[media] si4713: Added the USB driver for Si4713

This is the USB driver for the Silicon Labs development board.
It contains the Si4713 FM transmitter chip.

Signed-off-by: Dinesh Ram <dinesh.ram@cern.ch>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Tested-by: Eduardo Valentin <edubezval@gmail.com>
Acked-by: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

3 files changed, 556 insertions, 0 deletions

diff --git a/drivers/media/radio/si4713/Kconfig b/drivers/media/radio/si4713/Kconfig
index ec640b86994b..a7c3ba85d12b 100644
--- a/drivers/media/radio/si4713/Kconfig
+++ b/drivers/media/radio/si4713/Kconfig
@@ -1,3 +1,18 @@
+config USB_SI4713
+        tristate "Silicon Labs Si4713 FM Radio Transmitter support with USB"
+        depends on USB && RADIO_SI4713
+        select SI4713
+        ---help---
+          This is a driver for USB devices with the Silicon Labs SI4713
+          chip. Currently these devices are known to work.
+          - 10c4:8244: Silicon Labs FM Transmitter USB device.
+
+          Say Y here if you want to connect this type of radio to your
+          computer's USB port.
+
+          To compile this driver as a module, choose M here: the
+          module will be called radio-usb-si4713.
+
 config PLATFORM_SI4713
         tristate "Silicon Labs Si4713 FM Radio Transmitter support with I2C"
         depends on I2C && RADIO_SI4713
diff --git a/drivers/media/radio/si4713/Makefile b/drivers/media/radio/si4713/Makefile
index a8c1194dac73..ddaaf925e883 100644
--- a/drivers/media/radio/si4713/Makefile
+++ b/drivers/media/radio/si4713/Makefile
@@ -3,4 +3,5 @@
 #
 
 obj-$(CONFIG_I2C_SI4713) += si4713.o
+obj-$(CONFIG_USB_SI4713) += radio-usb-si4713.o
 obj-$(CONFIG_PLATFORM_SI4713) += radio-platform-si4713.o
diff --git a/drivers/media/radio/si4713/radio-usb-si4713.c b/drivers/media/radio/si4713/radio-usb-si4713.c
new file mode 100644
index 000000000000..d97884494d04
--- /dev/null
+++ b/drivers/media/radio/si4713/radio-usb-si4713.c
@@ -0,0 +1,540 @@
+/*
+ * Copyright 2013 Cisco Systems, Inc. and/or its affiliates.
+ * All rights reserved.
+ *
+ * This program is free software; you may redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+/* kernel includes */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/input.h>
+#include <linux/mutex.h>
+#include <linux/i2c.h>
+/* V4l includes */
+#include <linux/videodev2.h>
+#include <media/v4l2-common.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-ioctl.h>
+#include <media/v4l2-event.h>
+#include <media/si4713.h>
+
+#include "si4713.h"
+
+/* driver and module definitions */
+MODULE_AUTHOR("Dinesh Ram <dinesh.ram@cern.ch>");
+MODULE_DESCRIPTION("Si4713 FM Transmitter USB driver");
+MODULE_LICENSE("GPL v2");
+
+/* The Device announces itself as Cygnal Integrated Products, Inc. */
+#define USB_SI4713_VENDOR               0x10c4
+#define USB_SI4713_PRODUCT              0x8244
+
+#define BUFFER_LENGTH                   64
+#define USB_TIMEOUT                     1000
+#define USB_RESP_TIMEOUT                50000
+
+/* USB Device ID List */
+static struct usb_device_id usb_si4713_usb_device_table[] = {
+        {USB_DEVICE_AND_INTERFACE_INFO(USB_SI4713_VENDOR, USB_SI4713_PRODUCT,
+                                                        USB_CLASS_HID, 0, 0) },
+        { }                                             /* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE(usb, usb_si4713_usb_device_table);
+
+struct si4713_usb_device {
+        struct usb_device       *usbdev;
+        struct usb_interface    *intf;
