1 files changed, 88 insertions, 0 deletions
diff --git a/sound/soc/fsl/fsl_utils.c b/sound/soc/fsl/fsl_utils.c
new file mode 100644
index 000000000..cca33ab70
--- /dev/null
+++ b/sound/soc/fsl/fsl_utils.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Freescale ALSA SoC Machine driver utility
+//
+// Author: Timur Tabi <timur@freescale.com>
+//
+// Copyright 2010 Freescale Semiconductor, Inc.
+
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <sound/soc.h>
+
+#include "fsl_utils.h"
+
+/**
+ * fsl_asoc_get_dma_channel - determine the dma channel for a SSI node
+ *
+ * @ssi_np: pointer to the SSI device tree node
+ * @name: name of the phandle pointing to the dma channel
+ * @dai: ASoC DAI link pointer to be filled with platform_name
+ * @dma_channel_id: dma channel id to be returned
+ * @dma_id: dma id to be returned
+ *
+ * This function determines the dma and channel id for given SSI node.  It
+ * also discovers the platform_name for the ASoC DAI link.
+ */
+int fsl_asoc_get_dma_channel(struct device_node *ssi_np,
+			     const char *name,
+			     struct snd_soc_dai_link *dai,
+			     unsigned int *dma_channel_id,
+			     unsigned int *dma_id)
+{
+	struct resource res;
+	struct device_node *dma_channel_np, *dma_np;
+	const __be32 *iprop;
+	int ret;
+
+	dma_channel_np = of_parse_phandle(ssi_np, name, 0);
+	if (!dma_channel_np)
+		return -EINVAL;
+
+	if (!of_device_is_compatible(dma_channel_np, "fsl,ssi-dma-channel")) {
+		of_node_put(dma_channel_np);
+		return -EINVAL;
+	}
+
+	/* Determine the dev_name for the device_node.  This code mimics the
+	 * behavior of of_device_make_bus_id(). We need this because ASoC uses
+	 * the dev_name() of the device to match the platform (DMA) device with
+	 * the CPU (SSI) device.  It's all ugly and hackish, but it works (for
+	 * now).
+	 *
+	 * dai->platform name should already point to an allocated buffer.
+	 */
+	ret = of_address_to_resource(dma_channel_np, 0, &res);
+	if (ret) {
+		of_node_put(dma_channel_np);
+		return ret;
+	}
+	snprintf((char *)dai->platform_name, DAI_NAME_SIZE, "%llx.%s",
+		 (unsigned long long) res.start, dma_channel_np->name);
+
+	iprop = of_get_property(dma_channel_np, "cell-index", NULL);
+	if (!iprop) {
+		of_node_put(dma_channel_np);
+		return -EINVAL;
+	}
+	*dma_channel_id = be32_to_cpup(iprop);
+
+	dma_np = of_get_parent(dma_channel_np);
+	iprop = of_get_property(dma_np, "cell-index", NULL);
+	if (!iprop) {
+		of_node_put(dma_np);
+		of_node_put(dma_channel_np);
+		return -EINVAL;
+	}
+	*dma_id = be32_to_cpup(iprop);
+
+	of_node_put(dma_np);
+	of_node_put(dma_channel_np);
+
+	return 0;
+}
+EXPORT_SYMBOL(fsl_asoc_get_dma_channel);
+
+MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
+MODULE_DESCRIPTION("Freescale ASoC utility code");
+MODULE_LICENSE("GPL v2");