static int bcm2835_i2s_hw_params(struct snd_pcm_substream *substream,
				 struct snd_pcm_hw_params *params,
				 struct snd_soc_dai *dai)
{
	struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);

	unsigned int sampling_rate = params_rate(params);
	unsigned int data_length, data_delay, bclk_ratio;
	unsigned int ch1pos, ch2pos, mode, format;
	unsigned int mash = BCM2835_CLK_MASH_1;
	unsigned int divi, divf, target_frequency;
	int clk_src = -1;
	unsigned int master = dev->fmt & SND_SOC_DAIFMT_MASTER_MASK;
	bool bit_master =	(master == SND_SOC_DAIFMT_CBS_CFS
					|| master == SND_SOC_DAIFMT_CBS_CFM);

	bool frame_master =	(master == SND_SOC_DAIFMT_CBS_CFS
					|| master == SND_SOC_DAIFMT_CBM_CFS);
	uint32_t csreg;

	/*
	 * If a stream is already enabled,
	 * the registers are already set properly.
	 */
	regmap_read(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, &csreg);

	if (csreg & (BCM2835_I2S_TXON | BCM2835_I2S_RXON))
		return 0;

	/*
	 * Adjust the data length according to the format.
	 * We prefill the half frame length with an integer
	 * divider of 2400 as explained at the clock settings.
	 * Maybe it is overwritten there, if the Integer mode
	 * does not apply.
	 */
	switch (params_format(params)) {
	case SNDRV_PCM_FORMAT_S16_LE:
		data_length = 16;
		bclk_ratio = 40;
		break;
	case SNDRV_PCM_FORMAT_S32_LE:
		data_length = 32;
		bclk_ratio = 80;
		break;
	default:
		return -EINVAL;
	}

	/* If bclk_ratio already set, use that one. */
	if (dev->bclk_ratio)
		bclk_ratio = dev->bclk_ratio;

	/*
	 * Clock Settings
	 *
	 * The target frequency of the bit clock is
	 *	sampling rate * frame length
	 *
	 * Integer mode:
	 * Sampling rates that are multiples of 8000 kHz
	 * can be driven by the oscillator of 19.2 MHz
	 * with an integer divider as long as the frame length
	 * is an integer divider of 19200000/8000=2400 as set up above.
	 * This is no longer possible if the sampling rate
	 * is too high (e.g. 192 kHz), because the oscillator is too slow.
	 *
	 * MASH mode:
	 * For all other sampling rates, it is not possible to
	 * have an integer divider. Approximate the clock
	 * with the MASH module that induces a slight frequency
	 * variance. To minimize that it is best to have the fastest
	 * clock here. That is PLLD with 500 MHz.
	 */
	target_frequency = sampling_rate * bclk_ratio;
	clk_src = BCM2835_CLK_SRC_OSC;
	mash = BCM2835_CLK_MASH_0;

	if (bcm2835_clk_freq[clk_src] % target_frequency == 0
			&& bit_master && frame_master) {
		divi = bcm2835_clk_freq[clk_src] / target_frequency;
		divf = 0;
	} else {
		uint64_t dividend;

		if (!dev->bclk_ratio) {
			/*
			 * Overwrite bclk_ratio, because the
			 * above trick is not needed or can
			 * not be used.
			 */
			bclk_ratio = 2 * data_length;
		}

		target_frequency = sampling_rate * bclk_ratio;

		clk_src = BCM2835_CLK_SRC_PLLD;
		mash = BCM2835_CLK_MASH_1;

		dividend = bcm2835_clk_freq[clk_src];
		dividend <<= BCM2835_CLK_SHIFT;
		do_div(dividend, target_frequency);
		divi = dividend >> BCM2835_CLK_SHIFT;
		divf = dividend & BCM2835_CLK_DIVF_MASK;
	}

