V4L/DVB (5766): ET61x251 driver updates

- Make the driver depend on V4L2 only (KConfig)
- Better and safe locking mechanism of the device structure on open(),
  close() and disconnect()
- Use kref for handling device deallocation
- Generic cleanups

Signed-off-by: Luca Risolia <luca.risolia@studio.unibo.it>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

5 files changed, 120 insertions, 104 deletions

diff --git a/drivers/media/video/et61x251/Kconfig b/drivers/media/video/et61x251/Kconfig
index 664676f44068..dcc1a0335440 100644
--- a/drivers/media/video/et61x251/Kconfig
+++ b/drivers/media/video/et61x251/Kconfig
@@ -1,6 +1,6 @@
 config USB_ET61X251
         tristate "USB ET61X[12]51 PC Camera Controller support"
-        depends on VIDEO_V4L1
+        depends on VIDEO_V4L2
         ---help---
           Say Y here if you want support for cameras based on Etoms ET61X151
           or ET61X251 PC Camera Controllers.
diff --git a/drivers/media/video/et61x251/et61x251.h b/drivers/media/video/et61x251/et61x251.h
index 262f98e12409..02c741d8f85a 100644
--- a/drivers/media/video/et61x251/et61x251.h
+++ b/drivers/media/video/et61x251/et61x251.h
@@ -36,6 +36,7 @@
 #include <linux/mutex.h>
 #include <linux/stddef.h>
 #include <linux/string.h>
+#include <linux/kref.h>
 
 #include "et61x251_sensor.h"
 
@@ -134,7 +135,7 @@ struct et61x251_module_param {
 };
 
 static DEFINE_MUTEX(et61x251_sysfs_lock);
-static DECLARE_RWSEM(et61x251_disconnect);
+static DECLARE_RWSEM(et61x251_dev_lock);
 
 struct et61x251_device {
         struct video_device* v4ldev;
@@ -158,12 +159,14 @@ struct et61x251_device {
         struct et61x251_sysfs_attr sysfs;
         struct et61x251_module_param module_param;
 
+        struct kref kref;
         enum et61x251_dev_state state;
         u8 users;
 
-        struct mutex dev_mutex, fileop_mutex;
+        struct completion probe;
+        struct mutex open_mutex, fileop_mutex;
         spinlock_t queue_lock;
-        wait_queue_head_t open, wait_frame, wait_stream;
+        wait_queue_head_t wait_open, wait_frame, wait_stream;
 };
 
 /*****************************************************************************/
@@ -177,7 +180,7 @@ et61x251_match_id(struct et61x251_device* cam, const struct usb_device_id *id)
 
 void
 et61x251_attach_sensor(struct et61x251_device* cam,
-                       struct et61x251_sensor* sensor)
+                       const struct et61x251_sensor* sensor)
 {
         memcpy(&cam->sensor, sensor, sizeof(struct et61x251_sensor));
 }
@@ -195,8 +198,8 @@ do {                                                                          \
                 else if ((level) == 2)                                        \
                         dev_info(&cam->usbdev->dev, fmt "\n", ## args);       \
                 else if ((level) >= 3)                                        \
-                        dev_info(&cam->usbdev->dev, "[%s:%d] " fmt "\n",      \
-                                 __FUNCTION__, __LINE__ , ## args);           \
+                        dev_info(&cam->usbdev->dev, "[%s:%s:%d] " fmt "\n",   \
+                                 __FILE__, __FUNCTION__, __LINE__ , ## args); \
         }                                                                     \
 } while (0)
 #       define KDBG(level, fmt, args...)                                      \
@@ -205,8 +208,8 @@ do {                                                                          \
                 if ((level) == 1 || (level) == 2)                             \
                         pr_info("et61x251: " fmt "\n", ## args);              \
                 else if ((level) == 3)                                        \
-                        pr_debug("et61x251: [%s:%d] " fmt "\n", __FUNCTION__, \
-                                 __LINE__ , ## args);                         \
+                        pr_debug("sn9c102: [%s:%s:%d] " fmt "\n", __FILE__,   \
+                                 __FUNCTION__, __LINE__ , ## args);           \
         }                                                                     \
 } while (0)
 #       define V4LDBG(level, name, cmd)                                       \
@@ -222,8 +225,8 @@ do {                                                                          \
 
