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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Generic Exynos Bus frequency driver with DEVFREQ Framework
4 *
5 * Copyright (c) 2016 Samsung Electronics Co., Ltd.
6 * Author : Chanwoo Choi <cw00.choi@samsung.com>
7 *
8 * This driver support Exynos Bus frequency feature by using
9 * DEVFREQ framework and is based on drivers/devfreq/exynos/exynos4_bus.c.
10 */
11
12#include <linux/clk.h>
13#include <linux/devfreq.h>
14#include <linux/devfreq-event.h>
15#include <linux/device.h>
16#include <linux/export.h>
17#include <linux/module.h>
18#include <linux/of_device.h>
19#include <linux/pm_opp.h>
20#include <linux/platform_device.h>
21#include <linux/regulator/consumer.h>
22#include <linux/slab.h>
23
24#define DEFAULT_SATURATION_RATIO 40
25
26struct exynos_bus {
27 struct device *dev;
28
29 struct devfreq *devfreq;
30 struct devfreq_event_dev **edev;
31 unsigned int edev_count;
32 struct mutex lock;
33
34 unsigned long curr_freq;
35
36 struct opp_table *opp_table;
37 struct clk *clk;
38 unsigned int ratio;
39};
40
41/*
42 * Control the devfreq-event device to get the current state of bus
43 */
44#define exynos_bus_ops_edev(ops) \
45static int exynos_bus_##ops(struct exynos_bus *bus) \
46{ \
47 int i, ret; \
48 \
49 for (i = 0; i < bus->edev_count; i++) { \
50 if (!bus->edev[i]) \
51 continue; \
52 ret = devfreq_event_##ops(bus->edev[i]); \
53 if (ret < 0) \
54 return ret; \
55 } \
56 \
57 return 0; \
58}
59exynos_bus_ops_edev(enable_edev);
60exynos_bus_ops_edev(disable_edev);
61exynos_bus_ops_edev(set_event);
62
63static int exynos_bus_get_event(struct exynos_bus *bus,
64 struct devfreq_event_data *edata)
65{
66 struct devfreq_event_data event_data;
67 unsigned long load_count = 0, total_count = 0;
68 int i, ret = 0;
69
70 for (i = 0; i < bus->edev_count; i++) {
71 if (!bus->edev[i])
72 continue;
73
74 ret = devfreq_event_get_event(bus->edev[i], &event_data);
75 if (ret < 0)
76 return ret;
77
78 if (i == 0 || event_data.load_count > load_count) {
79 load_count = event_data.load_count;
80 total_count = event_data.total_count;
81 }
82 }
83
84 edata->load_count = load_count;
85 edata->total_count = total_count;
86
87 return ret;
88}
89
90/*
91 * devfreq function for both simple-ondemand and passive governor
92 */
93static int exynos_bus_target(struct device *dev, unsigned long *freq, u32 flags)
94{
95 struct exynos_bus *bus = dev_get_drvdata(dev);
96 struct dev_pm_opp *new_opp;
97 int ret = 0;
98
99 /* Get correct frequency for bus. */
100 new_opp = devfreq_recommended_opp(dev, freq, flags);
101 if (IS_ERR(new_opp)) {
102 dev_err(dev, "failed to get recommended opp instance\n");
103 return PTR_ERR(new_opp);
104 }
105
106 dev_pm_opp_put(new_opp);
107
108 /* Change voltage and frequency according to new OPP level */
109 mutex_lock(&bus->lock);
110 ret = dev_pm_opp_set_rate(dev, *freq);
111 if (!ret)
112 bus->curr_freq = *freq;
113
114 mutex_unlock(&bus->lock);
115
116 return ret;
117}
118
119static int exynos_bus_get_dev_status(struct device *dev,
120 struct devfreq_dev_status *stat)
