1 // SPDX-License-Identifier: GPL-2.0 2 // 3 // Freescale ALSA SoC Machine driver utility 4 // 5 // Author: Timur Tabi <timur@freescale.com> 6 // 7 // Copyright 2010 Freescale Semiconductor, Inc. 8 9 #include <linux/module.h> 10 #include <linux/of_address.h> 11 #include <sound/soc.h> 12 13 #include "fsl_utils.h" 14 15 /** 16 * fsl_asoc_get_dma_channel - determine the dma channel for a SSI node 17 * 18 * @ssi_np: pointer to the SSI device tree node 19 * @name: name of the phandle pointing to the dma channel 20 * @dai: ASoC DAI link pointer to be filled with platform_name 21 * @dma_channel_id: dma channel id to be returned 22 * @dma_id: dma id to be returned 23 * 24 * This function determines the dma and channel id for given SSI node. It 25 * also discovers the platform_name for the ASoC DAI link. 26 */ 27 int fsl_asoc_get_dma_channel(struct device_node *ssi_np, 28 const char *name, 29 struct snd_soc_dai_link *dai, 30 unsigned int *dma_channel_id, 31 unsigned int *dma_id) 32 { 33 struct resource res; 34 struct device_node *dma_channel_np, *dma_np; 35 const __be32 *iprop; 36 int ret; 37 38 dma_channel_np = of_parse_phandle(ssi_np, name, 0); 39 if (!dma_channel_np) 40 return -EINVAL; 41 42 if (!of_device_is_compatible(dma_channel_np, "fsl,ssi-dma-channel")) { 43 of_node_put(dma_channel_np); 44 return -EINVAL; 45 } 46 47 /* Determine the dev_name for the device_node. This code mimics the 48 * behavior of of_device_make_bus_id(). We need this because ASoC uses 49 * the dev_name() of the device to match the platform (DMA) device with 50 * the CPU (SSI) device. It's all ugly and hackish, but it works (for 51 * now). 52 * 53 * dai->platform name should already point to an allocated buffer. 54 */ 55 ret = of_address_to_resource(dma_channel_np, 0, &res); 56 if (ret) { 57 of_node_put(dma_channel_np); 58 return ret; 59 } 60 snprintf((char *)dai->platform_name, DAI_NAME_SIZE, "%llx.%s", 61 (unsigned long long) res.start, dma_channel_np->name); 62 63 iprop = of_get_property(dma_channel_np, "cell-index", NULL); 64 if (!iprop) { 65 of_node_put(dma_channel_np); 66 return -EINVAL; 67 } 68 *dma_channel_id = be32_to_cpup(iprop); 69 70 dma_np = of_get_parent(dma_channel_np); 71 iprop = of_get_property(dma_np, "cell-index", NULL); 72 if (!iprop) { 73 of_node_put(dma_np); 74 return -EINVAL; 75 } 76 *dma_id = be32_to_cpup(iprop); 77 78 of_node_put(dma_np); 79 of_node_put(dma_channel_np); 80 81 return 0; 82 } 83 EXPORT_SYMBOL(fsl_asoc_get_dma_channel); 84 85 MODULE_AUTHOR("Timur Tabi <timur@freescale.com>"); 86 MODULE_DESCRIPTION("Freescale ASoC utility code"); 87 MODULE_LICENSE("GPL v2"); 88