sound/soc/fsl/lpc3xxx-i2s.c

Source file repositories/reference/linux-study-clean/sound/soc/fsl/lpc3xxx-i2s.c

File Facts

System
Linux kernel
Corpus path
sound/soc/fsl/lpc3xxx-i2s.c
Extension
.c
Size
10561 bytes
Lines
373
Domain
Driver Families
Bucket
sound/soc
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (abs(trate - i2srate) < diff) {
				diff = abs(trate - i2srate);
				*clkx = idxx;
				*clky = idyy;
			}
		}
	}
}

static int lpc3xxx_i2s_startup(struct snd_pcm_substream *substream, struct snd_soc_dai *cpu_dai)
{
	struct lpc3xxx_i2s_info *i2s_info_p = snd_soc_dai_get_drvdata(cpu_dai);
	struct device *dev = i2s_info_p->dev;
	u32 flag;
	int ret = 0;

	guard(mutex)(&i2s_info_p->lock);

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
		flag = I2S_PLAYBACK_FLAG;
	else
		flag = I2S_CAPTURE_FLAG;

	if (flag & i2s_info_p->streams_in_use) {
		dev_warn(dev, "I2S channel is busy\n");
		ret = -EBUSY;
		return ret;
	}

	if (i2s_info_p->streams_in_use == 0) {
		ret = clk_prepare_enable(i2s_info_p->clk);
		if (ret) {
			dev_err(dev, "Can't enable clock, err=%d\n", ret);
			return ret;
		}
	}

	i2s_info_p->streams_in_use |= flag;
	return 0;
}

static void lpc3xxx_i2s_shutdown(struct snd_pcm_substream *substream, struct snd_soc_dai *cpu_dai)
{
	struct lpc3xxx_i2s_info *i2s_info_p = snd_soc_dai_get_drvdata(cpu_dai);
	struct regmap *regs = i2s_info_p->regs;
	const u32 stop_bits = (LPC3XXX_I2S_RESET | LPC3XXX_I2S_STOP);
	u32 flag;

	guard(mutex)(&i2s_info_p->lock);

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
		flag = I2S_PLAYBACK_FLAG;
		regmap_write(regs, LPC3XXX_REG_I2S_TX_RATE, 0);
		regmap_update_bits(regs, LPC3XXX_REG_I2S_DAO, stop_bits, stop_bits);
	} else {
		flag = I2S_CAPTURE_FLAG;
		regmap_write(regs, LPC3XXX_REG_I2S_RX_RATE, 0);
		regmap_update_bits(regs, LPC3XXX_REG_I2S_DAI, stop_bits, stop_bits);
	}
	i2s_info_p->streams_in_use &= ~flag;

	if (i2s_info_p->streams_in_use == 0)
		clk_disable_unprepare(i2s_info_p->clk);
}

static int lpc3xxx_i2s_set_dai_sysclk(struct snd_soc_dai *cpu_dai,
				      int clk_id, unsigned int freq, int dir)
{
	struct lpc3xxx_i2s_info *i2s_info_p = snd_soc_dai_get_drvdata(cpu_dai);

	/* Will use in HW params later */
	i2s_info_p->freq = freq;

	return 0;
}

static int lpc3xxx_i2s_set_dai_fmt(struct snd_soc_dai *cpu_dai, unsigned int fmt)
{
	struct lpc3xxx_i2s_info *i2s_info_p = snd_soc_dai_get_drvdata(cpu_dai);
	struct device *dev = i2s_info_p->dev;

	if ((fmt & SND_SOC_DAIFMT_FORMAT_MASK) != SND_SOC_DAIFMT_I2S) {
		dev_warn(dev, "unsupported bus format %d\n", fmt);
		return -EINVAL;
	}

	if ((fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK) != SND_SOC_DAIFMT_BP_FP) {
		dev_warn(dev, "unsupported clock provider %d\n", fmt);
		return -EINVAL;
	}

Annotation

Implementation Notes