1 /* 2 * Copyright (c) 2015, National Instruments Corp. 3 * 4 * Xilinx Zynq Reset controller driver 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; version 2 of the License. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 */ 15 16 #include <linux/err.h> 17 #include <linux/io.h> 18 #include <linux/module.h> 19 #include <linux/mfd/syscon.h> 20 #include <linux/of.h> 21 #include <linux/platform_device.h> 22 #include <linux/reset-controller.h> 23 #include <linux/regmap.h> 24 #include <linux/types.h> 25 26 struct zynq_reset_data { 27 struct regmap *slcr; 28 struct reset_controller_dev rcdev; 29 u32 offset; 30 }; 31 32 #define to_zynq_reset_data(p) \ 33 container_of((p), struct zynq_reset_data, rcdev) 34 35 static int zynq_reset_assert(struct reset_controller_dev *rcdev, 36 unsigned long id) 37 { 38 struct zynq_reset_data *priv = to_zynq_reset_data(rcdev); 39 40 int bank = id / BITS_PER_LONG; 41 int offset = id % BITS_PER_LONG; 42 43 pr_debug("%s: %s reset bank %u offset %u\n", KBUILD_MODNAME, __func__, 44 bank, offset); 45 46 return regmap_update_bits(priv->slcr, 47 priv->offset + (bank * 4), 48 BIT(offset), 49 BIT(offset)); 50 } 51 52 static int zynq_reset_deassert(struct reset_controller_dev *rcdev, 53 unsigned long id) 54 { 55 struct zynq_reset_data *priv = to_zynq_reset_data(rcdev); 56 57 int bank = id / BITS_PER_LONG; 58 int offset = id % BITS_PER_LONG; 59 60 pr_debug("%s: %s reset bank %u offset %u\n", KBUILD_MODNAME, __func__, 61 bank, offset); 62 63 return regmap_update_bits(priv->slcr, 64 priv->offset + (bank * 4), 65 BIT(offset), 66 ~BIT(offset)); 67 } 68 69 static int zynq_reset_status(struct reset_controller_dev *rcdev, 70 unsigned long id) 71 { 72 struct zynq_reset_data *priv = to_zynq_reset_data(rcdev); 73 74 int bank = id / BITS_PER_LONG; 75 int offset = id % BITS_PER_LONG; 76 int ret; 77 u32 reg; 78 79 pr_debug("%s: %s reset bank %u offset %u\n", KBUILD_MODNAME, __func__, 80 bank, offset); 81 82 ret = regmap_read(priv->slcr, priv->offset + (bank * 4), ®); 83 if (ret) 84 return ret; 85 86 return !!(reg & BIT(offset)); 87 } 88 89 static const struct reset_control_ops zynq_reset_ops = { 90 .assert = zynq_reset_assert, 91 .deassert = zynq_reset_deassert, 92 .status = zynq_reset_status, 93 }; 94 95 static int zynq_reset_probe(struct platform_device *pdev) 96 { 97 struct resource *res; 98 struct zynq_reset_data *priv; 99 100 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 101 if (!priv) 102 return -ENOMEM; 103 platform_set_drvdata(pdev, priv); 104 105 priv->slcr = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, 106 "syscon"); 107 if (IS_ERR(priv->slcr)) { 108 dev_err(&pdev->dev, "unable to get zynq-slcr regmap"); 109 return PTR_ERR(priv->slcr); 110 } 111 112 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 113 if (!res) { 114 dev_err(&pdev->dev, "missing IO resource\n"); 115 return -ENODEV; 116 } 117 118 priv->offset = res->start; 119 120 priv->rcdev.owner = THIS_MODULE; 121 priv->rcdev.nr_resets = resource_size(res) / 4 * BITS_PER_LONG; 122 priv->rcdev.ops = &zynq_reset_ops; 123 priv->rcdev.of_node = pdev->dev.of_node; 124 125 return reset_controller_register(&priv->rcdev); 126 } 127 128 static int zynq_reset_remove(struct platform_device *pdev) 129 { 130 struct zynq_reset_data *priv = platform_get_drvdata(pdev); 131 132 reset_controller_unregister(&priv->rcdev); 133 134 return 0; 135 } 136 137 static const struct of_device_id zynq_reset_dt_ids[] = { 138 { .compatible = "xlnx,zynq-reset", }, 139 { /* sentinel */ }, 140 }; 141 142 static struct platform_driver zynq_reset_driver = { 143 .probe = zynq_reset_probe, 144 .remove = zynq_reset_remove, 145 .driver = { 146 .name = KBUILD_MODNAME, 147 .of_match_table = zynq_reset_dt_ids, 148 }, 149 }; 150 module_platform_driver(zynq_reset_driver); 151 152 MODULE_LICENSE("GPL v2"); 153 MODULE_AUTHOR("Moritz Fischer <moritz.fischer@ettus.com>"); 154 MODULE_DESCRIPTION("Zynq Reset Controller Driver"); 155