RE: [PATCH 2/3] phy: rcar-gen2 usb: Add Host/Function switching for USB0

From: Phil Edworthy
Date: Thu Jul 02 2015 - 08:45:56 EST

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In reply to: Kishon Vijay Abraham I: "Re: [PATCH 2/3] phy: rcar-gen2 usb: Add Host/Function switching for USB0"
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Hi Kishon,

On 02 July 2015 09:22, Kishon wrote:
> Hi,
>
> On Monday 22 June 2015 08:12 PM, Phil Edworthy wrote:
> > Instead of statically selecting the PHY connection to either the
> > USBHS (Function) or PCI0 (Host) IP blocks, this change allows the
> > dts to specifiy gpio pins for the vbus and id signals. Additional
> > gpio pins are used to control power to an external OTG device and
> > an override to turn vbus on/off.
> >
> > Note: the R-Car USB PHY only allows this Host/Function switching
> > on channel 0.
> >
> > This has been tested on a r8a7791 based Koelsch board, which uses
> > a MAX3355 device to supply vbus power when needed.
> >
> > Signed-off-by: Phil Edworthy <phil.edworthy@xxxxxxxxxxx>
> > ---
> > drivers/phy/phy-rcar-gen2.c | 269
> ++++++++++++++++++++++++++++++++++++++++----
> > 1 file changed, 247 insertions(+), 22 deletions(-)
> >
> > diff --git a/drivers/phy/phy-rcar-gen2.c b/drivers/phy/phy-rcar-gen2.c
> > index 97d45f4..8564e7d 100644
> > --- a/drivers/phy/phy-rcar-gen2.c
> > +++ b/drivers/phy/phy-rcar-gen2.c
> > @@ -1,5 +1,5 @@
> > /*
> > - * Renesas R-Car Gen2 PHY driver
> > + * Renesas R-Car Gen2 USB PHY driver
> > *
> > * Copyright (C) 2014 Renesas Solutions Corp.
> > * Copyright (C) 2014 Cogent Embedded, Inc.
> > @@ -12,11 +12,16 @@
> > #include <linux/clk.h>
> > #include <linux/delay.h>
> > #include <linux/io.h>
> > +#include <linux/interrupt.h>
> > #include <linux/module.h>
> > #include <linux/of.h>
> > +#include <linux/of_gpio.h>
> > #include <linux/phy/phy.h>
> > #include <linux/platform_device.h>
> > #include <linux/spinlock.h>
> > +#include <linux/usb/gadget.h>
> > +#include <linux/usb/otg.h>
> > +#include <linux/workqueue.h>
> >
> > #include <asm/cmpxchg.h>
> >
> > @@ -58,6 +63,18 @@ struct rcar_gen2_channel {
> > struct rcar_gen2_phy phys[PHYS_PER_CHANNEL];
> > int selected_phy;
> > u32 select_mask;
> > +
> > + /* external power enable pin */
> > + int gpio_pwr;
> > +
> > + /* Host/Function switching */
> > + struct delayed_work work;
> > + int use_otg;
> > + int gpio_vbus;
> > + int gpio_id;
> > + int gpio_vbus_pwr;
> > + struct usb_phy *usbphy;
>
> Using usb_phy is a step backwards IMO. We should rather try to get the missing
> functionality adding in Generic PHY.
Ok, that will take quite a bit more work. Do you know if anyone is working on this?

> Thanks
> Kishon
>
> > + struct usb_otg *otg;
> > };
> >
> > struct rcar_gen2_phy_driver {
> > @@ -68,31 +85,50 @@ struct rcar_gen2_phy_driver {
> > struct rcar_gen2_channel *channels;
> > };
> >
> > -static int rcar_gen2_phy_init(struct phy *p)
> > +static void rcar_gen2_phy_switch(struct rcar_gen2_channel *channel,
> > + u32 select_value)
> > {
> > - struct rcar_gen2_phy *phy = phy_get_drvdata(p);
> > - struct rcar_gen2_channel *channel = phy->channel;
> > struct rcar_gen2_phy_driver *drv = channel->drv;
> > unsigned long flags;
> > u32 ugctrl2;
> >
> > - /*
> > - * Try to acquire exclusive access to PHY. The first driver calling
> > - * phy_init() on a given channel wins, and all attempts to use another
> > - * PHY on this channel will fail until phy_exit() is called by the first
> > - * driver. Achieving this with cmpxcgh() should be SMP-safe.
