usb: gadget: tegra_udc: use USB charging spec 1.2

Enable the USB charging based on the USB charging spec 1.2. Now we can
detect:
1. SDP (stanardard downstream port)
2. CDP (charging downstream port)
3. DCP (dedicated charging port)
4. None (no cable connected)
5. Non-standard charger

For some non-standard charger, we cannot detect it as DCP device.
If we find a charger detected as USB device but no EP0 packet recieved
with 1s, we then decided this is 1A charger.

bug 968345

Change-Id: I804f90ea6e4794da8f52b1c3ebd694828d99f40e
Signed-off-by: Xin Xie <xxie@nvidia.com>
Reviewed-on: http://git-master/r/120218
Reviewed-by: Simone Willett <swillett@nvidia.com>
Tested-by: Simone Willett <swillett@nvidia.com>

2 files changed, 108 insertions, 29 deletions

diff --git a/drivers/usb/gadget/tegra_udc.c b/drivers/usb/gadget/tegra_udc.c
index ace9f2ecaff1..8b8828d731af 100644
--- a/drivers/usb/gadget/tegra_udc.c
+++ b/drivers/usb/gadget/tegra_udc.c
@@ -1240,6 +1240,76 @@ static int tegra_set_selfpowered(struct usb_gadget *gadget, int is_on)
 	return 0;
 }
 
+static int tegra_usb_set_charging_current(struct tegra_udc *udc)
+{
+	int max_ua;
+
+	if (NULL == udc->vbus_reg)
+		return 0;
+
+	switch (udc->connect_type) {
+	case CONNECT_TYPE_NONE:
+		pr_debug("detected USB charging is disabled");
+		max_ua = 0;
+		break;
+	case CONNECT_TYPE_SDP:
+		pr_debug("detected SDP port");
+		max_ua = USB_CHARGING_SDP_CURRENT_LIMIT_UA;
+		break;
+	case CONNECT_TYPE_DCP:
+		pr_debug("detected DCP port(wall charger)");
+		max_ua = USB_CHARGING_DCP_CURRENT_LIMIT_UA;
+		break;
+	case CONNECT_TYPE_CDP:
+		pr_debug("detected CDP port(1A USB port)");
+		max_ua = USB_CHARGING_CDP_CURRENT_LIMIT_UA;
+		break;
+	case CONNECT_TYPE_NON_STANDARD_CHARGER:
+		pr_debug("detected non-standard charging port");
+		max_ua = USB_CHARGING_NON_STANDARD_CHARGER_CURRENT_LIMIT_UA;
+		break;
+	default:
+		pr_debug("detected USB charging type is unknown");
+		max_ua = 0;
+	}
+
+	return regulator_set_current_limit(udc->vbus_reg, 0, max_ua);
+}
+
+static void tegra_detect_charging_type_is_cdp_or_dcp(struct tegra_udc *udc)
+{
+	u32 portsc;
+	u32 temp;
+	unsigned long flags;
+
+	/* use spinlock to prevent kernel preemption here */
+	spin_lock_irqsave(&udc->lock, flags);
+
+	/* set controller to run which cause D+ pull high */
+	temp = udc_readl(udc, USB_CMD_REG_OFFSET);
+	temp |= USB_CMD_RUN_STOP;
+	udc_writel(udc, temp, USB_CMD_REG_OFFSET);
+
+	udelay(10);
+
+	/* use D+ and D- status to check it is CDP or DCP */
+	portsc = udc_readl(udc, PORTSCX_REG_OFFSET) & PORTSCX_LINE_STATUS_BITS;
+	if (portsc == (PORTSCX_LINE_STATUS_DP_BIT | PORTSCX_LINE_STATUS_DM_BIT))
+		udc->connect_type = CONNECT_TYPE_DCP;
+	else if (portsc == PORTSCX_LINE_STATUS_DP_BIT)
+		udc->connect_type = CONNECT_TYPE_CDP;
+	else
+		/*
+		 * If it take more 100mS between D+ pull high and read Line
+		 * Status, host might initiate the RESET, then we see both
+		 * line status as 0 (SE0). This really should not happen as we
+		 * disabled the kernel preemption before reaching here.
+		 */
+		BUG();
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+}
+
 /**
  * Notify controller that VBUS is powered, called by whatever
  * detects VBUS sessions
@@ -1262,13 +1332,10 @@ static int tegra_vbus_session(struct usb_gadget *gadget, int is_active)
 		dr_controller_reset(udc);
 		udc->vbus_active = 0;
 		udc->usb_state = USB_STATE_DEFAULT;
+		udc->connect_type = CONNECT_TYPE_NONE;
 		spin_unlock_irqrestore(&udc->lock,flags);
 		tegra_usb_phy_power_off(udc->phy);
-		if (udc->vbus_reg) {
-			/* set the current limit to 0mA */
-			regulator_set_current_limit(
-				udc->vbus_reg, 0, 0);
-		}
+		tegra_usb_set_charging_current(udc);
 	} else if (!udc->vbus_active && is_active) {
 		tegra_usb_phy_power_on(udc->phy);
 		/* setup the controller in the device mode */
@@ -1280,18 +1347,23 @@ static int tegra_vbus_session(struct usb_gadget *gadget, int is_active)
 		udc->ep0_state = WAIT_FOR_SETUP;
 		udc->ep0_dir = 0;
 		udc->vbus_active = 1;
+		if (tegra_usb_phy_charger_detected(udc->phy)) {
+			tegra_detect_charging_type_is_cdp_or_dcp(udc);
+		} else {
+			udc->connect_type = CONNECT_TYPE_SDP;
+			/*
+			 * Schedule work to wait for 1000 msec and check for
+			 * a non-standard charger if setup packet is not
+			 * received.
+			 */
+			schedule_delayed_work(&udc->work, msecs_to_jiffies(
+					USB_CHARGER_DETECTION_WAIT_TIME_MS));
+		}
 		/* start the controller */
 		dr_controller_run(udc);
-		if (udc->vbus_reg) {
-			/* set the current limit to 100mA */
-			regulator_set_current_limit(
-				udc->vbus_reg, 0, 100);
-		}
-		/* Schedule work to wait for 1000 msec and check for
-		 * charger if setup packet is not received */
-		schedule_delayed_work(&udc->work,
-			USB_CHARGER_DETECTION_WAIT_TIME_MS);
+		tegra_usb_set_charging_current(udc);
 	}
+
 	return 0;
 }
 