+        struct video_device     vdev;
+        struct v4l2_device      v4l2_dev;
+        struct v4l2_subdev      *v4l2_subdev;
+        struct mutex            lock;
+        struct i2c_adapter      i2c_adapter;
+
+        u8                      *buffer;
+};
+
+static inline struct si4713_usb_device *to_si4713_dev(struct v4l2_device *v4l2_dev)
+{
+        return container_of(v4l2_dev, struct si4713_usb_device, v4l2_dev);
+}
+
+static int vidioc_querycap(struct file *file, void *priv,
+                                        struct v4l2_capability *v)
+{
+        struct si4713_usb_device *radio = video_drvdata(file);
+
+        strlcpy(v->driver, "radio-usb-si4713", sizeof(v->driver));
+        strlcpy(v->card, "Si4713 FM Transmitter", sizeof(v->card));
+        usb_make_path(radio->usbdev, v->bus_info, sizeof(v->bus_info));
+        v->device_caps = V4L2_CAP_MODULATOR | V4L2_CAP_RDS_OUTPUT;
+        v->capabilities = v->device_caps | V4L2_CAP_DEVICE_CAPS;
+
+        return 0;
+}
+
+static int vidioc_g_modulator(struct file *file, void *priv,
+                                struct v4l2_modulator *vm)
+{
+        struct si4713_usb_device *radio = video_drvdata(file);
+
+        return v4l2_subdev_call(radio->v4l2_subdev, tuner, g_modulator, vm);
+}
+
+static int vidioc_s_modulator(struct file *file, void *priv,
+                                const struct v4l2_modulator *vm)
+{
+        struct si4713_usb_device *radio = video_drvdata(file);
+
+        return v4l2_subdev_call(radio->v4l2_subdev, tuner, s_modulator, vm);
+}
+
+static int vidioc_s_frequency(struct file *file, void *priv,
+                                const struct v4l2_frequency *vf)
+{
+        struct si4713_usb_device *radio = video_drvdata(file);
+
+        return v4l2_subdev_call(radio->v4l2_subdev, tuner, s_frequency, vf);
+}
+
+static int vidioc_g_frequency(struct file *file, void *priv,
+                                struct v4l2_frequency *vf)
+{
+        struct si4713_usb_device *radio = video_drvdata(file);
+
+        return v4l2_subdev_call(radio->v4l2_subdev, tuner, g_frequency, vf);
+}
+
+static const struct v4l2_ioctl_ops usb_si4713_ioctl_ops = {
+        .vidioc_querycap          = vidioc_querycap,
+        .vidioc_g_modulator       = vidioc_g_modulator,
+        .vidioc_s_modulator       = vidioc_s_modulator,
+        .vidioc_g_frequency       = vidioc_g_frequency,
+        .vidioc_s_frequency       = vidioc_s_frequency,
+        .vidioc_log_status        = v4l2_ctrl_log_status,
+        .vidioc_subscribe_event   = v4l2_ctrl_subscribe_event,
+        .vidioc_unsubscribe_event = v4l2_event_unsubscribe,
+};
+
+/* File system interface */
+static const struct v4l2_file_operations usb_si4713_fops = {
+        .owner          = THIS_MODULE,
+        .open           = v4l2_fh_open,
+        .release        = v4l2_fh_release,
+        .poll           = v4l2_ctrl_poll,
+        .unlocked_ioctl = video_ioctl2,
+};
+
+static void usb_si4713_video_device_release(struct v4l2_device *v4l2_dev)
+{
+        struct si4713_usb_device *radio = to_si4713_dev(v4l2_dev);
+        struct i2c_adapter *adapter = &radio->i2c_adapter;
+
+        i2c_del_adapter(adapter);
+        v4l2_device_unregister(&radio->v4l2_dev);
+        kfree(radio->buffer);
+        kfree(radio);
+}
+
+/*
+ * This command sequence emulates the behaviour of the Windows driver.
+ * The structure of these commands was determined by sniffing the
+ * usb traffic of the device during startup.
+ * Most likely, these commands make some queries to the device.
