V4L/DVB: Add SPI support to V4L2

Add support SPI bus to v4l2. Useful for control some device with SPI bus like
hardware MPEG2 encoders and etc.

Signed-off-by: Beholder Intl. Ltd. Dmitry Belimov <d.belimov@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

4 files changed, 95 insertions, 0 deletions

diff --git a/drivers/media/video/v4l2-common.c b/drivers/media/video/v4l2-common.c
index 6a3d0b71f78f..cd1f21d9b079 100644
--- a/drivers/media/video/v4l2-common.c
+++ b/drivers/media/video/v4l2-common.c
@@ -51,6 +51,9 @@
 #include <linux/string.h>
 #include <linux/errno.h>
 #include <linux/i2c.h>
+#if defined(CONFIG_SPI)
+#include <linux/spi/spi.h>
+#endif
 #include <asm/uaccess.h>
 #include <asm/system.h>
 #include <asm/pgtable.h>
@@ -955,6 +958,66 @@ EXPORT_SYMBOL_GPL(v4l2_i2c_tuner_addrs);
 
 #endif /* defined(CONFIG_I2C) */
 
+#if defined(CONFIG_SPI)
+
+/* Load a spi sub-device. */
+
+void v4l2_spi_subdev_init(struct v4l2_subdev *sd, struct spi_device *spi,
+                const struct v4l2_subdev_ops *ops)
+{
+        v4l2_subdev_init(sd, ops);
+        sd->flags |= V4L2_SUBDEV_FL_IS_SPI;
+        /* the owner is the same as the spi_device's driver owner */
+        sd->owner = spi->dev.driver->owner;
+        /* spi_device and v4l2_subdev point to one another */
+        v4l2_set_subdevdata(sd, spi);
+        spi_set_drvdata(spi, sd);
+        /* initialize name */
+        strlcpy(sd->name, spi->dev.driver->name, sizeof(sd->name));
+}
+EXPORT_SYMBOL_GPL(v4l2_spi_subdev_init);
+
+struct v4l2_subdev *v4l2_spi_new_subdev(struct v4l2_device *v4l2_dev,
+                struct spi_master *master, struct spi_board_info *info)
+{
+        struct v4l2_subdev *sd = NULL;
+        struct spi_device *spi = NULL;
+
+        BUG_ON(!v4l2_dev);
+
+        if (info->modalias)
+                request_module(info->modalias);
+
+        spi = spi_new_device(master, info);
+
+        if (spi == NULL || spi->dev.driver == NULL)
+                goto error;
+
+        if (!try_module_get(spi->dev.driver->owner))
+                goto error;
+
+        sd = spi_get_drvdata(spi);
+
+        /* Register with the v4l2_device which increases the module's
+           use count as well. */
+        if (v4l2_device_register_subdev(v4l2_dev, sd))
+                sd = NULL;
+
+        /* Decrease the module use count to match the first try_module_get. */
+        module_put(spi->dev.driver->owner);
+
+error:
+        /* If we have a client but no subdev, then something went wrong and
+           we must unregister the client. */
+        if (spi && sd == NULL)
+                spi_unregister_device(spi);
+
+        return sd;
+}
+EXPORT_SYMBOL_GPL(v4l2_spi_new_subdev);
+
+#endif /* defined(CONFIG_SPI) */
+
 /* Clamp x to be between min and max, aligned to a multiple of 2^align.  min
  * and max don't have to be aligned, but there must be at least one valid
  * value.  E.g., min=17,max=31,align=4 is not allowed as there are no multiples
diff --git a/drivers/media/video/v4l2-device.c b/drivers/media/video/v4l2-device.c
index 0d06e7cbd5b3..5a7dc4afe92a 100644
--- a/drivers/media/video/v4l2-device.c
+++ b/drivers/media/video/v4l2-device.c
@@ -21,6 +21,9 @@
 #include <linux/types.h>
 #include <linux/ioctl.h>
 #include <linux/i2c.h>
+#if defined(CONFIG_SPI)
+#include <linux/spi/spi.h>
+#endif
 #include <linux/videodev2.h>
 #include <media/v4l2-device.h>
 
@@ -97,6 +100,14 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
                                 i2c_unregister_device(client);
                 }
 #endif
+#if defined(CONFIG_SPI)
+                if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) {
+                        struct spi_device *spi = v4l2_get_subdevdata(sd);
+
+                        if (spi)
+                                spi_unregister_device(spi);
+                }
+#endif
         }
 }
 EXPORT_SYMBOL_GPL(v4l2_device_unregister);
diff --git a/include/media/v4l2-common.h b/include/media/v4l2-common.h
index 1c7b259f341c..3b2efdc6d065 100644
--- a/include/media/v4l2-common.h
+++ b/include/media/v4l2-common.h
@@ -184,6 +184,25 @@ const unsigned short *v4l2_i2c_tuner_addrs(enum v4l2_i2c_tuner_type type);
 
 /* ------------------------------------------------------------------------- */
 
+/* SPI Helper functions */
+#if defined(CONFIG_SPI)
+
+#include <linux/spi/spi.h>
+
+struct spi_device;
+
+/* Load an spi module and return an initialized v4l2_subdev struct.
+   The client_type argument is the name of the chip that's on the adapter. */
+struct v4l2_subdev *v4l2_spi_new_subdev(struct v4l2_device *v4l2_dev,
+                struct spi_master *master, struct spi_board_info *info);
+
+/* Initialize an v4l2_subdev with data from an spi_device struct */
+void v4l2_spi_subdev_init(struct v4l2_subdev *sd, struct spi_device *spi,
+                const struct v4l2_subdev_ops *ops);
+#endif
+
+/* ------------------------------------------------------------------------- */
+
 /* Note: these remaining ioctls/structs should be removed as well, but they are
    still used in tuner-simple.c (TUNER_SET_CONFIG), cx18/ivtv (RESET) and
    v4l2-int-device.h (v4l2_routing). To remove these ioctls some more cleanup
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index 2bcdca0a57fc..09758789be02 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -387,6 +387,8 @@ struct v4l2_subdev_ops {
 
 /* Set this flag if this subdev is a i2c device. */
 #define V4L2_SUBDEV_FL_IS_I2C (1U << 0)
+/* Set this flag if this subdev is a spi device. */
+#define V4L2_SUBDEV_FL_IS_SPI (1U << 1)
 
 /* Each instance of a subdev driver should create this struct, either
    stand-alone or embedded in a larger struct.