 #undef PDBG
 #define PDBG(fmt, args...)                                                    \
-dev_info(&cam->usbdev->dev, "[%s:%d] " fmt "\n",                              \
-         __FUNCTION__, __LINE__ , ## args)
+dev_info(&cam->usbdev->dev, "[%s:%s:%d] " fmt "\n", __FILE__, __FUNCTION__,   \
+         __LINE__ , ## args)
 
 #undef PDBGG
 #define PDBGG(fmt, args...) do {;} while(0) /* placeholder */
diff --git a/drivers/media/video/et61x251/et61x251_core.c b/drivers/media/video/et61x251/et61x251_core.c
index a6525513cd1e..585bd1fe0765 100644
--- a/drivers/media/video/et61x251/et61x251_core.c
+++ b/drivers/media/video/et61x251/et61x251_core.c
@@ -45,11 +45,11 @@
 
 #define ET61X251_MODULE_NAME    "V4L2 driver for ET61X[12]51 "                \
                                 "PC Camera Controllers"
-#define ET61X251_MODULE_AUTHOR  "(C) 2006 Luca Risolia"
+#define ET61X251_MODULE_AUTHOR  "(C) 2006-2007 Luca Risolia"
 #define ET61X251_AUTHOR_EMAIL   "<luca.risolia@studio.unibo.it>"
 #define ET61X251_MODULE_LICENSE "GPL"
-#define ET61X251_MODULE_VERSION "1:1.04"
-#define ET61X251_MODULE_VERSION_CODE  KERNEL_VERSION(1, 1, 4)
+#define ET61X251_MODULE_VERSION "1:1.09"
+#define ET61X251_MODULE_VERSION_CODE  KERNEL_VERSION(1, 1, 9)
 
 /*****************************************************************************/
 
@@ -245,7 +245,8 @@ int et61x251_read_reg(struct et61x251_device* cam, u16 index)
 
 
 static int
-et61x251_i2c_wait(struct et61x251_device* cam, struct et61x251_sensor* sensor)
+et61x251_i2c_wait(struct et61x251_device* cam,
+                  const struct et61x251_sensor* sensor)
 {
         int i, r;
 
@@ -270,7 +271,7 @@ et61x251_i2c_wait(struct et61x251_device* cam, struct et61x251_sensor* sensor)
 
 int
 et61x251_i2c_try_read(struct et61x251_device* cam,
-                      struct et61x251_sensor* sensor, u8 address)
+                      const struct et61x251_sensor* sensor, u8 address)
 {
         struct usb_device* udev = cam->usbdev;
         u8* data = cam->control_buffer;
@@ -303,7 +304,8 @@ et61x251_i2c_try_read(struct et61x251_device* cam,
 
 int
 et61x251_i2c_try_write(struct et61x251_device* cam,
-                       struct et61x251_sensor* sensor, u8 address, u8 value)
+                       const struct et61x251_sensor* sensor, u8 address,
+                       u8 value)
 {
         struct usb_device* udev = cam->usbdev;
         u8* data = cam->control_buffer;
@@ -615,7 +617,7 @@ static int et61x251_start_transfer(struct et61x251_device* cam)
         return 0;
 
 free_urbs:
-        for (i = 0; (i < ET61X251_URBS) &&  cam->urb[i]; i++)
+        for (i = 0; (i < ET61X251_URBS) && cam->urb[i]; i++)
                 usb_free_urb(cam->urb[i]);
 
 free_buffers:
@@ -682,7 +684,7 @@ static u8 et61x251_strtou8(const char* buff, size_t len, ssize_t* count)
 
         if (len < 4) {
                 strncpy(str, buff, len);
-                str[len+1] = '\0';
+                str[len] = '\0';
         } else {
                 strncpy(str, buff, 4);
                 str[4] = '\0';
@@ -977,30 +979,30 @@ static CLASS_DEVICE_ATTR(i2c_val, S_IRUGO | S_IWUSR,
 
 static int et61x251_create_sysfs(struct et61x251_device* cam)
 {
-        struct video_device *v4ldev = cam->v4ldev;
+        struct class_device *classdev = &(cam->v4ldev->class_dev);
         int err = 0;
 
