1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 *  Copyright Intel Corporation (C) 2017. All Rights Reserved
  4 *
  5 * Reset driver for Altera Arria10 MAX5 System Resource Chip
  6 *
  7 * Adapted from reset-socfpga.c
  8 */
  9
 10#include <linux/err.h>
 11#include <linux/mfd/altera-a10sr.h>
 12#include <linux/module.h>
 13#include <linux/of.h>
 14#include <linux/platform_device.h>
 15#include <linux/reset-controller.h>
 16
 17#include <dt-bindings/reset/altr,rst-mgr-a10sr.h>
 18
 19struct a10sr_reset {
 20	struct reset_controller_dev     rcdev;
 21	struct regmap *regmap;
 22};
 23
 24static inline struct a10sr_reset *to_a10sr_rst(struct reset_controller_dev *rc)
 25{
 26	return container_of(rc, struct a10sr_reset, rcdev);
 27}
 28
 29static inline int a10sr_reset_shift(unsigned long id)
 30{
 31	switch (id) {
 32	case A10SR_RESET_ENET_HPS:
 33		return 1;
 34	case A10SR_RESET_PCIE:
 35	case A10SR_RESET_FILE:
 36	case A10SR_RESET_BQSPI:
 37	case A10SR_RESET_USB:
 38		return id + 11;
 39	default:
 40		return -EINVAL;
 41	}
 42}
 43
 44static int a10sr_reset_update(struct reset_controller_dev *rcdev,
 45			      unsigned long id, bool assert)
 46{
 47	struct a10sr_reset *a10r = to_a10sr_rst(rcdev);
 48	int offset = a10sr_reset_shift(id);
 49	u8 mask = ALTR_A10SR_REG_BIT_MASK(offset);
 50	int index = ALTR_A10SR_HPS_RST_REG + ALTR_A10SR_REG_OFFSET(offset);
 51
 52	return regmap_update_bits(a10r->regmap, index, mask, assert ? 0 : mask);
 53}
 54
 55static int a10sr_reset_assert(struct reset_controller_dev *rcdev,
 56			      unsigned long id)
 57{
 58	return a10sr_reset_update(rcdev, id, true);
 59}
 60
 61static int a10sr_reset_deassert(struct reset_controller_dev *rcdev,
 62				unsigned long id)
 63{
 64	return a10sr_reset_update(rcdev, id, false);
 65}
 66
 67static int a10sr_reset_status(struct reset_controller_dev *rcdev,
 68			      unsigned long id)
 69{
 70	int ret;
 71	struct a10sr_reset *a10r = to_a10sr_rst(rcdev);
 72	int offset = a10sr_reset_shift(id);
 73	u8 mask = ALTR_A10SR_REG_BIT_MASK(offset);
 74	int index = ALTR_A10SR_HPS_RST_REG + ALTR_A10SR_REG_OFFSET(offset);
 75	unsigned int value;
 76
 77	ret = regmap_read(a10r->regmap, index, &value);
 78	if (ret < 0)
 79		return ret;
 80
 81	return !!(value & mask);
 82}
 83
 84static const struct reset_control_ops a10sr_reset_ops = {
 85	.assert		= a10sr_reset_assert,
 86	.deassert	= a10sr_reset_deassert,
 87	.status		= a10sr_reset_status,
 88};
 89
 90static int a10sr_reset_probe(struct platform_device *pdev)
 91{
 92	struct altr_a10sr *a10sr = dev_get_drvdata(pdev->dev.parent);
 93	struct a10sr_reset *a10r;
 94
 95	a10r = devm_kzalloc(&pdev->dev, sizeof(struct a10sr_reset),
 96			    GFP_KERNEL);
 97	if (!a10r)
 98		return -ENOMEM;
 99
100	a10r->rcdev.owner = THIS_MODULE;
101	a10r->rcdev.nr_resets = A10SR_RESET_NUM;
102	a10r->rcdev.ops = &a10sr_reset_ops;
103	a10r->rcdev.of_node = pdev->dev.of_node;
104	a10r->regmap = a10sr->regmap;
105
106	platform_set_drvdata(pdev, a10r);
107
108	return devm_reset_controller_register(&pdev->dev, &a10r->rcdev);
109}
110
111static const struct of_device_id a10sr_reset_of_match[] = {
112	{ .compatible = "altr,a10sr-reset" },
113	{ },
114};
115MODULE_DEVICE_TABLE(of, a10sr_reset_of_match);
116
117static struct platform_driver a10sr_reset_driver = {
118	.probe	= a10sr_reset_probe,
119	.driver = {
120		.name		= "altr_a10sr_reset",
121		.of_match_table	= a10sr_reset_of_match,
122	},
123};
124module_platform_driver(a10sr_reset_driver);
125
126MODULE_AUTHOR("Thor Thayer <thor.thayer@linux.intel.com>");
127MODULE_DESCRIPTION("Altera Arria10 System Resource Reset Controller Driver");
128MODULE_LICENSE("GPL v2");