Re: [PATCH v2 1/3] ASoC: rockchip: i2s: switch BCLK to GPIO

From: Brian Norris
Date: Thu Jun 16 2022 - 16:49:14 EST


Hi,

On Thu, Jun 16, 2022 at 03:58:34PM +0000, Judy Hsiao wrote:
> We discoverd that the state of BCLK on, LRCLK off and SD_MODE on
> may cause the speaker melting issue. Removing LRCLK while BCLK
> is present can cause unexpected output behavior including a large
> DC output voltage as described in the Max98357a datasheet.
>
> In order to:
> 1. prevent BCLK from turning on by other component.
> 2. keep BCLK and LRCLK being present at the same time
>
> This patch switches BCLK to GPIO func before LRCLK output, and
> configures BCLK func back during LRCLK is output.
>
> Without this fix, BCLK is turned on 11 ms earlier than LRCK by the
> da7219.
> With this fix, BCLK is turned on only 0.4 ms earlier than LRCK by
> the rockchip codec.
>
> Signed-off-by: Judy Hsiao <judyhsiao@xxxxxxxxxxxx>

It feels like a lot of the noise in this patch is due to adding
additional error handling, unrelated to the real change you're making.
Maybe that deserves a separate patch?

> ---
> sound/soc/rockchip/rockchip_i2s.c | 134 ++++++++++++++++++++++++------
> 1 file changed, 108 insertions(+), 26 deletions(-)
>
> diff --git a/sound/soc/rockchip/rockchip_i2s.c b/sound/soc/rockchip/rockchip_i2s.c
> index 47a3971a9ce1..574d3d0900c4 100644
> --- a/sound/soc/rockchip/rockchip_i2s.c
> +++ b/sound/soc/rockchip/rockchip_i2s.c
> @@ -54,8 +54,40 @@ struct rk_i2s_dev {
> const struct rk_i2s_pins *pins;
> unsigned int bclk_ratio;
> spinlock_t lock; /* tx/rx lock */
> + struct pinctrl *pinctrl;
> + struct pinctrl_state *bclk_on;
> + struct pinctrl_state *bclk_off;
> };
>
> +static int i2s_pinctrl_select_bclk_on(struct rk_i2s_dev *i2s)
> +{
> + int ret = 0;
> +
> + if (!IS_ERR(i2s->pinctrl) && !IS_ERR_OR_NULL(i2s->bclk_on))
> + ret = pinctrl_select_state(i2s->pinctrl,
> + i2s->bclk_on);
> +
> + if (ret)
> + dev_err(i2s->dev, "bclk enable failed %d\n", ret);
> +
> + return ret;
> +}
> +
> +static int i2s_pinctrl_select_bclk_off(struct rk_i2s_dev *i2s)
> +{
> +
> + int ret = 0;
> +
> + if (!IS_ERR(i2s->pinctrl) && !IS_ERR_OR_NULL(i2s->bclk_off))
> + ret = pinctrl_select_state(i2s->pinctrl,
> + i2s->bclk_off);
> +
> + if (ret)
> + dev_err(i2s->dev, "bclk disable failed %d\n", ret);
> +
> + return ret;
> +}
> +
> static int i2s_runtime_suspend(struct device *dev)
> {
> struct rk_i2s_dev *i2s = dev_get_drvdata(dev);
> @@ -92,39 +124,46 @@ static inline struct rk_i2s_dev *to_info(struct snd_soc_dai *dai)
> return snd_soc_dai_get_drvdata(dai);
> }
>
> -static void rockchip_snd_txctrl(struct rk_i2s_dev *i2s, int on)
> +static int rockchip_snd_txctrl(struct rk_i2s_dev *i2s, int on)
> {
> unsigned int val = 0;
> int retry = 10;
> -
> + int ret = 0;
> +
> spin_lock(&i2s->lock);
> if (on) {
> - regmap_update_bits(i2s->regmap, I2S_DMACR,
> + ret = regmap_update_bits(i2s->regmap, I2S_DMACR,
> I2S_DMACR_TDE_ENABLE, I2S_DMACR_TDE_ENABLE);

