@@ -194,7 +194,7 @@ The minimum flow for PCI soundcards is as follows:
- create ``remove`` callback.
-- create a :c:type:`struct pci_driver <pci_driver>` structure
+- create a struct pci_driver structure
containing the three pointers above.
- create an ``init`` function just calling the
@@ -487,7 +487,7 @@ The destructor, remove callback, simply releases the card instance. Then
the ALSA middle layer will release all the attached components
automatically.
-It would be typically just :c:func:`calling snd_card_free()`:
+It would be typically just calling :c:func:`snd_card_free()`:
::
@@ -560,16 +560,15 @@ return the card instance. The extra_size argument is used to allocate
card->private_data for the chip-specific data. Note that these data are
allocated by :c:func:`snd_card_new()`.
-The first argument, the pointer of struct :c:type:`struct device
-<device>`, specifies the parent device. For PCI devices, typically
-``&pci->`` is passed there.
+The first argument, the pointer of struct device, specifies the parent
+device. For PCI devices, typically ``&pci->`` is passed there.
Components
----------
After the card is created, you can attach the components (devices) to
the card instance. In an ALSA driver, a component is represented as a
-:c:type:`struct snd_device <snd_device>` object. A component
+struct snd_device object. A component
can be a PCM instance, a control interface, a raw MIDI interface, etc.
Each such instance has one component entry.
@@ -628,7 +627,7 @@ argument of :c:func:`snd_card_new()`, i.e.
err = snd_card_new(&pci->dev, index[dev], id[dev], THIS_MODULE,
sizeof(struct mychip), &card);
-:c:type:`struct mychip <mychip>` is the type of the chip record.
+struct mychip is the type of the chip record.
In return, the allocated record can be accessed as
@@ -890,7 +889,7 @@ functions. These resources must be released in the destructor
function (see below).
Now assume that the PCI device has an I/O port with 8 bytes and an
-interrupt. Then :c:type:`struct mychip <mychip>` will have the
+interrupt. Then struct mychip will have the
following fields:
::
@@ -1094,7 +1093,7 @@ PCI Entries
-----------
So far, so good. Let's finish the missing PCI stuff. At first, we need a
-:c:type:`struct pci_device_id <pci_device_id>` table for
+struct pci_device_id table for
this chipset. It's a table of PCI vendor/device ID number, and some
masks.
@@ -1110,19 +1109,17 @@ For example,
};
MODULE_DEVICE_TABLE(pci, snd_mychip_ids);
-The first and second fields of the :c:type:`struct pci_device_id
-<pci_device_id>` structure are the vendor and device IDs. If you
-have no reason to filter the matching devices, you can leave the
-remaining fields as above. The last field of the :c:type:`struct
-pci_device_id <pci_device_id>` struct contains private data
-for this entry. You can specify any value here, for example, to define
-specific operations for supported device IDs. Such an example is found
-in the intel8x0 driver.
+The first and second fields of the struct pci_device_id are the vendor
+and device IDs. If you have no reason to filter the matching devices, you can
+leave the remaining fields as above. The last field of the
+struct pci_device_id contains private data for this entry. You can specify
+any value here, for example, to define specific operations for supported
+device IDs. Such an example is found in the intel8x0 driver.
The last entry of this list is the terminator. You must specify this
all-zero entry.
-Then, prepare the :c:type:`struct pci_driver <pci_driver>`
+Then, prepare the struct pci_driver
record:
::
@@ -1439,8 +1436,8 @@ corresponding argument.
If a chip supports multiple playbacks or captures, you can specify more
numbers, but they must be handled properly in open/close, etc.
callbacks. When you need to know which substream you are referring to,
-then it can be obtained from :c:type:`struct snd_pcm_substream
-<snd_pcm_substream>` data passed to each callback as follows:
+then it can be obtained from struct snd_pcm_substream data passed to each
+callback as follows:
::
@@ -1639,10 +1636,9 @@ In the sections below, important records are explained.