121{
122 struct exynos_bus *bus = dev_get_drvdata(dev);
123 struct devfreq_event_data edata;
124 int ret;
125
126 stat->current_frequency = bus->curr_freq;
127
128 ret = exynos_bus_get_event(bus, &edata);
129 if (ret < 0) {
130 stat->total_time = stat->busy_time = 0;
131 goto err;
132 }
133
134 stat->busy_time = (edata.load_count * 100) / bus->ratio;
135 stat->total_time = edata.total_count;
136
137 dev_dbg(dev, "Usage of devfreq-event : %lu/%lu\n", stat->busy_time,
138 stat->total_time);
139
140err:
141 ret = exynos_bus_set_event(bus);
142 if (ret < 0) {
143 dev_err(dev, "failed to set event to devfreq-event devices\n");
144 return ret;
145 }
146
147 return ret;
148}
149
150static void exynos_bus_exit(struct device *dev)
151{
152 struct exynos_bus *bus = dev_get_drvdata(dev);
153 int ret;
154
155 ret = exynos_bus_disable_edev(bus);
156 if (ret < 0)
157 dev_warn(dev, "failed to disable the devfreq-event devices\n");
158
159 dev_pm_opp_of_remove_table(dev);
160 clk_disable_unprepare(bus->clk);
161 if (bus->opp_table) {
162 dev_pm_opp_put_regulators(bus->opp_table);
163 bus->opp_table = NULL;
164 }
165}
166
167static void exynos_bus_passive_exit(struct device *dev)
168{
169 struct exynos_bus *bus = dev_get_drvdata(dev);
170
171 dev_pm_opp_of_remove_table(dev);
172 clk_disable_unprepare(bus->clk);
173}
174
175static int exynos_bus_parent_parse_of(struct device_node *np,
176 struct exynos_bus *bus)
177{
178 struct device *dev = bus->dev;
179 struct opp_table *opp_table;
180 const char *vdd = "vdd";
181 int i, ret, count, size;
182
183 opp_table = dev_pm_opp_set_regulators(dev, &vdd, 1);
184 if (IS_ERR(opp_table)) {
185 ret = PTR_ERR(opp_table);
186 dev_err(dev, "failed to set regulators %d\n", ret);
187 return ret;
188 }
189
190 bus->opp_table = opp_table;
191
192 /*
193 * Get the devfreq-event devices to get the current utilization of
194 * buses. This raw data will be used in devfreq ondemand governor.
195 */
196 count = devfreq_event_get_edev_count(dev);
197 if (count < 0) {
198 dev_err(dev, "failed to get the count of devfreq-event dev\n");
199 ret = count;
200 goto err_regulator;
201 }
202 bus->edev_count = count;
203
204 size = sizeof(*bus->edev) * count;
205 bus->edev = devm_kzalloc(dev, size, GFP_KERNEL);
206 if (!bus->edev) {
207 ret = -ENOMEM;
208 goto err_regulator;
209 }
210
211 for (i = 0; i < count; i++) {
212 bus->edev[i] = devfreq_event_get_edev_by_phandle(dev, i);
213 if (IS_ERR(bus->edev[i])) {
214 ret = -EPROBE_DEFER;
215 goto err_regulator;
216 }
217 }
218
219 /*
220 * Optionally, Get the saturation ratio according to Exynos SoC
221 * When measuring the utilization of each AXI bus with devfreq-event
222 * devices, the measured real cycle might be much lower than the
223 * total cycle of bus during sampling rate. In result, the devfreq
224 * simple-ondemand governor might not decide to change the current
225 * frequency due to too utilization (= real cycle/total cycle).
226 * So, this property is used to adjust the utilization when calculating
227 * the busy_time in exynos_bus_get_dev_status().