-        if ((err = video_device_create_file(v4ldev, &class_device_attr_reg)))
+        if ((err = class_device_create_file(classdev, &class_device_attr_reg)))
                 goto err_out;
-        if ((err = video_device_create_file(v4ldev, &class_device_attr_val)))
+        if ((err = class_device_create_file(classdev, &class_device_attr_val)))
                 goto err_reg;
 
         if (cam->sensor.sysfs_ops) {
-                if ((err = video_device_create_file(v4ldev,
+                if ((err = class_device_create_file(classdev,
                                                   &class_device_attr_i2c_reg)))
                         goto err_val;
-                if ((err = video_device_create_file(v4ldev,
+                if ((err = class_device_create_file(classdev,
                                                   &class_device_attr_i2c_val)))
                         goto err_i2c_reg;
         }
 
 err_i2c_reg:
         if (cam->sensor.sysfs_ops)
-        video_device_remove_file(v4ldev, &class_device_attr_i2c_reg);
+                class_device_remove_file(classdev, &class_device_attr_i2c_reg);
 err_val:
-        video_device_remove_file(v4ldev, &class_device_attr_val);
+        class_device_remove_file(classdev, &class_device_attr_val);
 err_reg:
-        video_device_remove_file(v4ldev, &class_device_attr_reg);
+        class_device_remove_file(classdev, &class_device_attr_reg);
 err_out:
         return err;
 }
@@ -1103,7 +1105,8 @@ static int et61x251_init(struct et61x251_device* cam)
         int err = 0;
 
         if (!(cam->state & DEV_INITIALIZED)) {
-                init_waitqueue_head(&cam->open);
+                mutex_init(&cam->open_mutex);
+                init_waitqueue_head(&cam->wait_open);
                 qctrl = s->qctrl;
                 rect = &(s->cropcap.defrect);
                 cam->compression.quality = ET61X251_COMPRESSION_QUALITY;
@@ -1177,64 +1180,80 @@ static int et61x251_init(struct et61x251_device* cam)
         return 0;
 }
 
+/*****************************************************************************/
 
-static void et61x251_release_resources(struct et61x251_device* cam)
+static void et61x251_release_resources(struct kref *kref)
 {
+        struct et61x251_device *cam;
+
         mutex_lock(&et61x251_sysfs_lock);
 
+        cam = container_of(kref, struct et61x251_device, kref);
+
         DBG(2, "V4L2 device /dev/video%d deregistered", cam->v4ldev->minor);
         video_set_drvdata(cam->v4ldev, NULL);
         video_unregister_device(cam->v4ldev);
+        usb_put_dev(cam->usbdev);
+        kfree(cam->control_buffer);
+        kfree(cam);
 
         mutex_unlock(&et61x251_sysfs_lock);
-
-        kfree(cam->control_buffer);
 }
 
-/*****************************************************************************/
 
 static int et61x251_open(struct inode* inode, struct file* filp)
 {
         struct et61x251_device* cam;
         int err = 0;
 
-        /*
-           This is the only safe way to prevent race conditions with
-           disconnect
-        */
-        if (!down_read_trylock(&et61x251_disconnect))
+        if (!down_read_trylock(&et61x251_dev_lock))
                 return -ERESTARTSYS;
 
         cam = video_get_drvdata(video_devdata(filp));
 
-        if (mutex_lock_interruptible(&cam->dev_mutex)) {
-                up_read(&et61x251_disconnect);
+        if (wait_for_completion_interruptible(&cam->probe)) {
+                up_read(&et61x251_dev_lock);
                 return -ERESTARTSYS;
         }
 
+        kref_get(&cam->kref);
+
+        if (mutex_lock_interruptible(&cam->open_mutex)) {
+                kref_put(&cam->kref, et61x251_release_resources);
+                up_read(&et61x251_dev_lock);
+                return -ERESTARTSYS;
+        }
+
+        if (cam->state & DEV_DISCONNECTED) {
+                DBG(1, "Device not present");
+                err = -ENODEV;
+                goto out;
+        }
+
         if (cam->users) {
-                DBG(2, "Device /dev/video%d is busy...", cam->v4ldev->minor);
+                DBG(2, "Device /dev/video%d is already in use",
+                       cam->v4ldev->minor);
+                DBG(3, "Simultaneous opens are not supported");
                 if ((filp->f_flags & O_NONBLOCK) ||
                     (filp->f_flags & O_NDELAY)) {
                         err = -EWOULDBLOCK;
                         goto out;
                 }
-                mutex_unlock(&cam->dev_mutex);
-                err = wait_event_interruptible_exclusive(cam->open,
-                                                  cam->state & DEV_DISCONNECTED
+                DBG(2, "A blocking open() has been requested. Wait for the "
+                       "device to be released...");
+                up_read(&et61x251_dev_lock);
+                err = wait_event_interruptible_exclusive(cam->wait_open,
+                                                (cam->state & DEV_DISCONNECTED)
                                                          || !cam->users);
-                if (err) {
-                        up_read(&et61x251_disconnect);
-                        return err;
-                }
+                down_read(&et61x251_dev_lock);
+                if (err)
+                        goto out;
                 if (cam->state & DEV_DISCONNECTED) {
-                        up_read(&et61x251_disconnect);
-                        return -ENODEV;
+                        err = -ENODEV;
+                        goto out;
                 }
-                mutex_lock(&cam->dev_mutex);
         }
 
