sound/soc/fsl/mpc5200_psc_i2s.c

Source file repositories/reference/linux-study-clean/sound/soc/fsl/mpc5200_psc_i2s.c

File Facts

System
Linux kernel
Corpus path
sound/soc/fsl/mpc5200_psc_i2s.c
Extension
.c
Size
6750 bytes
Lines
241
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

// SPDX-License-Identifier: GPL-2.0-only
//
// Freescale MPC5200 PSC in I2S mode
// ALSA SoC Digital Audio Interface (DAI) driver
//
// Copyright (C) 2008 Secret Lab Technologies Ltd.
// Copyright (C) 2009 Jon Smirl, Digispeaker

#include <linux/module.h>
#include <linux/of.h>

#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include <asm/mpc52xx_psc.h>

#include "mpc5200_dma.h"

/**
 * PSC_I2S_RATES: sample rates supported by the I2S
 *
 * This driver currently only supports the PSC running in I2S slave mode,
 * which means the codec determines the sample rate.  Therefore, we tell
 * ALSA that we support all rates and let the codec driver decide what rates
 * are really supported.
 */
#define PSC_I2S_RATES SNDRV_PCM_RATE_CONTINUOUS

/**
 * PSC_I2S_FORMATS: audio formats supported by the PSC I2S mode
 */
#define PSC_I2S_FORMATS (SNDRV_PCM_FMTBIT_S8 | SNDRV_PCM_FMTBIT_S16_BE | \
			 SNDRV_PCM_FMTBIT_S24_BE | SNDRV_PCM_FMTBIT_S32_BE)

static int psc_i2s_hw_params(struct snd_pcm_substream *substream,
				 struct snd_pcm_hw_params *params,
				 struct snd_soc_dai *dai)
{
	struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
	struct psc_dma *psc_dma = snd_soc_dai_get_drvdata(snd_soc_rtd_to_cpu(rtd, 0));
	u32 mode;

	dev_dbg(psc_dma->dev, "%s(substream=%p) p_size=%i p_bytes=%i"
		" periods=%i buffer_size=%i  buffer_bytes=%i\n",
		__func__, substream, params_period_size(params),
		params_period_bytes(params), params_periods(params),
		params_buffer_size(params), params_buffer_bytes(params));

	switch (params_format(params)) {
	case SNDRV_PCM_FORMAT_S8:
		mode = MPC52xx_PSC_SICR_SIM_CODEC_8;
		break;
	case SNDRV_PCM_FORMAT_S16_BE:
		mode = MPC52xx_PSC_SICR_SIM_CODEC_16;
		break;
	case SNDRV_PCM_FORMAT_S24_BE:
		mode = MPC52xx_PSC_SICR_SIM_CODEC_24;
		break;
	case SNDRV_PCM_FORMAT_S32_BE:
		mode = MPC52xx_PSC_SICR_SIM_CODEC_32;
		break;
	default:
		dev_dbg(psc_dma->dev, "invalid format\n");
		return -EINVAL;
	}
	out_be32(&psc_dma->psc_regs->sicr, psc_dma->sicr | mode);

	return 0;
}

/**
 * psc_i2s_set_sysclk: set the clock frequency and direction
 *
 * This function is called by the machine driver to tell us what the clock
 * frequency and direction are.
 *
 * Currently, we only support operating as a clock slave (SND_SOC_CLOCK_IN),
 * and we don't care about the frequency.  Return an error if the direction
 * is not SND_SOC_CLOCK_IN.
 *
 * @clk_id: reserved, should be zero
 * @freq: the frequency of the given clock ID, currently ignored
 * @dir: SND_SOC_CLOCK_IN (clock slave) or SND_SOC_CLOCK_OUT (clock master)
 */
static int psc_i2s_set_sysclk(struct snd_soc_dai *cpu_dai,
			      int clk_id, unsigned int freq, int dir)
{
	struct psc_dma *psc_dma = snd_soc_dai_get_drvdata(cpu_dai);
	dev_dbg(psc_dma->dev, "psc_i2s_set_sysclk(cpu_dai=%p, dir=%i)\n",

Annotation

Implementation Notes