1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Toshiba Visconti ARM SoC reset controller
4  *
5  * Copyright (c) 2021 TOSHIBA CORPORATION
6  * Copyright (c) 2021 Toshiba Electronic Devices & Storage Corporation
7  *
8  * Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
9  */
10 #include <linux/delay.h>
11 #include <linux/device.h>
12 #include <linux/mfd/syscon.h>
13 #include <linux/regmap.h>
14 #include <linux/slab.h>
15 
16 #include "reset.h"
17 
to_visconti_reset(struct reset_controller_dev * rcdev)18 static inline struct visconti_reset *to_visconti_reset(struct reset_controller_dev *rcdev)
19 {
20 	return container_of(rcdev, struct visconti_reset, rcdev);
21 }
22 
visconti_reset_assert(struct reset_controller_dev * rcdev,unsigned long id)23 static int visconti_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
24 {
25 	struct visconti_reset *reset = to_visconti_reset(rcdev);
26 	const struct visconti_reset_data *data = &reset->resets[id];
27 	u32 rst = BIT(data->rs_idx);
28 	unsigned long flags;
29 	int ret;
30 
31 	spin_lock_irqsave(reset->lock, flags);
32 	ret = regmap_update_bits(reset->regmap, data->rson_offset, rst, rst);
33 	spin_unlock_irqrestore(reset->lock, flags);
34 
35 	return ret;
36 }
37 
visconti_reset_deassert(struct reset_controller_dev * rcdev,unsigned long id)38 static int visconti_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
39 {
40 	struct visconti_reset *reset = to_visconti_reset(rcdev);
41 	const struct visconti_reset_data *data = &reset->resets[id];
42 	u32 rst = BIT(data->rs_idx);
43 	unsigned long flags;
44 	int ret;
45 
46 	spin_lock_irqsave(reset->lock, flags);
47 	ret = regmap_update_bits(reset->regmap, data->rsoff_offset, rst, rst);
48 	spin_unlock_irqrestore(reset->lock, flags);
49 
50 	return ret;
51 }
52 
visconti_reset_reset(struct reset_controller_dev * rcdev,unsigned long id)53 static int visconti_reset_reset(struct reset_controller_dev *rcdev, unsigned long id)
54 {
55 	visconti_reset_assert(rcdev, id);
56 	udelay(1);
57 	visconti_reset_deassert(rcdev, id);
58 
59 	return 0;
60 }
61 
visconti_reset_status(struct reset_controller_dev * rcdev,unsigned long id)62 static int visconti_reset_status(struct reset_controller_dev *rcdev, unsigned long id)
63 {
64 	struct visconti_reset *reset = to_visconti_reset(rcdev);
65 	const struct visconti_reset_data *data = &reset->resets[id];
66 	unsigned long flags;
67 	u32 reg;
68 	int ret;
69 
70 	spin_lock_irqsave(reset->lock, flags);
71 	ret = regmap_read(reset->regmap, data->rson_offset, &reg);
72 	spin_unlock_irqrestore(reset->lock, flags);
73 	if (ret)
74 		return ret;
75 
76 	return !(reg & data->rs_idx);
77 }
78 
79 const struct reset_control_ops visconti_reset_ops = {
80 	.assert		= visconti_reset_assert,
81 	.deassert	= visconti_reset_deassert,
82 	.reset		= visconti_reset_reset,
83 	.status		= visconti_reset_status,
84 };
85 
visconti_register_reset_controller(struct device * dev,struct regmap * regmap,const struct visconti_reset_data * resets,unsigned int num_resets,const struct reset_control_ops * reset_ops,spinlock_t * lock)86 int visconti_register_reset_controller(struct device *dev,
87 				       struct regmap *regmap,
88 				       const struct visconti_reset_data *resets,
89 				       unsigned int num_resets,
90 				       const struct reset_control_ops *reset_ops,
91 				       spinlock_t *lock)
92 {
93 	struct visconti_reset *reset;
94 
95 	reset = devm_kzalloc(dev, sizeof(*reset), GFP_KERNEL);
96 	if (!reset)
97 		return -ENOMEM;
98 
99 	reset->regmap = regmap;
100 	reset->resets = resets;
101 	reset->rcdev.ops = reset_ops;
102 	reset->rcdev.nr_resets = num_resets;
103 	reset->rcdev.of_node = dev->of_node;
104 	reset->lock = lock;
105 
106 	return devm_reset_controller_register(dev, &reset->rcdev);
107 }
108