1 /* 2 * Copyright Intel Corporation (C) 2017. All Rights Reserved 3 * 4 * This program is free software; you can redistribute it and/or modify it 5 * under the terms and conditions of the GNU General Public License, 6 * version 2, as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 11 * more details. 12 * 13 * You should have received a copy of the GNU General Public License along with 14 * this program. If not, see <http://www.gnu.org/licenses/>. 15 * 16 * Reset driver for Altera Arria10 MAX5 System Resource Chip 17 * 18 * Adapted from reset-socfpga.c 19 */ 20 21 #include <linux/err.h> 22 #include <linux/mfd/altera-a10sr.h> 23 #include <linux/module.h> 24 #include <linux/of.h> 25 #include <linux/platform_device.h> 26 #include <linux/reset-controller.h> 27 28 #include <dt-bindings/reset/altr,rst-mgr-a10sr.h> 29 30 struct a10sr_reset { 31 struct reset_controller_dev rcdev; 32 struct regmap *regmap; 33 }; 34 35 static inline struct a10sr_reset *to_a10sr_rst(struct reset_controller_dev *rc) 36 { 37 return container_of(rc, struct a10sr_reset, rcdev); 38 } 39 40 static inline int a10sr_reset_shift(unsigned long id) 41 { 42 switch (id) { 43 case A10SR_RESET_ENET_HPS: 44 return 1; 45 case A10SR_RESET_PCIE: 46 case A10SR_RESET_FILE: 47 case A10SR_RESET_BQSPI: 48 case A10SR_RESET_USB: 49 return id + 11; 50 default: 51 return -EINVAL; 52 } 53 } 54 55 static int a10sr_reset_update(struct reset_controller_dev *rcdev, 56 unsigned long id, bool assert) 57 { 58 struct a10sr_reset *a10r = to_a10sr_rst(rcdev); 59 int offset = a10sr_reset_shift(id); 60 u8 mask = ALTR_A10SR_REG_BIT_MASK(offset); 61 int index = ALTR_A10SR_HPS_RST_REG + ALTR_A10SR_REG_OFFSET(offset); 62 63 return regmap_update_bits(a10r->regmap, index, mask, assert ? 0 : mask); 64 } 65 66 static int a10sr_reset_assert(struct reset_controller_dev *rcdev, 67 unsigned long id) 68 { 69 return a10sr_reset_update(rcdev, id, true); 70 } 71 72 static int a10sr_reset_deassert(struct reset_controller_dev *rcdev, 73 unsigned long id) 74 { 75 return a10sr_reset_update(rcdev, id, false); 76 } 77 78 static int a10sr_reset_status(struct reset_controller_dev *rcdev, 79 unsigned long id) 80 { 81 int ret; 82 struct a10sr_reset *a10r = to_a10sr_rst(rcdev); 83 int offset = a10sr_reset_shift(id); 84 u8 mask = ALTR_A10SR_REG_BIT_MASK(offset); 85 int index = ALTR_A10SR_HPS_RST_REG + ALTR_A10SR_REG_OFFSET(offset); 86 unsigned int value; 87 88 ret = regmap_read(a10r->regmap, index, &value); 89 if (ret < 0) 90 return ret; 91 92 return !!(value & mask); 93 } 94 95 static const struct reset_control_ops a10sr_reset_ops = { 96 .assert = a10sr_reset_assert, 97 .deassert = a10sr_reset_deassert, 98 .status = a10sr_reset_status, 99 }; 100 101 static int a10sr_reset_probe(struct platform_device *pdev) 102 { 103 struct altr_a10sr *a10sr = dev_get_drvdata(pdev->dev.parent); 104 struct a10sr_reset *a10r; 105 106 a10r = devm_kzalloc(&pdev->dev, sizeof(struct a10sr_reset), 107 GFP_KERNEL); 108 if (!a10r) 109 return -ENOMEM; 110 111 a10r->rcdev.owner = THIS_MODULE; 112 a10r->rcdev.nr_resets = A10SR_RESET_NUM; 113 a10r->rcdev.ops = &a10sr_reset_ops; 114 a10r->rcdev.of_node = pdev->dev.of_node; 115 a10r->regmap = a10sr->regmap; 116 117 platform_set_drvdata(pdev, a10r); 118 119 return devm_reset_controller_register(&pdev->dev, &a10r->rcdev); 120 } 121 122 static const struct of_device_id a10sr_reset_of_match[] = { 123 { .compatible = "altr,a10sr-reset" }, 124 { }, 125 }; 126 MODULE_DEVICE_TABLE(of, a10sr_reset_of_match); 127 128 static struct platform_driver a10sr_reset_driver = { 129 .probe = a10sr_reset_probe, 130 .driver = { 131 .name = "altr_a10sr_reset", 132 }, 133 }; 134 module_platform_driver(a10sr_reset_driver); 135 136 MODULE_AUTHOR("Thor Thayer <thor.thayer@linux.intel.com>"); 137 MODULE_DESCRIPTION("Altera Arria10 System Resource Reset Controller Driver"); 138 MODULE_LICENSE("GPL v2"); 139