Hardware Description
~~~~~~~~~~~~~~~~~~~~
-The hardware descriptor (:c:type:`struct snd_pcm_hardware
-<snd_pcm_hardware>`) contains the definitions of the fundamental
-hardware configuration. Above all, you'll need to define this in the
-`PCM open callback`_. Note that the runtime instance holds the copy of
+The hardware descriptor (struct snd_pcm_hardware) contains the definitions of
+the fundamental hardware configuration. Above all, you'll need to define this
+in the `PCM open callback`_. Note that the runtime instance holds the copy of
the descriptor, not the pointer to the existing descriptor. That is,
in the open callback, you can modify the copied descriptor
(``runtime->hw``) as you need. For example, if the maximum number of
@@ -1800,14 +1796,13 @@ Running Status
~~~~~~~~~~~~~~
The running status can be referred via ``runtime->status``. This is
-the pointer to the :c:type:`struct snd_pcm_mmap_status
-<snd_pcm_mmap_status>` record. For example, you can get the current
+the pointer to the struct snd_pcm_mmap_status record.
+For example, you can get the current
DMA hardware pointer via ``runtime->status->hw_ptr``.
The DMA application pointer can be referred via ``runtime->control``,
-which points to the :c:type:`struct snd_pcm_mmap_control
-<snd_pcm_mmap_control>` record. However, accessing directly to
-this value is not recommended.
+which points to the struct snd_pcm_mmap_control record.
+However, accessing directly to this value is not recommended.
Private Data
~~~~~~~~~~~~
@@ -1843,8 +1838,8 @@ error number such as ``-EINVAL``. To choose an appropriate error
number, it is advised to check what value other parts of the kernel
return when the same kind of request fails.
-The callback function takes at least the argument with :c:type:`struct
-snd_pcm_substream <snd_pcm_substream>` pointer. To retrieve the chip
+The callback function takes at least the argument with
+struct snd_pcm_substream pointer. To retrieve the chip
record from the given substream instance, you can use the following
macro.
@@ -2313,10 +2308,10 @@ non-atomic contexts. For example, the function
:c:func:`snd_pcm_period_elapsed()` is called typically from the
interrupt handler. But, if you set up the driver to use a threaded
interrupt handler, this call can be in non-atomic context, too. In such
-a case, you can set ``nonatomic`` filed of :c:type:`struct snd_pcm
-<snd_pcm>` object after creating it. When this flag is set, mutex
-and rwsem are used internally in the PCM core instead of spin and
-rwlocks, so that you can call all PCM functions safely in a non-atomic
+a case, you can set ``nonatomic`` filed of struct snd_pcm object
+after creating it. When this flag is set, mutex and rwsem are used internally
+in the PCM core instead of spin and rwlocks, so that you can call all PCM
+functions safely in a non-atomic
context.
Constraints
@@ -2357,8 +2352,7 @@ There are many different constraints. Look at ``sound/pcm.h`` for a
complete list. You can even define your own constraint rules. For
example, let's suppose my_chip can manage a substream of 1 channel if
and only if the format is ``S16_LE``, otherwise it supports any format
-specified in the :c:type:`struct snd_pcm_hardware
-<snd_pcm_hardware>` structure (or in any other
+specified in struct snd_pcm_hardware> (or in any other
constraint_list). You can build a rule like this:
::
@@ -2467,7 +2461,7 @@ Definition of Controls
To create a new control, you need to define the following three
callbacks: ``info``, ``get`` and ``put``. Then, define a
-:c:type:`struct snd_kcontrol_new <snd_kcontrol_new>` record, such as:
+struct snd_kcontrol_new record, such as:
::
@@ -2602,8 +2596,8 @@ info callback
~~~~~~~~~~~~~
The ``info`` callback is used to get detailed information on this
-control. This must store the values of the given :c:type:`struct
-snd_ctl_elem_info <snd_ctl_elem_info>` object. For example,
+control. This must store the values of the given
+struct snd_ctl_elem_info object. For example,
for a boolean control with a single element:
::
@@ -2774,13 +2768,11 @@ In the simplest way, you can do like this:
if (err < 0)
return err;
-where ``my_control`` is the :c:type:`struct snd_kcontrol_new
-<snd_kcontrol_new>` object defined above, and chip is the object
-pointer to be passed to kcontrol->private_data which can be referred
-to in callbacks.
