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authorMauro Carvalho Chehab <mchehab@s-opensource.com>2017-09-22 09:03:54 -0400
committerMauro Carvalho Chehab <mchehab@s-opensource.com>2017-12-18 09:25:26 -0500
commit76a59fe77022cb01df8b866d09f23c37e9af8924 (patch)
tree09a1e71d1a21704257a4323ca17f8ff0b02b5207 /include
parent0545629e50af60e7afad9d6023a546aed1081a8e (diff)
media: v4l2-common.h: document helper functions
There are several helper functions that aren't documented. Document them. Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'include')
-rw-r--r--include/media/v4l2-common.h107
1 files changed, 96 insertions, 11 deletions
diff --git a/include/media/v4l2-common.h b/include/media/v4l2-common.h
index 835164f45038..f420c45f7915 100644
--- a/include/media/v4l2-common.h
+++ b/include/media/v4l2-common.h
@@ -28,7 +28,7 @@
#include <media/v4l2-dev.h>
-/* Common printk constucts for v4l-i2c drivers. These macros create a unique
+/* Common printk constructs for v4l-i2c drivers. These macros create a unique
prefix consisting of the driver name, the adapter number and the i2c
address. */
#define v4l_printk(level, name, adapter, addr, fmt, arg...) \
@@ -174,17 +174,43 @@ void v4l2_i2c_subdev_init(struct v4l2_subdev *sd, struct i2c_client *client,
*/
unsigned short v4l2_i2c_subdev_addr(struct v4l2_subdev *sd);
+/**
+ * enum v4l2_i2c_tuner_type - specifies the range of tuner address that
+ * should be used when seeking for I2C devices.
+ *
+ * @ADDRS_RADIO: Radio tuner addresses.
+ * Represent the following I2C addresses:
+ * 0x10 (if compiled with tea5761 support)
+ * and 0x60.
+ * @ADDRS_DEMOD: Demod tuner addresses.
+ * Represent the following I2C addresses:
+ * 0x42, 0x43, 0x4a and 0x4b.
+ * @ADDRS_TV: TV tuner addresses.
+ * Represent the following I2C addresses:
+ * 0x42, 0x43, 0x4a, 0x4b, 0x60, 0x61, 0x62,
+ * 0x63 and 0x64.
+ * @ADDRS_TV_WITH_DEMOD: TV tuner addresses if demod is present, this
+ * excludes addresses used by the demodulator
+ * from the list of candidates.
+ * Represent the following I2C addresses:
+ * 0x60, 0x61, 0x62, 0x63 and 0x64.
+ *
+ * NOTE: All I2C addresses above use the 7-bit notation.
+ */
enum v4l2_i2c_tuner_type {
- ADDRS_RADIO, /* Radio tuner addresses */
- ADDRS_DEMOD, /* Demod tuner addresses */
- ADDRS_TV, /* TV tuner addresses */
- /* TV tuner addresses if demod is present, this excludes
- addresses used by the demodulator from the list of
- candidates. */
+ ADDRS_RADIO,
+ ADDRS_DEMOD,
+ ADDRS_TV,
ADDRS_TV_WITH_DEMOD,
};
-/* Return a list of I2C tuner addresses to probe. Use only if the tuner
- addresses are unknown. */
+/**
+ * v4l2_i2c_tuner_addrs - Return a list of I2C tuner addresses to probe.
+ *
+ * @type: type of the tuner to seek, as defined by
+ * &enum v4l2_i2c_tuner_type.
+ *
+ * NOTE: Use only if the tuner addresses are unknown.
+ */
const unsigned short *v4l2_i2c_tuner_addrs(enum v4l2_i2c_tuner_type type);
/* ------------------------------------------------------------------------- */
@@ -228,6 +254,9 @@ void v4l2_spi_subdev_init(struct v4l2_subdev *sd, struct spi_device *spi,
* FIXME: these remaining ioctls/structs should be removed as well, but they
* are still used in tuner-simple.c (TUNER_SET_CONFIG) and cx18/ivtv (RESET).
* To remove these ioctls some more cleanup is needed in those modules.
+ *
+ * It doesn't make much sense on documenting them, as what we really want is
+ * to get rid of them.
*/
/* s_config */
@@ -243,17 +272,73 @@ struct v4l2_priv_tun_config {
/* Miscellaneous helper functions */
-void v4l_bound_align_image(unsigned int *w, unsigned int wmin,
+/**
+ * v4l_bound_align_image - adjust video dimensions according to
+ * a given constraints.
+ *
+ * @width: pointer to width that will be adjusted if needed.
+ * @wmin: minimum width.
+ * @wmax: maximum width.
+ * @walign: least significant bit on width.
+ * @height: pointer to height that will be adjusted if needed.
+ * @hmin: minimum height.
+ * @hmax: maximum height.
+ * @halign: least significant bit on width.
+ * @salign: least significant bit for the image size (e. g.
+ * :math:`width * height`).
+ *
+ * Clip an image to have @width between @wmin and @wmax, and @height between
+ * @hmin and @hmax, inclusive.
+ *
+ * Additionally, the @width will be a multiple of :math:`2^{walign}`,
+ * the @height will be a multiple of :math:`2^{halign}`, and the overall
+ * size :math:`width * height` will be a multiple of :math:`2^{salign}`.
+ *
+ * .. note::
+ *
+ * #. The clipping rectangle may be shrunk or enlarged to fit the alignment
+ * constraints.
+ * #. @wmax must not be smaller than @wmin.
+ * #. @hmax must not be smaller than @hmin.
+ * #. The alignments must not be so high there are no possible image
+ * sizes within the allowed bounds.
+ * #. @wmin and @hmin must be at least 1 (don't use 0).
+ * #. For @walign, @halign and @salign, if you don't care about a certain
+ * alignment, specify ``0``, as :math:`2^0 = 1` and one byte alignment
+ * is equivalent to no alignment.
+ * #. If you only want to adjust downward, specify a maximum that's the
+ * same as the initial value.
+ */
+void v4l_bound_align_image(unsigned int *width, unsigned int wmin,
unsigned int wmax, unsigned int walign,
- unsigned int *h, unsigned int hmin,
+ unsigned int *height, unsigned int hmin,
unsigned int hmax, unsigned int halign,
unsigned int salign);
+/**
+ * v4l2_find_nearest_format - find the nearest format size among a discrete
+ * set of resolutions.
+ *
+ * @sizes: array of &struct v4l2_frmsize_discrete image sizes.
+ * @num_sizes: length of @sizes array.
+ * @width: desired width.
+ * @height: desired height.
+ *
+ * Finds the closest resolution to minimize the width and height differences
+ * between what requested and the supported resolutions.
+ */
const struct v4l2_frmsize_discrete *
v4l2_find_nearest_format(const struct v4l2_frmsize_discrete *sizes,
const size_t num_sizes,
s32 width, s32 height);
+/**
+ * v4l2_get_timestamp - helper routine to get a timestamp to be used when
+ * filling streaming metadata. Internally, it uses ktime_get_ts(),
+ * which is the recommended way to get it.
+ *
+ * @tv: pointer to &struct timeval to be filled.
+ */
void v4l2_get_timestamp(struct timeval *tv);
#endif /* V4L2_COMMON_H_ */