GNU Linux-libre 6.8.9-gnu
[releases.git] / drivers / clk / clk-scpi.c
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/platform_device.h>
14 #include <linux/scpi_protocol.h>
15
16 struct scpi_clk {
17         u32 id;
18         struct clk_hw hw;
19         struct scpi_dvfs_info *info;
20         struct scpi_ops *scpi_ops;
21 };
22
23 #define to_scpi_clk(clk) container_of(clk, struct scpi_clk, hw)
24
25 static struct platform_device *cpufreq_dev;
26
27 static unsigned long scpi_clk_recalc_rate(struct clk_hw *hw,
28                                           unsigned long parent_rate)
29 {
30         struct scpi_clk *clk = to_scpi_clk(hw);
31
32         return clk->scpi_ops->clk_get_val(clk->id);
33 }
34
35 static long scpi_clk_round_rate(struct clk_hw *hw, unsigned long rate,
36                                 unsigned long *parent_rate)
37 {
38         /*
39          * We can't figure out what rate it will be, so just return the
40          * rate back to the caller. scpi_clk_recalc_rate() will be called
41          * after the rate is set and we'll know what rate the clock is
42          * running at then.
43          */
44         return rate;
45 }
46
47 static int scpi_clk_set_rate(struct clk_hw *hw, unsigned long rate,
48                              unsigned long parent_rate)
49 {
50         struct scpi_clk *clk = to_scpi_clk(hw);
51
52         return clk->scpi_ops->clk_set_val(clk->id, rate);
53 }
54
55 static const struct clk_ops scpi_clk_ops = {
56         .recalc_rate = scpi_clk_recalc_rate,
57         .round_rate = scpi_clk_round_rate,
58         .set_rate = scpi_clk_set_rate,
59 };
60
61 /* find closest match to given frequency in OPP table */
62 static long __scpi_dvfs_round_rate(struct scpi_clk *clk, unsigned long rate)
63 {
64         int idx;
65         unsigned long fmin = 0, fmax = ~0, ftmp;
66         const struct scpi_opp *opp = clk->info->opps;
67
68         for (idx = 0; idx < clk->info->count; idx++, opp++) {
69                 ftmp = opp->freq;
70                 if (ftmp >= rate) {
71                         if (ftmp <= fmax)
72                                 fmax = ftmp;
73                         break;
74                 } else if (ftmp >= fmin) {
75                         fmin = ftmp;
76                 }
77         }
78         return fmax != ~0 ? fmax : fmin;
79 }
80
81 static unsigned long scpi_dvfs_recalc_rate(struct clk_hw *hw,
82                                            unsigned long parent_rate)
83 {
84         struct scpi_clk *clk = to_scpi_clk(hw);
85         int idx = clk->scpi_ops->dvfs_get_idx(clk->id);
86         const struct scpi_opp *opp;
87
88         if (idx < 0)
89                 return 0;
90
91         opp = clk->info->opps + idx;
92         return opp->freq;
93 }
94
95 static long scpi_dvfs_round_rate(struct clk_hw *hw, unsigned long rate,
96                                  unsigned long *parent_rate)
97 {
98         struct scpi_clk *clk = to_scpi_clk(hw);
99
100         return __scpi_dvfs_round_rate(clk, rate);
101 }
102
103 static int __scpi_find_dvfs_index(struct scpi_clk *clk, unsigned long rate)
104 {
105         int idx, max_opp = clk->info->count;
106         const struct scpi_opp *opp = clk->info->opps;
107
108         for (idx = 0; idx < max_opp; idx++, opp++)
109                 if (opp->freq == rate)
110                         return idx;
111         return -EINVAL;
112 }
113
114 static int scpi_dvfs_set_rate(struct clk_hw *hw, unsigned long rate,
115                               unsigned long parent_rate)
116 {
117         struct scpi_clk *clk = to_scpi_clk(hw);
118         int ret = __scpi_find_dvfs_index(clk, rate);
119
120         if (ret < 0)
121                 return ret;
122         return clk->scpi_ops->dvfs_set_idx(clk->id, (u8)ret);
123 }
124
125 static const struct clk_ops scpi_dvfs_ops = {
126         .recalc_rate = scpi_dvfs_recalc_rate,
127         .round_rate = scpi_dvfs_round_rate,
128         .set_rate = scpi_dvfs_set_rate,
129 };
130
131 static const struct of_device_id scpi_clk_match[] __maybe_unused = {
132         { .compatible = "arm,scpi-dvfs-clocks", .data = &scpi_dvfs_ops, },
133         { .compatible = "arm,scpi-variable-clocks", .data = &scpi_clk_ops, },
134         {}
135 };
136
137 static int
138 scpi_clk_ops_init(struct device *dev, const struct of_device_id *match,
139                   struct scpi_clk *sclk, const char *name)
140 {
141         struct clk_init_data init;
142         unsigned long min = 0, max = 0;
143         int ret;
144
145         init.name = name;
146         init.flags = 0;
147         init.num_parents = 0;
148         init.ops = match->data;
149         sclk->hw.init = &init;
150         sclk->scpi_ops = get_scpi_ops();
151
152         if (init.ops == &scpi_dvfs_ops) {
153                 sclk->info = sclk->scpi_ops->dvfs_get_info(sclk->id);
154                 if (IS_ERR(sclk->info))
155                         return PTR_ERR(sclk->info);
156         } else if (init.ops == &scpi_clk_ops) {
157                 if (sclk->scpi_ops->clk_get_range(sclk->id, &min, &max) || !max)
158                         return -EINVAL;
159         } else {
160                 return -EINVAL;
161         }
162
163         ret = devm_clk_hw_register(dev, &sclk->hw);
164         if (!ret && max)