228 */
229 if (of_property_read_u32(np, "exynos,saturation-ratio", &bus->ratio))
230 bus->ratio = DEFAULT_SATURATION_RATIO;
231
232 return 0;
233
234err_regulator:
235 dev_pm_opp_put_regulators(bus->opp_table);
236 bus->opp_table = NULL;
237
238 return ret;
239}
240
241static int exynos_bus_parse_of(struct device_node *np,
242 struct exynos_bus *bus)
243{
244 struct device *dev = bus->dev;
245 struct dev_pm_opp *opp;
246 unsigned long rate;
247 int ret;
248
249 /* Get the clock to provide each bus with source clock */
250 bus->clk = devm_clk_get(dev, "bus");
251 if (IS_ERR(bus->clk)) {
252 dev_err(dev, "failed to get bus clock\n");
253 return PTR_ERR(bus->clk);
254 }
255
256 ret = clk_prepare_enable(bus->clk);
257 if (ret < 0) {
258 dev_err(dev, "failed to get enable clock\n");
259 return ret;
260 }
261
262 /* Get the freq and voltage from OPP table to scale the bus freq */
263 ret = dev_pm_opp_of_add_table(dev);
264 if (ret < 0) {
265 dev_err(dev, "failed to get OPP table\n");
266 goto err_clk;
267 }
268
269 rate = clk_get_rate(bus->clk);
270
271 opp = devfreq_recommended_opp(dev, &rate, 0);
272 if (IS_ERR(opp)) {
273 dev_err(dev, "failed to find dev_pm_opp\n");
274 ret = PTR_ERR(opp);
275 goto err_opp;
276 }
277 bus->curr_freq = dev_pm_opp_get_freq(opp);
278 dev_pm_opp_put(opp);
279
280 return 0;
281
282err_opp:
283 dev_pm_opp_of_remove_table(dev);
284err_clk:
285 clk_disable_unprepare(bus->clk);
286
287 return ret;
288}
289
290static int exynos_bus_probe(struct platform_device *pdev)
291{
292 struct device *dev = &pdev->dev;
293 struct device_node *np = dev->of_node, *node;
294 struct devfreq_dev_profile *profile;
295 struct devfreq_simple_ondemand_data *ondemand_data;
296 struct devfreq_passive_data *passive_data;
297 struct devfreq *parent_devfreq;
298 struct exynos_bus *bus;
299 int ret, max_state;
300 unsigned long min_freq, max_freq;
301 bool passive = false;
302
303 if (!np) {
304 dev_err(dev, "failed to find devicetree node\n");
305 return -EINVAL;
306 }
307
308 bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
309 if (!bus)
310 return -ENOMEM;
311 mutex_init(&bus->lock);
312 bus->dev = &pdev->dev;
313 platform_set_drvdata(pdev, bus);
314
315 profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
316 if (!profile)
317 return -ENOMEM;
318
319 node = of_parse_phandle(dev->of_node, "devfreq", 0);
320 if (node) {
321 of_node_put(node);
322 passive = true;
323 } else {
324 ret = exynos_bus_parent_parse_of(np, bus);
325 if (ret < 0)
326 return ret;
327 }
328
329 /* Parse the device-tree to get the resource information */
330 ret = exynos_bus_parse_of(np, bus);
331 if (ret < 0)
332 goto err_reg;
333
334 if (passive)
335 goto passive;
336
337 /* Initialize the struct profile and governor data for parent device */
338 profile->polling_ms = 50;
339 profile->target = exynos_bus_target;
340 profile->get_dev_status = exynos_bus_get_dev_status;
341 profile->exit = exynos_bus_exit;
342
343 ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL);
344 if (!ondemand_data) {
345 ret = -ENOMEM;
346 goto err;
347 }
348 ondemand_data->upthreshold = 40;
349 ondemand_data->downdifferential = 5;
350
351 /* Add devfreq device to monitor and handle the exynos bus */
352 bus->devfreq = devm_devfreq_add_device(dev, profile,
353 DEVFREQ_GOV_SIMPLE_ONDEMAND,
354 ondemand_data);
355 if (IS_ERR(bus->devfreq)) {
356 dev_err(dev, "failed to add devfreq device\n");
357 ret = PTR_ERR(bus->devfreq);
358 goto err;
359 }
360
361 /* Register opp_notifier to catch the change of OPP */
362 ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq);
363 if (ret < 0) {
364 dev_err(dev, "failed to register opp notifier\n");
365 goto err;
366 }
367
368 /*
369 * Enable devfreq-event to get raw data which is used to determine
370 * current bus load.
