GNU Linux-libre 4.4.289-gnu1
[releases.git] / drivers / clk / clk-scpi.c
1 /*
2  * System Control and Power Interface (SCPI) Protocol based clock driver
3  *
4  * Copyright (C) 2015 ARM Ltd.
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms and conditions of the GNU General Public License,
8  * version 2, as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13  * more details.
14  *
15  * You should have received a copy of the GNU General Public License along with
16  * this program. If not, see <http://www.gnu.org/licenses/>.
17  */
18
19 #include <linux/clk-provider.h>
20 #include <linux/device.h>
21 #include <linux/err.h>
22 #include <linux/of.h>
23 #include <linux/module.h>
24 #include <linux/of_platform.h>
25 #include <linux/platform_device.h>
26 #include <linux/scpi_protocol.h>
27
28 struct scpi_clk {
29         u32 id;
30         struct clk_hw hw;
31         struct scpi_dvfs_info *info;
32         struct scpi_ops *scpi_ops;
33 };
34
35 #define to_scpi_clk(clk) container_of(clk, struct scpi_clk, hw)
36
37 static struct platform_device *cpufreq_dev;
38
39 static unsigned long scpi_clk_recalc_rate(struct clk_hw *hw,
40                                           unsigned long parent_rate)
41 {
42         struct scpi_clk *clk = to_scpi_clk(hw);
43
44         return clk->scpi_ops->clk_get_val(clk->id);
45 }
46
47 static long scpi_clk_round_rate(struct clk_hw *hw, unsigned long rate,
48                                 unsigned long *parent_rate)
49 {
50         /*
51          * We can't figure out what rate it will be, so just return the
52          * rate back to the caller. scpi_clk_recalc_rate() will be called
53          * after the rate is set and we'll know what rate the clock is
54          * running at then.
55          */
56         return rate;
57 }
58
59 static int scpi_clk_set_rate(struct clk_hw *hw, unsigned long rate,
60                              unsigned long parent_rate)
61 {
62         struct scpi_clk *clk = to_scpi_clk(hw);
63
64         return clk->scpi_ops->clk_set_val(clk->id, rate);
65 }
66
67 static const struct clk_ops scpi_clk_ops = {
68         .recalc_rate = scpi_clk_recalc_rate,
69         .round_rate = scpi_clk_round_rate,
70         .set_rate = scpi_clk_set_rate,
71 };
72
73 /* find closest match to given frequency in OPP table */
74 static long __scpi_dvfs_round_rate(struct scpi_clk *clk, unsigned long rate)
75 {
76         int idx;
77         unsigned long fmin = 0, fmax = ~0, ftmp;
78         const struct scpi_opp *opp = clk->info->opps;
79
80         for (idx = 0; idx < clk->info->count; idx++, opp++) {
81                 ftmp = opp->freq;
82                 if (ftmp >= rate) {
83                         if (ftmp <= fmax)
84                                 fmax = ftmp;
85                         break;
86                 } else if (ftmp >= fmin) {
87                         fmin = ftmp;
88                 }
89         }
90         return fmax != ~0 ? fmax : fmin;
91 }
92
93 static unsigned long scpi_dvfs_recalc_rate(struct clk_hw *hw,
94                                            unsigned long parent_rate)
95 {
96         struct scpi_clk *clk = to_scpi_clk(hw);
97         int idx = clk->scpi_ops->dvfs_get_idx(clk->id);
98         const struct scpi_opp *opp;
99
100         if (idx < 0)
101                 return 0;
102
103         opp = clk->info->opps + idx;
104         return opp->freq;
105 }
106
107 static long scpi_dvfs_round_rate(struct clk_hw *hw, unsigned long rate,
108                                  unsigned long *parent_rate)
109 {
110         struct scpi_clk *clk = to_scpi_clk(hw);
111
112         return __scpi_dvfs_round_rate(clk, rate);
113 }
114
115 static int __scpi_find_dvfs_index(struct scpi_clk *clk, unsigned long rate)
116 {
117         int idx, max_opp = clk->info->count;
118         const struct scpi_opp *opp = clk->info->opps;
119
120         for (idx = 0; idx < max_opp; idx++, opp++)
121                 if (opp->freq == rate)
122                         return idx;
123         return -EINVAL;
124 }
125
126 static int scpi_dvfs_set_rate(struct clk_hw *hw, unsigned long rate,
127                               unsigned long parent_rate)
128 {
129         struct scpi_clk *clk = to_scpi_clk(hw);
130         int ret = __scpi_find_dvfs_index(clk, rate);
131
132         if (ret < 0)
133                 return ret;
134         return clk->scpi_ops->dvfs_set_idx(clk->id, (u8)ret);
135 }
136
137 static const struct clk_ops scpi_dvfs_ops = {
138         .recalc_rate = scpi_dvfs_recalc_rate,
139         .round_rate = scpi_dvfs_round_rate,
140         .set_rate = scpi_dvfs_set_rate,
141 };
142
143 static const struct of_device_id scpi_clk_match[] = {
144         { .compatible = "arm,scpi-dvfs-clocks", .data = &scpi_dvfs_ops, },
145         { .compatible = "arm,scpi-variable-clocks", .data = &scpi_clk_ops, },
146         {}
147 };
148
149 static struct clk *
150 scpi_clk_ops_init(struct device *dev, const struct of_device_id *match,
151                   struct scpi_clk *sclk, const char *name)
152 {
153         struct clk_init_data init;
154         struct clk *clk;
155         unsigned long min = 0, max = 0;
156
157         init.name = name;
158         init.flags = CLK_IS_ROOT;
159         init.num_parents = 0;
160         init.ops = match->data;
161         sclk->hw.init = &init;
162         sclk->scpi_ops = get_scpi_ops();
163
164         if (init.ops == &scpi_dvfs_ops) {
165                 sclk->info = sclk->scpi_ops->dvfs_get_info(sclk->id);
166                 if (IS_ERR(sclk->info))
167                         return NULL;
168         } else if (init.ops == &scpi_clk_ops) {
