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
 30struct a10sr_reset {
 31	struct reset_controller_dev     rcdev;
 32	struct regmap *regmap;
 33};
 34
 35static inline struct a10sr_reset *to_a10sr_rst(struct reset_controller_dev *rc)
 36{
 37	return container_of(rc, struct a10sr_reset, rcdev);
 38}
 39
 40static 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
 55static 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
 66static int a10sr_reset_assert(struct reset_controller_dev *rcdev,
 67			      unsigned long id)
 68{
 69	return a10sr_reset_update(rcdev, id, true);
 70}
 71
 72static int a10sr_reset_deassert(struct reset_controller_dev *rcdev,
 73				unsigned long id)
 74{
 75	return a10sr_reset_update(rcdev, id, false);
 76}
 77
 78static 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
 95static 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
101static 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
122static const struct of_device_id a10sr_reset_of_match[] = {
123	{ .compatible = "altr,a10sr-reset" },
124	{ },
125};
126MODULE_DEVICE_TABLE(of, a10sr_reset_of_match);
127
128static struct platform_driver a10sr_reset_driver = {
129	.probe	= a10sr_reset_probe,
130	.driver = {
131		.name		= "altr_a10sr_reset",
132	},
133};
134module_platform_driver(a10sr_reset_driver);
135
136MODULE_AUTHOR("Thor Thayer <thor.thayer@linux.intel.com>");
137MODULE_DESCRIPTION("Altera Arria10 System Resource Reset Controller Driver");
138MODULE_LICENSE("GPL v2");