1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Pistachio SoC Reset Controller driver
4 *
5 * Copyright (C) 2015 Imagination Technologies Ltd.
6 *
7 * Author: Damien Horsley <Damien.Horsley@imgtec.com>
8 */
9
10#include <linux/init.h>
11#include <linux/of.h>
12#include <linux/platform_device.h>
13#include <linux/regmap.h>
14#include <linux/reset-controller.h>
15#include <linux/slab.h>
16#include <linux/mfd/syscon.h>
17
18#include <dt-bindings/reset/pistachio-resets.h>
19
20#define	PISTACHIO_SOFT_RESET		0
21
22struct pistachio_reset_data {
23	struct reset_controller_dev	rcdev;
24	struct regmap			*periph_regs;
25};
26
27static inline int pistachio_reset_shift(unsigned long id)
28{
29	switch (id) {
30	case PISTACHIO_RESET_I2C0:
31	case PISTACHIO_RESET_I2C1:
32	case PISTACHIO_RESET_I2C2:
33	case PISTACHIO_RESET_I2C3:
34	case PISTACHIO_RESET_I2S_IN:
35	case PISTACHIO_RESET_PRL_OUT:
36	case PISTACHIO_RESET_SPDIF_OUT:
37	case PISTACHIO_RESET_SPI:
38	case PISTACHIO_RESET_PWM_PDM:
39	case PISTACHIO_RESET_UART0:
40	case PISTACHIO_RESET_UART1:
41	case PISTACHIO_RESET_QSPI:
42	case PISTACHIO_RESET_MDC:
43	case PISTACHIO_RESET_SDHOST:
44	case PISTACHIO_RESET_ETHERNET:
45	case PISTACHIO_RESET_IR:
46	case PISTACHIO_RESET_HASH:
47	case PISTACHIO_RESET_TIMER:
48		return id;
49	case PISTACHIO_RESET_I2S_OUT:
50	case PISTACHIO_RESET_SPDIF_IN:
51	case PISTACHIO_RESET_EVT:
52		return id + 6;
53	case PISTACHIO_RESET_USB_H:
54	case PISTACHIO_RESET_USB_PR:
55	case PISTACHIO_RESET_USB_PHY_PR:
56	case PISTACHIO_RESET_USB_PHY_PON:
57		return id + 7;
58	default:
59		return -EINVAL;
60	}
61}
62
63static int pistachio_reset_assert(struct reset_controller_dev *rcdev,
64				  unsigned long id)
65{
66	struct pistachio_reset_data *rd;
67	u32 mask;
68	int shift;
69
70	rd = container_of(rcdev, struct pistachio_reset_data, rcdev);
71	shift = pistachio_reset_shift(id);
72	if (shift < 0)
73		return shift;
74	mask = BIT(shift);
75
76	return regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET,
77				  mask, mask);
78}
79
80static int pistachio_reset_deassert(struct reset_controller_dev *rcdev,
81				    unsigned long id)
82{
83	struct pistachio_reset_data *rd;
84	u32 mask;
85	int shift;
86
87	rd = container_of(rcdev, struct pistachio_reset_data, rcdev);
88	shift = pistachio_reset_shift(id);
89	if (shift < 0)
90		return shift;
91	mask = BIT(shift);
92
93	return regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET,
94				  mask, 0);
95}
96
97static const struct reset_control_ops pistachio_reset_ops = {
98	.assert		= pistachio_reset_assert,
99	.deassert	= pistachio_reset_deassert,
100};
101
102static int pistachio_reset_probe(struct platform_device *pdev)
103{
104	struct pistachio_reset_data *rd;
105	struct device *dev = &pdev->dev;
106	struct device_node *np = pdev->dev.of_node;
107
108	rd = devm_kzalloc(dev, sizeof(*rd), GFP_KERNEL);
109	if (!rd)
110		return -ENOMEM;
111
112	rd->periph_regs = syscon_node_to_regmap(np->parent);
113	if (IS_ERR(rd->periph_regs))
114		return PTR_ERR(rd->periph_regs);
115
116	rd->rcdev.owner = THIS_MODULE;
117	rd->rcdev.nr_resets = PISTACHIO_RESET_MAX + 1;
118	rd->rcdev.ops = &pistachio_reset_ops;
119	rd->rcdev.of_node = np;
120
121	return devm_reset_controller_register(dev, &rd->rcdev);
122}
123
124static const struct of_device_id pistachio_reset_dt_ids[] = {
125	 { .compatible = "img,pistachio-reset", },
126	 { /* sentinel */ },
127};
128
129static struct platform_driver pistachio_reset_driver = {
130	.probe	= pistachio_reset_probe,
131	.driver = {
132		.name		= "pistachio-reset",
133		.of_match_table	= pistachio_reset_dt_ids,
134	},
135};
136builtin_platform_driver(pistachio_reset_driver);
137