-
         if (cam->state & DEV_MISCONFIGURED) {
                 err = et61x251_init(cam);
                 if (err) {
@@ -1259,36 +1278,32 @@ static int et61x251_open(struct inode* inode, struct file* filp)
         DBG(3, "Video device /dev/video%d is open", cam->v4ldev->minor);
 
 out:
-        mutex_unlock(&cam->dev_mutex);
-        up_read(&et61x251_disconnect);
+        mutex_unlock(&cam->open_mutex);
+        if (err)
+                kref_put(&cam->kref, et61x251_release_resources);
+        up_read(&et61x251_dev_lock);
         return err;
 }
 
 
 static int et61x251_release(struct inode* inode, struct file* filp)
 {
-        struct et61x251_device* cam = video_get_drvdata(video_devdata(filp));
+        struct et61x251_device* cam;
 
-        mutex_lock(&cam->dev_mutex); /* prevent disconnect() to be called */
+        down_write(&et61x251_dev_lock);
 
-        et61x251_stop_transfer(cam);
+        cam = video_get_drvdata(video_devdata(filp));
 
+        et61x251_stop_transfer(cam);
         et61x251_release_buffers(cam);
-
-        if (cam->state & DEV_DISCONNECTED) {
-                et61x251_release_resources(cam);
-                usb_put_dev(cam->usbdev);
-                mutex_unlock(&cam->dev_mutex);
-                kfree(cam);
-                return 0;
-        }
-
         cam->users--;
-        wake_up_interruptible_nr(&cam->open, 1);
+        wake_up_interruptible_nr(&cam->wait_open, 1);
 
         DBG(3, "Video device /dev/video%d closed", cam->v4ldev->minor);
 
-        mutex_unlock(&cam->dev_mutex);
+        kref_put(&cam->kref, et61x251_release_resources);
+
+        up_write(&et61x251_dev_lock);
 
         return 0;
 }
@@ -1324,7 +1339,7 @@ et61x251_read(struct file* filp, char __user * buf,
                 DBG(3, "Close and open the device again to choose the read "
                        "method");
                 mutex_unlock(&cam->fileop_mutex);
-                return -EINVAL;
+                return -EBUSY;
         }
 
         if (cam->io == IO_NONE) {
@@ -1504,7 +1519,12 @@ static int et61x251_mmap(struct file* filp, struct vm_area_struct *vma)
                 return -EIO;
         }
 
-        if (cam->io != IO_MMAP || !(vma->vm_flags & VM_WRITE) ||
+        if (!(vma->vm_flags & (VM_WRITE | VM_READ))) {
+                mutex_unlock(&cam->fileop_mutex);
+                return -EACCES;
+        }
+
+        if (cam->io != IO_MMAP ||
             size != PAGE_ALIGN(cam->frame[0].buf.length)) {
                 mutex_unlock(&cam->fileop_mutex);
                 return -EINVAL;
@@ -1535,7 +1555,6 @@ static int et61x251_mmap(struct file* filp, struct vm_area_struct *vma)
 
         vma->vm_ops = &et61x251_vm_ops;
         vma->vm_private_data = &cam->frame[i];
-
         et61x251_vm_open(vma);
 
         mutex_unlock(&cam->fileop_mutex);
@@ -1764,7 +1783,7 @@ et61x251_vidioc_s_crop(struct et61x251_device* cam, void __user * arg)
                         if (cam->frame[i].vma_use_count) {
                                 DBG(3, "VIDIOC_S_CROP failed. "
                                        "Unmap the buffers first.");
-                                return -EINVAL;
+                                return -EBUSY;
                         }
 
         /* Preserve R,G or B origin */
@@ -1921,6 +1940,8 @@ et61x251_vidioc_g_fmt(struct et61x251_device* cam, void __user * arg)
         if (format.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                 return -EINVAL;
 
