Date:   Fri, 02 Mar 2018 09:39:07 +0900
From:   Chanwoo Choi <cw00.choi@...sung.com>
To:     Hans de Goede <hdegoede@...hat.com>,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Mathias Nyman <mathias.nyman@...el.com>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Guenter Roeck <linux@...ck-us.net>
Cc:     platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-usb@...r.kernel.org
Subject: Re: [PATCH v5 12/12] extcon: axp288: Set USB role where necessary

Hi,

Basically, I have no objection. But I'll reply the my ack tag 
after finishing the review of 'devcon and usb_role_switch' from USB maintainer.

And I have a question.
Before this patch, extcon-axp288 is used to detect charger connector
and extcon-intel-int3496 is used to detect the USB_HOST connector
on one h/w device?

Best Regards,
Chanwoo Choi
Samsung Electronics

On 2018년 03월 01일 00:07, Hans de Goede wrote:
> The AXP288 BC1.2 charger detection / extcon code may seem like a strange
> place to add code to control the USB role-switch on devices with an AXP288,
> but there are 2 reasons to do this inside the axp288 extcon code:
> 
> 1) On many devices the USB role is controlled by ACPI AML code, but the AML
>    code only switches between the host and none roles, because of Windows
>    not really using device mode. To make device mode work we need to toggle
>    between the none/device roles based on Vbus presence, and the axp288
>    extcon gets interrupts on Vbus insertion / removal.
> 
> 2) In order for our BC1.2 charger detection to work properly the role
>    mux must be properly set to device mode before we do the detection.
> 
> Also note the Kconfig help-text / obsolete depends on USB_PHY which are
> remnants from older never upstreamed code also controlling the mux from
> the axp288 extcon code.
> 
> This commit also adds code to get notifications from the INT3496 extcon
> device, which is used on some devices to notify the kernel about id-pin
> changes instead of them being handled through AML code.
> 
> This fixes:
> -Device mode not working on most CHT devices with an AXP288
> -Host mode not working on devices with an INT3496 ACPI device
> -Charger-type misdetection (always SDP) on devices with an INT3496 when the
>  USB role (always) gets initialized as host
> 
> Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
> Signed-off-by: Hans de Goede <hdegoede@...hat.com>
> ---
> Changes in v4:
> -Add Andy's Reviewed-by
> 
> Changes in v2:
> -Add depends on X86 to Kconfig (the AXP288 PMIC is only used on X86)
> -Use new acpi_dev_get_first_match_name() helper to get the INT3496 device-name
> -Add Heikki's Reviewed-by
> ---
>  drivers/extcon/Kconfig         |   3 +-
>  drivers/extcon/extcon-axp288.c | 177 +++++++++++++++++++++++++++++++++++++++--
>  2 files changed, 171 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
> index a7bca4207f44..de15bf55895b 100644
> --- a/drivers/extcon/Kconfig
> +++ b/drivers/extcon/Kconfig
> @@ -30,7 +30,8 @@ config EXTCON_ARIZONA
>  
>  config EXTCON_AXP288
>  	tristate "X-Power AXP288 EXTCON support"
> -	depends on MFD_AXP20X && USB_PHY
> +	depends on MFD_AXP20X && USB_SUPPORT && X86
> +	select USB_ROLE_SWITCH
>  	help
>  	  Say Y here to enable support for USB peripheral detection
>  	  and USB MUX switching by X-Power AXP288 PMIC.
> diff --git a/drivers/extcon/extcon-axp288.c b/drivers/extcon/extcon-axp288.c
> index 3ec4c715e240..51e77c7a32c2 100644
> --- a/drivers/extcon/extcon-axp288.c
> +++ b/drivers/extcon/extcon-axp288.c
> @@ -1,6 +1,7 @@
>  /*
>   * extcon-axp288.c - X-Power AXP288 PMIC extcon cable detection driver
>   *
> + * Copyright (c) 2017-2018 Hans de Goede <hdegoede@...hat.com>
>   * Copyright (C) 2015 Intel Corporation
>   * Author: Ramakrishna Pallala <ramakrishna.pallala@...el.com>
>   *
> @@ -14,6 +15,8 @@
>   * GNU General Public License for more details.
>   */
>  
> +#include <linux/acpi.h>
> +#include <linux/connection.h>
>  #include <linux/module.h>
>  #include <linux/kernel.h>
>  #include <linux/io.h>
> @@ -25,6 +28,11 @@