169                 if (sclk->scpi_ops->clk_get_range(sclk->id, &min, &max) || !max)
170                         return NULL;
171         } else {
172                 return NULL;
173         }
174
175         clk = devm_clk_register(dev, &sclk->hw);
176         if (!IS_ERR(clk) && max)
177                 clk_hw_set_rate_range(&sclk->hw, min, max);
178         return clk;
179 }
180
181 struct scpi_clk_data {
182         struct scpi_clk **clk;
183         unsigned int clk_num;
184 };
185
186 static struct clk *
187 scpi_of_clk_src_get(struct of_phandle_args *clkspec, void *data)
188 {
189         struct scpi_clk *sclk;
190         struct scpi_clk_data *clk_data = data;
191         unsigned int idx = clkspec->args[0], count;
192
193         for (count = 0; count < clk_data->clk_num; count++) {
194                 sclk = clk_data->clk[count];
195                 if (idx == sclk->id)
196                         return sclk->hw.clk;
197         }
198
199         return ERR_PTR(-EINVAL);
200 }
201
202 static int scpi_clk_add(struct device *dev, struct device_node *np,
203                         const struct of_device_id *match)
204 {
205         struct clk **clks;
206         int idx, count;
207         struct scpi_clk_data *clk_data;
208
209         count = of_property_count_strings(np, "clock-output-names");
210         if (count < 0) {
211                 dev_err(dev, "%s: invalid clock output count\n", np->name);
212                 return -EINVAL;
213         }
214
215         clk_data = devm_kmalloc(dev, sizeof(*clk_data), GFP_KERNEL);
216         if (!clk_data)
217                 return -ENOMEM;
218
219         clk_data->clk_num = count;
220         clk_data->clk = devm_kcalloc(dev, count, sizeof(*clk_data->clk),
221                                      GFP_KERNEL);
222         if (!clk_data->clk)
223                 return -ENOMEM;
224
225         clks = devm_kcalloc(dev, count, sizeof(*clks), GFP_KERNEL);
226         if (!clks)
227                 return -ENOMEM;
228
229         for (idx = 0; idx < count; idx++) {
230                 struct scpi_clk *sclk;
231                 const char *name;
232                 u32 val;
233
234                 sclk = devm_kzalloc(dev, sizeof(*sclk), GFP_KERNEL);
235                 if (!sclk)
236                         return -ENOMEM;
237
238                 if (of_property_read_string_index(np, "clock-output-names",
239                                                   idx, &name)) {
240                         dev_err(dev, "invalid clock name @ %s\n", np->name);
241                         return -EINVAL;
242                 }
243
244                 if (of_property_read_u32_index(np, "clock-indices",
245                                                idx, &val)) {
246                         dev_err(dev, "invalid clock index @ %s\n", np->name);
247                         return -EINVAL;
248                 }
249
250                 sclk->id = val;
251
252                 clks[idx] = scpi_clk_ops_init(dev, match, sclk, name);
253                 if (IS_ERR_OR_NULL(clks[idx]))
254                         dev_err(dev, "failed to register clock '%s'\n", name);
255                 else
256                         dev_dbg(dev, "Registered clock '%s'\n", name);
257                 clk_data->clk[idx] = sclk;
258         }
259
260         return of_clk_add_provider(np, scpi_of_clk_src_get, clk_data);
261 }
262
263 static int scpi_clocks_remove(struct platform_device *pdev)
264 {
265         struct device *dev = &pdev->dev;
266         struct device_node *child, *np = dev->of_node;
267
268         if (cpufreq_dev) {
269                 platform_device_unregister(cpufreq_dev);
270                 cpufreq_dev = NULL;
271         }
272
273         for_each_available_child_of_node(np, child)
274                 of_clk_del_provider(np);
275         return 0;
276 }
277
278 static int scpi_clocks_probe(struct platform_device *pdev)
279 {
280         int ret;
281         struct device *dev = &pdev->dev;
282         struct device_node *child, *np = dev->of_node;
283         const struct of_device_id *match;
284
285         if (!get_scpi_ops())
286                 return -ENXIO;
287
288         for_each_available_child_of_node(np, child) {
289                 match = of_match_node(scpi_clk_match, child);
290                 if (!match)
291                         continue;
292                 ret = scpi_clk_add(dev, child, match);
293                 if (ret) {
294                         scpi_clocks_remove(pdev);
295                         of_node_put(child);
296                         return ret;
297                 }
298         }
299         /* Add the virtual cpufreq device */
300         cpufreq_dev = platform_device_register_simple("scpi-cpufreq",
301                                                       -1, NULL, 0);
302         if (!cpufreq_dev)
303                 pr_warn("unable to register cpufreq device");
304
305         return 0;
306 }
307
308 static const struct of_device_id scpi_clocks_ids[] = {
309         { .compatible = "arm,scpi-clocks", },
310         {}
311 };
312 MODULE_DEVICE_TABLE(of, scpi_clocks_ids);
313
314 static struct platform_driver scpi_clocks_driver = {
315         .driver = {
316                 .name = "scpi_clocks",
317                 .of_match_table = scpi_clocks_ids,
318         },
319         .probe = scpi_clocks_probe,
320         .remove = scpi_clocks_remove,
321 };
322 module_platform_driver(scpi_clocks_driver);
323
324 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
325 MODULE_DESCRIPTION("ARM SCPI clock driver");
326 MODULE_LICENSE("GPL v2");