1 /** 2 * Freescale ALSA SoC Machine driver utility 3 * 4 * Author: Timur Tabi <timur@freescale.com> 5 * 6 * Copyright 2010 Freescale Semiconductor, Inc. 7 * 8 * This file is licensed under the terms of the GNU General Public License 9 * version 2. This program is licensed "as is" without any warranty of any 10 * kind, whether express or implied. 11 */ 12 13 #include <linux/module.h> 14 #include <linux/of_address.h> 15 #include <sound/soc.h> 16 17 #include "fsl_utils.h" 18 19 /** 20 * fsl_asoc_get_dma_channel - determine the dma channel for a SSI node 21 * 22 * @ssi_np: pointer to the SSI device tree node 23 * @name: name of the phandle pointing to the dma channel 24 * @dai: ASoC DAI link pointer to be filled with platform_name 25 * @dma_channel_id: dma channel id to be returned 26 * @dma_id: dma id to be returned 27 * 28 * This function determines the dma and channel id for given SSI node. It 29 * also discovers the platform_name for the ASoC DAI link. 30 */ 31 int fsl_asoc_get_dma_channel(struct device_node *ssi_np, 32 const char *name, 33 struct snd_soc_dai_link *dai, 34 unsigned int *dma_channel_id, 35 unsigned int *dma_id) 36 { 37 struct resource res; 38 struct device_node *dma_channel_np, *dma_np; 39 const __be32 *iprop; 40 int ret; 41 42 dma_channel_np = of_parse_phandle(ssi_np, name, 0); 43 if (!dma_channel_np) 44 return -EINVAL; 45 46 if (!of_device_is_compatible(dma_channel_np, "fsl,ssi-dma-channel")) { 47 of_node_put(dma_channel_np); 48 return -EINVAL; 49 } 50 51 /* Determine the dev_name for the device_node. This code mimics the 52 * behavior of of_device_make_bus_id(). We need this because ASoC uses 53 * the dev_name() of the device to match the platform (DMA) device with 54 * the CPU (SSI) device. It's all ugly and hackish, but it works (for 55 * now). 56 * 57 * dai->platform name should already point to an allocated buffer. 58 */ 59 ret = of_address_to_resource(dma_channel_np, 0, &res); 60 if (ret) { 61 of_node_put(dma_channel_np); 62 return ret; 63 } 64 snprintf((char *)dai->platform_name, DAI_NAME_SIZE, "%llx.%s", 65 (unsigned long long) res.start, dma_channel_np->name); 66 67 iprop = of_get_property(dma_channel_np, "cell-index", NULL); 68 if (!iprop) { 69 of_node_put(dma_channel_np); 70 return -EINVAL; 71 } 72 *dma_channel_id = be32_to_cpup(iprop); 73 74 dma_np = of_get_parent(dma_channel_np); 75 iprop = of_get_property(dma_np, "cell-index", NULL); 76 if (!iprop) { 77 of_node_put(dma_np); 78 return -EINVAL; 79 } 80 *dma_id = be32_to_cpup(iprop); 81 82 of_node_put(dma_np); 83 of_node_put(dma_channel_np); 84 85 return 0; 86 } 87 EXPORT_SYMBOL(fsl_asoc_get_dma_channel); 88 89 MODULE_AUTHOR("Timur Tabi <timur@freescale.com>"); 90 MODULE_DESCRIPTION("Freescale ASoC utility code"); 91 MODULE_LICENSE("GPL v2"); 92