	/* Set clock divider */
	regmap_write(dev->clk_regmap, BCM2835_CLK_PCMDIV_REG, BCM2835_CLK_PASSWD
			| BCM2835_CLK_DIVI(divi)
			| BCM2835_CLK_DIVF(divf));

	/* Setup clock, but don't start it yet */
	regmap_write(dev->clk_regmap, BCM2835_CLK_PCMCTL_REG, BCM2835_CLK_PASSWD
			| BCM2835_CLK_MASH(mash)
			| BCM2835_CLK_SRC(clk_src));

	/* Setup the frame format */
	format = BCM2835_I2S_CHEN;

	if (data_length > 24)
		format |= BCM2835_I2S_CHWEX;

	format |= BCM2835_I2S_CHWID((data_length-8)&0xf);

	switch (dev->fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
	case SND_SOC_DAIFMT_I2S:
		data_delay = 1;
		break;
	default:
		/*
		 * TODO
		 * Others are possible but are not implemented at the moment.
		 */
		dev_err(dev->dev, "%s:bad format\n", __func__);
		return -EINVAL;
	}

	ch1pos = data_delay;
	ch2pos = bclk_ratio / 2 + data_delay;

	switch (params_channels(params)) {
	case 2:
		format = BCM2835_I2S_CH1(format) | BCM2835_I2S_CH2(format);
		format |= BCM2835_I2S_CH1(BCM2835_I2S_CHPOS(ch1pos));
		format |= BCM2835_I2S_CH2(BCM2835_I2S_CHPOS(ch2pos));
		break;
	default:
		return -EINVAL;
	}

	/*
	 * Set format for both streams.
	 * We cannot set another frame length
	 * (and therefore word length) anyway,
	 * so the format will be the same.
	 */
	regmap_write(dev->i2s_regmap, BCM2835_I2S_RXC_A_REG, format);
	regmap_write(dev->i2s_regmap, BCM2835_I2S_TXC_A_REG, format);

	/* Setup the I2S mode */
	mode = 0;

	if (data_length <= 16) {
		/*
		 * Use frame packed mode (2 channels per 32 bit word)
		 * We cannot set another frame length in the second stream
		 * (and therefore word length) anyway,
		 * so the format will be the same.
		 */
		mode |= BCM2835_I2S_FTXP | BCM2835_I2S_FRXP;
	}

	mode |= BCM2835_I2S_FLEN(bclk_ratio - 1);
	mode |= BCM2835_I2S_FSLEN(bclk_ratio / 2);

	/* Master or slave? */
	switch (dev->fmt & SND_SOC_DAIFMT_MASTER_MASK) {
	case SND_SOC_DAIFMT_CBS_CFS:
		/* CPU is master */
		break;
	case SND_SOC_DAIFMT_CBM_CFS:
		/*
		 * CODEC is bit clock master
		 * CPU is frame master
		 */
		mode |= BCM2835_I2S_CLKM;
		break;
	case SND_SOC_DAIFMT_CBS_CFM:
		/*
		 * CODEC is frame master
		 * CPU is bit clock master
		 */
		mode |= BCM2835_I2S_FSM;
		break;
	case SND_SOC_DAIFMT_CBM_CFM:
		/* CODEC is master */
		mode |= BCM2835_I2S_CLKM;
		mode |= BCM2835_I2S_FSM;
		break;
	default:
		dev_err(dev->dev, "%s:bad master\n", __func__);
		return -EINVAL;
	}

