Message-ID: <20150605070332.GI15169@shlinux2>
Date:	Fri, 5 Jun 2015 15:03:34 +0800
From:	Peter Chen <peter.chen@...escale.com>
To:	"Ivan T. Ivanov" <ivan.ivanov@...aro.org>
CC:	Kumar Gala <galak@...eaurora.org>,
	Rob Herring <robh+dt@...nel.org>,
	"Pawel Moll" <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-usb@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>
Subject: Re: [PATCH v3] usb: chipidea: Use extcon framework for VBUS and ID
 detect

On Tue, Jun 02, 2015 at 04:14:33PM +0300, Ivan T. Ivanov wrote:
> On recent Qualcomm platforms VBUS and ID lines are not routed to
> USB PHY LINK controller. Use extcon framework to receive connect
> and disconnect ID and VBUS notification.
> 
> Signed-off-by: Ivan T. Ivanov <ivan.ivanov@...aro.org>
> ---
> Changes sice v2 [1].
> 
> * Simulate IRQ on extcon event - used to trigger OTG state machine.
> 

No, you may not need to trigger complicate OTG FSM, instead, the
role switch based on ID value is ok.

> I have to admit that I couldn't test complete Chipidea OTG state machine,
> because my setup is little weird. I am using "qcom,usb-otg-ci" as PHY/OTG
> provider, "qcom,ehci-host" as host controller driver and "qcom,ci-hdrc" for
> device role.
> 

Then, I am puzzled what kinds of flow you have tested in this patch?
extcon is really needed for chipidea core, but I hope we have tested
patch set based on it. Rob Herring have tested Marvell's host controller
can also use chipidea host driver, I think the same for qualcomm's.
The otg flow at phy-msm-usb.c can be removed and use chipidea's instead, and
only remain phy part at it.

Current role switch and vbus flow are based on otgsc register, you can
improve it by adding extcon support.