@@ -2119,26 +2191,18 @@ static void tegra_udc_irq_work(struct work_struct *irq_work)
 	DBG("%s(%d) END\n", __func__, __LINE__);
 }
 
-/**
- * If VBUS is detected and setup packet is not received in 100ms then
- * work thread starts and checks for the USB charger detection.
+/*
+ * When VBUS is detected we already know it is DCP/SDP/CDP devices if it is a
+ * standard device; If we did not receive EP0 setup packet, we can assuming it
+ * is a charger capable of 1.8A charging.
  */
 static void tegra_udc_charger_detect_work(struct work_struct *work)
 {
 	struct tegra_udc *udc = container_of(work, struct tegra_udc, work.work);
 	DBG("%s(%d) BEGIN\n", __func__, __LINE__);
 
-	/* check for the platform charger detection */
-	if (tegra_usb_phy_charger_detected(udc->phy)) {
-		printk(KERN_INFO "USB compliant charger detected\n");
-		/* check udc regulator is available for drawing vbus current*/
-		if (udc->vbus_reg) {
-			/* set the current limit in uA */
-			regulator_set_current_limit(
-				udc->vbus_reg, 0,
-				USB_CHARGING_CURRENT_LIMIT_MA*1000);
-		}
-	}
+	udc->connect_type = CONNECT_TYPE_NON_STANDARD_CHARGER;
+	tegra_usb_set_charging_current(udc);
 
 	DBG("%s(%d) END\n", __func__, __LINE__);
 }
diff --git a/drivers/usb/gadget/tegra_udc.h b/drivers/usb/gadget/tegra_udc.h
index 50e2a3193648..094e3eb0e458 100644
--- a/drivers/usb/gadget/tegra_udc.h
+++ b/drivers/usb/gadget/tegra_udc.h
@@ -38,7 +38,11 @@
 #define USB_MAX_CTRL_PAYLOAD		64
 
  /* Charger current limit=1800mA, as per the USB charger spec */
-#define USB_CHARGING_CURRENT_LIMIT_MA 1800
+#define USB_CHARGING_DCP_CURRENT_LIMIT_UA 1800000
+#define USB_CHARGING_CDP_CURRENT_LIMIT_UA 900000
+#define USB_CHARGING_SDP_CURRENT_LIMIT_UA 100000
+#define USB_CHARGING_NON_STANDARD_CHARGER_CURRENT_LIMIT_UA 1800000
+
  /* 1 sec wait time for charger detection after vbus is detected */
 #define USB_CHARGER_DETECTION_WAIT_TIME_MS 1000
 #define BOOST_TRIGGER_SIZE 4096
@@ -156,6 +160,8 @@
 #define  PORTSCX_PORT_SUSPEND                 0x00000080
 #define  PORTSCX_PORT_RESET                   0x00000100
 #define  PORTSCX_LINE_STATUS_BITS             0x00000C00
+#define  PORTSCX_LINE_STATUS_DP_BIT           0x00000800
+#define  PORTSCX_LINE_STATUS_DM_BIT           0x00000400
 #define  PORTSCX_PORT_POWER                   0x00001000
 #define  PORTSCX_PORT_INDICTOR_CTRL           0x0000C000
 #define  PORTSCX_PORT_TEST_CTRL               0x000F0000
@@ -397,6 +403,14 @@ struct tegra_ep {
 	unsigned stopped:1;
 };
 
+enum tegra_connect_type {
+	CONNECT_TYPE_NONE,
+	CONNECT_TYPE_SDP,
+	CONNECT_TYPE_DCP,
+	CONNECT_TYPE_CDP,
+	CONNECT_TYPE_NON_STANDARD_CHARGER
+};
+
 struct tegra_udc {
 	struct usb_gadget gadget;
 	struct usb_gadget_driver *driver;
@@ -417,6 +431,7 @@ struct tegra_udc {
 	struct work_struct boost_cpufreq_work;
 	/* irq work for controlling the usb power */
 	struct work_struct irq_work;
+	enum tegra_connect_type connect_type;
 	void __iomem *regs;
 	size_t ep_qh_size;		/* size after alignment adjustment*/
 	dma_addr_t ep_qh_dma;		/* dma address of QH */