tegra udc: Add USB charger support

Adding support for usb charger detection and setting the charging current
limit through the regulator for drawing the vbus current.

Bug 631316 USB charging support in Android
Tested on: whistler/Android

Change-Id: Ib73ac660d1546fbbdc0ed19ca0f25e04b3676886
Reviewed-on: http://git-master/r/693
Reviewed-by: Gary King <gking@nvidia.com>
Tested-by: Gary King <gking@nvidia.com>

3 files changed, 117 insertions, 3 deletions

diff --git a/drivers/usb/gadget/fsl_udc_core.c b/drivers/usb/gadget/fsl_udc_core.c
index f5a2d0a42f7a..33502502c67e 100755
--- a/drivers/usb/gadget/fsl_udc_core.c
+++ b/drivers/usb/gadget/fsl_udc_core.c
@@ -39,6 +39,8 @@
 #include <linux/fsl_devices.h>
 #include <linux/dmapool.h>
 #include <linux/delay.h>
+#include <linux/regulator/consumer.h>
+#include <linux/workqueue.h>
 
 #include <asm/byteorder.h>
 #include <asm/io.h>
@@ -70,6 +72,11 @@ static struct usb_dr_device *dr_regs;
 static struct usb_sys_interface *usb_sys_regs;
 #endif
 
+/* Charger current limit=1800mA, as per the USB charger spec */
+#define USB_CHARGING_CURRENT_LIMIT_MA 1800
+/* 100msec wait time for charger detection after vbus is detected */
+#define USB_CHARGER_DETECTION_WAIT_TIME_MS 100
+
 /* it is initialized in probe()  */
 static struct fsl_udc *udc_controller = NULL;
 
@@ -1158,6 +1165,12 @@ static int fsl_vbus_draw(struct usb_gadget *gadget, unsigned mA)
 	struct fsl_udc *udc;
 
 	udc = container_of(gadget, struct fsl_udc, gadget);
+	/* check udc regulator is avalable for drawing the vbus current */
+	if (udc->vbus_regulator) {
+		/* set the current limit in uA and return */
+		return regulator_set_current_limit(udc->vbus_regulator, 0, mA*1000);
+	}
+
 	if (udc->transceiver)
 		return otg_set_power(udc->transceiver, mA);
 	return -ENOTSUPP;
@@ -1775,6 +1788,28 @@ static void reset_irq(struct fsl_udc *udc)
 #endif
 }
 
