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Subject[PATCH 1/3 v2] pch_udc: Detecting VBUS through GPIO
Date
Problem:
In USB Suspend, pch_udc handles 'disconnect'.

Root cause:
The current pch_udc is not monitoring VBUS.
When USB cable is disconnected, USB Device Controller generates
an interrupt of USB Suspend.
pch_udc cannot distinguish it is USB Suspend or disconnect.
Therefore, pch_udc handles 'disconnect' after an interrupt of
USB Suspend happend.

Solution:
VBUS is detected through GPIO.
After an interrupt produced USB Suspend, if VBUS is Low,
pch_udc handles 'disconnect'.
If VBUS is High, pch_udc handles 'suspend'.

Signed-off-by: Tomoya MORINAGA <tomoya.rohm@gmail.com>
---
v2: add changelog (v1 doesn't include any changelog.)
---
drivers/usb/gadget/pch_udc.c | 145 +++++++++++++++++++++++++++++++++++++++++-
1 files changed, 142 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/gadget/pch_udc.c b/drivers/usb/gadget/pch_udc.c
index 01ff48d..d77211c 100644
--- a/drivers/usb/gadget/pch_udc.c
+++ b/drivers/usb/gadget/pch_udc.c
@@ -15,6 +15,13 @@
#include <linux/interrupt.h>
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>
+#include <linux/gpio.h>
+
+/* GPIO port for VBUS detecting */
+static int vbus_gpio_port = -1; /* GPIO port number (-1:Not used) */
+
+#define PCH_VBUS_PERIOD 3000 /* VBUS polling period (msec) */
+#define PCH_VBUS_INTERVAL 10 /* VBUS polling interval (msec) */

/* Address offset of Registers */
#define UDC_EP_REG_SHIFT 0x20 /* Offset to next EP */
@@ -296,6 +303,17 @@ struct pch_udc_ep {
};

/**
+ * struct pch_vbus_gpio_data - Structure holding GPIO informaton
+ * for detecting VBUS
+ * @port: gpio port number
+ * @irq_work_fall Structure for WorkQueue
+ */
+struct pch_vbus_gpio_data {
+ int port;
+ struct work_struct irq_work_fall;
+};
+
+/**
* struct pch_udc_dev - Structure holding complete information
* of the PCH USB device
* @gadget: gadget driver data
@@ -323,6 +341,7 @@ struct pch_udc_ep {
* @base_addr: for mapped device memory
* @irq: IRQ line for the device
* @cfg_data: current cfg, intf, and alt in use
+ * @vbus_gpio: GPIO informaton for detecting VBUS
*/
struct pch_udc_dev {
struct usb_gadget gadget;
@@ -349,7 +368,8 @@ struct pch_udc_dev {
unsigned long phys_addr;
void __iomem *base_addr;
unsigned irq;
- struct pch_udc_cfg_data cfg_data;
+ struct pch_udc_cfg_data cfg_data;
+ struct pch_vbus_gpio_data vbus_gpio;
};

#define PCH_UDC_PCI_BAR 1
@@ -1226,6 +1246,115 @@ static const struct usb_gadget_ops pch_udc_ops = {
};

