint8_t enabled;
> +	uint8_t role;
> +	uint8_t polarity;
> +	char state[32];
> +} __packed;
> +
> +#define EC_CMD_USB_PD_PORTS 0x102
> +
> +struct ec_response_usb_pd_ports {
> +	uint8_t num_ports;
> +} __packed;
> +
> +#define EC_CMD_USB_PD_POWER_INFO 0x103
> +
> +#define PD_POWER_CHARGING_PORT 0xff
> +struct ec_params_usb_pd_power_info {
> +	uint8_t port;
> +} __packed;
> +
> +enum usb_chg_type {
> +	USB_CHG_TYPE_NONE,
> +	USB_CHG_TYPE_PD,
> +	USB_CHG_TYPE_C,
> +	USB_CHG_TYPE_PROPRIETARY,
> +	USB_CHG_TYPE_BC12_DCP,
> +	USB_CHG_TYPE_BC12_CDP,
> +	USB_CHG_TYPE_BC12_SDP,
> +	USB_CHG_TYPE_OTHER,
> +	USB_CHG_TYPE_VBUS,
> +	USB_CHG_TYPE_UNKNOWN,
> +};
> +
> +struct usb_chg_measures {
> +	uint16_t voltage_max;
> +	uint16_t voltage_now;
> +	uint16_t current_max;
> +	uint16_t current_lim;
> +} __packed;
> +
> +struct ec_response_usb_pd_power_info {
> +	uint8_t role;
> +	uint8_t type;
> +	uint8_t dualrole;
> +	uint8_t reserved1;
> +	struct usb_chg_measures meas;
> +	uint32_t max_power;
> +} __packed;
> +
> +/* Get info about USB-C SS muxes */
> +#define EC_CMD_USB_PD_MUX_INFO 0x11a
> +
> +struct ec_params_usb_pd_mux_info {
> +	uint8_t port; /* USB-C port number */
> +} __packed;
> +
> +/* Flags representing mux state */
> +#define USB_PD_MUX_USB_ENABLED       (1 << 0)
> +#define USB_PD_MUX_DP_ENABLED        (1 << 1)
> +#define USB_PD_MUX_POLARITY_INVERTED (1 << 2)
> +#define USB_PD_MUX_HPD_IRQ           (1 << 3)
> +
> +struct ec_response_usb_pd_mux_info {
> +	uint8_t flags; /* USB_PD_MUX_*-encoded USB mux state */
> +} __packed;
> +
>  /*****************************************************************************/
>  /*
>   * Passthru commands

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Powered by blists - more mailing lists