target/linux/brcm2708/patches-4.19/950-0064-ASoC-pcm512x-implement-set_tdm_slot-interface.patch

   1 From 5fd7bb26ef791a7da1c0573b980ab4fe6b9c2641 Mon Sep 17 00:00:00 2001
   2 From: Matthias Reichl <hias@horus.com>
   3 Date: Thu, 22 Feb 2018 11:55:06 +0100
   4 Subject: [PATCH] ASoC: pcm512x: implement set_tdm_slot interface
   5
   6 PCM512x can accept data padded with additional BCLK cycles
   7 but the driver currently lacks an interface to configure this.
   8
   9 This leads to the problem that S24_LE format in master mode
  10 can result in non-integer clock divisors and pcm512x running
  11 at a rather off rate.
  12
  13 For example 48kHz with 48fs BCLK and SCLK at 24.576MHz uses
  14 a divisor of 10 (rounded down from 10.6666) and results in a
  15 51.2kHz LRCLK. With 64fs BCLK a divisor of 8 is used and
  16 LRCLK runs at exactly 48kHz.
  17
  18 Fix this by providing a minimal set_tdm_slot implementation
  19 so machine drivers can optionally configure custom BCLK ratios.
  20
  21 Signed-off-by: Matthias Reichl <hias@horus.com>
  22 ---
  23  sound/soc/codecs/pcm512x.c | 28 +++++++++++++++++++++++++++-
  24  1 file changed, 27 insertions(+), 1 deletion(-)
  25
  26 --- a/sound/soc/codecs/pcm512x.c
  27 +++ b/sound/soc/codecs/pcm512x.c
  28 @@ -53,6 +53,7 @@ struct pcm512x_priv {
  29         unsigned long overclock_pll;
  30         unsigned long overclock_dac;
  31         unsigned long overclock_dsp;
  32 +       int lrclk_div;
  33  };
  34
  35  /*
  36 @@ -851,7 +852,10 @@ static int pcm512x_set_dividers(struct s
  37         int fssp;
  38         int gpio;
  39
  40 -       lrclk_div = snd_soc_params_to_frame_size(params);
  41 +       if (pcm512x->lrclk_div)
  42 +               lrclk_div = pcm512x->lrclk_div;
  43 +       else
  44 +               lrclk_div = snd_soc_params_to_frame_size(params);
  45         if (lrclk_div == 0) {
  46                 dev_err(dev, "No LRCLK?\n");
  47                 return -EINVAL;
  48 @@ -1319,10 +1323,32 @@ static int pcm512x_set_fmt(struct snd_so
  49         return 0;
  50  }
  51
  52 +static int pcm512x_set_tdm_slot(struct snd_soc_dai *dai,
  53 +       unsigned int tx_mask, unsigned int rx_mask,
  54 +       int slots, int width)
  55 +{
  56 +       struct snd_soc_component *component = dai->component;
  57 +       struct pcm512x_priv *pcm512x = snd_soc_component_get_drvdata(component);
  58 +
  59 +       switch (slots) {
  60 +       case 0:
  61 +               pcm512x->lrclk_div = 0;
  62 +               return 0;
  63 +       case 2:
  64 +               if (tx_mask != 0x03 || rx_mask != 0x03)
  65 +                       return -EINVAL;
  66 +               pcm512x->lrclk_div = slots * width;
  67 +               return 0;
  68 +       default:
  69 +               return -EINVAL;
  70 +       }
  71 +}
  72 +
  73  static const struct snd_soc_dai_ops pcm512x_dai_ops = {
  74         .startup = pcm512x_dai_startup,
  75         .hw_params = pcm512x_hw_params,
  76         .set_fmt = pcm512x_set_fmt,
  77 +       .set_tdm_slot = pcm512x_set_tdm_slot,
  78  };
  79
  80  static struct snd_soc_dai_driver pcm512x_dai = {