+/*
+ * If VBUS is detected and setup packet is not received in 100ms then
+ * work thread starts and checks for the USB charger detection.
+ */
+static void fsl_udc_charger_detection(struct work_struct* work)
+{
+	struct fsl_udc *udc = container_of (work, struct fsl_udc, work);
+
+	/* check for the platform charger detection */
+	if (platform_udc_charger_detection()) {
+		printk("Dedicated charger detected\n");
+	} else {
+		printk("Dumb charger detected\n");
+	}
+	/* check udc regulator is avalable for drawing the vbus current */
+	if (udc->vbus_regulator) {
+		/* set the current limit in uA */
+		regulator_set_current_limit(udc->vbus_regulator, 0,
+					USB_CHARGING_CURRENT_LIMIT_MA*1000);
+	}
+}
+
 #if defined(CONFIG_ARCH_TEGRA)
 /*
  * Restart device controller in the OTG mode on VBUS detection
@@ -1820,15 +1855,25 @@ static irqreturn_t fsl_udc_irq(int irq, void *_udc)
 				udc->vbus_active = 1;
 				platform_udc_clk_resume();
 				fsl_udc_restart(udc);
+				/* Schedule work to wait for 100msec and check for
+				 * charger if setup packet is not received */
+				schedule_delayed_work(&udc->work,
+					USB_CHARGER_DETECTION_WAIT_TIME_MS);
 			}
 		} else if (udc->transceiver->state == OTG_STATE_A_SUSPEND) {
 			if (udc->vbus_active) {
+				/* If cable disconnected, cancel any delayed work */
+				cancel_delayed_work(&udc->work);
 				/* stop the controller and turn off the clocks */
 				dr_controller_stop(udc);
 				platform_udc_clk_suspend();
 				udc->vbus_active = 0;
 				udc->usb_state = USB_STATE_DEFAULT;
 				udc->transceiver->state = OTG_STATE_UNDEFINED;
+				if (udc->vbus_regulator) {
+					/* set the current limit to 0mA */
+					regulator_set_current_limit(udc->vbus_regulator, 0, 0);
+				}
 			}
 		} else {
 			spin_unlock_irqrestore(&udc->lock, flags);
@@ -1845,13 +1890,23 @@ static irqreturn_t fsl_udc_irq(int irq, void *_udc)
 			if (temp & USB_SYS_VBUS_STATUS) {
 				udc->vbus_active = 1;
 				platform_udc_clk_resume();
-				//printk(KERN_INFO "USB cable connected\n");
+				/* Schedule work to wait for 100msec and check for
+				 * charger if setup packet is not received */
+				schedule_delayed_work(&udc->work,
+					USB_CHARGER_DETECTION_WAIT_TIME_MS);
+				/* printk("USB cable connected\n"); */
 			} else {
+				/* If cable disconnected, cancel any delayed work */
+				cancel_delayed_work(&udc->work);
 				reset_queues(udc);
 				udc->vbus_active = 0;
 				udc->usb_state = USB_STATE_DEFAULT;
 				platform_udc_clk_suspend();
-				//printk("USB cable dis-connected\n");
+				if (udc->vbus_regulator) {
+					/* set the current limit to 0mA */
+					regulator_set_current_limit(udc->vbus_regulator, 0, 0);
+				}
+				/* printk("USB cable dis-connected\n"); */
 			}
 			status = IRQ_HANDLED;
 		}
@@ -1880,6 +1935,9 @@ static irqreturn_t fsl_udc_irq(int irq, void *_udc)
 		VDBG("Packet int");
 		/* Setup package, we only support ep0 as control ep */
 		if (fsl_readl(&dr_regs->endptsetupstat) & EP_SETUP_STATUS_EP0) {
+			/* Setup packet received, we are connected to host and
+			 * not charger. Cancel any delayed work */
+			cancel_delayed_work(&udc->work);
 			tripwire_handler(udc, 0,
 					(u8 *) (&udc->local_setup_buff));
 			setup_received_irq(udc, &udc->local_setup_buff);
@@ -2439,6 +2497,7 @@ static int __init fsl_udc_probe(struct platform_device *pdev)
 	u32 dccparams;
 #if defined(CONFIG_ARCH_TEGRA)
 	struct resource *res_sys = NULL;
+	struct fsl_usb2_platform_data *pdata = pdev->dev.platform_data;
 #endif
 
 
@@ -2585,6 +2644,9 @@ static int __init fsl_udc_probe(struct platform_device *pdev)
 	}
 	create_proc_file();
 
+	/* create a delayed work for detecting the USB charger */
+	INIT_DELAYED_WORK(&udc_controller->work, fsl_udc_charger_detection);
+
 #if defined(CONFIG_ARCH_TEGRA)
 #ifdef CONFIG_USB_OTG_UTILS
 	/* Get the OTG transceiver. If OTG is enabled then transceiver
@@ -2593,6 +2655,16 @@ static int __init fsl_udc_probe(struct platform_device *pdev)
 #else
 	udc_controller->transceiver = NULL;
 #endif
+	/* Get the regulator for drawing the vbus current in udc driver */
+	if (pdata->regulator_dev) {
+		udc_controller->vbus_regulator =
+				regulator_get(&pdata->regulator_dev->dev, "vbus_draw");
+		if (IS_ERR(udc_controller->vbus_regulator)) {
+			dev_err(&pdev->dev, "can't get vbus_draw regulator, err: %ld\n",
+				PTR_ERR(udc_controller->vbus_regulator));
+			udc_controller->vbus_regulator = NULL;
+		}
+	}
 	/* Power down the phy if cable is not connected */
 	if (!(fsl_readl(&usb_sys_regs->vbus_wakeup) & USB_SYS_VBUS_STATUS))
 		platform_udc_clk_suspend();
@@ -2628,6 +2700,10 @@ static int __exit fsl_udc_remove(struct platform_device *pdev)
 		return -ENODEV;
 	udc_controller->done = &done;
 