I mentioned this off-list, but the 2nd-line indentation alignment *used*
to be in a very particular style, and you've moved that around a lot. To
match the previous style, it should be:

ret = regmap_update_bits(i2s->regmap, I2S_DMACR,
I2S_DMACR_TDE_ENABLE,
I2S_DMACR_TDE_ENABLE);

(BTW, if you're using Gmail to view this, you're going to have no idea
what I'm talking about, since it doesn't do whitespace or monospace font
correctly...)

The same applies throughout; most of the 2nd-line, 3rd-line, ...
indentation is a little weird.

> -
> - regmap_update_bits(i2s->regmap, I2S_XFER,
> + if (ret < 0)
> + goto end;
> + ret = regmap_update_bits(i2s->regmap, I2S_XFER,
> I2S_XFER_TXS_START | I2S_XFER_RXS_START,
> I2S_XFER_TXS_START | I2S_XFER_RXS_START);
> -
> + if (ret < 0)
> + goto end;
> i2s->tx_start = true;
> } else {
> i2s->tx_start = false;
>
> - regmap_update_bits(i2s->regmap, I2S_DMACR,
> + ret = regmap_update_bits(i2s->regmap, I2S_DMACR,
> I2S_DMACR_TDE_ENABLE, I2S_DMACR_TDE_DISABLE);
> + if (ret < 0)
> + goto end;
>
> if (!i2s->rx_start) {
> - regmap_update_bits(i2s->regmap, I2S_XFER,
> + ret = regmap_update_bits(i2s->regmap, I2S_XFER,
> I2S_XFER_TXS_START |
> I2S_XFER_RXS_START,
> I2S_XFER_TXS_STOP |
> I2S_XFER_RXS_STOP);
> -
> + if (ret < 0)
> + goto end;
> udelay(150);
> - regmap_update_bits(i2s->regmap, I2S_CLR,
> + ret = regmap_update_bits(i2s->regmap, I2S_CLR,
> I2S_CLR_TXC | I2S_CLR_RXC,
> I2S_CLR_TXC | I2S_CLR_RXC);
> -
> + if (ret < 0)
> + goto end;
> regmap_read(i2s->regmap, I2S_CLR, &val);
>
> /* Should wait for clear operation to finish */
> @@ -138,42 +177,55 @@ static void rockchip_snd_txctrl(struct rk_i2s_dev *i2s, int on)
> }
> }
> }
> +end:
> spin_unlock(&i2s->lock);
> + if (ret < 0)
> + dev_err(i2s->dev, "lrclk update failed\n");
> +
> + return ret;
> }
>
> static void rockchip_snd_rxctrl(struct rk_i2s_dev *i2s, int on)
> {
> unsigned int val = 0;
> int retry = 10;
> + int ret = 0;
>
> spin_lock(&i2s->lock);
> if (on) {
> - regmap_update_bits(i2s->regmap, I2S_DMACR,
> + ret = regmap_update_bits(i2s->regmap, I2S_DMACR,
> I2S_DMACR_RDE_ENABLE, I2S_DMACR_RDE_ENABLE);
> + if (ret < 0)
> + goto end;
>
> - regmap_update_bits(i2s->regmap, I2S_XFER,
> + ret = regmap_update_bits(i2s->regmap, I2S_XFER,
> I2S_XFER_TXS_START | I2S_XFER_RXS_START,
> I2S_XFER_TXS_START | I2S_XFER_RXS_START);
> -
> + if (ret < 0)
> + goto end;
> i2s->rx_start = true;
> } else {
> i2s->rx_start = false;
>
> - regmap_update_bits(i2s->regmap, I2S_DMACR,
> + ret = regmap_update_bits(i2s->regmap, I2S_DMACR,
> I2S_DMACR_RDE_ENABLE, I2S_DMACR_RDE_DISABLE);
> + if (ret < 0)
> + goto end;
>
> if (!i2s->tx_start) {
> - regmap_update_bits(i2s->regmap, I2S_XFER,
