ASoC: xilinx: xlnx_i2s: Handle sysclk setting

This driver previously only handled the set_clkdiv divider callback when
setting the SCLK Out Divider field in the I2S Timing Control register.
However, when using the simple-audio-card driver, the set_sysclk function
is called but not set_clkdiv. This caused the divider not to be set,
leaving it at an invalid value of 0 and resulting in a very low SCLK
output rate.

Handle set_clkdiv and store the sysclk (MCLK) value for later use in
hw_params to set the SCLK Out Divider such that:
MCLK/SCLK = divider * 2

Signed-off-by: Robert Hancock <robert.hancock@calian.com>
Link: https://lore.kernel.org/r/20220120195832.1742271-4-robert.hancock@calian.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/xilinx/xlnx_i2s.c b/sound/soc/xilinx/xlnx_i2s.c
index 3bafa34..4cc6ee7 100644 (file)
--- a/sound/soc/xilinx/xlnx_i2s.c
+++ b/sound/soc/xilinx/xlnx_i2s.c
@@ -18,6 +18,8 @@
 #define DRV_NAME "xlnx_i2s"
 
 #define I2S_CORE_CTRL_OFFSET           0x08
+#define I2S_CORE_CTRL_32BIT_LRCLK      BIT(3)
+#define I2S_CORE_CTRL_ENABLE           BIT(0)
 #define I2S_I2STIM_OFFSET              0x20
 #define I2S_CH0_OFFSET                 0x30
 #define I2S_I2STIM_VALID_MASK          GENMASK(7, 0)
@@ -25,6 +27,12 @@
 struct xlnx_i2s_drv_data {
        struct snd_soc_dai_driver dai_drv;
        void __iomem *base;
+       unsigned int sysclk;
+       u32 data_width;
+       u32 channels;
+       bool is_32bit_lrclk;
+       struct snd_ratnum ratnum;
+       struct snd_pcm_hw_constraint_ratnums rate_constraints;
 };
 
 static int xlnx_i2s_set_sclkout_div(struct snd_soc_dai *cpu_dai,
@@ -35,11 +43,50 @@ static int xlnx_i2s_set_sclkout_div(struct snd_soc_dai *cpu_dai,
        if (!div || (div & ~I2S_I2STIM_VALID_MASK))
                return -EINVAL;
 
+       drv_data->sysclk = 0;
+
        writel(div, drv_data->base + I2S_I2STIM_OFFSET);
 
        return 0;
 }
 
+static int xlnx_i2s_set_sysclk(struct snd_soc_dai *dai,
+                              int clk_id, unsigned int freq, int dir)
+{
+       struct xlnx_i2s_drv_data *drv_data = snd_soc_dai_get_drvdata(dai);
+
+       drv_data->sysclk = freq;
+       if (freq) {
+               unsigned int bits_per_sample;
+
+               if (drv_data->is_32bit_lrclk)
+                       bits_per_sample = 32;
+               else
+                       bits_per_sample = drv_data->data_width;
+
+               drv_data->ratnum.num = freq / (bits_per_sample * drv_data->channels) / 2;
+               drv_data->ratnum.den_step = 1;
+               drv_data->ratnum.den_min = 1;
+               drv_data->ratnum.den_max = 255;
+               drv_data->rate_constraints.rats = &drv_data->ratnum;
+               drv_data->rate_constraints.nrats = 1;
+       }
+       return 0;
+}
+
+static int xlnx_i2s_startup(struct snd_pcm_substream *substream,
+                           struct snd_soc_dai *dai)
+{
+       struct xlnx_i2s_drv_data *drv_data = snd_soc_dai_get_drvdata(dai);
+
+       if (drv_data->sysclk)
+               return snd_pcm_hw_constraint_ratnums(substream->runtime, 0,
+                                                    SNDRV_PCM_HW_PARAM_RATE,
+                                                    &drv_data->rate_constraints);
+
+       return 0;
+}
+
 static int xlnx_i2s_hw_params(struct snd_pcm_substream *substream,
                              struct snd_pcm_hw_params *params,
                              struct snd_soc_dai *i2s_dai)
@@ -47,6 +94,26 @@ static int xlnx_i2s_hw_params(struct snd_pcm_substream *substream,
        u32 reg_off, chan_id;
        struct xlnx_i2s_drv_data *drv_data = snd_soc_dai_get_drvdata(i2s_dai);
 