+where ``my_control`` is the struct snd_kcontrol_new object defined above,
+and chip is the object pointer to be passed to kcontrol->private_data which
+can be referred to in callbacks.
-:c:func:`snd_ctl_new1()` allocates a new :c:type:`struct
-snd_kcontrol <snd_kcontrol>` instance, and
+:c:func:`snd_ctl_new1()` allocates a new struct snd_kcontrol instance, and
:c:func:`snd_ctl_add()` assigns the given control component to the
card.
@@ -2797,10 +2789,9 @@ can call :c:func:`snd_ctl_notify()`. For example,
This function takes the card pointer, the event-mask, and the control id
pointer for the notification. The event-mask specifies the types of
notification, for example, in the above example, the change of control
-values is notified. The id pointer is the pointer of :c:type:`struct
-snd_ctl_elem_id <snd_ctl_elem_id>` to be notified. You can
-find some examples in ``es1938.c`` or ``es1968.c`` for hardware volume
-interrupts.
+values is notified. The id pointer is the pointer of struct snd_ctl_elem_id
+to be notified. You can find some examples in ``es1938.c`` or ``es1968.c``
+for hardware volume interrupts.
Metadata
--------
@@ -2915,9 +2906,8 @@ with an ``ac97_bus_ops_t`` record with callback functions.
The bus record is shared among all belonging ac97 instances.
-And then call :c:func:`snd_ac97_mixer()` with an :c:type:`struct
-snd_ac97_template <snd_ac97_template>` record together with
-the bus pointer created above.
+And then call :c:func:`snd_ac97_mixer()` with an struct snd_ac97_template
+record together with the bus pointer created above.
::
@@ -3118,11 +3108,10 @@ devices on the card, set ``MPU401_INFO_IRQ_HOOK`` (see
Usually, the port address corresponds to the command port and port + 1
corresponds to the data port. If not, you may change the ``cport``
-field of :c:type:`struct snd_mpu401 <snd_mpu401>` manually afterward.
-However, :c:type:`struct snd_mpu401 <snd_mpu401>` pointer is
+field of struct snd_mpu401 manually afterward.
+However, struct snd_mpu401 pointer is
not returned explicitly by :c:func:`snd_mpu401_uart_new()`. You
-need to cast ``rmidi->private_data`` to :c:type:`struct snd_mpu401
-<snd_mpu401>` explicitly,
+need to cast ``rmidi->private_data`` to struct snd_mpu401 explicitly,
::
@@ -3772,7 +3761,7 @@ For creating the SG-buffer handler, call
:c:func:`snd_pcm_set_managed_buffer_all()` with
``SNDRV_DMA_TYPE_DEV_SG`` in the PCM constructor like other PCI
pre-allocator. You need to pass ``&pci->dev``, where pci is
-the :c:type:`struct pci_dev <pci_dev>` pointer of the chip as
+the struct pci_dev pointer of the chip as
well.
::
the :c:type shouldn't be used with structs with Sphinx 3, as the C domain there uses .. c:struct for structs. As we have the automarkup extension, let's just get rid of all :c:type as a hole, as those will be automagically marked as such. This solves a bunch of warnings with Sphinx 3, like those: .../Documentation/sound/kernel-api/writing-an-alsa-driver.rst:490: WARNING: Unparseable C cross-reference: 'calling snd_card_free' Invalid C declaration: Expected end of definition. [error at 8] calling snd_card_free --------^ .../Documentation/sound/kernel-api/writing-an-alsa-driver.rst:3328: WARNING: Unparseable C cross-reference: 'snd_rawmidi_transmit*' Invalid C declaration: Expected end of definition. [error at 20] snd_rawmidi_transmit* --------------------^ .../Documentation/sound/kernel-api/writing-an-alsa-driver.rst:3928: WARNING: Unparseable C cross-reference: 'copy_from/to_user' Invalid C declaration: Expected end of definition. [error at 9] copy_from/to_user ---------^ Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> --- .../kernel-api/writing-an-alsa-driver.rst | 105 ++++++++---------- 1 file changed, 47 insertions(+), 58 deletions(-)