Peter

> There could be patch conflict regarding ci-hdrc-qcom.txt, because Rob Herring
> is consolidating DT binding for all vendors which integrate this device [2]
> 
> [1] https://lkml.org/lkml/2015/4/15/283
> [2] http://www.spinics.net/lists/linux-usb/msg125453.html
> 
>  .../devicetree/bindings/usb/ci-hdrc-qcom.txt       |   9 ++
>  drivers/usb/chipidea/Kconfig                       |   1 +
>  drivers/usb/chipidea/core.c                        | 125 +++++++++++++++++++++
>  drivers/usb/chipidea/otg.c                         |  55 ++++++++-
>  include/linux/usb/chipidea.h                       |  24 ++++
>  5 files changed, 212 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/usb/ci-hdrc-qcom.txt b/Documentation/devicetree/bindings/usb/ci-hdrc-qcom.txt
> index f2899b5..c635aca 100644
> --- a/Documentation/devicetree/bindings/usb/ci-hdrc-qcom.txt
> +++ b/Documentation/devicetree/bindings/usb/ci-hdrc-qcom.txt
> @@ -7,6 +7,14 @@ Required properties:
>  - usb-phy:      phandle for the PHY device
>  - dr_mode:      Should be "peripheral"
> 
> +Optional properties:
> +- extcon:       phandles to external connector devices. First phandle
> +                should point to external connector, which provide "USB"
> +                cable events, the second should point to external connector
> +                device, which provide "USB-HOST" cable events. If one of
> +                the external connector devices is not required, empty <0>
> +                phandle should be specified.
> +
>  Examples:
>  	gadget@...55000 {
>  		compatible = "qcom,ci-hdrc";
> @@ -14,4 +22,5 @@ Examples:
>  		dr_mode = "peripheral";
>  		interrupts = <0 134 0>;
>  		usb-phy = <&usbphy0>;
> +		extcon = <0>, <&usb_id>;
>  	};
> diff --git a/drivers/usb/chipidea/Kconfig b/drivers/usb/chipidea/Kconfig
> index 5ce3f1d..5619b8c 100644
> --- a/drivers/usb/chipidea/Kconfig
> +++ b/drivers/usb/chipidea/Kconfig
> @@ -1,6 +1,7 @@
>  config USB_CHIPIDEA
>  	tristate "ChipIdea Highspeed Dual Role Controller"
>  	depends on ((USB_EHCI_HCD && USB_GADGET) || (USB_EHCI_HCD && !USB_GADGET) || (!USB_EHCI_HCD && USB_GADGET)) && HAS_DMA
> +	select EXTCON
>  	help
>  	  Say Y here if your system has a dual role high speed USB
>  	  controller based on ChipIdea silicon IP. Currently, only the
> diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
> index 74fea4f..2ae2c09 100644
> --- a/drivers/usb/chipidea/core.c
> +++ b/drivers/usb/chipidea/core.c
> @@ -47,6 +47,7 @@
>  #include <linux/delay.h>
>  #include <linux/device.h>
>  #include <linux/dma-mapping.h>
> +#include <linux/extcon.h>
>  #include <linux/phy/phy.h>
>  #include <linux/platform_device.h>
>  #include <linux/module.h>
> @@ -557,9 +558,47 @@ static irqreturn_t ci_irq(int irq, void *data)
>  	return ret;
>  }
> 
> +static int ci_vbus_notifier(struct notifier_block *nb, unsigned long event,
> +			    void *ptr)
> +{
> +	struct ci_hdrc_cable *vbus = container_of(nb, struct ci_hdrc_cable, nb);
> +	struct ci_hdrc *ci = vbus->ci;
> +
> +	if (event)
> +		vbus->state = true;
> +	else
> +		vbus->state = false;
> +
> +	vbus->changed = true;
> +
> +	ci_irq(ci->irq, ci);
> +	return NOTIFY_DONE;
> +}
> +
> +static int ci_id_notifier(struct notifier_block *nb, unsigned long event,
> +			  void *ptr)
> +{
> +	struct ci_hdrc_cable *id = container_of(nb, struct ci_hdrc_cable, nb);
> +	struct ci_hdrc *ci = id->ci;
> +
