1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * TI SYSCON regmap reset driver |
4 | * |
5 | * Copyright (C) 2015-2016 Texas Instruments Incorporated - https://www.ti.com/ |
6 | * Andrew F. Davis <afd@ti.com> |
7 | * Suman Anna <afd@ti.com> |
8 | */ |
9 | |
10 | #include <linux/mfd/syscon.h> |
11 | #include <linux/module.h> |
12 | #include <linux/of.h> |
13 | #include <linux/platform_device.h> |
14 | #include <linux/regmap.h> |
15 | #include <linux/reset-controller.h> |
16 | |
17 | #include <dt-bindings/reset/ti-syscon.h> |
18 | |
19 | /** |
20 | * struct ti_syscon_reset_control - reset control structure |
21 | * @assert_offset: reset assert control register offset from syscon base |
22 | * @assert_bit: reset assert bit in the reset assert control register |
23 | * @deassert_offset: reset deassert control register offset from syscon base |
24 | * @deassert_bit: reset deassert bit in the reset deassert control register |
25 | * @status_offset: reset status register offset from syscon base |
26 | * @status_bit: reset status bit in the reset status register |
27 | * @flags: reset flag indicating how the (de)assert and status are handled |
28 | */ |
29 | struct ti_syscon_reset_control { |
30 | unsigned int assert_offset; |
31 | unsigned int assert_bit; |
32 | unsigned int deassert_offset; |
33 | unsigned int deassert_bit; |
34 | unsigned int status_offset; |
35 | unsigned int status_bit; |
36 | u32 flags; |
37 | }; |
38 | |
39 | /** |
40 | * struct ti_syscon_reset_data - reset controller information structure |
41 | * @rcdev: reset controller entity |
42 | * @regmap: regmap handle containing the memory-mapped reset registers |
43 | * @controls: array of reset controls |
44 | * @nr_controls: number of controls in control array |
45 | */ |
46 | struct ti_syscon_reset_data { |
47 | struct reset_controller_dev rcdev; |
48 | struct regmap *regmap; |
49 | struct ti_syscon_reset_control *controls; |
50 | unsigned int nr_controls; |
51 | }; |
52 | |
53 | #define to_ti_syscon_reset_data(_rcdev) \ |
54 | container_of(_rcdev, struct ti_syscon_reset_data, rcdev) |
55 | |
56 | /** |
57 | * ti_syscon_reset_assert() - assert device reset |
58 | * @rcdev: reset controller entity |
59 | * @id: ID of the reset to be asserted |
60 | * |
61 | * This function implements the reset driver op to assert a device's reset. |
62 | * This asserts the reset in a manner prescribed by the reset flags. |
63 | * |
64 | * Return: 0 for successful request, else a corresponding error value |
65 | */ |
66 | static int ti_syscon_reset_assert(struct reset_controller_dev *rcdev, |
67 | unsigned long id) |
68 | { |
69 | struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev); |
70 | struct ti_syscon_reset_control *control; |
71 | unsigned int mask, value; |
72 | |
73 | if (id >= data->nr_controls) |
74 | return -EINVAL; |
75 | |
76 | control = &data->controls[id]; |
77 | |
78 | if (control->flags & ASSERT_NONE) |
79 | return -ENOTSUPP; /* assert not supported for this reset */ |
80 | |
81 | mask = BIT(control->assert_bit); |
82 | value = (control->flags & ASSERT_SET) ? mask : 0x0; |
83 | |
84 | return regmap_write_bits(map: data->regmap, reg: control->assert_offset, mask, val: value); |
85 | } |
86 | |
87 | /** |
88 | * ti_syscon_reset_deassert() - deassert device reset |
89 | * @rcdev: reset controller entity |
90 | * @id: ID of reset to be deasserted |
91 | * |
92 | * This function implements the reset driver op to deassert a device's reset. |
93 | * This deasserts the reset in a manner prescribed by the reset flags. |
94 | * |
95 | * Return: 0 for successful request, else a corresponding error value |
96 | */ |
97 | static int ti_syscon_reset_deassert(struct reset_controller_dev *rcdev, |
98 | unsigned long id) |
99 | { |
100 | struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev); |
101 | struct ti_syscon_reset_control *control; |
102 | unsigned int mask, value; |
103 | |
104 | if (id >= data->nr_controls) |
105 | return -EINVAL; |
106 | |
107 | control = &data->controls[id]; |
108 | |
109 | if (control->flags & DEASSERT_NONE) |
110 | return -ENOTSUPP; /* deassert not supported for this reset */ |
111 | |
112 | mask = BIT(control->deassert_bit); |
113 | value = (control->flags & DEASSERT_SET) ? mask : 0x0; |