> > - */
> > - if (cmpxchg(&channel->selected_phy, -1, phy->number) != -1)
> > - return -EBUSY;
> > -
> > - clk_prepare_enable(drv->clk);
> > -
> > spin_lock_irqsave(&drv->lock, flags);
> > ugctrl2 = readl(drv->base + USBHS_UGCTRL2);
> > ugctrl2 &= ~channel->select_mask;
> > - ugctrl2 |= phy->select_value;
> > + ugctrl2 |= select_value;
> > writel(ugctrl2, drv->base + USBHS_UGCTRL2);
> > spin_unlock_irqrestore(&drv->lock, flags);
> > +}
> > +
> > +static int rcar_gen2_phy_init(struct phy *p)
> > +{
> > + struct rcar_gen2_phy *phy = phy_get_drvdata(p);
> > + struct rcar_gen2_channel *channel = phy->channel;
> > + struct rcar_gen2_phy_driver *drv = channel->drv;
> > +
> > + if (!channel->use_otg) {
> > + /*
> > + * Static Host/Function role.
> > + * Try to acquire exclusive access to PHY. The first driver
> > + * calling phy_init() on a given channel wins, and all attempts
> > + * to use another PHY on this channel will fail until
> > + * phy_exit() is called by the first driver. Achieving this
> > + * with cmpxcgh() should be SMP-safe.
> > + */
> > + if (cmpxchg(&channel->selected_phy, -1, phy->number) != -1)
> > + return -EBUSY;
> > +
> > + clk_prepare_enable(drv->clk);
> > + rcar_gen2_phy_switch(channel, phy->select_value);
> > + } else {
> > + /*
> > + * Using Host/Function switching, so schedule work to determine
> > + * which role to use.
> > + */
> > + clk_prepare_enable(drv->clk);
> > + schedule_delayed_work(&channel->work, 100);
> > + }
> > +
> > return 0;
> > }
> >
> > @@ -117,9 +153,9 @@ static int rcar_gen2_phy_power_on(struct phy *p)
> > u32 value;
> > int err = 0, i;
> >
> > - /* Skip if it's not USBHS */
> > - if (phy->select_value != USBHS_UGCTRL2_USB0SEL_HS_USB)
> > - return 0;
> > + /* Optional external power pin */
> > + if (gpio_is_valid(phy->channel->gpio_pwr))
> > + gpio_direction_output(phy->channel->gpio_pwr, 1);
> >
> > spin_lock_irqsave(&drv->lock, flags);
> >
> > @@ -160,9 +196,9 @@ static int rcar_gen2_phy_power_off(struct phy *p)
> > unsigned long flags;
> > u32 value;
> >
> > - /* Skip if it's not USBHS */
> > - if (phy->select_value != USBHS_UGCTRL2_USB0SEL_HS_USB)
> > - return 0;
> > + /* External power pin */
> > + if (gpio_is_valid(phy->channel->gpio_pwr))
> > + gpio_direction_output(phy->channel->gpio_pwr, 0);
> >
> > spin_lock_irqsave(&drv->lock, flags);
> >
> > @@ -236,6 +272,132 @@ static const u32 select_value[][PHYS_PER_CHANNEL]
> = {
> > [2] = { USBHS_UGCTRL2_USB2SEL_PCI,
> USBHS_UGCTRL2_USB2SEL_USB30 },
> > };
> >
> > +
> > +#define VBUS_IRQ_FLAGS \
> > + (IRQF_SHARED | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
> > +
> > +static void gpio_vbus_work(struct work_struct *work)
> > +{
> > + struct rcar_gen2_channel *channel = container_of(work,
> > + struct rcar_gen2_channel, work.work);
> > + struct usb_phy *usbphy = channel->usbphy;
> > + int status, vbus, id;
> > +
> > + vbus = !!gpio_get_value(channel->gpio_vbus);
> > + id = !!gpio_get_value(channel->gpio_id);
> > +
> > + /* Switch the PHY over */
> > + if (id)
> > + rcar_gen2_phy_switch(channel,
> USBHS_UGCTRL2_USB0SEL_HS_USB);
> > + else
> > + rcar_gen2_phy_switch(channel,
> USBHS_UGCTRL2_USB0SEL_PCI);
> > +
> > + /* If VBUS is powered and we are not the initial Host, turn off VBUS */
> > + if (gpio_is_valid(channel->gpio_vbus_pwr))
