Difference between revisions of "I2S Linux driver"

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1 Article purpose[edit]

This article introduces the I2S Linux® driver for the SPI/I2S internal peripheral.

2 Short Description[edit]

The I2S Linux driver is an ASoC CPU DAI driver implemented in the Linux ALSA framework.

3 Configuration[edit]

3.1 Kernel Configuration[edit]

Activate the I2S Linux driver in the kernel configuration using the Linux Menuconfig tool: Menuconfig or how to configure kernel.

[*] Device Drivers
    [*] Sound card support
        [*] Advanced Linux Sound Architecture
            [*] ALSA for SoC audio support
                STMicroelectronics STM32 SOC audio support
	             [*] STM32 I2S interface (SPI/I2S block) support

3.2 Device tree[edit]

Refer to the I2S_device_tree_configuration article when configuring the I2S Linux kernel driver.

4 How to use[edit]

The I2S Linux driver can be accessed from userland through an ALSA device. Refer to ALSA overview for information on how to list and use ALSA devices.

5 How to trace and debug[edit]

The debugfs and procfs file system can be checked to get information on the I2S driver and the resources it uses. A non-exhaustive list of these file system entries is provided below. Refer to ALSA overview for more details on debugging tools.

  • debugfs entries:
$ cat /sys/kernel/debug/regmap/xxx.audio-controller/registers
  • procfs entries:
$ cat /proc/interrupts

6 Source code location[edit]

sound/soc/stm/stm32_i2s.c : implements the I2S Linux driver.

7 References[edit]

<noinclude>

{{ArticleBasedOnModel | [[Linux driver article model]]}}
{{ArticleMainWriter | OlivierM}}
{{ArticleApprovedVersion | OlivierM | ArnaudP(Pass, 14/01/2019) | No previous approved version | BrunoB - 29Jan'19 - 10338 | 29Jan'19}}
[[Category:ALSA]]</noinclude>


== Article purpose ==
This article introduces the I2S Linux<sup>&reg;</sup> driver for the [[SPI internal peripheral|SPI/I2S internal peripheral]].

== Short Description ==
The I2S Linux driver is an ASoC CPU DAI driver implemented in the Linux [[ALSA_overview|ALSA framework]].

== Configuration ==

=== Kernel Configuration ===
Activate the I2S Linux driver in the kernel configuration using the Linux Menuconfig tool: [[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 I2S interface (SPI/I2S block) support</pre>


=== Device tree ===
Refer to the [[I2S _device _tree _configuration]] article when configuring the I2S Linux kernel driver.


{{ReviewsComments| olivierM w902: Device tree configuration to be detailed in specific article}}
== How to use ==
The I2S 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 I2S 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 SPI/I2S 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 ==
{{CodeSource | Linux kernel | sound/soc/stm/stm32_i2s.c}}: implements the I2S Linux driver.

==References==<references />
Line 26: Line 26:
   
 
=== Device tree ===
 
=== Device tree ===
Refer to the I2S device tree configuration article when configuring the I2S Linux kernel driver.
+
Refer to the [[I2S_device_tree_configuration]] article when configuring the I2S Linux kernel driver.
 
{{ReviewsComments| olivierM w902: Device tree configuration to be detailed in specific article}}
 
   
 
== How to use ==
 
== How to use ==