> +	if (event)
> +		id->state = false;
> +	else
> +		id->state = true;
> +
> +	id->changed = true;
> +
> +	ci_irq(ci->irq, ci);
> +	return NOTIFY_DONE;
> +}
> +
>  static int ci_get_platdata(struct device *dev,
>  		struct ci_hdrc_platform_data *platdata)
>  {
> +	struct extcon_dev *ext_vbus, *ext_id;
> +	struct ci_hdrc_cable *cable;
> +	int ret;
> +
>  	if (!platdata->phy_mode)
>  		platdata->phy_mode = of_usb_get_phy_mode(dev->of_node);
> 
> @@ -591,9 +630,89 @@ static int ci_get_platdata(struct device *dev,
>  	if (of_usb_get_maximum_speed(dev->of_node) == USB_SPEED_FULL)
>  		platdata->flags |= CI_HDRC_FORCE_FULLSPEED;
> 
> +	ext_id = ERR_PTR(-ENODEV);
> +	ext_vbus = ERR_PTR(-ENODEV);
> +	if (of_property_read_bool(dev->of_node, "extcon")) {
> +		/* Each one of them is not mandatory */
> +		ext_vbus = extcon_get_edev_by_phandle(dev, 0);
> +		if (IS_ERR(ext_vbus) && PTR_ERR(ext_vbus) != -ENODEV)
> +			return PTR_ERR(ext_vbus);
> +
> +		ext_id = extcon_get_edev_by_phandle(dev, 1);
> +		if (IS_ERR(ext_id) && PTR_ERR(ext_id) != -ENODEV)
> +			return PTR_ERR(ext_id);
> +	}
> +
> +	cable = &platdata->vbus_extcon;
> +	cable->nb.notifier_call = ci_vbus_notifier;
> +	cable->edev = ext_vbus;
> +
> +	if (!IS_ERR(ext_vbus)) {
> +		ret = extcon_get_cable_state(cable->edev, "USB");
> +		if (ret)
> +			cable->state = true;
> +		else
> +			cable->state = false;
> +	}
> +
> +	cable = &platdata->id_extcon;
> +	cable->nb.notifier_call = ci_id_notifier;
> +	cable->edev = ext_id;
> +
> +	if (!IS_ERR(ext_id)) {
> +		ret = extcon_get_cable_state(cable->edev, "USB-HOST");
> +		if (ret)
> +			cable->state = false;
> +		else
> +			cable->state = true;
> +	}
> +	return 0;
> +}
> +
> +static int ci_extcon_register(struct ci_hdrc *ci)
> +{
> +	struct ci_hdrc_cable *id, *vbus;
> +	int ret;
> +
> +	id = &ci->platdata->id_extcon;
> +	id->ci = ci;
> +	if (!IS_ERR(id->edev)) {
> +		ret = extcon_register_interest(&id->conn, id->edev->name,
> +					       "USB-HOST", &id->nb);
> +		if (ret < 0) {
> +			dev_err(ci->dev, "register ID failed\n");
> +			return ret;
> +		}
> +	}
> +
> +	vbus = &ci->platdata->vbus_extcon;
> +	vbus->ci = ci;
> +	if (!IS_ERR(vbus->edev)) {
> +		ret = extcon_register_interest(&vbus->conn, vbus->edev->name,
> +					       "USB", &vbus->nb);
> +		if (ret < 0) {
> +			extcon_unregister_interest(&id->conn);
> +			dev_err(ci->dev, "register VBUS failed\n");
> +			return ret;
> +		}
> +	}
> +
>  	return 0;
>  }
> 
> +static void ci_extcon_unregister(struct ci_hdrc *ci)
> +{
> +	struct ci_hdrc_cable *cable;
> +
> +	cable = &ci->platdata->id_extcon;
> +	if (!IS_ERR(cable->edev))
> +		extcon_unregister_interest(&cable->conn);
> +
> +	cable = &ci->platdata->vbus_extcon;
> +	if (!IS_ERR(cable->edev))
> +		extcon_unregister_interest(&cable->conn);
> +}
> +
>  static DEFINE_IDA(ci_ida);
> 
>  struct platform_device *ci_hdrc_add_device(struct device *dev,
> @@ -817,6 +936,10 @@ static int ci_hdrc_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto stop;
> 
> +	ret = ci_extcon_register(ci);
> +	if (ret)
> +		goto stop;
> +
>  	if (ci->supports_runtime_pm) {
>  		pm_runtime_set_active(&pdev->dev);
>  		pm_runtime_enable(&pdev->dev);
> @@ -834,6 +957,7 @@ static int ci_hdrc_probe(struct platform_device *pdev)
>  	if (!ret)
>  		return 0;
> 
> +	ci_extcon_unregister(ci);
>  stop:
>  	ci_role_destroy(ci);
>  deinit_phy:
> @@ -853,6 +977,7 @@ static int ci_hdrc_remove(struct platform_device *pdev)