+       if (drv_data->sysclk) {
+               unsigned int bits_per_sample, sclk, sclk_div;
+
+               if (drv_data->is_32bit_lrclk)
+                       bits_per_sample = 32;
+               else
+                       bits_per_sample = drv_data->data_width;
+
+               sclk = params_rate(params) * bits_per_sample * params_channels(params);
+               sclk_div = drv_data->sysclk / sclk / 2;
+
+               if ((drv_data->sysclk % sclk != 0) ||
+                   !sclk_div || (sclk_div & ~I2S_I2STIM_VALID_MASK)) {
+                       dev_warn(i2s_dai->dev, "invalid SCLK divisor for sysclk %u and sclk %u\n",
+                                drv_data->sysclk, sclk);
+                       return -EINVAL;
+               }
+               writel(sclk_div, drv_data->base + I2S_I2STIM_OFFSET);
+       }
+
        chan_id = params_channels(params) / 2;
 
        while (chan_id > 0) {
@@ -67,7 +134,7 @@ static int xlnx_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_RESUME:
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
-               writel(1, drv_data->base + I2S_CORE_CTRL_OFFSET);
+               writel(I2S_CORE_CTRL_ENABLE, drv_data->base + I2S_CORE_CTRL_OFFSET);
                break;
        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_SUSPEND:
@@ -83,7 +150,9 @@ static int xlnx_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
 
 static const struct snd_soc_dai_ops xlnx_i2s_dai_ops = {
        .trigger = xlnx_i2s_trigger,
+       .set_sysclk = xlnx_i2s_set_sysclk,
        .set_clkdiv = xlnx_i2s_set_sclkout_div,
+       .startup = xlnx_i2s_startup,
        .hw_params = xlnx_i2s_hw_params
 };
 
@@ -102,7 +171,7 @@ static int xlnx_i2s_probe(struct platform_device *pdev)
 {
        struct xlnx_i2s_drv_data *drv_data;
        int ret;
-       u32 ch, format, data_width;
+       u32 format;
        struct device *dev = &pdev->dev;
        struct device_node *node = dev->of_node;
 
@@ -114,19 +183,19 @@ static int xlnx_i2s_probe(struct platform_device *pdev)
        if (IS_ERR(drv_data->base))
                return PTR_ERR(drv_data->base);
 
-       ret = of_property_read_u32(node, "xlnx,num-channels", &ch);
+       ret = of_property_read_u32(node, "xlnx,num-channels", &drv_data->channels);
        if (ret < 0) {
                dev_err(dev, "cannot get supported channels\n");
                return ret;
        }
-       ch = ch * 2;
+       drv_data->channels *= 2;
 
-       ret = of_property_read_u32(node, "xlnx,dwidth", &data_width);
+       ret = of_property_read_u32(node, "xlnx,dwidth", &drv_data->data_width);
        if (ret < 0) {
                dev_err(dev, "cannot get data width\n");
                return ret;
        }
-       switch (data_width) {
+       switch (drv_data->data_width) {
        case 16:
                format = SNDRV_PCM_FMTBIT_S16_LE;
                break;
@@ -141,21 +210,23 @@ static int xlnx_i2s_probe(struct platform_device *pdev)
                drv_data->dai_drv.name = "xlnx_i2s_playback";
                drv_data->dai_drv.playback.stream_name = "Playback";
                drv_data->dai_drv.playback.formats = format;
-               drv_data->dai_drv.playback.channels_min = ch;
-               drv_data->dai_drv.playback.channels_max = ch;
+               drv_data->dai_drv.playback.channels_min = drv_data->channels;
+               drv_data->dai_drv.playback.channels_max = drv_data->channels;
                drv_data->dai_drv.playback.rates        = SNDRV_PCM_RATE_8000_192000;
                drv_data->dai_drv.ops = &xlnx_i2s_dai_ops;
        } else if (of_device_is_compatible(node, "xlnx,i2s-receiver-1.0")) {
                drv_data->dai_drv.name = "xlnx_i2s_capture";
                drv_data->dai_drv.capture.stream_name = "Capture";
                drv_data->dai_drv.capture.formats = format;
-               drv_data->dai_drv.capture.channels_min = ch;
-               drv_data->dai_drv.capture.channels_max = ch;
+               drv_data->dai_drv.capture.channels_min = drv_data->channels;
+               drv_data->dai_drv.capture.channels_max = drv_data->channels;
                drv_data->dai_drv.capture.rates = SNDRV_PCM_RATE_8000_192000;
                drv_data->dai_drv.ops = &xlnx_i2s_dai_ops;
        } else {
                return -ENODEV;
        }
+       drv_data->is_32bit_lrclk = readl(drv_data->base + I2S_CORE_CTRL_OFFSET) &
+                                  I2S_CORE_CTRL_32BIT_LRCLK;
 
        dev_set_drvdata(&pdev->dev, drv_data);