DSP

WM8960驱动的移植记录

2019-07-13 16:50发布

站内文章 / DSP
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转载地址：http://blog.chinaunix.net/uid-22950545-id-2600582.html一，前言：WM8960是一个音频CODEC，与CPU通过I2S进行数据传输，CPU通过I2C对WM8960进行控制。Kernel:linux- 2.6.28.10 +TCC8900平台二，实现I2C控制接口，在drivers/i2c/chips下加一个i2c驱动。Tcc_wm8960.c#include#include#include#include  #define WM8960_SLAVE_ADDR  0x1astatic unsigned short probe_i2c[] = {0, WM8960_SLAVE_ADDR, I2C_CLIENT_END}; /* { i2c_num, i2c_addr } */static unsigned short dummy[] = {I2C_CLIENT_END}; static struct i2c_client_address_data addr_data = {       .normal_i2c = dummy,       .probe = probe_i2c,       .ignore = dummy,}; static struct i2c_driver wm8960_i2c_driver;struct i2c_client *wm8960_i2c_client;EXPORT_SYMBOL(wm8960_i2c_client); static int wm8960_i2c_probe(struct i2c_adapter *adap, int addr, int kind){       struct i2c_client *i2c;        i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);       if (!i2c)              return -ENOMEM;        strcpy(i2c->name, "WM8960");       i2c->flags = 0;       i2c->addr = addr;       i2c->adapter = adap;       i2c->driver = &wm8960_i2c_driver;        wm8960_i2c_client = i2c;        return i2c_attach_client(i2c);} static int wm8960_i2c_detach(struct i2c_client *client){       i2c_detach_client(client);       kfree(wm8960_i2c_client);       return 0;} static int wm8960_i2c_attach(struct i2c_adapter *adap){       return i2c_probe(adap, &addr_data, wm8960_i2c_probe);} static struct i2c_driver wm8960_i2c_driver = {       .driver = {              .name = "WM8960",              .owner = THIS_MODULE,       },       .id = -1,       .attach_adapter = wm8960_i2c_attach,       .detach_client = wm8960_i2c_detach,}; static int __init wm8960_i2c_init(void){       return i2c_add_driver(&wm8960_i2c_driver);} static void __exit wm8960_i2c_exit(void){       i2c_del_driver(&wm8960_i2c_driver);} module_init(wm8960_i2c_init);module_exit(wm8960_i2c_exit); MODULE_AUTHOR("Telechips Inc. SYS4-3 linux@telechips.com");MODULE_DESCRIPTION("WM8960 I2C driver");MODULE_LICENSE("GPL"); 这个i2c驱动写得很简单，最重要的是导出了wm8960_i2c_client这样一个i2c_client，写wm8960寄存器就是通过这个i2c_client完成的。三，参照sound/soc/codecs目录下的wm8731.c写出一个wm8960.c。四，修改一下sound/soc/tcc/tcc_board.c，主要是与wm8960有联系的地方改一下。关于声卡驱动的架构以后有空再写一篇分析出来。五，修改一下相应目录下的Kconfig和Makefile。六，测试结果如下：/nand2/mplayer # ./mplayer-y justonelastdance.mp3MPlayer SVN-r4-4.3.2 (C) 2000-2009 MPlayer Team Playing justonelastdance.mp3.Audio only file format detected.Clip info: Title: Just One Last Dance Artist: Sarah Connor Album: Key To My Soul Year: 2003 Comment: http://www.joyui.com        Track: 3 Genre: Pop==========================================================================Opening audio decoder: [mp3lib] MPEG layer-2, layer-3AUDIO: 44100 Hz, 2 ch, s16le, 192.0 kbit/13.61% (ratio: 24000->176400)Selected audio codec: [mp3] afm: mp3lib (mp3lib MPEG layer-2, layer-3)==========================================================================[AO OSS] audio_setup: Can't open audio device /dev/dsp: No such device or addressalsa-init: requested format: 44100 Hz, 2 channels, 9alsa-init: using ALSA 1.0.15soc_pcm_open[AO] device [default], mode [0], return [0]== alsa-debug == totsize=0x10000 period=0x4000  period num=4== alsa-debug == set_dma_outbuffer, addr[0x41040000], len[65536], period[16384]== alsa-debug == [set_dma_outbuffer] HwTxDaParam [0xFFF00004]== alsa-debug == [set_dma_outbuffer] HwTxDaTCnt [1023]======================================    set [2] channels======================================AO: [alsa] 44100Hz 2ch s16le (2 bytes per sample)Video: no videoStarting playback...A:   8.3 (08.2) of 268.0 (04:28.0) 10.4%                                        MPlayer interrupted by signal 2 in module: play_audioA:   8.4 (08.4) of 268.0 (04:28.0) 10.4% 动人的声音就出来了。

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