+ * Commands are sent to enquire parameters like the bus mode,
+ * component revision, boot mode, the device serial number etc.
+ *
+ * These commands are necessary to be sent in this order during startup.
+ * The device fails to powerup if these commands are not sent.
+ *
+ * The complete list of startup commands is given in the start_seq table below.
+ */
+static int si4713_send_startup_command(struct si4713_usb_device *radio)
+{
+        unsigned long until_jiffies = jiffies + usecs_to_jiffies(USB_RESP_TIMEOUT) + 1;
+        u8 *buffer = radio->buffer;
+        int retval;
+
+        /* send the command */
+        retval = usb_control_msg(radio->usbdev, usb_sndctrlpipe(radio->usbdev, 0),
+                                        0x09, 0x21, 0x033f, 0, radio->buffer,
+                                        BUFFER_LENGTH, USB_TIMEOUT);
+        if (retval < 0)
+                return retval;
+
+        for (;;) {
+                /* receive the response */
+                retval = usb_control_msg(radio->usbdev, usb_rcvctrlpipe(radio->usbdev, 0),
+                                0x01, 0xa1, 0x033f, 0, radio->buffer,
+                                BUFFER_LENGTH, USB_TIMEOUT);
+                if (retval < 0)
+                        return retval;
+                if (!radio->buffer[1]) {
+                        /* USB traffic sniffing showed that some commands require
+                         * additional checks. */
+                        switch (buffer[1]) {
+                        case 0x32:
+                                if (radio->buffer[2] == 0)
+                                        return 0;
+                                break;
+                        case 0x14:
+                        case 0x12:
+                                if (radio->buffer[2] & SI4713_CTS)
+                                        return 0;
+                                break;
+                        case 0x06:
+                                if ((radio->buffer[2] & SI4713_CTS) && radio->buffer[9] == 0x08)
+                                        return 0;
+                                break;
+                        default:
+                                return 0;
+                        }
+                }
+                if (time_is_before_jiffies(until_jiffies))
+                        return -EIO;
+                msleep(3);
+        }
+
+        return retval;
+}
+
+struct si4713_start_seq_table {
+        int len;
+        u8 payload[8];
+};
+
+/*
+ * Some of the startup commands that could be recognized are :
+ * (0x03): Get serial number of the board (Response : CB000-00-00)
+ * (0x06, 0x03, 0x03, 0x08, 0x01, 0x0f) : Get Component revision
+ */
+struct si4713_start_seq_table start_seq[] = {
+
+        { 1, { 0x03 } },
+        { 2, { 0x32, 0x7f } },
+        { 6, { 0x06, 0x03, 0x03, 0x08, 0x01, 0x0f } },
+        { 2, { 0x14, 0x02 } },
+        { 2, { 0x09, 0x90 } },
+        { 3, { 0x08, 0x90, 0xfa } },
+        { 2, { 0x36, 0x01 } },
+        { 2, { 0x05, 0x03 } },
+        { 7, { 0x06, 0x00, 0x06, 0x0e, 0x01, 0x0f, 0x05 } },
+        { 1, { 0x12 } },
+        /* Commands that are sent after pressing the 'Initialize'
+                button in the windows application */
+        { 1, { 0x03 } },
+        { 1, { 0x01 } },
+        { 2, { 0x09, 0x90 } },
+        { 3, { 0x08, 0x90, 0xfa } },
+        { 1, { 0x34 } },
+        { 2, { 0x35, 0x01 } },
+        { 2, { 0x36, 0x01 } },
+        { 2, { 0x30, 0x09 } },
+        { 4, { 0x30, 0x06, 0x00, 0xe2 } },
+        { 3, { 0x31, 0x01, 0x30 } },
+        { 3, { 0x31, 0x04, 0x09 } },
+        { 2, { 0x05, 0x02 } },
+        { 6, { 0x06, 0x03, 0x03, 0x08, 0x01, 0x0f } },
+};
+
+static int si4713_start_seq(struct si4713_usb_device *radio)
+{
+        int retval = 0;
+        int i;
+
