target/linux/brcm2708/patches-4.19/950-0187-rpi-wm8804-soundcard-configure-wm8804-clocks-only-on.patch

   1 From f6b133a056e8fde7f4707e2874e204c7d5d671a2 Mon Sep 17 00:00:00 2001
   2 From: Matthias Reichl <hias@horus.com>
   3 Date: Sun, 18 Nov 2018 15:32:28 +0100
   4 Subject: [PATCH] rpi-wm8804-soundcard: configure wm8804 clocks only on
   5  rate change
   6
   7 This should avoid clicks when stopping and immediately afterwards
   8 starting a stream with the same samplerate as before.
   9
  10 Signed-off-by: Matthias Reichl <hias@horus.com>
  11 ---
  12  sound/soc/bcm/rpi-wm8804-soundcard.c | 9 +++++++++
  13  1 file changed, 9 insertions(+)
  14
  15 --- a/sound/soc/bcm/rpi-wm8804-soundcard.c
  16 +++ b/sound/soc/bcm/rpi-wm8804-soundcard.c
  17 @@ -64,6 +64,7 @@ struct snd_rpi_wm8804_drvdata {
  18
  19  static struct gpio_desc *snd_clk44gpio;
  20  static struct gpio_desc *snd_clk48gpio;
  21 +static int wm8804_samplerate = 0;
  22
  23  #define CLK_44EN_RATE 22579200UL
  24  #define CLK_48EN_RATE 24576000UL
  25 @@ -117,6 +118,12 @@ static int snd_rpi_wm8804_hw_params(stru
  26         struct wm8804_clk_cfg clk_cfg;
  27         int samplerate = params_rate(params);
  28
  29 +       if (samplerate == wm8804_samplerate)
  30 +               return 0;
  31 +
  32 +       /* clear until all clocks are setup properly */
  33 +       wm8804_samplerate = 0;
  34 +
  35         snd_rpi_wm8804_clk_cfg(samplerate, &clk_cfg);
  36
  37         pr_debug("%s samplerate: %d mclk_freq: %u mclk_div: %u sysclk: %u\n",
  38 @@ -163,6 +170,8 @@ static int snd_rpi_wm8804_hw_params(stru
  39                 return ret;
  40         }
  41
  42 +       wm8804_samplerate = samplerate;
  43 +
  44         /* set sampling frequency status bits */
  45         snd_soc_component_update_bits(component, WM8804_SPDTX4, 0x0f,
  46                         sampling_freq);