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 
22 struct pistachio_reset_data {
23 	struct reset_controller_dev	rcdev;
24 	struct regmap			*periph_regs;
25 };
26 
27 static 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 
63 static 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 
80 static 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 
97 static const struct reset_control_ops pistachio_reset_ops = {
98 	.assert		= pistachio_reset_assert,
99 	.deassert	= pistachio_reset_deassert,
100 };
101 
102 static 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 
124 static const struct of_device_id pistachio_reset_dt_ids[] = {
125 	 { .compatible = "img,pistachio-reset", },
126 	 { /* sentinel */ },
127 };
128 
129 static 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 };
136 builtin_platform_driver(pistachio_reset_driver);
137