+        radio->buffer[0] = 0x3f;
+
+        for (i = 0; i < ARRAY_SIZE(start_seq); i++) {
+                int len = start_seq[i].len;
+                u8 *payload = start_seq[i].payload;
+
+                memcpy(radio->buffer + 1, payload, len);
+                memset(radio->buffer + len + 1, 0, BUFFER_LENGTH - 1 - len);
+                retval = si4713_send_startup_command(radio);
+        }
+
+        return retval;
+}
+
+static struct i2c_board_info si4713_board_info = {
+        I2C_BOARD_INFO("si4713", SI4713_I2C_ADDR_BUSEN_HIGH),
+};
+
+struct si4713_command_table {
+        int command_id;
+        u8 payload[8];
+};
+
+/*
+ * Structure of a command :
+ *      Byte 1 : 0x3f (always)
+ *      Byte 2 : 0x06 (send a command)
+ *      Byte 3 : Unknown
+ *      Byte 4 : Number of arguments + 1 (for the command byte)
+ *      Byte 5 : Number of response bytes
+ */
+struct si4713_command_table command_table[] = {
+
+        { SI4713_CMD_POWER_UP,          { 0x00, SI4713_PWUP_NARGS + 1, SI4713_PWUP_NRESP} },
+        { SI4713_CMD_GET_REV,           { 0x03, 0x01, SI4713_GETREV_NRESP } },
+        { SI4713_CMD_POWER_DOWN,        { 0x00, 0x01, SI4713_PWDN_NRESP} },
+        { SI4713_CMD_SET_PROPERTY,      { 0x00, SI4713_SET_PROP_NARGS + 1, SI4713_SET_PROP_NRESP } },
+        { SI4713_CMD_GET_PROPERTY,      { 0x00, SI4713_GET_PROP_NARGS + 1, SI4713_GET_PROP_NRESP } },
+        { SI4713_CMD_TX_TUNE_FREQ,      { 0x03, SI4713_TXFREQ_NARGS + 1, SI4713_TXFREQ_NRESP } },
+        { SI4713_CMD_TX_TUNE_POWER,     { 0x03, SI4713_TXPWR_NARGS + 1, SI4713_TXPWR_NRESP } },
+        { SI4713_CMD_TX_TUNE_MEASURE,   { 0x03, SI4713_TXMEA_NARGS + 1, SI4713_TXMEA_NRESP } },
+        { SI4713_CMD_TX_TUNE_STATUS,    { 0x00, SI4713_TXSTATUS_NARGS + 1, SI4713_TXSTATUS_NRESP } },
+        { SI4713_CMD_TX_ASQ_STATUS,     { 0x03, SI4713_ASQSTATUS_NARGS + 1, SI4713_ASQSTATUS_NRESP } },
+        { SI4713_CMD_GET_INT_STATUS,    { 0x03, 0x01, SI4713_GET_STATUS_NRESP } },
+        { SI4713_CMD_TX_RDS_BUFF,       { 0x03, SI4713_RDSBUFF_NARGS + 1, SI4713_RDSBUFF_NRESP } },
+        { SI4713_CMD_TX_RDS_PS,         { 0x00, SI4713_RDSPS_NARGS + 1, SI4713_RDSPS_NRESP } },
+};
+
+static int send_command(struct si4713_usb_device *radio, u8 *payload, char *data, int len)
+{
+        int retval;
+
+        radio->buffer[0] = 0x3f;
+        radio->buffer[1] = 0x06;
+
+        memcpy(radio->buffer + 2, payload, 3);
+        memcpy(radio->buffer + 5, data, len);
+        memset(radio->buffer + 5 + len, 0, BUFFER_LENGTH - 5 - len);
+
+        /* send the command */
+        retval = usb_control_msg(radio->usbdev, usb_sndctrlpipe(radio->usbdev, 0),
+                                        0x09, 0x21, 0x033f, 0, radio->buffer,
+                                        BUFFER_LENGTH, USB_TIMEOUT);
+
+        return retval < 0 ? retval : 0;
+}
+
+static int si4713_i2c_read(struct si4713_usb_device *radio, char *data, int len)
+{
+        unsigned long until_jiffies = jiffies + usecs_to_jiffies(USB_RESP_TIMEOUT) + 1;
+        int retval;
+
+        /* receive the response */
+        for (;;) {
+                retval = usb_control_msg(radio->usbdev,
+                                        usb_rcvctrlpipe(radio->usbdev, 0),
+                                        0x01, 0xa1, 0x033f, 0, radio->buffer,
+                                        BUFFER_LENGTH, USB_TIMEOUT);
+                if (retval < 0)
+                        return retval;
+
+                /*
+                 * Check that we get a valid reply back (buffer[1] == 0) and
+                 * that CTS is set before returning, otherwise we wait and try
+                 * again. The i2c driver also does the CTS check, but the timeouts
+                 * used there are much too small for this USB driver, so we wait
+                 * for it here.