> + ret = regmap_update_bits(i2s->regmap, I2S_XFER,
> I2S_XFER_TXS_START |
> - I2S_XFER_RXS_START,
> + I2S_XFER_RXS_START,
> I2S_XFER_TXS_STOP |
> I2S_XFER_RXS_STOP);
> -
> + if (ret < 0)
> + goto end;
> udelay(150);
> - regmap_update_bits(i2s->regmap, I2S_CLR,
> + ret = regmap_update_bits(i2s->regmap, I2S_CLR,
> I2S_CLR_TXC | I2S_CLR_RXC,
> I2S_CLR_TXC | I2S_CLR_RXC);
> -
> + if (ret < 0)
> + goto end;
> regmap_read(i2s->regmap, I2S_CLR, &val);
>
> /* Should wait for clear operation to finish */
> @@ -187,7 +239,12 @@ static void rockchip_snd_rxctrl(struct rk_i2s_dev *i2s, int on)
> }
> }
> }
> +end:
> spin_unlock(&i2s->lock);
> + if (ret < 0)
> + dev_err(i2s->dev, "lrclk update failed\n");
> +
> + return ret;
> }
>
> static int rockchip_i2s_set_fmt(struct snd_soc_dai *cpu_dai,
> @@ -425,17 +482,25 @@ static int rockchip_i2s_trigger(struct snd_pcm_substream *substream,
> case SNDRV_PCM_TRIGGER_RESUME:
> case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
> if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
> - rockchip_snd_rxctrl(i2s, 1);
> + ret = rockchip_snd_rxctrl(i2s, 1);
> else
> - rockchip_snd_txctrl(i2s, 1);
> + ret = rockchip_snd_txctrl(i2s, 1);
> + if (ret < 0)
> + return ret;
> + i2s_pinctrl_select_bclk_on(i2s);
> break;
> case SNDRV_PCM_TRIGGER_SUSPEND:
> case SNDRV_PCM_TRIGGER_STOP:
> case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
> - if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
> - rockchip_snd_rxctrl(i2s, 0);
> - else
> - rockchip_snd_txctrl(i2s, 0);
> + if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
> + if (!i2s->tx_start)
> + i2s_pinctrl_select_bclk_off(i2s);
> + ret = rockchip_snd_rxctrl(i2s, 0);
> + } else {
> + if (!i2s->rx_start)
> + i2s_pinctrl_select_bclk_off(i2s);
> + ret = rockchip_snd_txctrl(i2s, 0);
> + }
> break;
> default:
> ret = -EINVAL;
> @@ -736,6 +801,23 @@ static int rockchip_i2s_probe(struct platform_device *pdev)
> }
>
> i2s->bclk_ratio = 64;
> + i2s->pinctrl = devm_pinctrl_get(&pdev->dev);
> + if (IS_ERR(i2s->pinctrl))
> + dev_err(&pdev->dev, "failed to find i2s pinctrl\n");
> +
> + i2s->bclk_on = pinctrl_lookup_state(i2s->pinctrl,
> + "bclk_on");
> + if (!IS_ERR_OR_NULL(i2s->bclk_on)) {
> + dev_info(&pdev->dev, "switch bclk to GPIO func\n");

I don't think we need this printed at the KERN_INFO level. Either drop
it, or maybe dev_dbg().

Brian

> + i2s->bclk_off = pinctrl_lookup_state(i2s->pinctrl,
> + "bclk_off");
> + if (IS_ERR_OR_NULL(i2s->bclk_off)) {
> + dev_err(&pdev->dev, "failed to find i2s bclk_off\n");
> + goto err_clk;
> + }
> + }
> +
> + i2s_pinctrl_select_bclk_off(i2s);
>
> dev_set_drvdata(&pdev->dev, i2s);
>
> --
> 2.36.1.476.g0c4daa206d-goog
>