	/*
	 * Invert clocks?
	 *
	 * The BCM approach seems to be inverted to the classical I2S approach.
	 */
	switch (dev->fmt & SND_SOC_DAIFMT_INV_MASK) {
	case SND_SOC_DAIFMT_NB_NF:
		/* None. Therefore, both for BCM */
		mode |= BCM2835_I2S_CLKI;
		mode |= BCM2835_I2S_FSI;
		break;
	case SND_SOC_DAIFMT_IB_IF:
		/* Both. Therefore, none for BCM */
		break;
	case SND_SOC_DAIFMT_NB_IF:
		/*
		 * Invert only frame sync. Therefore,
		 * invert only bit clock for BCM
		 */
		mode |= BCM2835_I2S_CLKI;
		break;
	case SND_SOC_DAIFMT_IB_NF:
		/*
		 * Invert only bit clock. Therefore,
		 * invert only frame sync for BCM
		 */
		mode |= BCM2835_I2S_FSI;
		break;
	default:
		return -EINVAL;
	}

	regmap_write(dev->i2s_regmap, BCM2835_I2S_MODE_A_REG, mode);

	/* Setup the DMA parameters */
	regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
			BCM2835_I2S_RXTHR(1)
			| BCM2835_I2S_TXTHR(1)
			| BCM2835_I2S_DMAEN, 0xffffffff);

	regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_DREQ_A_REG,
			  BCM2835_I2S_TX_PANIC(0x10)
			| BCM2835_I2S_RX_PANIC(0x30)
			| BCM2835_I2S_TX(0x30)
			| BCM2835_I2S_RX(0x20), 0xffffffff);

	/* Clear FIFOs */
	bcm2835_i2s_clear_fifos(dev, true, true);

	return 0;
}
Exemple #2
0
static int bcm2835_i2s_hw_params(struct snd_pcm_substream *substream,
				 struct snd_pcm_hw_params *params,
				 struct snd_soc_dai *dai)
{
	struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
	unsigned int sampling_rate = params_rate(params);
	unsigned int data_length, data_delay, bclk_ratio;
	unsigned int ch1pos, ch2pos, mode, format;
	uint32_t csreg;

	/*
	 * If a stream is already enabled,
	 * the registers are already set properly.
	 */
	regmap_read(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, &csreg);

	if (csreg & (BCM2835_I2S_TXON | BCM2835_I2S_RXON))
		return 0;

	/*
	 * Adjust the data length according to the format.
	 * We prefill the half frame length with an integer
	 * divider of 2400 as explained at the clock settings.
	 * Maybe it is overwritten there, if the Integer mode
	 * does not apply.
	 */
	switch (params_format(params)) {
	case SNDRV_PCM_FORMAT_S16_LE:
		data_length = 16;
		break;
	case SNDRV_PCM_FORMAT_S24_LE:
		data_length = 24;
		break;
	case SNDRV_PCM_FORMAT_S32_LE:
		data_length = 32;
		break;
	default:
		return -EINVAL;
	}

	/* If bclk_ratio already set, use that one. */
	if (dev->bclk_ratio)
		bclk_ratio = dev->bclk_ratio;
	else
		/* otherwise calculate a fitting block ratio */
		bclk_ratio = 2 * data_length;

	/* Clock should only be set up here if CPU is clock master */
	switch (dev->fmt & SND_SOC_DAIFMT_MASTER_MASK) {
	case SND_SOC_DAIFMT_CBS_CFS:
	case SND_SOC_DAIFMT_CBS_CFM:
		clk_set_rate(dev->clk, sampling_rate * bclk_ratio);
		break;
	default:
		break;
	}

	/* Setup the frame format */
	format = BCM2835_I2S_CHEN;

	if (data_length >= 24)
		format |= BCM2835_I2S_CHWEX;

	format |= BCM2835_I2S_CHWID((data_length-8)&0xf);

	switch (dev->fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
	case SND_SOC_DAIFMT_I2S:
		data_delay = 1;
		break;
	default:
		/*
		 * TODO
		 * Others are possible but are not implemented at the moment.
		 */
		dev_err(dev->dev, "%s:bad format\n", __func__);
		return -EINVAL;
	}

	ch1pos = data_delay;
	ch2pos = bclk_ratio / 2 + data_delay;

	switch (params_channels(params)) {
	case 2:
		format = BCM2835_I2S_CH1(format) | BCM2835_I2S_CH2(format);
		format |= BCM2835_I2S_CH1(BCM2835_I2S_CHPOS(ch1pos));
		format |= BCM2835_I2S_CH2(BCM2835_I2S_CHPOS(ch2pos));
		break;
	default:
		return -EINVAL;
	}