+        pfmt->colorspace = (pfmt->pixelformat == V4L2_PIX_FMT_ET61X251) ?
+                           0 : V4L2_COLORSPACE_SRGB;
         pfmt->bytesperline = (pfmt->pixelformat==V4L2_PIX_FMT_ET61X251)
                              ? 0 : (pfmt->width * pfmt->priv) / 8;
         pfmt->sizeimage = pfmt->height * ((pfmt->width*pfmt->priv)/8);
@@ -1996,6 +2017,8 @@ et61x251_vidioc_try_s_fmt(struct et61x251_device* cam, unsigned int cmd,
             pix->pixelformat != V4L2_PIX_FMT_SBGGR8)
                 pix->pixelformat = pfmt->pixelformat;
         pix->priv = pfmt->priv; /* bpp */
+        pix->colorspace = (pix->pixelformat == V4L2_PIX_FMT_ET61X251) ?
+                          0 : V4L2_COLORSPACE_SRGB;
         pix->colorspace = pfmt->colorspace;
         pix->bytesperline = (pix->pixelformat == V4L2_PIX_FMT_ET61X251)
                             ? 0 : (pix->width * pix->priv) / 8;
@@ -2013,7 +2036,7 @@ et61x251_vidioc_try_s_fmt(struct et61x251_device* cam, unsigned int cmd,
                         if (cam->frame[i].vma_use_count) {
                                 DBG(3, "VIDIOC_S_FMT failed. "
                                        "Unmap the buffers first.");
-                                return -EINVAL;
+                                return -EBUSY;
                         }
 
         if (cam->stream == STREAM_ON)
@@ -2129,14 +2152,14 @@ et61x251_vidioc_reqbufs(struct et61x251_device* cam, void __user * arg)
         if (cam->io == IO_READ) {
                 DBG(3, "Close and open the device again to choose the mmap "
                        "I/O method");
-                return -EINVAL;
+                return -EBUSY;
         }
 
         for (i = 0; i < cam->nbuffers; i++)
                 if (cam->frame[i].vma_use_count) {
                         DBG(3, "VIDIOC_REQBUFS failed. "
                                "Previous buffers are still mapped.");
-                        return -EINVAL;
+                        return -EBUSY;
                 }
 
         if (cam->stream == STREAM_ON)
@@ -2284,9 +2307,6 @@ et61x251_vidioc_streamon(struct et61x251_device* cam, void __user * arg)
         if (type != V4L2_BUF_TYPE_VIDEO_CAPTURE || cam->io != IO_MMAP)
                 return -EINVAL;
 
-        if (list_empty(&cam->inqueue))
-                return -EINVAL;
-
         cam->stream = STREAM_ON;
 
         DBG(3, "Stream on");
@@ -2535,8 +2555,6 @@ et61x251_usb_probe(struct usb_interface* intf, const struct usb_device_id* id)
                 goto fail;
         }
 
-        mutex_init(&cam->dev_mutex);
-
         DBG(2, "ET61X[12]51 PC Camera Controller detected "
                "(vid/pid 0x%04X:0x%04X)",id->idVendor, id->idProduct);
 
@@ -2568,7 +2586,7 @@ et61x251_usb_probe(struct usb_interface* intf, const struct usb_device_id* id)
         cam->v4ldev->release = video_device_release;
         video_set_drvdata(cam->v4ldev, cam);
 
-        mutex_lock(&cam->dev_mutex);
+        init_completion(&cam->probe);
 
         err = video_register_device(cam->v4ldev, VFL_TYPE_GRABBER,
                                     video_nr[dev_nr]);
@@ -2578,7 +2596,7 @@ et61x251_usb_probe(struct usb_interface* intf, const struct usb_device_id* id)
                         DBG(1, "Free /dev/videoX node not found");
                 video_nr[dev_nr] = -1;
                 dev_nr = (dev_nr < ET61X251_MAX_DEVICES-1) ? dev_nr+1 : 0;
-                mutex_unlock(&cam->dev_mutex);
+                complete_all(&cam->probe);
                 goto fail;
         }
 
@@ -2599,11 +2617,15 @@ et61x251_usb_probe(struct usb_interface* intf, const struct usb_device_id* id)
                        "device controlling. Error #%d", err);
 #else
         DBG(2, "Optional device control through 'sysfs' interface disabled");
+        DBG(3, "Compile the kernel with the 'CONFIG_VIDEO_ADV_DEBUG' "
+               "configuration option to enable it.");
 #endif
 
         usb_set_intfdata(intf, cam);
+        kref_init(&cam->kref);
+        usb_get_dev(cam->usbdev);
 
