target/linux/brcm2708/patches-4.4/0566-bcm2835-i2s-Changes-for-allowing-asymmetric-sample-f.patch

   1 From b97a67a14e5c5904b84e52150e0d13da794fc9d7 Mon Sep 17 00:00:00 2001
   2 From: gtrainavicius <gtrainavicius@users.noreply.github.com>
   3 Date: Tue, 10 Jan 2017 21:59:39 +0200
   4 Subject: [PATCH] bcm2835-i2s: Changes for allowing asymmetric sample formats.
   5  (#1783)
   6
   7 This is achieved by making changes only to the requested
   8 stream direction format, keeping the other stream direction
   9 configuration intact.
  10
  11 Signed-off-by: Giedrius Trainavicius <giedrius@blokas.io>
  12 ---
  13  sound/soc/bcm/bcm2835-i2s.c | 54 +++++++++++++++++++++++++++++++--------------
  14  1 file changed, 38 insertions(+), 16 deletions(-)
  15
  16 diff --git a/sound/soc/bcm/bcm2835-i2s.c b/sound/soc/bcm/bcm2835-i2s.c
  17 index aedb01f..d2b0801 100644
  18 --- a/sound/soc/bcm/bcm2835-i2s.c
  19 +++ b/sound/soc/bcm/bcm2835-i2s.c
  20 @@ -310,6 +310,7 @@ static int bcm2835_i2s_hw_params(struct snd_pcm_substream *substream,
  21         unsigned int sampling_rate = params_rate(params);
  22         unsigned int data_length, data_delay, bclk_ratio;
  23         unsigned int ch1pos, ch2pos, mode, format;
  24 +       unsigned int previous_ftxp, previous_frxp;
  25         unsigned int mash = BCM2835_CLK_MASH_1;
  26         unsigned int divi, divf, target_frequency;
  27         int clk_src = -1;
  28 @@ -320,6 +321,7 @@ static int bcm2835_i2s_hw_params(struct snd_pcm_substream *substream,
  29         bool frame_master =     (master == SND_SOC_DAIFMT_CBS_CFS
  30                                         || master == SND_SOC_DAIFMT_CBM_CFS);
  31         uint32_t csreg;
  32 +       bool packed;
  33
  34         /*
  35          * If a stream is already enabled,
  36 @@ -465,26 +467,46 @@ static int bcm2835_i2s_hw_params(struct snd_pcm_substream *substream,
  37                 return -EINVAL;
  38         }
  39
  40 -       /*
  41 -        * Set format for both streams.
  42 -        * We cannot set another frame length
  43 -        * (and therefore word length) anyway,
  44 -        * so the format will be the same.
  45 -        */
  46 -       regmap_write(dev->i2s_regmap, BCM2835_I2S_RXC_A_REG, format);
  47 -       regmap_write(dev->i2s_regmap, BCM2835_I2S_TXC_A_REG, format);
  48 +       /* Set the format for the matching stream direction. */
  49 +       switch (substream->stream) {
  50 +       case SNDRV_PCM_STREAM_PLAYBACK:
  51 +               regmap_write(dev->i2s_regmap, BCM2835_I2S_TXC_A_REG, format);
  52 +               break;
  53 +       case SNDRV_PCM_STREAM_CAPTURE:
  54 +               regmap_write(dev->i2s_regmap, BCM2835_I2S_RXC_A_REG, format);
  55 +               break;
  56 +       default:
  57 +               return -EINVAL;
  58 +       }
  59
  60         /* Setup the I2S mode */
  61 +       /* Keep existing FTXP and FRXP values. */
  62 +       regmap_read(dev->i2s_regmap, BCM2835_I2S_MODE_A_REG, &mode);
  63 +
  64 +       previous_ftxp = mode & BCM2835_I2S_FTXP;
  65 +       previous_frxp = mode & BCM2835_I2S_FRXP;
  66 +
  67         mode = 0;
  68
  69 -       if (data_length <= 16) {
  70 -               /*
  71 -                * Use frame packed mode (2 channels per 32 bit word)
  72 -                * We cannot set another frame length in the second stream
  73 -                * (and therefore word length) anyway,
  74 -                * so the format will be the same.
  75 -                */
  76 -               mode |= BCM2835_I2S_FTXP | BCM2835_I2S_FRXP;
  77 +       /*
  78 +        * Retain the frame packed mode (2 channels per 32 bit word)
  79 +        * of the other direction stream intact. The formats of each
  80 +        * direction can be different as long as the frame length is
  81 +        * shared for both.
  82 +        */
  83 +       packed = data_length <= 16;
  84 +
  85 +       switch (substream->stream) {
  86 +       case SNDRV_PCM_STREAM_PLAYBACK:
  87 +               mode |= previous_frxp;
  88 +               mode |= packed ? BCM2835_I2S_FTXP : 0;
  89 +               break;
  90 +       case SNDRV_PCM_STREAM_CAPTURE:
  91 +               mode |= previous_ftxp;
  92 +               mode |= packed ? BCM2835_I2S_FRXP : 0;
  93 +               break;
  94 +       default:
  95 +               return -EINVAL;
  96         }
  97
  98         mode |= BCM2835_I2S_FLEN(bclk_ratio - 1);
  99 --
 100 2.1.4
 101