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Subject[PATCH 2/2] ASoC: audio_graph_card2: Add support for variable slot widths
Date
Some audio hardware cannot support a fixed slot width or a slot width
equal to the sample width in all cases. This is usually due either to
limitations of the audio serial port or system clocking restrictions.
A typical example would be:

- 16-bit samples in 16-bit slots
- 24-bit samples in 32-bit slots

The new dai-tdm-slot-width-map property allows setting a mapping of
sample widths and the corresponding tdm slot widths. The content is
an array of integers. Each pair of values are the sample_width and
the corresponding slot width.

The property is added to each endpoint node that needs the restriction.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
---
include/sound/simple_card_utils.h | 11 ++++
sound/soc/generic/audio-graph-card2.c | 4 ++
sound/soc/generic/simple-card-utils.c | 95 +++++++++++++++++++++++++++
3 files changed, 110 insertions(+)

diff --git a/include/sound/simple_card_utils.h b/include/sound/simple_card_utils.h
index 5ee269c59aac..1c966efe0187 100644
--- a/include/sound/simple_card_utils.h
+++ b/include/sound/simple_card_utils.h
@@ -16,6 +16,11 @@
#define asoc_simple_init_mic(card, sjack, prefix) \
asoc_simple_init_jack(card, sjack, 0, prefix, NULL)

+struct asoc_simple_tdm_width_map {
+ int sample_bits;
+ int slot_width;
+};
+
struct asoc_simple_dai {
const char *name;
unsigned int sysclk;
@@ -26,6 +31,9 @@ struct asoc_simple_dai {
unsigned int rx_slot_mask;
struct clk *clk;
bool clk_fixed;
+ struct asoc_simple_tdm_width_map *tdm_width_map;
+ int n_tdm_widths;
+ struct snd_soc_dai *dai;
};

struct asoc_simple_data {
@@ -132,6 +140,9 @@ int asoc_simple_parse_daifmt(struct device *dev,
struct device_node *codec,
char *prefix,
unsigned int *retfmt);
+int asoc_simple_parse_tdm_width_map(struct device *dev, struct device_node *np,
+ struct asoc_simple_dai *dai);
+
__printf(3, 4)
int asoc_simple_set_dailink_name(struct device *dev,
struct snd_soc_dai_link *dai_link,
diff --git a/sound/soc/generic/audio-graph-card2.c b/sound/soc/generic/audio-graph-card2.c
index c3947347dda3..c0f3907a01fd 100644
--- a/sound/soc/generic/audio-graph-card2.c
+++ b/sound/soc/generic/audio-graph-card2.c
@@ -503,6 +503,10 @@ static int __graph_parse_node(struct asoc_simple_priv *priv,
if (ret < 0)
return ret;

+ ret = asoc_simple_parse_tdm_width_map(dev, ep, dai);
+ if (ret < 0)
+ return ret;
+
ret = asoc_simple_parse_clk(dev, ep, dai, dlc);
if (ret < 0)
return ret;
diff --git a/sound/soc/generic/simple-card-utils.c b/sound/soc/generic/simple-card-utils.c
index a4babfb63175..60653d7d7ae7 100644
--- a/sound/soc/generic/simple-card-utils.c
+++ b/sound/soc/generic/simple-card-utils.c
@@ -12,6 +12,7 @@
#include <linux/of_gpio.h>
#include <linux/of_graph.h>
#include <sound/jack.h>
+#include <sound/pcm_params.h>
#include <sound/simple_card_utils.h>

void asoc_simple_convert_fixup(struct asoc_simple_data *data,
@@ -87,6 +88,49 @@ int asoc_simple_parse_daifmt(struct device *dev,
}
EXPORT_SYMBOL_GPL(asoc_simple_parse_daifmt);

