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1 | // SPDX-License-Identifier: GPL-2.0-only | |
2 | /* | |
3 | * System Control and Power Interface (SCPI) Protocol based clock driver | |
4 | * | |
5 | * Copyright (C) 2015 ARM Ltd. | |
6 | */ | |
7 | ||
8 | #include <linux/clk-provider.h> | |
9 | #include <linux/device.h> | |
10 | #include <linux/err.h> | |
11 | #include <linux/of.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/of_platform.h> | |
14 | #include <linux/platform_device.h> | |
15 | #include <linux/scpi_protocol.h> | |
16 | ||
17 | struct scpi_clk { | |
18 | u32 id; | |
19 | struct clk_hw hw; | |
20 | struct scpi_dvfs_info *info; | |
21 | struct scpi_ops *scpi_ops; | |
22 | }; | |
23 | ||
24 | #define to_scpi_clk(clk) container_of(clk, struct scpi_clk, hw) | |
25 | ||
26 | static struct platform_device *cpufreq_dev; | |
27 | ||
28 | static unsigned long scpi_clk_recalc_rate(struct clk_hw *hw, | |
29 | unsigned long parent_rate) | |
30 | { | |
31 | struct scpi_clk *clk = to_scpi_clk(hw); | |
32 | ||
33 | return clk->scpi_ops->clk_get_val(clk->id); | |
34 | } | |
35 | ||
36 | static long scpi_clk_round_rate(struct clk_hw *hw, unsigned long rate, | |
37 | unsigned long *parent_rate) | |
38 | { | |
39 | /* | |
40 | * We can't figure out what rate it will be, so just return the | |
41 | * rate back to the caller. scpi_clk_recalc_rate() will be called | |
42 | * after the rate is set and we'll know what rate the clock is | |
43 | * running at then. | |
44 | */ | |
45 | return rate; | |
46 | } | |
47 | ||
48 | static int scpi_clk_set_rate(struct clk_hw *hw, unsigned long rate, | |
49 | unsigned long parent_rate) | |
50 | { | |
51 | struct scpi_clk *clk = to_scpi_clk(hw); | |
52 | ||
53 | return clk->scpi_ops->clk_set_val(clk->id, rate); | |
54 | } | |
55 | ||
56 | static const struct clk_ops scpi_clk_ops = { | |
57 | .recalc_rate = scpi_clk_recalc_rate, | |
58 | .round_rate = scpi_clk_round_rate, | |
59 | .set_rate = scpi_clk_set_rate, | |
60 | }; | |
61 | ||
62 | /* find closest match to given frequency in OPP table */ | |
63 | static long __scpi_dvfs_round_rate(struct scpi_clk *clk, unsigned long rate) | |
64 | { | |
65 | int idx; | |
66 | unsigned long fmin = 0, fmax = ~0, ftmp; | |
67 | const struct scpi_opp *opp = clk->info->opps; | |
68 | ||
69 | for (idx = 0; idx < clk->info->count; idx++, opp++) { | |
70 | ftmp = opp->freq; | |
71 | if (ftmp >= rate) { | |
72 | if (ftmp <= fmax) | |
73 | fmax = ftmp; | |
74 | break; | |
75 | } else if (ftmp >= fmin) { | |
76 | fmin = ftmp; | |
77 | } | |
78 | } | |
79 | return fmax != ~0 ? fmax : fmin; | |
80 | } | |
81 | ||
82 | static unsigned long scpi_dvfs_recalc_rate(struct clk_hw *hw, | |
83 | unsigned long parent_rate) | |
84 | { | |
85 | struct scpi_clk *clk = to_scpi_clk(hw); | |
86 | int idx = clk->scpi_ops->dvfs_get_idx(clk->id); | |
87 | const struct scpi_opp *opp; | |
88 | ||
89 | if (idx < 0) | |
90 | return 0; | |
91 | ||
92 | opp = clk->info->opps + idx; | |
93 | return opp->freq; | |
94 | } | |
95 | ||
96 | static long scpi_dvfs_round_rate(struct clk_hw *hw, unsigned long rate, | |
97 | unsigned long *parent_rate) | |
98 | { | |
99 | struct scpi_clk *clk = to_scpi_clk(hw); | |
100 | ||
101 | return __scpi_dvfs_round_rate(clk, rate); | |
102 | } | |
103 | ||
104 | static int __scpi_find_dvfs_index(struct scpi_clk *clk, unsigned long rate) | |
105 | { | |
