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70 lines
2.1 KiB
70 lines
2.1 KiB
6 years ago
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From 0f409e6c30a04eb85792a6883e81ad2af118c7bd Mon Sep 17 00:00:00 2001
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From: Matthias Reichl <github@hias.horus.com>
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Date: Thu, 18 Jan 2018 12:36:44 +0100
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Subject: [PATCH 161/454] ASoC: bcm2835: fix hw_params error when device is in
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prepared state (#2345)
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commit 8d5737a5f53902a916ee1e1cb248c9b8b883b2ea upstream.
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If bcm2835 is configured as bitclock master calling hw_params()
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after prepare() fails with EBUSY. This also makes it impossible to
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use bcm2835 in full duplex mode.
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The error is caused by the split clock setup: clk_set_rate
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is called in hw_params, clk_prepare_enable in prepare. As hw_params
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doesn't check if the clock was already enabled clk_set_rate
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fails with EBUSY.
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Fix this by moving clock startup from prepare to hw_params and
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let hw_params properly deal with an already set up or enabled
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clock.
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Signed-off-by: Matthias Reichl <hias@horus.com>
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---
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sound/soc/bcm/bcm2835-i2s.c | 20 ++++++++++++++------
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1 file changed, 14 insertions(+), 6 deletions(-)
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--- a/sound/soc/bcm/bcm2835-i2s.c
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+++ b/sound/soc/bcm/bcm2835-i2s.c
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@@ -130,6 +130,7 @@ struct bcm2835_i2s_dev {
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struct regmap *i2s_regmap;
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struct clk *clk;
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bool clk_prepared;
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+ int clk_rate;
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};
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static void bcm2835_i2s_start_clock(struct bcm2835_i2s_dev *dev)
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@@ -419,10 +420,19 @@ static int bcm2835_i2s_hw_params(struct
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}
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/* Clock should only be set up here if CPU is clock master */
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- if (bit_clock_master) {
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- ret = clk_set_rate(dev->clk, bclk_rate);
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- if (ret)
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- return ret;
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+ if (bit_clock_master &&
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+ (!dev->clk_prepared || dev->clk_rate != bclk_rate)) {
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+ if (dev->clk_prepared)
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+ bcm2835_i2s_stop_clock(dev);
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+
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+ if (dev->clk_rate != bclk_rate) {
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+ ret = clk_set_rate(dev->clk, bclk_rate);
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+ if (ret)
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+ return ret;
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+ dev->clk_rate = bclk_rate;
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+ }
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+
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+ bcm2835_i2s_start_clock(dev);
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}
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/* Setup the frame format */
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@@ -618,8 +628,6 @@ static int bcm2835_i2s_prepare(struct sn
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struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
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uint32_t cs_reg;
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- bcm2835_i2s_start_clock(dev);
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-
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/*
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* Clear both FIFOs if the one that should be started
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* is not empty at the moment. This should only happen
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