ASoC: bcm2835: fix hw_params error when device is in prepared state (8d5737a5) · Commits · 戴 / test

If bcm2835 is configured as bitclock master calling hw_params() after prepare() fails with EBUSY. This also makes it impossible to use bcm2835 in full duplex mode. The error is caused by the split clock setup: clk_set_rate is called in hw_params, clk_prepare_enable in prepare. As hw_params doesn't check if the clock was already enabled clk_set_rate fails with EBUSY. Fix this by moving clock startup from prepare to hw_params and let hw_params properly deal with an already set up or enabled clock. Signed-off-by:

Matthias Reichl <hias@horus.com> Signed-off-by:

Mark Brown <broonie@kernel.org>

sound/soc/bcm/bcm2835-i2s.c

+14 −6

Original line number	Diff line number	Diff line
		@@ -130,6 +130,7 @@ struct bcm2835_i2s_dev {
		struct regmap *i2s_regmap;
		struct clk *clk;
		bool clk_prepared;
		int clk_rate;
		};

		static void bcm2835_i2s_start_clock(struct bcm2835_i2s_dev *dev)
		@@ -419,10 +420,19 @@ static int bcm2835_i2s_hw_params(struct snd_pcm_substream *substream,
		}

		/* Clock should only be set up here if CPU is clock master */
		if (bit_clock_master) {
		if (bit_clock_master &&
		(!dev->clk_prepared \|\| dev->clk_rate != bclk_rate)) {
		if (dev->clk_prepared)
		bcm2835_i2s_stop_clock(dev);

		if (dev->clk_rate != bclk_rate) {
		ret = clk_set_rate(dev->clk, bclk_rate);
		if (ret)
		return ret;
		dev->clk_rate = bclk_rate;
		}

		bcm2835_i2s_start_clock(dev);
		}

		/* Setup the frame format */
		@@ -618,8 +628,6 @@ static int bcm2835_i2s_prepare(struct snd_pcm_substream *substream,
		struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
		uint32_t cs_reg;

		bcm2835_i2s_start_clock(dev);

		/*
		* Clear both FIFOs if the one that should be started
		* is not empty at the moment. This should only happen

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