> > + gpio_direction_output(channel->gpio_vbus_pwr, !(id && vbus));
> > +
> > + if (!channel->otg->gadget)
> > + return;
> > +
> > + /* Function handling: vbus=1 when initially plugged into a Host */
> > + if (vbus) {
> > + status = USB_EVENT_VBUS;
> > + usbphy->otg->state = OTG_STATE_B_PERIPHERAL;
> > + usbphy->last_event = status;
> > + usb_gadget_vbus_connect(usbphy->otg->gadget);
> > +
> > + atomic_notifier_call_chain(&usbphy->notifier,
> > + status, usbphy->otg->gadget);
> > + } else {
> > + usb_gadget_vbus_disconnect(usbphy->otg->gadget);
> > + status = USB_EVENT_NONE;
> > + usbphy->otg->state = OTG_STATE_B_IDLE;
> > + usbphy->last_event = status;
> > +
> > + atomic_notifier_call_chain(&usbphy->notifier,
> > + status, usbphy->otg->gadget);
> > + }
> > +}
> > +
> > +/* VBUS change IRQ handler */
> > +static irqreturn_t gpio_vbus_irq(int irq, void *data)
> > +{
> > + struct rcar_gen2_channel *channel = data;
> > +
> > + /* Wait 20ms before doing anything as VBUS needs to settle */
> > + schedule_delayed_work(&channel->work, msecs_to_jiffies(20));
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static int probe_otg(struct platform_device *pdev,
> > + struct rcar_gen2_phy_driver *drv)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct rcar_gen2_channel *ch = drv->channels;
> > + int irq;
> > + int ret;
> > +
> > + /* GPIOs for Host/Fn switching */
> > + ch->gpio_id = of_get_named_gpio_flags(dev->of_node, "renesas,id",
> > + 0, NULL);
> > + ch->gpio_vbus = of_get_named_gpio_flags(dev->of_node,
> "renesas,vbus",
> > + 0, NULL);
> > +
> > + /* Need valid ID and VBUS gpios for Host/Fn switching */
> > + if (gpio_is_valid(ch->gpio_id) && gpio_is_valid(ch->gpio_vbus)) {
> > + ch->use_otg = 1;
> > +
> > + /* GPIO for ID input */
> > + ret = devm_gpio_request_one(dev, ch->gpio_id, GPIOF_IN,
> "id");
> > + if (ret)
> > + return ret;
> > +
> > + /* GPIO for VBUS input */
> > + ret = devm_gpio_request_one(dev, ch->gpio_vbus, GPIOF_IN,
> "vbus");
> > + if (ret)
> > + return ret;
> > +
> > + irq = gpio_to_irq(ch->gpio_vbus);
> > + ret = devm_request_irq(dev, irq, gpio_vbus_irq,
> VBUS_IRQ_FLAGS,
> > + "vbus_detect", ch);
> > + if (ret)
> > + return ret;
> > +
> > + /* Optional GPIO for VBUS power */
> > + ch->gpio_vbus_pwr = of_get_named_gpio_flags(dev->of_node,
> > + "renesas,vbus-pwr", 0, NULL);
> > + if (gpio_is_valid(ch->gpio_id)) {
> > + ret = devm_gpio_request_one(dev, ch->gpio_vbus_pwr,
> > + GPIOF_OUT_INIT_LOW, "vbus-pwr");
> > + if (ret)
> > + return ret;
> > + }
> > +
> > + } else if (gpio_is_valid(ch->gpio_id)) {
> > + dev_err(dev, "Failed to get VBUS gpio\n");
> > + return ch->gpio_vbus;
> > + } else if (gpio_is_valid(ch->gpio_vbus)) {
> > + dev_err(dev, "Failed to get ID gpio\n");
> > + return ch->gpio_id;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +/* bind/unbind the peripheral controller */
> > +static int rcar_gen2_usb_set_peripheral(struct usb_otg *otg,
> > + struct usb_gadget *gadget)
> > +{
> > + otg->gadget = gadget;
> > + if (!gadget) {
> > + usb_gadget_vbus_disconnect(otg->gadget);
> > + otg->state = OTG_STATE_UNDEFINED;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > static int rcar_gen2_phy_probe(struct platform_device *pdev)
> > {
> > struct device *dev = &pdev->dev;