+	cancel_delayed_work(&udc_controller->work);
+	if (udc_controller->vbus_regulator)
+		regulator_put(udc_controller->vbus_regulator);
+
 	platform_udc_clk_release();
 
 	/* DR has been stopped in usb_gadget_unregister_driver() */
diff --git a/drivers/usb/gadget/fsl_usb2_udc.h b/drivers/usb/gadget/fsl_usb2_udc.h
index b06d36c1cd4c..d2225d89ad66 100644..100755
--- a/drivers/usb/gadget/fsl_usb2_udc.h
+++ b/drivers/usb/gadget/fsl_usb2_udc.h
@@ -513,6 +513,8 @@ struct fsl_udc {
 	u32 ep0_dir;		/* Endpoint zero direction: can be
 				   USB_DIR_IN or USB_DIR_OUT */
 	u8 device_address;	/* Device USB address */
+	struct regulator *vbus_regulator;	/* regulator for drawing VBUS */
+	struct delayed_work work; /* delayed work for charger detection */
 };
 
 /*-------------------------------------------------------------------------*/
@@ -612,13 +614,14 @@ struct platform_device;
 #define platform_udc_clk_release	__glue(_UDC_NAME,_udc_clk_release)
 #define platform_udc_clk_suspend	__glue(_UDC_NAME,_udc_clk_suspend)
 #define platform_udc_clk_resume		__glue(_UDC_NAME,_udc_clk_resume)
-
+#define platform_udc_charger_detection	__glue(_UDC_NAME,_udc_charger_detection)
 
 extern int platform_udc_clk_init(struct platform_device *pdev);
 extern void platform_udc_clk_finalize(struct platform_device *pdev);
 extern void platform_udc_clk_release(void);
 extern void platform_udc_clk_suspend(void);
 extern void platform_udc_clk_resume(void);
+extern bool platform_udc_charger_detection(void);
 #else
 static inline int platform_udc_clk_init(struct platform_device *pdev)
 {
@@ -628,6 +631,10 @@ static inline void platform_udc_clk_finalize(struct platform_device *pdev)
 { }
 static inline void platform_udc_clk_release(void)
 { }
+static inline bool platform_udc_charger_detection(void)
+{
+	return 0;
+}
 #endif
 
 #endif
diff --git a/drivers/usb/gadget/tegra_udc.c b/drivers/usb/gadget/tegra_udc.c
index c55712c3f9fc..a455a85741cb 100755
--- a/drivers/usb/gadget/tegra_udc.c
+++ b/drivers/usb/gadget/tegra_udc.c
@@ -61,3 +61,34 @@ void tegra_udc_clk_resume(void)
 {
 	NV_ASSERT_SUCCESS(NvDdkUsbPhyPowerUp(s_hUsbPhy, NV_FALSE, 0));
 }
+
+bool tegra_udc_charger_detection(void)
+{
+	NvDdkUsbPhyIoctl_DedicatedChargerDetectionInputArgs Charger;
+	NvDdkUsbPhyIoctl_DedicatedChargerStatusOutputArgs Status;
+
+	/* clear the input args */
+	NvOsMemset(&Charger, 0, sizeof(Charger));
+	/* enable the charger detection logic */
+	Charger.EnableChargerDetection = NV_TRUE;
+	NV_ASSERT_SUCCESS(NvDdkUsbPhyIoctl(
+		s_hUsbPhy,
+		NvDdkUsbPhyIoctlType_DedicatedChargerDetection,
+		&Charger,
+		NULL));
+	/* get the charger detection status */
+	NV_ASSERT_SUCCESS(NvDdkUsbPhyIoctl(
+		s_hUsbPhy,
+		NvDdkUsbPhyIoctlType_DedicatedChargerStatus,
+		NULL,
+		&Status));
+	/* disable the charger detection */
+	Charger.EnableChargerDetection = NV_FALSE;
+	NV_ASSERT_SUCCESS(NvDdkUsbPhyIoctl(
+		s_hUsbPhy,
+		NvDdkUsbPhyIoctlType_DedicatedChargerDetection,
+		&Charger,
+		NULL));
+
+	return Status.ChargerDetected;
+}