查看“SAI Linux driver”的源代码

== Article purpose ==
本文介绍了适用于[[SAI internal peripheral]]的SAI Linux<sup>&reg;</sup> 驱动程序。

== Short Description ==
SAI<ref name="SAI internal peripheral">[[SAI internal peripheral]]</ref> Linux驱动程序是在Linux [[ALSA_overview|ALSA framework]]中实现的ASoC CPU DAI驱动程序。

== Configuration ==

=== Kernel Configuration ===
使用Linux Menuconfig工具在内核配置中激活SAI <ref name="SAI internal peripheral"/> Linux驱动程序： [[Menuconfig or how to configure kernel]].
<pre>
[*] Device Drivers
    [*] Sound card support
        [*] Advanced Linux Sound Architecture
            [*] ALSA for SoC audio support
                STMicroelectronics STM32 SOC audio support
	             [*] STM32 SAI interface (Serial Audio Interface) support
</pre>

=== Device tree ===
Refer to the [[SAI device tree configuration]] article when configuring the SAI Linux kernel driver. 

== How to use ==
The SAI Linux driver can be accessed from userland through an ALSA device. Refer to [[ALSA_overview#How_to_use|ALSA overview]] for information on how to list and use ALSA devices.

==How to trace and debug==
The [[Debugfs|debugfs]] and procfs file system can be checked to get information on the SAI driver and the resources it uses. A non-exhaustive list of these file system entries is provided below. Refer to [[ALSA_overview#How_to_trace_and_debug_the_framework|ALSA overview]] for more details on debugging tools.

* debugfs entries:
:* '''asoc''': refer to [[ALSA_overview#How_to_monitor]]
:* '''clk''': refer to [[Clock_overview#How_to_monitor_with_debugfs]] to get information on clocks.
:* '''pinctrl''': refer to [[Pinctrl_overview#How_to_monitor]] to get information on pins.
:* '''regmap''': allow to monitor SAI peripheral registers.
<div style="margin-left: 2em;">
 $ cat /sys/kernel/debug/regmap/xxx.audio-controller/registers
</div>
* procfs entries:
:* '''asound''': refer to [[ALSA_overview#How_to_debug]]
:* '''interrupts''': allow to check interrupts.
<div style="margin-left: 2em;">
 $ cat /proc/interrupts
</div>

== Source code location ==
The STM32 SAI peripheral includes two independent audio subblocks that share common resources. The driver source code reflects this architecture.

{{CodeSource | Linux kernel | sound/soc/stm/stm32_sai.c}}: handles common resources such as clock, interrupt, reset and shared register.

{{CodeSource | Linux kernel | sound/soc/stm/stm32_sai_sub.c}}: handles the resources dedicated to each subblock.

==References==
<references />