106 | int idx, max_opp = clk->info->count; | |
107 | const struct scpi_opp *opp = clk->info->opps; | |
108 | ||
109 | for (idx = 0; idx < max_opp; idx++, opp++) | |
110 | if (opp->freq == rate) | |
111 | return idx; | |
112 | return -EINVAL; | |
113 | } | |
114 | ||
115 | static int scpi_dvfs_set_rate(struct clk_hw *hw, unsigned long rate, | |
116 | unsigned long parent_rate) | |
117 | { | |
118 | struct scpi_clk *clk = to_scpi_clk(hw); | |
119 | int ret = __scpi_find_dvfs_index(clk, rate); | |
120 | ||
121 | if (ret < 0) | |
122 | return ret; | |
123 | return clk->scpi_ops->dvfs_set_idx(clk->id, (u8)ret); | |
124 | } | |
125 | ||
126 | static const struct clk_ops scpi_dvfs_ops = { | |
127 | .recalc_rate = scpi_dvfs_recalc_rate, | |
128 | .round_rate = scpi_dvfs_round_rate, | |
129 | .set_rate = scpi_dvfs_set_rate, | |
130 | }; | |
131 | ||
132 | static const struct of_device_id scpi_clk_match[] __maybe_unused = { | |
133 | { .compatible = "arm,scpi-dvfs-clocks", .data = &scpi_dvfs_ops, }, | |
134 | { .compatible = "arm,scpi-variable-clocks", .data = &scpi_clk_ops, }, | |
135 | {} | |
136 | }; | |
137 | ||
138 | static int | |
139 | scpi_clk_ops_init(struct device *dev, const struct of_device_id *match, | |
140 | struct scpi_clk *sclk, const char *name) | |
141 | { | |
142 | struct clk_init_data init; | |
143 | unsigned long min = 0, max = 0; | |
144 | int ret; | |
145 | ||
146 | init.name = name; | |
147 | init.flags = 0; | |
148 | init.num_parents = 0; | |
149 | init.ops = match->data; | |
150 | sclk->hw.init = &init; | |
151 | sclk->scpi_ops = get_scpi_ops(); | |
152 | ||
153 | if (init.ops == &scpi_dvfs_ops) { | |
154 | sclk->info = sclk->scpi_ops->dvfs_get_info(sclk->id); | |
155 | if (IS_ERR(sclk->info)) | |
156 | return PTR_ERR(sclk->info); | |
157 | } else if (init.ops == &scpi_clk_ops) { | |
158 | if (sclk->scpi_ops->clk_get_range(sclk->id, &min, &max) || !max) | |
159 | return -EINVAL; | |
160 | } else { | |
161 | return -EINVAL; | |
162 | } | |
163 | ||
164 | ret = devm_clk_hw_register(dev, &sclk->hw); | |
165 | if (!ret && max) | |
166 | clk_hw_set_rate_range(&sclk->hw, min, max); | |
167 | return ret; | |
168 | } | |
169 | ||
170 | struct scpi_clk_data { | |
171 | struct scpi_clk **clk; | |
172 | unsigned int clk_num; | |
173 | }; | |
174 | ||
175 | static struct clk_hw * | |
176 | scpi_of_clk_src_get(struct of_phandle_args *clkspec, void *data) | |
177 | { | |
178 | struct scpi_clk *sclk; | |
179 | struct scpi_clk_data *clk_data = data; | |
180 | unsigned int idx = clkspec->args[0], count; | |
181 | ||
182 | for (count = 0; count < clk_data->clk_num; count++) { | |
183 | sclk = clk_data->clk[count]; | |
184 | if (idx == sclk->id) | |
185 | return &sclk->hw; | |
186 | } | |
187 | ||
188 | return ERR_PTR(-EINVAL); | |
189 | } | |
190 | ||
191 | static int scpi_clk_add(struct device *dev, struct device_node *np, | |
192 | const struct of_device_id *match) | |
193 | { | |
194 | int idx, count, err; | |
195 | struct scpi_clk_data *clk_data; | |
196 | ||
197 | count = of_property_count_strings(np, "clock-output-names"); | |
198 | if (count < 0) { | |
199 | dev_err(dev, "%pOFn: invalid clock output count\n", np); | |
200 | return -EINVAL; | |
201 | } | |
202 | ||
203 | clk_data = devm_kmalloc(dev, sizeof(*clk_data), GFP_KERNEL); | |
204 | if (!clk_data) | |
205 | return -ENOMEM; | |
206 | ||
207 | clk_data->clk_num = count; | |
