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 --- a/sound/soc/bcm/bcm2835-i2s.c
  17 +++ b/sound/soc/bcm/bcm2835-i2s.c
  18 @@ -310,6 +310,7 @@ static int bcm2835_i2s_hw_params(struct
  19         unsigned int sampling_rate = params_rate(params);
  20         unsigned int data_length, data_delay, bclk_ratio;
  21         unsigned int ch1pos, ch2pos, mode, format;
  22 +       unsigned int previous_ftxp, previous_frxp;
  23         unsigned int mash = BCM2835_CLK_MASH_1;
  24         unsigned int divi, divf, target_frequency;
  25         int clk_src = -1;
  26 @@ -320,6 +321,7 @@ static int bcm2835_i2s_hw_params(struct
  27         bool frame_master =     (master == SND_SOC_DAIFMT_CBS_CFS
  28                                         || master == SND_SOC_DAIFMT_CBM_CFS);
  29         uint32_t csreg;
  30 +       bool packed;
  31
  32         /*
  33          * If a stream is already enabled,
  34 @@ -465,26 +467,46 @@ static int bcm2835_i2s_hw_params(struct
  35                 return -EINVAL;
  36         }
  37
  38 -       /*
  39 -        * Set format for both streams.
  40 -        * We cannot set another frame length
  41 -        * (and therefore word length) anyway,
  42 -        * so the format will be the same.
  43 -        */
  44 -       regmap_write(dev->i2s_regmap, BCM2835_I2S_RXC_A_REG, format);
  45 -       regmap_write(dev->i2s_regmap, BCM2835_I2S_TXC_A_REG, format);
  46 +       /* Set the format for the matching stream direction. */
  47 +       switch (substream->stream) {
  48 +       case SNDRV_PCM_STREAM_PLAYBACK:
  49 +               regmap_write(dev->i2s_regmap, BCM2835_I2S_TXC_A_REG, format);
  50 +               break;
  51 +       case SNDRV_PCM_STREAM_CAPTURE:
  52 +               regmap_write(dev->i2s_regmap, BCM2835_I2S_RXC_A_REG, format);
  53 +               break;
  54 +       default:
  55 +               return -EINVAL;
  56 +       }
  57
  58         /* Setup the I2S mode */
  59 +       /* Keep existing FTXP and FRXP values. */
  60 +       regmap_read(dev->i2s_regmap, BCM2835_I2S_MODE_A_REG, &mode);
  61 +
  62 +       previous_ftxp = mode & BCM2835_I2S_FTXP;
  63 +       previous_frxp = mode & BCM2835_I2S_FRXP;
  64 +
  65         mode = 0;
  66
  67 -       if (data_length <= 16) {
  68 -               /*
  69 -                * Use frame packed mode (2 channels per 32 bit word)
  70 -                * We cannot set another frame length in the second stream
  71 -                * (and therefore word length) anyway,
  72 -                * so the format will be the same.
  73 -                */
  74 -               mode |= BCM2835_I2S_FTXP | BCM2835_I2S_FRXP;
  75 +       /*
  76 +        * Retain the frame packed mode (2 channels per 32 bit word)
  77 +        * of the other direction stream intact. The formats of each
  78 +        * direction can be different as long as the frame length is
  79 +        * shared for both.
  80 +        */
  81 +       packed = data_length <= 16;
  82 +
  83 +       switch (substream->stream) {
  84 +       case SNDRV_PCM_STREAM_PLAYBACK:
  85 +               mode |= previous_frxp;
  86 +               mode |= packed ? BCM2835_I2S_FTXP : 0;
  87 +               break;
  88 +       case SNDRV_PCM_STREAM_CAPTURE:
  89 +               mode |= previous_ftxp;
  90 +               mode |= packed ? BCM2835_I2S_FRXP : 0;
  91 +               break;
  92 +       default:
  93 +               return -EINVAL;
  94         }
  95
  96         mode |= BCM2835_I2S_FLEN(bclk_ratio - 1);