ASoC: rockchip: i2s_tdm: Make the grf property optional

Only IO Multiplex and two TRCM modes need access to the GRF, so
making it a hard requirement is not a wise idea, as it complicates
support for newer SoCs which do not do these things.
Signed-off-by: Nicolas Frattaroli <frattaroli.nicolas@gmail.com>
Link: https://lore.kernel.org/r/20221025124132.399729-3-frattaroli.nicolas@gmail.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/rockchip/rockchip_i2s_tdm.c

@@ -756,6 +756,12 @@ static int rockchip_i2s_io_multiplex(struct snd_pcm_substream *substream,
 	if (!i2s_tdm->io_multiplex)
 		return 0;
 
+	if (IS_ERR_OR_NULL(i2s_tdm->grf)) {
+		dev_err(i2s_tdm->dev,
+			"io multiplex not supported for this device\n");
+		return -EINVAL;
+	}
+
 	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
 		struct snd_pcm_str *playback_str =
 			&substream->pcm->streams[SNDRV_PCM_STREAM_PLAYBACK];
@@ -1222,6 +1228,12 @@ static int common_soc_init(struct device *dev, u32 addr)
 	if (trcm == TRCM_TXRX)
 		return 0;
 
+	if (IS_ERR_OR_NULL(i2s_tdm->grf)) {
+		dev_err(i2s_tdm->dev,
+			"no grf present but non-txrx TRCM specified\n");
+		return -EINVAL;
+	}
+
 	for (i = 0; i < i2s_tdm->soc_data->config_count; i++) {
 		if (addr != configs[i].addr)
 			continue;
@@ -1568,10 +1580,6 @@ static int rockchip_i2s_tdm_probe(struct platform_device *pdev)
 		return ret;
 
 	i2s_tdm->grf = syscon_regmap_lookup_by_phandle(node, "rockchip,grf");
-	if (IS_ERR(i2s_tdm->grf))
-		return dev_err_probe(i2s_tdm->dev, PTR_ERR(i2s_tdm->grf),
-				     "Error in rockchip,grf\n");
-
 	i2s_tdm->tx_reset = devm_reset_control_get_optional_exclusive(&pdev->dev,
 								      "tx-m");
 	if (IS_ERR(i2s_tdm->tx_reset)) {