208 | clk_data->clk = devm_kcalloc(dev, count, sizeof(*clk_data->clk), | |
209 | GFP_KERNEL); | |
210 | if (!clk_data->clk) | |
211 | return -ENOMEM; | |
212 | ||
213 | for (idx = 0; idx < count; idx++) { | |
214 | struct scpi_clk *sclk; | |
215 | const char *name; | |
216 | u32 val; | |
217 | ||
218 | sclk = devm_kzalloc(dev, sizeof(*sclk), GFP_KERNEL); | |
219 | if (!sclk) | |
220 | return -ENOMEM; | |
221 | ||
222 | if (of_property_read_string_index(np, "clock-output-names", | |
223 | idx, &name)) { | |
224 | dev_err(dev, "invalid clock name @ %pOFn\n", np); | |
225 | return -EINVAL; | |
226 | } | |
227 | ||
228 | if (of_property_read_u32_index(np, "clock-indices", | |
229 | idx, &val)) { | |
230 | dev_err(dev, "invalid clock index @ %pOFn\n", np); | |
231 | return -EINVAL; | |
232 | } | |
233 | ||
234 | sclk->id = val; | |
235 | ||
236 | err = scpi_clk_ops_init(dev, match, sclk, name); | |
237 | if (err) { | |
238 | dev_err(dev, "failed to register clock '%s'\n", name); | |
239 | return err; | |
240 | } | |
241 | ||
242 | dev_dbg(dev, "Registered clock '%s'\n", name); | |
243 | clk_data->clk[idx] = sclk; | |
244 | } | |
245 | ||
246 | return of_clk_add_hw_provider(np, scpi_of_clk_src_get, clk_data); | |
247 | } | |
248 | ||
249 | static int scpi_clocks_remove(struct platform_device *pdev) | |
250 | { | |
251 | struct device *dev = &pdev->dev; | |
252 | struct device_node *child, *np = dev->of_node; | |
253 | ||
254 | if (cpufreq_dev) { | |
255 | platform_device_unregister(cpufreq_dev); | |
256 | cpufreq_dev = NULL; | |
257 | } | |
258 | ||
259 | for_each_available_child_of_node(np, child) | |
260 | of_clk_del_provider(np); | |
261 | return 0; | |
262 | } | |
263 | ||
264 | static int scpi_clocks_probe(struct platform_device *pdev) | |
265 | { | |
266 | int ret; | |
267 | struct device *dev = &pdev->dev; | |
268 | struct device_node *child, *np = dev->of_node; | |
269 | const struct of_device_id *match; | |
270 | ||
271 | if (!get_scpi_ops()) | |
272 | return -ENXIO; | |
273 | ||
274 | for_each_available_child_of_node(np, child) { | |
275 | match = of_match_node(scpi_clk_match, child); | |
276 | if (!match) | |
277 | continue; | |
278 | ret = scpi_clk_add(dev, child, match); | |
279 | if (ret) { | |
280 | scpi_clocks_remove(pdev); | |
281 | of_node_put(child); | |
282 | return ret; | |
283 | } | |
284 | ||
285 | if (match->data != &scpi_dvfs_ops) | |
286 | continue; | |
287 | /* Add the virtual cpufreq device if it's DVFS clock provider */ | |
288 | cpufreq_dev = platform_device_register_simple("scpi-cpufreq", | |
289 | -1, NULL, 0); | |
290 | if (IS_ERR(cpufreq_dev)) | |
291 | pr_warn("unable to register cpufreq device"); | |
292 | } | |
293 | return 0; | |
294 | } | |
295 | ||
296 | static const struct of_device_id scpi_clocks_ids[] = { | |
297 | { .compatible = "arm,scpi-clocks", }, | |
298 | {} | |
299 | }; | |
300 | MODULE_DEVICE_TABLE(of, scpi_clocks_ids); | |
301 | ||
302 | static struct platform_driver scpi_clocks_driver = { | |
303 | .driver = { | |
304 | .name = "scpi_clocks", | |
305 | .of_match_table = scpi_clocks_ids, | |
306 | }, | |
307 | .probe = scpi_clocks_probe, | |
308 | .remove = scpi_clocks_remove, | |
309 | }; | |
310 | module_platform_driver(scpi_clocks_driver); | |
311 | ||
312 | MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); | |
313 | MODULE_DESCRIPTION("ARM SCPI clock driver"); | |
314 | MODULE_LICENSE("GPL v2"); |