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Sudeep Hollacd52c2a2015-03-30 10:59:52 +01001/*
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
28struct 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
Sudeep Holla9490f012015-03-30 10:59:52 +010037static struct platform_device *cpufreq_dev;
38
Sudeep Hollacd52c2a2015-03-30 10:59:52 +010039static 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
47static 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
59static 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
67static 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 */
74static int __scpi_dvfs_round_rate(struct scpi_clk *clk, unsigned long rate)
75{
76 int idx;
77 u32 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 >= (u32)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
93static 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
107static 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
115static 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
126static 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
137static 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
143static 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
149static struct clk *
150scpi_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;
Stephen Boyd90593682016-03-01 11:00:22 -0800158 init.flags = 0;
Sudeep Hollacd52c2a2015-03-30 10:59:52 +0100159 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
181struct scpi_clk_data {
182 struct scpi_clk **clk;
183 unsigned int clk_num;
184};
185
186static struct clk *
187scpi_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
202static 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
263static 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
Sudeep Holla9490f012015-03-30 10:59:52 +0100268 if (cpufreq_dev) {
269 platform_device_unregister(cpufreq_dev);
270 cpufreq_dev = NULL;
271 }
272
Sudeep Hollacd52c2a2015-03-30 10:59:52 +0100273 for_each_available_child_of_node(np, child)
274 of_clk_del_provider(np);
275 return 0;
276}
277
278static 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);
Julia Lawalle80cf2e2015-10-21 22:41:40 +0200295 of_node_put(child);
Sudeep Hollacd52c2a2015-03-30 10:59:52 +0100296 return ret;
297 }
298 }
Sudeep Holla9490f012015-03-30 10:59:52 +0100299 /* Add the virtual cpufreq device */
300 cpufreq_dev = platform_device_register_simple("scpi-cpufreq",
301 -1, NULL, 0);
Axel Lind22eb662015-12-04 14:51:36 +0800302 if (IS_ERR(cpufreq_dev))
Sudeep Holla9490f012015-03-30 10:59:52 +0100303 pr_warn("unable to register cpufreq device");
304
Sudeep Hollacd52c2a2015-03-30 10:59:52 +0100305 return 0;
306}
307
308static const struct of_device_id scpi_clocks_ids[] = {
309 { .compatible = "arm,scpi-clocks", },
310 {}
311};
312MODULE_DEVICE_TABLE(of, scpi_clocks_ids);
313
314static 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};
322module_platform_driver(scpi_clocks_driver);
323
324MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
325MODULE_DESCRIPTION("ARM SCPI clock driver");
326MODULE_LICENSE("GPL v2");