+int asoc_simple_parse_tdm_width_map(struct device *dev, struct device_node *np,
+ struct asoc_simple_dai *dai)
+{
+ u32 *array_values;
+ int n, i, ret;
+
+ if (!of_property_read_bool(np, "dai-tdm-slot-width-map"))
+ return 0;
+
+ n = of_property_count_elems_of_size(np, "dai-tdm-slot-width-map", sizeof(u32));
+ if (n % 1) {
+ dev_err(dev, "Invalid number of cells for dai-tdm-slot-width-map\n");
+ return -EINVAL;
+ }
+
+ dai->tdm_width_map = devm_kcalloc(dev, n, sizeof(*dai->tdm_width_map), GFP_KERNEL);
+ if (!dai->tdm_width_map)
+ return -ENOMEM;
+
+ array_values = kcalloc(n, sizeof(*array_values), GFP_KERNEL);
+ if (!array_values)
+ return -ENOMEM;
+
+ ret = of_property_read_u32_array(np, "dai-tdm-slot-width-map", array_values, n);
+ if (ret < 0) {
+ dev_err(dev, "Could not read dai-tdm-slot-width-map: %d\n", ret);
+ goto out;
+ }
+
+ for (i = 0; i < n; i += 2) {
+ dai->tdm_width_map[i / 2].sample_bits = array_values[i];
+ dai->tdm_width_map[i / 2].slot_width = array_values[i + 1];
+ }
+
+ dai->n_tdm_widths = n / 2;
+ ret = 0;
+out:
+ kfree(array_values);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(asoc_simple_parse_tdm_width_map);
+
int asoc_simple_set_dailink_name(struct device *dev,
struct snd_soc_dai_link *dai_link,
const char *fmt, ...)
@@ -309,6 +353,42 @@ static int asoc_simple_set_clk_rate(struct device *dev,
return clk_set_rate(simple_dai->clk, rate);
}

+static int asoc_simple_set_tdm(struct asoc_simple_dai *simple_dai,
+ struct snd_pcm_hw_params *params)
+{
+ int slot_width = params_width(params);
+ int sample_bits = params_width(params);
+ int i, ret;
+
+ if (!simple_dai)
+ return 0;
+
+ if (!simple_dai->dai || !simple_dai->tdm_width_map)
+ return 0;
+
+ if (simple_dai->slot_width)
+ slot_width = simple_dai->slot_width;
+
+ for (i = 0; i < simple_dai->n_tdm_widths; ++i) {
+ if (simple_dai->tdm_width_map[i].sample_bits == sample_bits) {
+ slot_width = simple_dai->tdm_width_map[i].slot_width;
+ break;
+ }
+ }
+
+ ret = snd_soc_dai_set_tdm_slot(simple_dai->dai,
+ simple_dai->tx_slot_mask,
+ simple_dai->rx_slot_mask,
+ simple_dai->slots,
+ slot_width);
+ if (ret && ret != -ENOTSUPP) {
+ dev_err(simple_dai->dai->dev, "simple-card: set_tdm_slot error: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
int asoc_simple_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params)
{
@@ -362,6 +442,19 @@ int asoc_simple_hw_params(struct snd_pcm_substream *substream,
return ret;
}
}
+
+ for_each_prop_dai_codec(props, i, pdai) {
+ ret = asoc_simple_set_tdm(pdai, params);
+ if (ret < 0)
+ return ret;
+ }
+
+ for_each_prop_dai_cpu(props, i, pdai) {
+ ret = asoc_simple_set_tdm(pdai, params);
+ if (ret < 0)
+ return ret;
+ }
+
return 0;
}
EXPORT_SYMBOL_GPL(asoc_simple_hw_params);
@@ -386,6 +479,8 @@ static int asoc_simple_init_dai(struct snd_soc_dai *dai,
if (!simple_dai)
return 0;

+ simple_dai->dai = dai;
+
if (simple_dai->sysclk) {
ret = snd_soc_dai_set_sysclk(dai, 0, simple_dai->sysclk,
simple_dai->clk_direction);
--
2.30.2
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