165                 clk_hw_set_rate_range(&sclk->hw, min, max);
166         return ret;
167 }
168
169 struct scpi_clk_data {
170         struct scpi_clk **clk;
171         unsigned int clk_num;
172 };
173
174 static struct clk_hw *
175 scpi_of_clk_src_get(struct of_phandle_args *clkspec, void *data)
176 {
177         struct scpi_clk *sclk;
178         struct scpi_clk_data *clk_data = data;
179         unsigned int idx = clkspec->args[0], count;
180
181         for (count = 0; count < clk_data->clk_num; count++) {
182                 sclk = clk_data->clk[count];
183                 if (idx == sclk->id)
184                         return &sclk->hw;
185         }
186
187         return ERR_PTR(-EINVAL);
188 }
189
190 static int scpi_clk_add(struct device *dev, struct device_node *np,
191                         const struct of_device_id *match)
192 {
193         int idx, count, err;
194         struct scpi_clk_data *clk_data;
195
196         count = of_property_count_strings(np, "clock-output-names");
197         if (count < 0) {
198                 dev_err(dev, "%pOFn: invalid clock output count\n", np);
199                 return -EINVAL;
200         }
201
202         clk_data = devm_kmalloc(dev, sizeof(*clk_data), GFP_KERNEL);
203         if (!clk_data)
204                 return -ENOMEM;
205
206         clk_data->clk_num = count;
207         clk_data->clk = devm_kcalloc(dev, count, sizeof(*clk_data->clk),
208                                      GFP_KERNEL);
209         if (!clk_data->clk)
210                 return -ENOMEM;
211
212         for (idx = 0; idx < count; idx++) {
213                 struct scpi_clk *sclk;
214                 const char *name;
215                 u32 val;
216
217                 sclk = devm_kzalloc(dev, sizeof(*sclk), GFP_KERNEL);
218                 if (!sclk)
219                         return -ENOMEM;
220
221                 if (of_property_read_string_index(np, "clock-output-names",
222                                                   idx, &name)) {
223                         dev_err(dev, "invalid clock name @ %pOFn\n", np);
224                         return -EINVAL;
225                 }
226
227                 if (of_property_read_u32_index(np, "clock-indices",
228                                                idx, &val)) {
229                         dev_err(dev, "invalid clock index @ %pOFn\n", np);
230                         return -EINVAL;
231                 }
232
233                 sclk->id = val;
234
235                 err = scpi_clk_ops_init(dev, match, sclk, name);
236                 if (err) {
237                         dev_err(dev, "failed to register clock '%s'\n", name);
238                         return err;
239                 }
240
241                 dev_dbg(dev, "Registered clock '%s'\n", name);
242                 clk_data->clk[idx] = sclk;
243         }
244
245         return of_clk_add_hw_provider(np, scpi_of_clk_src_get, clk_data);
246 }
247
248 static void scpi_clocks_remove(struct platform_device *pdev)
249 {
250         struct device *dev = &pdev->dev;
251         struct device_node *child, *np = dev->of_node;
252
253         if (cpufreq_dev) {
254                 platform_device_unregister(cpufreq_dev);
255                 cpufreq_dev = NULL;
256         }
257
258         for_each_available_child_of_node(np, child)
259                 of_clk_del_provider(np);
260 }
261
262 static int scpi_clocks_probe(struct platform_device *pdev)
263 {
264         int ret;
265         struct device *dev = &pdev->dev;
266         struct device_node *child, *np = dev->of_node;
267         const struct of_device_id *match;
268
269         if (!get_scpi_ops())
270                 return -ENXIO;
271
272         for_each_available_child_of_node(np, child) {
273                 match = of_match_node(scpi_clk_match, child);
274                 if (!match)
275                         continue;
276                 ret = scpi_clk_add(dev, child, match);
277                 if (ret) {
278                         scpi_clocks_remove(pdev);
279                         of_node_put(child);
280                         return ret;
281                 }
282
283                 if (match->data != &scpi_dvfs_ops)
284                         continue;
285                 /* Add the virtual cpufreq device if it's DVFS clock provider */
286                 cpufreq_dev = platform_device_register_simple("scpi-cpufreq",
287                                                               -1, NULL, 0);
288                 if (IS_ERR(cpufreq_dev))
289                         pr_warn("unable to register cpufreq device");
290         }
291         return 0;
292 }
293
294 static const struct of_device_id scpi_clocks_ids[] = {
295         { .compatible = "arm,scpi-clocks", },
296         {}
297 };
298 MODULE_DEVICE_TABLE(of, scpi_clocks_ids);
299
300 static struct platform_driver scpi_clocks_driver = {
301         .driver = {
302                 .name = "scpi_clocks",
303                 .of_match_table = scpi_clocks_ids,
304         },
305         .probe = scpi_clocks_probe,
306         .remove_new = scpi_clocks_remove,
307 };
308 module_platform_driver(scpi_clocks_driver);
309
310 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
311 MODULE_DESCRIPTION("ARM SCPI clock driver");
312 MODULE_LICENSE("GPL v2");