/**
+ * pch_vbus_gpio_get_value() - This API gets value of GPIO port as VBUS status.
+ * @dev: Reference to the driver structure
+ *
+ * Return value:
+ * 1: VBUS is high
+ * 0: VBUS is low
+ * -1: It is not enable to detect VBUS using GPIO
+ */
+static int pch_vbus_gpio_get_value(struct pch_udc_dev *dev)
+{
+ int vbus = 0;
+
+ if (dev->vbus_gpio.port)
+ vbus = gpio_get_value(dev->vbus_gpio.port) ? 1 : 0;
+ else
+ vbus = -1;
+
+ return vbus;
+}
+
+/**
+ * pch_vbus_gpio_work_fall() - This API keeps watch on VBUS becoming Low.
+ * If VBUS is Low, disconnect is processed
+ * @irq_work: Structure for WorkQueue
+ *
+ */
+static void pch_vbus_gpio_work_fall(struct work_struct *irq_work)
+{
+ struct pch_vbus_gpio_data *vbus_gpio = container_of(irq_work,
+ struct pch_vbus_gpio_data, irq_work_fall);
+ struct pch_udc_dev *dev =
+ container_of(vbus_gpio, struct pch_udc_dev, vbus_gpio);
+ int vbus_saved = -1;
+ int vbus;
+ int count;
+
+ if (!dev->vbus_gpio.port)
+ return;
+
+ for (count = 0; count < (PCH_VBUS_PERIOD / PCH_VBUS_INTERVAL);
+ count++) {
+ vbus = pch_vbus_gpio_get_value(dev);
+
+ if ((vbus_saved == vbus) && (vbus == 0)) {
+ dev_dbg(&dev->pdev->dev, "VBUS fell");
+ if (dev->driver
+ && dev->driver->disconnect) {
+ dev->driver->disconnect(
+ &dev->gadget);
+ }
+ pch_udc_reconnect(dev);
+ dev_dbg(&dev->pdev->dev, "VBUS fell");
+ return;
+ }
+ vbus_saved = vbus;
+ mdelay(PCH_VBUS_INTERVAL);
+ }
+}
+
+/**
+ * pch_vbus_gpio_init() - This API initializes GPIO port detecting VBUS.
+ * @dev: Reference to the driver structure
+ * @vbus_gpio Number of GPIO port to detect gpio
+ *
+ * Return codes:
+ * 0: Success
+ * -EINVAL: GPIO port is invalid or can't be initialized.
+ */
+static int pch_vbus_gpio_init(struct pch_udc_dev *dev, int vbus_gpio_port)
+{
+ int err;
+
+ dev->vbus_gpio.port = 0;
+
+ if (vbus_gpio_port <= -1)
+ return -EINVAL;
+
+ err = gpio_is_valid(vbus_gpio_port);
+ if (!err) {
+ pr_err("%s: gpio port %d is invalid\n",
+ __func__, vbus_gpio_port);
+ return -EINVAL;
+ }
+
+ err = gpio_request(vbus_gpio_port, "pch_vbus");
+ if (err) {
+ pr_err("%s: can't request gpio port %d, err: %d\n",
+ __func__, vbus_gpio_port, err);
+ return -EINVAL;
+ }
+
+ dev->vbus_gpio.port = vbus_gpio_port;
+ gpio_direction_input(vbus_gpio_port);
+ INIT_WORK(&dev->vbus_gpio.irq_work_fall, pch_vbus_gpio_work_fall);
+
+ return 0;
+}
+
+/**
+ * pch_vbus_gpio_free() - This API frees resources of GPIO port
+ * @dev: Reference to the driver structure
+ */
+static void pch_vbus_gpio_free(struct pch_udc_dev *dev)
+{
+ if (dev->vbus_gpio.port)
+ gpio_free(dev->vbus_gpio.port);
+}
+
+/**
* complete_req() - This API is invoked from the driver when processing
* of a request is complete
* @ep: Reference to the endpoint structure
@@ -2510,6 +2639,8 @@ static void pch_udc_svc_cfg_interrupt(struct pch_udc_dev *dev)
*/
static void pch_udc_dev_isr(struct pch_udc_dev *dev, u32 dev_intr)
{
+ int vbus;
+
/* USB Reset Interrupt */
if (dev_intr & UDC_DEVINT_UR) {
pch_udc_svc_ur_interrupt(dev);
@@ -2535,14 +2666,19 @@ static void pch_udc_dev_isr(struct pch_udc_dev *dev, u32 dev_intr)
spin_lock(&dev->lock);
}

- if (dev->vbus_session == 0) {
+ vbus = pch_vbus_gpio_get_value(dev);
+ if ((dev->vbus_session == 0)
+ && (vbus != 1)) {
if (dev->driver && dev->driver->disconnect) {
spin_unlock(&dev->lock);
dev->driver->disconnect(&dev->gadget);
spin_lock(&dev->lock);
}
pch_udc_reconnect(dev);
- }
+ } else if ((dev->vbus_session == 0)
+ && (vbus == 1))
+ schedule_work(&dev->vbus_gpio.irq_work_fall);
+
dev_dbg(&dev->pdev->dev, "USB_SUSPEND\n");
}
/* Clear the SOF interrupt, if enabled */
@@ -2704,6 +2840,7 @@ static int pch_udc_pcd_init(struct pch_udc_dev *dev)
{
pch_udc_init(dev);
pch_udc_pcd_reinit(dev);
+ pch_vbus_gpio_init(dev, vbus_gpio_port);
return 0;
}

@@ -2882,6 +3019,8 @@ static void pch_udc_remove(struct pci_dev *pdev)
UDC_EP0OUT_BUFF_SIZE * 4, DMA_FROM_DEVICE);
kfree(dev->ep0out_buf);

+ pch_vbus_gpio_free(dev);
+
pch_udc_exit(dev);

if (dev->irq_registered)
--
1.7.7.6


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