+                 */
+                if (radio->buffer[1] == 0 && (radio->buffer[2] & SI4713_CTS)) {
+                        memcpy(data, radio->buffer + 2, len);
+                        return 0;
+                }
+                if (time_is_before_jiffies(until_jiffies)) {
+                        /* Zero the status value, ensuring CTS isn't set */
+                        data[0] = 0;
+                        return 0;
+                }
+                msleep(3);
+        }
+}
+
+static int si4713_i2c_write(struct si4713_usb_device *radio, char *data, int len)
+{
+        int retval = -EINVAL;
+        int i;
+
+        if (len > BUFFER_LENGTH - 5)
+                return -EINVAL;
+
+        for (i = 0; i < ARRAY_SIZE(command_table); i++) {
+                if (data[0] == command_table[i].command_id)
+                        retval = send_command(radio, command_table[i].payload,
+                                                data, len);
+        }
+
+        return retval < 0 ? retval : 0;
+}
+
+static int si4713_transfer(struct i2c_adapter *i2c_adapter,
+                                struct i2c_msg *msgs, int num)
+{
+        struct si4713_usb_device *radio = i2c_get_adapdata(i2c_adapter);
+        int retval = -EINVAL;
+        int i;
+
+        if (num <= 0)
+                return 0;
+
+        for (i = 0; i < num; i++) {
+                if (msgs[i].flags & I2C_M_RD)
+                        retval = si4713_i2c_read(radio, msgs[i].buf, msgs[i].len);
+                else
+                        retval = si4713_i2c_write(radio, msgs[i].buf, msgs[i].len);
+                if (retval)
+                        break;
+        }
+
+        return retval ? retval : num;
+}
+
+static u32 si4713_functionality(struct i2c_adapter *adapter)
+{
+        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static struct i2c_algorithm si4713_algo = {
+        .master_xfer   = si4713_transfer,
+        .functionality = si4713_functionality,
+};
+
+/* This name value shows up in the sysfs filename associated
+                with this I2C adapter */
+static struct i2c_adapter si4713_i2c_adapter_template = {
+        .name   = "si4713-i2c",
+        .owner  = THIS_MODULE,
+        .algo   = &si4713_algo,
+};
+
+int si4713_register_i2c_adapter(struct si4713_usb_device *radio)
+{
+        radio->i2c_adapter = si4713_i2c_adapter_template;
+        /* set up sysfs linkage to our parent device */
+        radio->i2c_adapter.dev.parent = &radio->usbdev->dev;
+        i2c_set_adapdata(&radio->i2c_adapter, radio);
+
+        return i2c_add_adapter(&radio->i2c_adapter);
+}
+
+/* check if the device is present and register with v4l and usb if it is */
+static int usb_si4713_probe(struct usb_interface *intf,
+                                const struct usb_device_id *id)
+{
+        struct si4713_usb_device *radio;
+        struct i2c_adapter *adapter;
+        struct v4l2_subdev *sd;
+        int retval = -ENOMEM;
+
+        dev_info(&intf->dev, "Si4713 development board discovered: (%04X:%04X)\n",
+                        id->idVendor, id->idProduct);
+
+        /* Initialize local device structure */
+        radio = kzalloc(sizeof(struct si4713_usb_device), GFP_KERNEL);
+        if (radio)
+                radio->buffer = kmalloc(BUFFER_LENGTH, GFP_KERNEL);
+
