1 /*
2  * Pistachio SoC Reset Controller driver
3  *
4  * Copyright (C) 2015 Imagination Technologies Ltd.
5  *
6  * Author: Damien Horsley <Damien.Horsley@imgtec.com>
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms and conditions of the GNU General Public License,
10  * version 2, as published by the Free Software Foundation.
11  */
12 
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/platform_device.h>
16 #include <linux/regmap.h>
17 #include <linux/reset-controller.h>
18 #include <linux/slab.h>
19 #include <linux/mfd/syscon.h>
20 
21 #include <dt-bindings/reset/pistachio-resets.h>
22 
23 #define	PISTACHIO_SOFT_RESET		0
24 
25 struct pistachio_reset_data {
26 	struct reset_controller_dev	rcdev;
27 	struct regmap			*periph_regs;
28 };
29 
30 static inline int pistachio_reset_shift(unsigned long id)
31 {
32 	switch (id) {
33 	case PISTACHIO_RESET_I2C0:
34 	case PISTACHIO_RESET_I2C1:
35 	case PISTACHIO_RESET_I2C2:
36 	case PISTACHIO_RESET_I2C3:
37 	case PISTACHIO_RESET_I2S_IN:
38 	case PISTACHIO_RESET_PRL_OUT:
39 	case PISTACHIO_RESET_SPDIF_OUT:
40 	case PISTACHIO_RESET_SPI:
41 	case PISTACHIO_RESET_PWM_PDM:
42 	case PISTACHIO_RESET_UART0:
43 	case PISTACHIO_RESET_UART1:
44 	case PISTACHIO_RESET_QSPI:
45 	case PISTACHIO_RESET_MDC:
46 	case PISTACHIO_RESET_SDHOST:
47 	case PISTACHIO_RESET_ETHERNET:
48 	case PISTACHIO_RESET_IR:
49 	case PISTACHIO_RESET_HASH:
50 	case PISTACHIO_RESET_TIMER:
51 		return id;
52 	case PISTACHIO_RESET_I2S_OUT:
53 	case PISTACHIO_RESET_SPDIF_IN:
54 	case PISTACHIO_RESET_EVT:
55 		return id + 6;
56 	case PISTACHIO_RESET_USB_H:
57 	case PISTACHIO_RESET_USB_PR:
58 	case PISTACHIO_RESET_USB_PHY_PR:
59 	case PISTACHIO_RESET_USB_PHY_PON:
60 		return id + 7;
61 	default:
62 		return -EINVAL;
63 	}
64 }
65 
66 static int pistachio_reset_assert(struct reset_controller_dev *rcdev,
67 				  unsigned long id)
68 {
69 	struct pistachio_reset_data *rd;
70 	u32 mask;
71 	int shift;
72 
73 	rd = container_of(rcdev, struct pistachio_reset_data, rcdev);
74 	shift = pistachio_reset_shift(id);
75 	if (shift < 0)
76 		return shift;
77 	mask = BIT(shift);
78 
79 	return regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET,
80 				  mask, mask);
81 }
82 
83 static int pistachio_reset_deassert(struct reset_controller_dev *rcdev,
84 				    unsigned long id)
85 {
86 	struct pistachio_reset_data *rd;
87 	u32 mask;
88 	int shift;
89 
90 	rd = container_of(rcdev, struct pistachio_reset_data, rcdev);
91 	shift = pistachio_reset_shift(id);
92 	if (shift < 0)
93 		return shift;
94 	mask = BIT(shift);
95 
96 	return regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET,
97 				  mask, 0);
98 }
99 
100 static const struct reset_control_ops pistachio_reset_ops = {
101 	.assert		= pistachio_reset_assert,
102 	.deassert	= pistachio_reset_deassert,
103 };
104 
105 static int pistachio_reset_probe(struct platform_device *pdev)
106 {
107 	struct pistachio_reset_data *rd;
108 	struct device *dev = &pdev->dev;
109 	struct device_node *np = pdev->dev.of_node;
110 
111 	rd = devm_kzalloc(dev, sizeof(*rd), GFP_KERNEL);
112 	if (!rd)
113 		return -ENOMEM;
114 
115 	rd->periph_regs = syscon_node_to_regmap(np->parent);
116 	if (IS_ERR(rd->periph_regs))
117 		return PTR_ERR(rd->periph_regs);
118 
119 	rd->rcdev.owner = THIS_MODULE;
120 	rd->rcdev.nr_resets = PISTACHIO_RESET_MAX + 1;
121 	rd->rcdev.ops = &pistachio_reset_ops;
122 	rd->rcdev.of_node = np;
123 
124 	return reset_controller_register(&rd->rcdev);
125 }
126 
127 static int pistachio_reset_remove(struct platform_device *pdev)
128 {
129 	struct pistachio_reset_data *data = platform_get_drvdata(pdev);
130 
131 	reset_controller_unregister(&data->rcdev);
132 
133 	return 0;
134 }
135 
136 static const struct of_device_id pistachio_reset_dt_ids[] = {
137 	 { .compatible = "img,pistachio-reset", },
138 	 { /* sentinel */ },
139 };
140 MODULE_DEVICE_TABLE(of, pistachio_reset_dt_ids);
141 
142 static struct platform_driver pistachio_reset_driver = {
143 	.probe	= pistachio_reset_probe,
144 	.remove	= pistachio_reset_remove,
145 	.driver = {
146 		.name		= "pistachio-reset",
147 		.of_match_table	= pistachio_reset_dt_ids,
148 	},
149 };
150 module_platform_driver(pistachio_reset_driver);
151 
152 MODULE_AUTHOR("Damien Horsley <Damien.Horsley@imgtec.com>");
153 MODULE_DESCRIPTION("Pistacho Reset Controller Driver");
154 MODULE_LICENSE("GPL v2");
155