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(map: rd->periph_regs, PISTACHIO_SOFT_RESET,
77 mask, val: 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(map: rd->periph_regs, PISTACHIO_SOFT_RESET,
94 mask, val: 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, size: sizeof(*rd), GFP_KERNEL);
109 if (!rd)
110 return -ENOMEM;
111
112 rd->periph_regs = syscon_node_to_regmap(np: np->parent);
113 if (IS_ERR(ptr: rd->periph_regs))
114 return PTR_ERR(ptr: 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, rcdev: &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

source code of linux/drivers/reset/reset-pistachio.c