[PATCH v6 06/16] ASoC: rsnd: Add audmacpp clock and reset support for RZ/G3E

[John Madieu <john.madieu.xa@bp.renesas.com>]

RZ/G3E requires additional audmapp clock and reset lines for
Audio DMA-PP operation.

Add global audmacpp clock/reset management in rsnd_dma_probe()
using optional APIs to remain transparent to other platforms.

Signed-off-by: John Madieu <john.madieu.xa@bp.renesas.com>
---

Changes:

v6:
 - Enable the audmapp clock before deasserting the audmapp reset
   so the block sees a stable clock on the way out of reset.
 - Drop redundant braces around single-statement if blocks (style).

v5:
 - Add comment on audmapp clock/reset acquisition clarifying these
   are optional and transparent to platforms that don't have them
   in DT, per Kuninori's request.
 - Drop spurious blank line added to struct rsnd_priv in rsnd.h.

v4:
 - Move audmapp_clk and audmapp_rstc from struct rsnd_priv into
   struct rsnd_dma_ctrl.

v3: No changes
v2: No changes

 sound/soc/renesas/rcar/dma.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/sound/soc/renesas/rcar/dma.c b/sound/soc/renesas/rcar/dma.c
index 68c859897e68..71774dae8847 100644
--- a/sound/soc/renesas/rcar/dma.c
+++ b/sound/soc/renesas/rcar/dma.c
@@ -47,6 +47,9 @@ struct rsnd_dma_ctrl {
 	phys_addr_t ppres;
 	int dmaen_num;
 	int dmapp_num;
+	/* RZ/G3E: Audio DMAC peri-peri clock and reset */
+	struct clk *audmapp_clk;
+	struct reset_control *audmapp_rstc;
 };
 
 #define rsnd_priv_to_dmac(p)	((struct rsnd_dma_ctrl *)(p)->dma)
@@ -864,6 +867,25 @@ int rsnd_dma_probe(struct rsnd_priv *priv)
 	if (rsnd_is_gen4(priv))
 		goto audmapp_end;
 
+	/*
+	 * Audio DMAC peri-peri clock and reset for RZ/G3E.
+	 * These use optional APIs, so they gracefully return NULL
+	 * (no error) on platforms whose DT does not provide them.
+	 *
+	 * Enable the clock first so the block sees a stable clock on
+	 * the way out of reset, then deassert the reset line.
+	 */
+	dmac->audmapp_clk = devm_clk_get_optional_enabled(dev, "audmapp");
+	if (IS_ERR(dmac->audmapp_clk))
+		return dev_err_probe(dev, PTR_ERR(dmac->audmapp_clk),
+				     "failed to get audmapp clock\n");
+
+	dmac->audmapp_rstc =
+		devm_reset_control_get_optional_exclusive_deasserted(dev, "audmapp");
+	if (IS_ERR(dmac->audmapp_rstc))
+		return dev_err_probe(dev, PTR_ERR(dmac->audmapp_rstc),
+				     "failed to get audmapp reset\n");
+
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "audmapp");
 	if (!res) {
 		dev_err(dev, "lack of audmapp in DT\n");
-- 
2.25.1