usb: phy: generic: add vbus support

Add support for vbus detection and power supply. This code is more or
less stolen from phy-gpio-vbus-usb.c, and aims at providing a detection
mechanism for VBus (ie. usb cable plug) based on a GPIO line, and a
power supply activation which draws current from the VBus.

[ balbi@ti.com : fix build break ]

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 90 insertions, 1 deletions

diff --git a/drivers/usb/phy/phy-generic.c b/drivers/usb/phy/phy-generic.c
index d53928f3a6ea..dd05254241fb 100644
--- a/drivers/usb/phy/phy-generic.c
+++ b/drivers/usb/phy/phy-generic.c
@@ -27,6 +27,7 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/dma-mapping.h>
+#include <linux/usb/gadget.h>
 #include <linux/usb/otg.h>
 #include <linux/usb/usb_phy_generic.h>
 #include <linux/slab.h>
@@ -39,6 +40,9 @@
 
 #include "phy-generic.h"
 
+#define VBUS_IRQ_FLAGS \
+        (IRQF_SHARED | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
+
 struct platform_device *usb_phy_generic_register(void)
 {
         return platform_device_register_simple("usb_phy_generic",
@@ -66,6 +70,73 @@ static void nop_reset_set(struct usb_phy_generic *nop, int asserted)
                 usleep_range(10000, 20000);
 }
 
+/* interface to regulator framework */
+static void nop_set_vbus_draw(struct usb_phy_generic *nop, unsigned mA)
+{
+        struct regulator *vbus_draw = nop->vbus_draw;
+        int enabled;
+        int ret;
+
+        if (!vbus_draw)
+                return;
+
+        enabled = nop->vbus_draw_enabled;
+        if (mA) {
+                regulator_set_current_limit(vbus_draw, 0, 1000 * mA);
+                if (!enabled) {
+                        ret = regulator_enable(vbus_draw);
+                        if (ret < 0)
+                                return;
+                        nop->vbus_draw_enabled = 1;
+                }
+        } else {
+                if (enabled) {
+                        ret = regulator_disable(vbus_draw);
+                        if (ret < 0)
+                                return;
+                        nop->vbus_draw_enabled = 0;
+                }
+        }
+        nop->mA = mA;
+}
+
+
+static irqreturn_t nop_gpio_vbus_thread(int irq, void *data)
+{
+        struct usb_phy_generic *nop = data;
+        struct usb_otg *otg = nop->phy.otg;
+        int vbus, status;
+
+        vbus = gpiod_get_value(nop->gpiod_vbus);
+        if ((vbus ^ nop->vbus) == 0)
+                return IRQ_HANDLED;
+        nop->vbus = vbus;
+
+        if (vbus) {
+                status = USB_EVENT_VBUS;
+                otg->state = OTG_STATE_B_PERIPHERAL;
+                nop->phy.last_event = status;
+                usb_gadget_vbus_connect(otg->gadget);
+
+                /* drawing a "unit load" is *always* OK, except for OTG */
+                nop_set_vbus_draw(nop, 100);
+
+                atomic_notifier_call_chain(&nop->phy.notifier, status,
+                                           otg->gadget);
+        } else {
+                nop_set_vbus_draw(nop, 0);
+
+                usb_gadget_vbus_disconnect(otg->gadget);
+                status = USB_EVENT_NONE;
+                otg->state = OTG_STATE_B_IDLE;
+                nop->phy.last_event = status;
+
+                atomic_notifier_call_chain(&nop->phy.notifier, status,
+                                           otg->gadget);
+        }
+        return IRQ_HANDLED;
+}
+
 int usb_gen_phy_init(struct usb_phy *phy)
 {
         struct usb_phy_generic *nop = dev_get_drvdata(phy->dev);
@@ -149,17 +220,23 @@ int usb_phy_gen_create_phy(struct device *dev, struct usb_phy_generic *nop,
                 needs_vcc = of_property_read_bool(node, "vcc-supply");
                 nop->gpiod_reset = devm_gpiod_get(dev, "reset-gpios");
                 err = PTR_ERR(nop->gpiod_reset);
+                if (!err) {
+                        nop->gpiod_vbus = devm_gpiod_get(dev,
+                                                         "vbus-detect-gpio");
+                        err = PTR_ERR(nop->gpiod_vbus);
+                }
         } else if (pdata) {
                 type = pdata->type;
                 clk_rate = pdata->clk_rate;
                 needs_vcc = pdata->needs_vcc;
-                if (gpio_is_valid(gpio->gpio_reset)) {
+                if (gpio_is_valid(pdata->gpio_reset)) {
                         err = devm_gpio_request_one(dev, pdata->gpio_reset, 0,
                                                     dev_name(dev));
                         if (!err)
                                 nop->gpiod_reset =
                                         gpio_to_desc(pdata->gpio_reset);
                 }
+                nop->gpiod_vbus = pdata->gpiod_vbus;
         }
 
         if (err == -EPROBE_DEFER)
@@ -224,6 +301,18 @@ static int usb_phy_generic_probe(struct platform_device *pdev)
         err = usb_phy_gen_create_phy(dev, nop, dev_get_platdata(&pdev->dev));
         if (err)
                 return err;
+        if (nop->gpiod_vbus) {
+                err = devm_request_threaded_irq(&pdev->dev,
+                                                gpiod_to_irq(nop->gpiod_vbus),
+                                                NULL, nop_gpio_vbus_thread,
+                                                VBUS_IRQ_FLAGS, "vbus_detect",
+                                                nop);
+                if (err) {
+                        dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
+                                gpiod_to_irq(nop->gpiod_vbus), err);
+                        return err;
+                }
+        }
 
         nop->phy.init           = usb_gen_phy_init;
         nop->phy.shutdown       = usb_gen_phy_shutdown;