114 | |
115 | return regmap_write_bits(map: data->regmap, reg: control->deassert_offset, mask, val: value); |
116 | } |
117 | |
118 | /** |
119 | * ti_syscon_reset_status() - check device reset status |
120 | * @rcdev: reset controller entity |
121 | * @id: ID of the reset for which the status is being requested |
122 | * |
123 | * This function implements the reset driver op to return the status of a |
124 | * device's reset. |
125 | * |
126 | * Return: 0 if reset is deasserted, true if reset is asserted, else a |
127 | * corresponding error value |
128 | */ |
129 | static int ti_syscon_reset_status(struct reset_controller_dev *rcdev, |
130 | unsigned long id) |
131 | { |
132 | struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev); |
133 | struct ti_syscon_reset_control *control; |
134 | unsigned int reset_state; |
135 | int ret; |
136 | |
137 | if (id >= data->nr_controls) |
138 | return -EINVAL; |
139 | |
140 | control = &data->controls[id]; |
141 | |
142 | if (control->flags & STATUS_NONE) |
143 | return -ENOTSUPP; /* status not supported for this reset */ |
144 | |
145 | ret = regmap_read(map: data->regmap, reg: control->status_offset, val: &reset_state); |
146 | if (ret) |
147 | return ret; |
148 | |
149 | return !(reset_state & BIT(control->status_bit)) == |
150 | !(control->flags & STATUS_SET); |
151 | } |
152 | |
153 | static const struct reset_control_ops ti_syscon_reset_ops = { |
154 | .assert = ti_syscon_reset_assert, |
155 | .deassert = ti_syscon_reset_deassert, |
156 | .status = ti_syscon_reset_status, |
157 | }; |
158 | |
159 | static int ti_syscon_reset_probe(struct platform_device *pdev) |
160 | { |
161 | struct device *dev = &pdev->dev; |
162 | struct device_node *np = dev->of_node; |
163 | struct ti_syscon_reset_data *data; |
164 | struct regmap *regmap; |
165 | const __be32 *list; |
166 | struct ti_syscon_reset_control *controls; |
167 | int size, nr_controls, i; |
168 | |
169 | data = devm_kzalloc(dev, size: sizeof(*data), GFP_KERNEL); |
170 | if (!data) |
171 | return -ENOMEM; |
172 | |
173 | regmap = syscon_node_to_regmap(np: np->parent); |
174 | if (IS_ERR(ptr: regmap)) |
175 | return PTR_ERR(ptr: regmap); |
176 | |
177 | list = of_get_property(node: np, name: "ti,reset-bits" , lenp: &size); |
178 | if (!list || (size / sizeof(*list)) % 7 != 0) { |
179 | dev_err(dev, "invalid DT reset description\n" ); |
180 | return -EINVAL; |
181 | } |
182 | |
183 | nr_controls = (size / sizeof(*list)) / 7; |
184 | controls = devm_kcalloc(dev, n: nr_controls, size: sizeof(*controls), |
185 | GFP_KERNEL); |
186 | if (!controls) |
187 | return -ENOMEM; |
188 | |
189 | for (i = 0; i < nr_controls; i++) { |
190 | controls[i].assert_offset = be32_to_cpup(p: list++); |
191 | controls[i].assert_bit = be32_to_cpup(p: list++); |
192 | controls[i].deassert_offset = be32_to_cpup(p: list++); |
193 | controls[i].deassert_bit = be32_to_cpup(p: list++); |
194 | controls[i].status_offset = be32_to_cpup(p: list++); |
195 | controls[i].status_bit = be32_to_cpup(p: list++); |
196 | controls[i].flags = be32_to_cpup(p: list++); |
197 | } |
198 | |
199 | data->rcdev.ops = &ti_syscon_reset_ops; |
200 | data->rcdev.owner = THIS_MODULE; |
201 | data->rcdev.of_node = np; |
202 | data->rcdev.nr_resets = nr_controls; |
203 | data->regmap = regmap; |
204 | data->controls = controls; |
205 | data->nr_controls = nr_controls; |
206 | |
207 | return devm_reset_controller_register(dev, rcdev: &data->rcdev); |
208 | } |
209 | |
210 | static const struct of_device_id ti_syscon_reset_of_match[] = { |
211 | { .compatible = "ti,syscon-reset" , }, |
212 | { /* sentinel */ }, |
213 | }; |
214 | MODULE_DEVICE_TABLE(of, ti_syscon_reset_of_match); |
215 | |
216 | static struct platform_driver ti_syscon_reset_driver = { |
217 | .probe = ti_syscon_reset_probe, |
218 | .driver = { |
219 | .name = "ti-syscon-reset" , |
220 | .of_match_table = ti_syscon_reset_of_match, |
221 | }, |
222 | }; |
223 | module_platform_driver(ti_syscon_reset_driver); |
224 | |
225 | MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>" ); |
226 | MODULE_AUTHOR("Suman Anna <s-anna@ti.com>" ); |
227 | MODULE_DESCRIPTION("TI SYSCON Regmap Reset Driver" ); |
228 | MODULE_LICENSE("GPL v2" ); |
229 | |