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

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