-        mutex_unlock(&cam->dev_mutex);
+        complete_all(&cam->probe);
 
         return 0;
 
@@ -2620,40 +2642,31 @@ fail:
 
 static void et61x251_usb_disconnect(struct usb_interface* intf)
 {
-        struct et61x251_device* cam = usb_get_intfdata(intf);
-
-        if (!cam)
-                return;
+        struct et61x251_device* cam;
 
-        down_write(&et61x251_disconnect);
+        down_write(&et61x251_dev_lock);
 
-        mutex_lock(&cam->dev_mutex);
+        cam = usb_get_intfdata(intf);
 
         DBG(2, "Disconnecting %s...", cam->v4ldev->name);
 
-        wake_up_interruptible_all(&cam->open);
-
         if (cam->users) {
                 DBG(2, "Device /dev/video%d is open! Deregistration and "
-                       "memory deallocation are deferred on close.",
+                       "memory deallocation are deferred.",
                     cam->v4ldev->minor);
                 cam->state |= DEV_MISCONFIGURED;
                 et61x251_stop_transfer(cam);
                 cam->state |= DEV_DISCONNECTED;
                 wake_up_interruptible(&cam->wait_frame);
                 wake_up(&cam->wait_stream);
-                usb_get_dev(cam->usbdev);
-        } else {
+        } else
                 cam->state |= DEV_DISCONNECTED;
-                et61x251_release_resources(cam);
-        }
 
-        mutex_unlock(&cam->dev_mutex);
+        wake_up_interruptible_all(&cam->wait_open);
 
-        if (!cam->users)
-                kfree(cam);
+        kref_put(&cam->kref, et61x251_release_resources);
 
-        up_write(&et61x251_disconnect);
+        up_write(&et61x251_dev_lock);
 }
 
 
diff --git a/drivers/media/video/et61x251/et61x251_sensor.h b/drivers/media/video/et61x251/et61x251_sensor.h
index 5fadb5de68bf..e14586330623 100644
--- a/drivers/media/video/et61x251/et61x251_sensor.h
+++ b/drivers/media/video/et61x251/et61x251_sensor.h
@@ -22,7 +22,7 @@
 #define _ET61X251_SENSOR_H_
 
 #include <linux/usb.h>
-#include <linux/videodev.h>
+#include <linux/videodev2.h>
 #include <linux/device.h>
 #include <linux/stddef.h>
 #include <linux/errno.h>
@@ -47,7 +47,7 @@ et61x251_match_id(struct et61x251_device* cam, const struct usb_device_id *id);
 
 extern void
 et61x251_attach_sensor(struct et61x251_device* cam,
-                       struct et61x251_sensor* sensor);
+                       const struct et61x251_sensor* sensor);
 
 /*****************************************************************************/
 
@@ -56,10 +56,10 @@ extern int et61x251_read_reg(struct et61x251_device*, u16 index);
 extern int et61x251_i2c_write(struct et61x251_device*, u8 address, u8 value);
 extern int et61x251_i2c_read(struct et61x251_device*, u8 address);
 extern int et61x251_i2c_try_write(struct et61x251_device*,
-                                  struct et61x251_sensor*, u8 address,
+                                  const struct et61x251_sensor*, u8 address,
                                   u8 value);
 extern int et61x251_i2c_try_read(struct et61x251_device*,
-                                 struct et61x251_sensor*, u8 address);
+                                 const struct et61x251_sensor*, u8 address);
 extern int et61x251_i2c_raw_write(struct et61x251_device*, u8 n, u8 data1,
                                   u8 data2, u8 data3, u8 data4, u8 data5,
                                   u8 data6, u8 data7, u8 data8, u8 address);
diff --git a/drivers/media/video/et61x251/et61x251_tas5130d1b.c b/drivers/media/video/et61x251/et61x251_tas5130d1b.c
index b06643409842..04b7fbb310a8 100644
--- a/drivers/media/video/et61x251/et61x251_tas5130d1b.c
+++ b/drivers/media/video/et61x251/et61x251_tas5130d1b.c
@@ -69,7 +69,7 @@ static int tas5130d1b_set_ctrl(struct et61x251_device* cam,
 }
 
 
-static struct et61x251_sensor tas5130d1b = {
+static const struct et61x251_sensor tas5130d1b = {
         .name = "TAS5130D1B",
         .interface = ET61X251_I2C_3WIRES,
         .rsta = ET61X251_I2C_RSTA_STOP,