	/*
	 * Set format for both streams.
	 * We cannot set another frame length
	 * (and therefore word length) anyway,
	 * so the format will be the same.
	 */
	regmap_write(dev->i2s_regmap, BCM2835_I2S_RXC_A_REG, format);
	regmap_write(dev->i2s_regmap, BCM2835_I2S_TXC_A_REG, format);

	/* Setup the I2S mode */
	mode = 0;

	if (data_length <= 16) {
		/*
		 * Use frame packed mode (2 channels per 32 bit word)
		 * We cannot set another frame length in the second stream
		 * (and therefore word length) anyway,
		 * so the format will be the same.
		 */
		mode |= BCM2835_I2S_FTXP | BCM2835_I2S_FRXP;
	}

	mode |= BCM2835_I2S_FLEN(bclk_ratio - 1);
	mode |= BCM2835_I2S_FSLEN(bclk_ratio / 2);

	/* Master or slave? */
	switch (dev->fmt & SND_SOC_DAIFMT_MASTER_MASK) {
	case SND_SOC_DAIFMT_CBS_CFS:
		/* CPU is master */
		break;
	case SND_SOC_DAIFMT_CBM_CFS:
		/*
		 * CODEC is bit clock master
		 * CPU is frame master
		 */
		mode |= BCM2835_I2S_CLKM;
		break;
	case SND_SOC_DAIFMT_CBS_CFM:
		/*
		 * CODEC is frame master
		 * CPU is bit clock master
		 */
		mode |= BCM2835_I2S_FSM;
		break;
	case SND_SOC_DAIFMT_CBM_CFM:
		/* CODEC is master */
		mode |= BCM2835_I2S_CLKM;
		mode |= BCM2835_I2S_FSM;
		break;
	default:
		dev_err(dev->dev, "%s:bad master\n", __func__);
		return -EINVAL;
	}

	/*
	 * Invert clocks?
	 *
	 * The BCM approach seems to be inverted to the classical I2S approach.
	 */
	switch (dev->fmt & SND_SOC_DAIFMT_INV_MASK) {
	case SND_SOC_DAIFMT_NB_NF:
		/* None. Therefore, both for BCM */
		mode |= BCM2835_I2S_CLKI;
		mode |= BCM2835_I2S_FSI;
		break;
	case SND_SOC_DAIFMT_IB_IF:
		/* Both. Therefore, none for BCM */
		break;
	case SND_SOC_DAIFMT_NB_IF:
		/*
		 * Invert only frame sync. Therefore,
		 * invert only bit clock for BCM
		 */
		mode |= BCM2835_I2S_CLKI;
		break;
	case SND_SOC_DAIFMT_IB_NF:
		/*
		 * Invert only bit clock. Therefore,
		 * invert only frame sync for BCM
		 */
		mode |= BCM2835_I2S_FSI;
		break;
	default:
		return -EINVAL;
	}

	regmap_write(dev->i2s_regmap, BCM2835_I2S_MODE_A_REG, mode);

	/* Setup the DMA parameters */
	regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
			BCM2835_I2S_RXTHR(1)
			| BCM2835_I2S_TXTHR(1)
			| BCM2835_I2S_DMAEN, 0xffffffff);

	regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_DREQ_A_REG,
			  BCM2835_I2S_TX_PANIC(0x10)
			| BCM2835_I2S_RX_PANIC(0x30)
			| BCM2835_I2S_TX(0x30)
			| BCM2835_I2S_RX(0x20), 0xffffffff);

	/* Clear FIFOs */
	bcm2835_i2s_clear_fifos(dev, true, true);

	return 0;
}