>  #include <linux/extcon-provider.h>
>  #include <linux/regmap.h>
>  #include <linux/mfd/axp20x.h>
> +#include <linux/usb/role.h>
> +#include <linux/workqueue.h>
> +
> +#include <asm/cpu_device_id.h>
> +#include <asm/intel-family.h>
>  
>  /* Power source status register */
>  #define PS_STAT_VBUS_TRIGGER		BIT(0)
> @@ -97,9 +105,19 @@ struct axp288_extcon_info {
>  	struct device *dev;
>  	struct regmap *regmap;
>  	struct regmap_irq_chip_data *regmap_irqc;
> +	struct usb_role_switch *role_sw;
> +	struct work_struct role_work;
>  	int irq[EXTCON_IRQ_END];
>  	struct extcon_dev *edev;
> +	struct extcon_dev *id_extcon;
> +	struct notifier_block id_nb;
>  	unsigned int previous_cable;
> +	bool vbus_attach;
> +};
> +
> +static const struct x86_cpu_id cherry_trail_cpu_ids[] = {
> +	{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_AIRMONT, X86_FEATURE_ANY },
> +	{}
>  };
>  
>  /* Power up/down reason string array */
> @@ -137,20 +155,74 @@ static void axp288_extcon_log_rsi(struct axp288_extcon_info *info)
>  	regmap_write(info->regmap, AXP288_PS_BOOT_REASON_REG, clear_mask);
>  }
>  
> -static int axp288_handle_chrg_det_event(struct axp288_extcon_info *info)
> +/*
> + * The below code to control the USB role-switch on devices with an AXP288
> + * may seem out of place, but there are 2 reasons why this is the best place
> + * to control the USB role-switch on such devices:
> + * 1) On many devices the USB role is controlled by AML code, but the AML code
> + *    only switches between the host and none roles, because of Windows not
> + *    really using device mode. To make device mode work we need to toggle
> + *    between the none/device roles based on Vbus presence, and this driver
> + *    gets interrupts on Vbus insertion / removal.
> + * 2) In order for our BC1.2 charger detection to work properly the role
> + *    mux must be properly set to device mode before we do the detection.
> + */
> +
> +/* Returns the id-pin value, note pulled low / false == host-mode */
> +static bool axp288_get_id_pin(struct axp288_extcon_info *info)
>  {
> -	int ret, stat, cfg, pwr_stat;
> -	u8 chrg_type;
> -	unsigned int cable = info->previous_cable;
> -	bool vbus_attach = false;
> +	enum usb_role role;
> +
> +	if (info->id_extcon)
> +		return extcon_get_state(info->id_extcon, EXTCON_USB_HOST) <= 0;
> +
> +	/* We cannot access the id-pin, see what mode the AML code has set */
> +	role = usb_role_switch_get_role(info->role_sw);
> +	return role != USB_ROLE_HOST;
> +}
> +
> +static void axp288_usb_role_work(struct work_struct *work)
> +{
> +	struct axp288_extcon_info *info =
> +		container_of(work, struct axp288_extcon_info, role_work);
> +	enum usb_role role;
> +	bool id_pin;
> +	int ret;
> +
> +	id_pin = axp288_get_id_pin(info);
> +	if (!id_pin)
> +		role = USB_ROLE_HOST;
> +	else if (info->vbus_attach)
> +		role = USB_ROLE_DEVICE;
> +	else
> +		role = USB_ROLE_NONE;
> +
> +	ret = usb_role_switch_set_role(info->role_sw, role);
> +	if (ret)
> +		dev_err(info->dev, "failed to set role: %d\n", ret);
> +}
> +
> +static bool axp288_get_vbus_attach(struct axp288_extcon_info *info)
> +{
> +	int ret, pwr_stat;
>  
>  	ret = regmap_read(info->regmap, AXP288_PS_STAT_REG, &pwr_stat);
>  	if (ret < 0) {
>  		dev_err(info->dev, "failed to read vbus status\n");
> -		return ret;
> +		return false;
>  	}
>  
> -	vbus_attach = (pwr_stat & PS_STAT_VBUS_VALID);
> +	return !!(pwr_stat & PS_STAT_VBUS_VALID);
> +}
> +
> +static int axp288_handle_chrg_det_event(struct axp288_extcon_info *info)
> +{
> +	int ret, stat, cfg;
> +	u8 chrg_type;
> +	unsigned int cable = info->previous_cable;
> +	bool vbus_attach = false;
> +
> +	vbus_attach = axp288_get_vbus_attach(info);
>  	if (!vbus_attach)
>  		goto no_vbus;
>  
> @@ -201,6 +273,12 @@ static int axp288_handle_chrg_det_event(struct axp288_extcon_info *info)
>  		info->previous_cable = cable;
>  	}
>  
> +	if (info->role_sw && info->vbus_attach != vbus_attach) {
> +		info->vbus_attach = vbus_attach;
> +		/* Setting the role can take a while */
> +		queue_work(system_long_wq, &info->role_work);
