ASoC: renesas: rz-ssi: Add suspend to RAM support

The SSIF-2 IP is available on the Renesas RZ/G3S SoC. The Renesas RZ/G3S
SoC supports a power-saving mode where power to most of the SoC
components is turned off. Add suspend/resume support to the SSIF-2 driver
to support this power-saving mode.

On SNDRV_PCM_TRIGGER_SUSPEND trigger the SSI is stopped (the stream
user pointer is left untouched to avoid breaking user space and the dma
buffer pointer is set to zero), on SNDRV_PCM_TRIGGER_RESUME software reset
is issued for the SSIF-2 IP and the clocks are re-configured.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://patch.msgid.link/20241210170953.2936724-18-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/renesas/rz-ssi.c b/sound/soc/renesas/rz-ssi.c
index 486822d7945861c8ebf654f04c4a129712fe9f15..d48e2e7356b607a1c741e1d6c1d3b30ce9eafd76 100644 (file)
--- a/sound/soc/renesas/rz-ssi.c
+++ b/sound/soc/renesas/rz-ssi.c
@@ -782,6 +782,32 @@ no_dma:
        return -ENODEV;
 }
 
+static int rz_ssi_trigger_resume(struct rz_ssi_priv *ssi)
+{
+       int ret;
+
+       if (rz_ssi_is_stream_running(&ssi->playback) ||
+           rz_ssi_is_stream_running(&ssi->capture))
+               return 0;
+
+       ret = rz_ssi_swreset(ssi);
+       if (ret)
+               return ret;
+
+       return rz_ssi_clk_setup(ssi, ssi->hw_params_cache.rate,
+                               ssi->hw_params_cache.channels);
+}
+
+static void rz_ssi_streams_suspend(struct rz_ssi_priv *ssi)
+{
+       if (rz_ssi_is_stream_running(&ssi->playback) ||
+           rz_ssi_is_stream_running(&ssi->capture))
+               return;
+
+       ssi->playback.dma_buffer_pos = 0;
+       ssi->capture.dma_buffer_pos = 0;
+}
+
 static int rz_ssi_dai_trigger(struct snd_pcm_substream *substream, int cmd,
                              struct snd_soc_dai *dai)
 {
@@ -790,8 +816,16 @@ static int rz_ssi_dai_trigger(struct snd_pcm_substream *substream, int cmd,
        int ret = 0, i, num_transfer = 1;
 
        switch (cmd) {
+       case SNDRV_PCM_TRIGGER_RESUME:
+               ret = rz_ssi_trigger_resume(ssi);
+               if (ret)
+                       return ret;
+
+               fallthrough;
+
        case SNDRV_PCM_TRIGGER_START:
-               rz_ssi_stream_init(strm, substream);
+               if (cmd == SNDRV_PCM_TRIGGER_START)
+                       rz_ssi_stream_init(strm, substream);
 
                if (ssi->dma_rt) {
                        bool is_playback;
@@ -819,6 +853,12 @@ static int rz_ssi_dai_trigger(struct snd_pcm_substream *substream, int cmd,
 
                ret = rz_ssi_start(ssi, strm);
                break;
+
+       case SNDRV_PCM_TRIGGER_SUSPEND:
+               rz_ssi_stop(ssi, strm);
+               rz_ssi_streams_suspend(ssi);
+               break;
+
        case SNDRV_PCM_TRIGGER_STOP:
                rz_ssi_stop(ssi, strm);
                rz_ssi_stream_quit(ssi, strm);
@@ -958,7 +998,8 @@ static const struct snd_soc_dai_ops rz_ssi_dai_ops = {
 static const struct snd_pcm_hardware rz_ssi_pcm_hardware = {
        .info                   = SNDRV_PCM_INFO_INTERLEAVED    |
                                  SNDRV_PCM_INFO_MMAP           |
-                                 SNDRV_PCM_INFO_MMAP_VALID,
+                                 SNDRV_PCM_INFO_MMAP_VALID     |
+                                 SNDRV_PCM_INFO_RESUME,
        .buffer_bytes_max       = PREALLOC_BUFFER,
        .period_bytes_min       = 32,
        .period_bytes_max       = 8192,
@@ -1201,6 +1242,7 @@ static int rz_ssi_runtime_resume(struct device *dev)
 
 static const struct dev_pm_ops rz_ssi_pm_ops = {
        RUNTIME_PM_OPS(rz_ssi_runtime_suspend, rz_ssi_runtime_resume, NULL)
+       SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
 };
 
 static struct platform_driver rz_ssi_driver = {