> > @@ -245,7 +407,9 @@ static int rcar_gen2_phy_probe(struct platform_device
> *pdev)
> > struct resource *res;
> > void __iomem *base;
> > struct clk *clk;
> > + struct usb_otg *otg;
> > int i = 0;
> > + int err;
> >
> > if (!dev->of_node) {
> > dev_err(dev,
> > @@ -280,6 +444,57 @@ static int rcar_gen2_phy_probe(struct platform_device
> *pdev)
> > if (!drv->channels)
> > return -ENOMEM;
> >
> > + /* USB0 optional GPIO power pin for external devices */
> > + drv->channels->gpio_pwr = of_get_named_gpio_flags(dev->of_node,
> > + "renesas,pwr", 0, NULL);
> > + if (drv->channels->gpio_pwr == -EPROBE_DEFER)
> > + return -EPROBE_DEFER;
> > +
> > + if (gpio_is_valid(drv->channels->gpio_pwr)) {
> > + err = devm_gpio_request(dev, drv->channels->gpio_pwr,
> "pwr");
> > + if (err)
> > + return err;
> > + }
> > +
> > + /* USB0 Host/Function switching info */
> > + err = probe_otg(pdev, drv);
> > + if (err)
> > + return err;
> > +
> > + /*
> > + * The PHY connected to channel 0 can be used to steer signals to the
> > + * USB Host IP that stils behind a PCI bridge (pci0), or the USB Func
> > + * IP (hsusb). We can dynamically switch this based on VBUS and ID
> > + * signals connected to gpios, to get something approaching OTG.
> > + */
> > + if (drv->channels->use_otg) {
> > + struct usb_phy *usbphy;
> > +
> > + usbphy = devm_kzalloc(dev, sizeof(*usbphy), GFP_KERNEL);
> > + if (!usbphy)
> > + return -ENOMEM;
> > +
> > + otg = devm_kzalloc(dev, sizeof(*otg), GFP_KERNEL);
> > + if (!otg)
> > + return -ENOMEM;
> > +
> > + usbphy->dev = dev;
> > + usbphy->otg = otg;
> > +
> > + otg->usb_phy = usbphy;
> > + otg->state = OTG_STATE_UNDEFINED;
> > + otg->set_peripheral = rcar_gen2_usb_set_peripheral;
> > +
> > + drv->channels->otg = otg;
> > + drv->channels->usbphy = usbphy;
> > +
> > + ATOMIC_INIT_NOTIFIER_HEAD(&usbphy->notifier);
> > +
> > + INIT_DELAYED_WORK(&drv->channels->work, gpio_vbus_work);
> > +
> > + usb_add_phy_dev(usbphy);
> > + }
> > +
> > for_each_child_of_node(dev->of_node, np) {
> > struct rcar_gen2_channel *channel = drv->channels + i;
> > u32 channel_num;
> > @@ -288,6 +503,8 @@ static int rcar_gen2_phy_probe(struct platform_device
> *pdev)
> > channel->of_node = np;
> > channel->drv = drv;
> > channel->selected_phy = -1;
> > + if (i != 0)
> > + channel->gpio_pwr = -ENOENT;
> >
> > error = of_property_read_u32(np, "reg", &channel_num);
> > if (error || channel_num > 2) {
> > @@ -323,6 +540,14 @@ static int rcar_gen2_phy_probe(struct platform_device
> *pdev)
> >
> > dev_set_drvdata(dev, drv);
> >
> > + /*
> > + * If we already have something plugged into USB0, we won't get an edge
> > + * on VBUS, so we have to manually schedule work to look at the VBUS
> > + * and ID signals.
> > + */
> > + if (drv->channels->use_otg)
> > + schedule_delayed_work(&drv->channels->work,
> msecs_to_jiffies(100));
> > +
> > return 0;
> > }

Thanks
Phil
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Next message: Miklos Szeredi: "[GIT PULL] overlayfs update for 4.2"
Previous message: Arnd Bergmann: "Re: [PATCH v2 3/9] arm: twr-k70f120m: clock driver for Kinetis SoC"
In reply to: Kishon Vijay Abraham I: "Re: [PATCH 2/3] phy: rcar-gen2 usb: Add Host/Function switching for USB0"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]