> +	}
> +
>  	return 0;
>  
>  dev_det_ret:
> @@ -210,6 +288,18 @@ static int axp288_handle_chrg_det_event(struct axp288_extcon_info *info)
>  	return ret;
>  }
>  
> +static int axp288_extcon_id_evt(struct notifier_block *nb,
> +				unsigned long event, void *param)
> +{
> +	struct axp288_extcon_info *info =
> +		container_of(nb, struct axp288_extcon_info, id_nb);
> +
> +	/* We may not sleep and setting the role can take a while */
> +	queue_work(system_long_wq, &info->role_work);
> +
> +	return NOTIFY_OK;
> +}
> +
>  static irqreturn_t axp288_extcon_isr(int irq, void *data)
>  {
>  	struct axp288_extcon_info *info = data;
> @@ -231,10 +321,20 @@ static void axp288_extcon_enable(struct axp288_extcon_info *info)
>  					BC_GLOBAL_RUN, BC_GLOBAL_RUN);
>  }
>  
> +static void axp288_put_role_sw(void *data)
> +{
> +	struct axp288_extcon_info *info = data;
> +
> +	cancel_work_sync(&info->role_work);
> +	usb_role_switch_put(info->role_sw);
> +}
> +
>  static int axp288_extcon_probe(struct platform_device *pdev)
>  {
>  	struct axp288_extcon_info *info;
>  	struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
> +	struct device *dev = &pdev->dev;
> +	const char *name;
>  	int ret, i, pirq;
>  
>  	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
> @@ -245,9 +345,33 @@ static int axp288_extcon_probe(struct platform_device *pdev)
>  	info->regmap = axp20x->regmap;
>  	info->regmap_irqc = axp20x->regmap_irqc;
>  	info->previous_cable = EXTCON_NONE;
> +	INIT_WORK(&info->role_work, axp288_usb_role_work);
> +	info->id_nb.notifier_call = axp288_extcon_id_evt;
>  
>  	platform_set_drvdata(pdev, info);
>  
> +	info->role_sw = usb_role_switch_get(dev);
> +	if (IS_ERR(info->role_sw))
> +		return PTR_ERR(info->role_sw);
> +	if (info->role_sw) {
> +		ret = devm_add_action_or_reset(dev, axp288_put_role_sw, info);
> +		if (ret)
> +			return ret;
> +
> +		name = acpi_dev_get_first_match_name("INT3496", NULL, -1);
> +		if (name) {
> +			info->id_extcon = extcon_get_extcon_dev(name);
> +			if (!info->id_extcon)
> +				return -EPROBE_DEFER;
> +
> +			dev_info(dev, "controlling USB role\n");
> +		} else {
> +			dev_info(dev, "controlling USB role based on Vbus presence\n");
> +		}
> +	}
> +
> +	info->vbus_attach = axp288_get_vbus_attach(info);
> +
>  	axp288_extcon_log_rsi(info);
>  
>  	/* Initialize extcon device */
> @@ -289,6 +413,19 @@ static int axp288_extcon_probe(struct platform_device *pdev)
>  		}
>  	}
>  
> +	if (info->id_extcon) {
> +		ret = devm_extcon_register_notifier_all(dev, info->id_extcon,
> +							&info->id_nb);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	/* Make sure the role-sw is set correctly before doing BC detection */
> +	if (info->role_sw) {
> +		queue_work(system_long_wq, &info->role_work);
> +		flush_work(&info->role_work);
> +	}
> +
>  	/* Start charger cable type detection */
>  	axp288_extcon_enable(info);
>  
> @@ -308,8 +445,32 @@ static struct platform_driver axp288_extcon_driver = {
>  		.name = "axp288_extcon",
>  	},
>  };
> -module_platform_driver(axp288_extcon_driver);
> +
> +static struct devcon axp288_extcon_role_sw_conn = {
> +	.endpoint[0] = "axp288_extcon",
> +	.endpoint[1] = "intel_xhci_usb_sw-role-switch",
> +	.id = "usb-role-switch",
> +};
> +
> +static int __init axp288_extcon_init(void)
> +{
> +	if (x86_match_cpu(cherry_trail_cpu_ids))
> +		add_device_connection(&axp288_extcon_role_sw_conn);
> +
> +	return platform_driver_register(&axp288_extcon_driver);
> +}
> +module_init(axp288_extcon_init);
> +
> +static void __exit axp288_extcon_exit(void)
> +{
> +	if (x86_match_cpu(cherry_trail_cpu_ids))
> +		remove_device_connection(&axp288_extcon_role_sw_conn);
> +
> +	platform_driver_unregister(&axp288_extcon_driver);
> +}
> +module_exit(axp288_extcon_exit);
>  
>  MODULE_AUTHOR("Ramakrishna Pallala <ramakrishna.pallala@...el.com>");
> +MODULE_AUTHOR("Hans de Goede <hdegoede@...hat.com>");
>  MODULE_DESCRIPTION("X-Powers AXP288 extcon driver");
>  MODULE_LICENSE("GPL v2");
> 

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