You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
151 lines
3.9 KiB
151 lines
3.9 KiB
/*
|
|
* =====================================================================================
|
|
*
|
|
* Filename: snd-i2smic-rpi
|
|
*
|
|
* Description: I2S microphone kernel module
|
|
*
|
|
* Version: 0.1.0
|
|
* Created: 2020-04-14
|
|
* Revision: none
|
|
* Compiler: gcc
|
|
*
|
|
* Pi4 Mods: Carter Nelson
|
|
* Orig Author: Huan Truong (htruong@tnhh.net), originally written by Paul Creaser
|
|
*
|
|
* =====================================================================================
|
|
*/
|
|
#include <linux/module.h>
|
|
#include <linux/moduleparam.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/kmod.h>
|
|
#include <linux/platform_device.h>
|
|
#include <sound/simple_card.h>
|
|
#include <linux/delay.h>
|
|
#include "snd-i2smic-rpi.h"
|
|
|
|
/*
|
|
* modified for linux 4.1.5
|
|
* inspired by https://github.com/msperl/spi-config
|
|
* with thanks for https://github.com/notro/rpi-source/wiki
|
|
* as well as Florian Meier for the rpi i2s and dma drivers
|
|
*
|
|
* to use a differant (simple-card compatible) codec
|
|
* change the codec name string in two places and the
|
|
* codec_dai name string. (see codec's source file)
|
|
*
|
|
*
|
|
* N.B. playback vs capture is determined by the codec choice
|
|
* */
|
|
|
|
static struct asoc_simple_card_info card_info;
|
|
static struct platform_device card_device;
|
|
|
|
/*
|
|
* Setup command line parameter
|
|
*/
|
|
static short rpi_platform_generation;
|
|
module_param(rpi_platform_generation, short, 0);
|
|
MODULE_PARM_DESC(rpi_platform_generation, "Raspberry Pi generation: 0=Pi0, 1=Pi2/3, 2=Pi4");
|
|
|
|
/*
|
|
* Dummy callback for release
|
|
*/
|
|
void device_release_callback(struct device *dev) { /* do nothing */ };
|
|
|
|
/*
|
|
* Setup the card info
|
|
*/
|
|
static struct asoc_simple_card_info default_card_info = {
|
|
.card = "snd_rpi_i2s_card", // -> snd_soc_card.name
|
|
.name = "simple-card_codec_link", // -> snd_soc_dai_link.name
|
|
.codec = "snd-soc-dummy", // "dmic-codec", // -> snd_soc_dai_link.codec_name
|
|
.platform = "not-set.i2s",
|
|
.daifmt = SND_SOC_DAIFMT_I2S | SND_SOC_DAIFMT_NB_NF | SND_SOC_DAIFMT_CBS_CFS,
|
|
.cpu_dai = {
|
|
.name = "not-set.i2s", // -> snd_soc_dai_link.cpu_dai_name
|
|
.sysclk = 0
|
|
},
|
|
.codec_dai = {
|
|
.name = "snd-soc-dummy-dai", //"dmic-codec", // -> snd_soc_dai_link.codec_dai_name
|
|
.sysclk = 0
|
|
},
|
|
};
|
|
|
|
/*
|
|
* Setup the card device
|
|
*/
|
|
static struct platform_device default_card_device = {
|
|
.name = "asoc-simple-card", //module alias
|
|
.id = 0,
|
|
.num_resources = 0,
|
|
.dev = {
|
|
.release = &device_release_callback,
|
|
.platform_data = &default_card_info, // *HACK ALERT*
|
|
},
|
|
};
|
|
|
|
/*
|
|
* Callback for module initialization
|
|
*/
|
|
int i2s_mic_rpi_init(void)
|
|
{
|
|
const char *dmaengine = "bcm2708-dmaengine"; //module name
|
|
static char *card_platform;
|
|
int ret;
|
|
|
|
printk(KERN_INFO "snd-i2smic-rpi: Version %s\n", SND_I2SMIC_RPI_VERSION);
|
|
|
|
// Set platform
|
|
switch (rpi_platform_generation) {
|
|
case 0:
|
|
// Pi Zero
|
|
card_platform = "20203000.i2s";
|
|
break;
|
|
case 1:
|
|
// Pi 2 and 3
|
|
card_platform = "3f203000.i2s";
|
|
break;
|
|
case 2:
|
|
default:
|
|
// Pi 4
|
|
card_platform = "fe203000.i2s";
|
|
break;
|
|
}
|
|
|
|
printk(KERN_INFO "snd-i2smic-rpi: Setting platform to %s\n", card_platform);
|
|
|
|
// request DMA engine module
|
|
ret = request_module(dmaengine);
|
|
pr_alert("request module load '%s': %d\n",dmaengine, ret);
|
|
|
|
// update info
|
|
card_info = default_card_info;
|
|
card_info.platform = card_platform;
|
|
card_info.cpu_dai.name = card_platform;
|
|
|
|
card_device = default_card_device;
|
|
card_device.dev.platform_data = &card_info;
|
|
|
|
// register the card device
|
|
ret = platform_device_register(&card_device);
|
|
pr_alert("register platform device '%s': %d\n",card_device.name, ret);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Callback for module exit
|
|
*/
|
|
void i2s_mic_rpi_exit(void)
|
|
{
|
|
platform_device_unregister(&card_device);
|
|
pr_alert("i2s mic module unloaded\n");
|
|
}
|
|
|
|
// Plumb it up
|
|
module_init(i2s_mic_rpi_init);
|
|
module_exit(i2s_mic_rpi_exit);
|
|
MODULE_DESCRIPTION("ASoC simple-card I2S Microphone");
|
|
MODULE_AUTHOR("Carter Nelson");
|
|
MODULE_LICENSE("GPL v2");
|