ASoC: rsnd: update pointer more accurate

Current rsnd driver updates pointer when DMA transfer was finished
in DMA transfer mode. But PulseAudio requests more accurate
pointer update when timer mode.
This patch consider about DMA transfer residue and update more
accurate pointer.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/soc/sh/rcar/ssi.c b/sound/soc/sh/rcar/ssi.c
index eddd8af..2363d0b 100644
--- a/sound/soc/sh/rcar/ssi.c
+++ b/sound/soc/sh/rcar/ssi.c
@@ -685,6 +685,17 @@
 	return ret;
 }
 
+static int rsnd_ssi_pointer(struct rsnd_mod *mod,
+			    struct rsnd_dai_stream *io,
+			    snd_pcm_uframes_t *pointer)
+{
+	struct snd_pcm_runtime *runtime = rsnd_io_to_runtime(io);
+
+	*pointer = bytes_to_frames(runtime, io->byte_pos);
+
+	return 0;
+}
+
 static struct rsnd_mod_ops rsnd_ssi_pio_ops = {
 	.name	= SSI_NAME,
 	.probe	= rsnd_ssi_common_probe,
@@ -693,6 +704,7 @@
 	.start	= rsnd_ssi_start,
 	.stop	= rsnd_ssi_stop,
 	.irq	= rsnd_ssi_irq,
+	.pointer= rsnd_ssi_pointer,
 	.pcm_new = rsnd_ssi_pcm_new,
 	.hw_params = rsnd_ssi_hw_params,
 };