The I2S reset may be asserted at a boot time, in particular this is the case on Tegra20 AC100 netbook. Tegra20 I2S driver doesn't manage the reset control and currently it happens to work because reset is implicitly deasserted by the tegra-clk driver when I2S clock is enabled. The I2S permanently stays in a reset once tegra-clk is fixed to not touch the resets, which it shouldn't be doing. Add reset control to the Tegra20 I2S driver.
Note that I2S reset was always specified in Tegra20 device-tree, hence DTB ABI changes aren't required.
Tested-by: Paul Fertser fercerpav@gmail.com # T20 AC100 Reported-by: Paul Fertser fercerpav@gmail.com Signed-off-by: Dmitry Osipenko digetx@gmail.com --- sound/soc/tegra/tegra20_i2s.c | 31 +++++++++++++++++++++++++++++++ sound/soc/tegra/tegra20_i2s.h | 1 + 2 files changed, 32 insertions(+)
diff --git a/sound/soc/tegra/tegra20_i2s.c b/sound/soc/tegra/tegra20_i2s.c index d7a3d046c8f8..c0af5352b483 100644 --- a/sound/soc/tegra/tegra20_i2s.c +++ b/sound/soc/tegra/tegra20_i2s.c @@ -22,6 +22,7 @@ #include <linux/platform_device.h> #include <linux/pm_runtime.h> #include <linux/regmap.h> +#include <linux/reset.h> #include <linux/slab.h> #include <sound/core.h> #include <sound/pcm.h> @@ -37,6 +38,8 @@ static int tegra20_i2s_runtime_suspend(struct device *dev) { struct tegra20_i2s *i2s = dev_get_drvdata(dev);
+ regcache_cache_only(i2s->regmap, true); + clk_disable_unprepare(i2s->clk_i2s);
return 0; @@ -47,13 +50,35 @@ static int tegra20_i2s_runtime_resume(struct device *dev) struct tegra20_i2s *i2s = dev_get_drvdata(dev); int ret;
+ ret = reset_control_assert(i2s->reset); + if (ret) + return ret; + ret = clk_prepare_enable(i2s->clk_i2s); if (ret) { dev_err(dev, "clk_enable failed: %d\n", ret); return ret; }
+ usleep_range(10, 100); + + ret = reset_control_deassert(i2s->reset); + if (ret) + goto disable_clocks; + + regcache_cache_only(i2s->regmap, false); + regcache_mark_dirty(i2s->regmap); + + ret = regcache_sync(i2s->regmap); + if (ret) + goto disable_clocks; + return 0; + +disable_clocks: + clk_disable_unprepare(i2s->clk_i2s); + + return ret; }
static int tegra20_i2s_set_fmt(struct snd_soc_dai *dai, @@ -339,6 +364,12 @@ static int tegra20_i2s_platform_probe(struct platform_device *pdev) i2s->dai = tegra20_i2s_dai_template; i2s->dai.name = dev_name(&pdev->dev);
+ i2s->reset = devm_reset_control_get_exclusive(&pdev->dev, "i2s"); + if (IS_ERR(i2s->reset)) { + dev_err(&pdev->dev, "Can't retrieve i2s reset\n"); + return PTR_ERR(i2s->reset); + } + i2s->clk_i2s = clk_get(&pdev->dev, NULL); if (IS_ERR(i2s->clk_i2s)) { dev_err(&pdev->dev, "Can't retrieve i2s clock\n"); diff --git a/sound/soc/tegra/tegra20_i2s.h b/sound/soc/tegra/tegra20_i2s.h index 628d3ca09f42..8233e5fa2eff 100644 --- a/sound/soc/tegra/tegra20_i2s.h +++ b/sound/soc/tegra/tegra20_i2s.h @@ -144,6 +144,7 @@ struct tegra20_i2s { struct snd_dmaengine_dai_dma_data capture_dma_data; struct snd_dmaengine_dai_dma_data playback_dma_data; struct regmap *regmap; + struct reset_control *reset; };
#endif