+        if (!radio || !radio->buffer) {
+                dev_err(&intf->dev, "kmalloc for si4713_usb_device failed\n");
+                kfree(radio);
+                return -ENOMEM;
+        }
+
+        mutex_init(&radio->lock);
+
+        radio->usbdev = interface_to_usbdev(intf);
+        radio->intf = intf;
+        usb_set_intfdata(intf, &radio->v4l2_dev);
+
+        retval = si4713_start_seq(radio);
+        if (retval < 0)
+                goto err_v4l2;
+
+        retval = v4l2_device_register(&intf->dev, &radio->v4l2_dev);
+        if (retval < 0) {
+                dev_err(&intf->dev, "couldn't register v4l2_device\n");
+                goto err_v4l2;
+        }
+
+        retval = si4713_register_i2c_adapter(radio);
+        if (retval < 0) {
+                dev_err(&intf->dev, "could not register i2c device\n");
+                goto err_i2cdev;
+        }
+
+        adapter = &radio->i2c_adapter;
+        sd = v4l2_i2c_new_subdev_board(&radio->v4l2_dev, adapter,
+                                          &si4713_board_info, NULL);
+        radio->v4l2_subdev = sd;
+        if (!sd) {
+                dev_err(&intf->dev, "cannot get v4l2 subdevice\n");
+                retval = -ENODEV;
+                goto del_adapter;
+        }
+
+        radio->vdev.ctrl_handler = sd->ctrl_handler;
+        radio->v4l2_dev.release = usb_si4713_video_device_release;
+        strlcpy(radio->vdev.name, radio->v4l2_dev.name,
+                sizeof(radio->vdev.name));
+        radio->vdev.v4l2_dev = &radio->v4l2_dev;
+        radio->vdev.fops = &usb_si4713_fops;
+        radio->vdev.ioctl_ops = &usb_si4713_ioctl_ops;
+        radio->vdev.lock = &radio->lock;
+        radio->vdev.release = video_device_release_empty;
+        radio->vdev.vfl_dir = VFL_DIR_TX;
+
+        video_set_drvdata(&radio->vdev, radio);
+        set_bit(V4L2_FL_USE_FH_PRIO, &radio->vdev.flags);
+
+        retval = video_register_device(&radio->vdev, VFL_TYPE_RADIO, -1);
+        if (retval < 0) {
+                dev_err(&intf->dev, "could not register video device\n");
+                goto del_adapter;
+        }
+
+        dev_info(&intf->dev, "V4L2 device registered as %s\n",
+                        video_device_node_name(&radio->vdev));
+
+        return 0;
+
+del_adapter:
+        i2c_del_adapter(adapter);
+err_i2cdev:
+        v4l2_device_unregister(&radio->v4l2_dev);
+err_v4l2:
+        kfree(radio->buffer);
+        kfree(radio);
+        return retval;
+}
+
+static void usb_si4713_disconnect(struct usb_interface *intf)
+{
+        struct si4713_usb_device *radio = to_si4713_dev(usb_get_intfdata(intf));
+
+        dev_info(&intf->dev, "Si4713 development board now disconnected\n");
+
+        mutex_lock(&radio->lock);
+        usb_set_intfdata(intf, NULL);
+        video_unregister_device(&radio->vdev);
+        v4l2_device_disconnect(&radio->v4l2_dev);
+        mutex_unlock(&radio->lock);
+        v4l2_device_put(&radio->v4l2_dev);
+}
+
+/* USB subsystem interface */
+static struct usb_driver usb_si4713_driver = {
+        .name                   = "radio-usb-si4713",
+        .probe                  = usb_si4713_probe,
+        .disconnect             = usb_si4713_disconnect,
+        .id_table               = usb_si4713_usb_device_table,
+};
+
+module_usb_driver(usb_si4713_driver);