>  	}
> 
>  	dbg_remove_files(ci);
> +	ci_extcon_unregister(ci);
>  	ci_role_destroy(ci);
>  	ci_hdrc_enter_lpm(ci, true);
>  	ci_usb_phy_exit(ci);
> diff --git a/drivers/usb/chipidea/otg.c b/drivers/usb/chipidea/otg.c
> index ad6c87a..77fe2df 100644
> --- a/drivers/usb/chipidea/otg.c
> +++ b/drivers/usb/chipidea/otg.c
> @@ -30,7 +30,41 @@
>   */
>  u32 hw_read_otgsc(struct ci_hdrc *ci, u32 mask)
>  {
> -	return hw_read(ci, OP_OTGSC, mask);
> +	struct ci_hdrc_cable *cable;
> +	u32 val = hw_read(ci, OP_OTGSC, mask);
> +
> +	/*
> +	 * If using extcon framework for VBUS and/or ID signal
> +	 * detection overwrite OTGSC resiter value
> +	 */
> +	cable = &ci->platdata->vbus_extcon;
> +	if (!IS_ERR(cable->edev)) {
> +		if (cable->changed)
> +			val |= OTGSC_BSVIS;
> +		else
> +			val &= ~OTGSC_BSVIS;
> +
> +		if (cable->state)
> +			val |= OTGSC_BSV;
> +		else
> +			val &= ~OTGSC_BSV;
> +	}
> +
> +	cable = &ci->platdata->id_extcon;
> +	if (!IS_ERR(cable->edev)) {
> +		if (cable->changed)
> +			val |= OTGSC_IDIS;
> +		else
> +			val &= ~OTGSC_IDIS;
> +
> +		if (cable->state)
> +			val |= OTGSC_ID;
> +		else
> +			val &= ~OTGSC_ID;
> +	}
> +
> +	val &= mask;
> +	return val;
>  }
> 
>  /**
> @@ -40,7 +74,24 @@ u32 hw_read_otgsc(struct ci_hdrc *ci, u32 mask)
>   */
>  void hw_write_otgsc(struct ci_hdrc *ci, u32 mask, u32 data)
>  {
> -	hw_write(ci, OP_OTGSC, mask | OTGSC_INT_STATUS_BITS, data);
> +	struct ci_hdrc_cable *cable;
> +
> +	mask |= OTGSC_INT_STATUS_BITS;
> +
> +	/* clear artificial bits */
> +	cable = &ci->platdata->vbus_extcon;
> +	if (!IS_ERR(cable->edev)) {
> +		if (data & OTGSC_BSVIS)
> +			cable->changed = false;
> +	}
> +
> +	cable = &ci->platdata->id_extcon;
> +	if (!IS_ERR(cable->edev)) {
> +		if (data & OTGSC_IDIS)
> +			cable->changed = false;
> +	}
> +
> +	hw_write(ci, OP_OTGSC, mask, data);
>  }
> 
>  /**
> diff --git a/include/linux/usb/chipidea.h b/include/linux/usb/chipidea.h
> index ab94f78..05915cb1 100644
> --- a/include/linux/usb/chipidea.h
> +++ b/include/linux/usb/chipidea.h
> @@ -5,9 +5,29 @@
>  #ifndef __LINUX_USB_CHIPIDEA_H
>  #define __LINUX_USB_CHIPIDEA_H
> 
> +#include <linux/extcon.h>
>  #include <linux/usb/otg.h>
> 
>  struct ci_hdrc;
> +
> +/**
> + * struct ci_hdrc_cable - structure for external connector cable state tracking
> + * @state: current state of the line
> + * @changed: set to true when extcon event happen
> + * @edev: device which generate events
> + * @ci: driver state of the chipidea device
> + * @nb: hold event notification callback
> + * @conn: used for notification registration
> + */
> +struct ci_hdrc_cable {
> +	bool				state;
> +	bool				changed;
> +	struct extcon_dev		*edev;
> +	struct ci_hdrc			*ci;
> +	struct notifier_block		nb;
> +	struct extcon_specific_cable_nb conn;
> +};
> +
>  struct ci_hdrc_platform_data {
>  	const char	*name;
>  	/* offset of the capability registers */
> @@ -35,6 +55,10 @@ struct ci_hdrc_platform_data {
>  	void	(*notify_event) (struct ci_hdrc *ci, unsigned event);
>  	struct regulator	*reg_vbus;
>  	bool			tpl_support;
> +
> +	/* VBUS and ID signal state tracking, using extcon framework */
> +	struct ci_hdrc_cable		vbus_extcon;
> +	struct ci_hdrc_cable		id_extcon;
>  };
> 
>  /* Default offset of capability registers */
> --
> 1.9.1
> 

-- 

Best Regards,
Peter Chen
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