dmaengine: sh: rcar-dmac: add comment for r8a779a0 compatible

Add the reason why we need r8a779a0 compatible.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87a5dlwlr0.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index 2679c1f09faf075159282eae26d888cd5b183684..0c45ce8c74aa2dedb2764856453da4d9944ab83f 100644 (file)
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -2023,6 +2023,10 @@ static const struct of_device_id rcar_dmac_of_ids[] = {
                .compatible = "renesas,rcar-gen4-dmac",
                .data = &rcar_gen4_dmac_data,
        }, {
+               /*
+                * Backward compatibility for between v5.12 - v5.19
+                * which didn't combined with "renesas,rcar-gen4-dmac"
+                */
                .compatible = "renesas,dmac-r8a779a0",
                .data = &rcar_gen4_dmac_data,
        },