Add the optional reset line handling which is present on the new SoC families, such as the g12a. Triggering this reset is not critical but it helps solve a channel shift issue on the g12a.
Signed-off-by: Jerome Brunet jbrunet@baylibre.com --- sound/soc/meson/axg-tdm-formatter.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)
diff --git a/sound/soc/meson/axg-tdm-formatter.c b/sound/soc/meson/axg-tdm-formatter.c index 0c6cce5c5773..2e498201139f 100644 --- a/sound/soc/meson/axg-tdm-formatter.c +++ b/sound/soc/meson/axg-tdm-formatter.c @@ -7,6 +7,7 @@ #include <linux/module.h> #include <linux/of_platform.h> #include <linux/regmap.h> +#include <linux/reset.h> #include <sound/soc.h>
#include "axg-tdm-formatter.h" @@ -20,6 +21,7 @@ struct axg_tdm_formatter { struct clk *lrclk; struct clk *sclk_sel; struct clk *lrclk_sel; + struct reset_control *reset; bool enabled; struct regmap *map; }; @@ -75,6 +77,24 @@ static int axg_tdm_formatter_enable(struct axg_tdm_formatter *formatter) if (formatter->enabled) return 0;
+ /* + * On the g12a (and possibly other SoCs), when a stream using + * multiple lanes is restarted, it will sometimes not start + * from the first lane, but randomly from another used one. + * The result is an unexpected and random channel shift. + * + * The hypothesis is that an HW counter is not properly reset + * and the formatter simply starts on the lane it stopped + * before. Unfortunately, there does not seems to be a way to + * reset this through the registers of the block. + * + * However, the g12a has indenpendent reset lines for each audio + * devices. Using this reset before each start solves the issue. + */ + ret = reset_control_reset(formatter->reset); + if (ret) + return ret; + /* * If sclk is inverted, invert it back and provide the inversion * required by the formatter @@ -306,6 +326,15 @@ int axg_tdm_formatter_probe(struct platform_device *pdev) return ret; }
+ /* Formatter dedicated reset line */ + formatter->reset = reset_control_get_optional_exclusive(dev, NULL); + if (IS_ERR(formatter->reset)) { + ret = PTR_ERR(formatter->reset); + if (ret != -EPROBE_DEFER) + dev_err(dev, "failed to get reset: %d\n", ret); + return ret; + } + return devm_snd_soc_register_component(dev, drv->component_drv, NULL, 0); }