371 */
372 ret = exynos_bus_enable_edev(bus);
373 if (ret < 0) {
374 dev_err(dev, "failed to enable devfreq-event devices\n");
375 goto err;
376 }
377
378 ret = exynos_bus_set_event(bus);
379 if (ret < 0) {
380 dev_err(dev, "failed to set event to devfreq-event devices\n");
381 goto err;
382 }
383
384 goto out;
385passive:
386 /* Initialize the struct profile and governor data for passive device */
387 profile->target = exynos_bus_target;
388 profile->exit = exynos_bus_passive_exit;
389
390 /* Get the instance of parent devfreq device */
391 parent_devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
392 if (IS_ERR(parent_devfreq)) {
393 ret = -EPROBE_DEFER;
394 goto err;
395 }
396
397 passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
398 if (!passive_data) {
399 ret = -ENOMEM;
400 goto err;
401 }
402 passive_data->parent = parent_devfreq;
403
404 /* Add devfreq device for exynos bus with passive governor */
405 bus->devfreq = devm_devfreq_add_device(dev, profile, DEVFREQ_GOV_PASSIVE,
406 passive_data);
407 if (IS_ERR(bus->devfreq)) {
408 dev_err(dev,
409 "failed to add devfreq dev with passive governor\n");
410 ret = PTR_ERR(bus->devfreq);
411 goto err;
412 }
413
414out:
415 max_state = bus->devfreq->profile->max_state;
416 min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
417 max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
418 pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
419 dev_name(dev), min_freq, max_freq);
420
421 return 0;
422
423err:
424 dev_pm_opp_of_remove_table(dev);
425 clk_disable_unprepare(bus->clk);
426err_reg:
427 if (!passive) {
428 dev_pm_opp_put_regulators(bus->opp_table);
429 bus->opp_table = NULL;
430 }
431
432 return ret;
433}
434
435static void exynos_bus_shutdown(struct platform_device *pdev)
436{
437 struct exynos_bus *bus = dev_get_drvdata(&pdev->dev);
438
439 devfreq_suspend_device(bus->devfreq);
440}
441
442#ifdef CONFIG_PM_SLEEP
443static int exynos_bus_resume(struct device *dev)
444{
445 struct exynos_bus *bus = dev_get_drvdata(dev);
446 int ret;
447
448 ret = exynos_bus_enable_edev(bus);
449 if (ret < 0) {
450 dev_err(dev, "failed to enable the devfreq-event devices\n");
451 return ret;
452 }
453
454 return 0;
455}
456
457static int exynos_bus_suspend(struct device *dev)
458{
459 struct exynos_bus *bus = dev_get_drvdata(dev);
460 int ret;
461
462 ret = exynos_bus_disable_edev(bus);
463 if (ret < 0) {
464 dev_err(dev, "failed to disable the devfreq-event devices\n");
465 return ret;
466 }
467
468 return 0;
469}
470#endif
471
472static const struct dev_pm_ops exynos_bus_pm = {
473 SET_SYSTEM_SLEEP_PM_OPS(exynos_bus_suspend, exynos_bus_resume)
474};
475
476static const struct of_device_id exynos_bus_of_match[] = {
477 { .compatible = "samsung,exynos-bus", },
478 { /* sentinel */ },
479};
480MODULE_DEVICE_TABLE(of, exynos_bus_of_match);
481
482static struct platform_driver exynos_bus_platdrv = {
483 .probe = exynos_bus_probe,
484 .shutdown = exynos_bus_shutdown,
485 .driver = {
486 .name = "exynos-bus",
487 .pm = &exynos_bus_pm,
488 .of_match_table = of_match_ptr(exynos_bus_of_match),
489 },
490};
491module_platform_driver(exynos_bus_platdrv);
492
493MODULE_DESCRIPTION("Generic Exynos Bus frequency driver");
494MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
495MODULE_LICENSE("GPL v2");
1/*
2 * Generic Exynos Bus frequency driver with DEVFREQ Framework
3 *
4 * Copyright (c) 2016 Samsung Electronics Co., Ltd.
5 * Author : Chanwoo Choi <cw00.choi@samsung.com>
6 *
7 * This driver support Exynos Bus frequency feature by using
8 * DEVFREQ framework and is based on drivers/devfreq/exynos/exynos4_bus.c.
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 */
14
15#include <linux/clk.h>
16#include <linux/devfreq.h>
17#include <linux/devfreq-event.h>
18#include <linux/device.h>
19#include <linux/export.h>
20#include <linux/module.h>
21#include <linux/of_device.h>
22#include <linux/pm_opp.h>
23#include <linux/platform_device.h>
24#include <linux/regulator/consumer.h>
25#include <linux/slab.h>
26
27#define DEFAULT_SATURATION_RATIO 40
28#define DEFAULT_VOLTAGE_TOLERANCE 2
29
30struct exynos_bus {
31 struct device *dev;
32
33 struct devfreq *devfreq;
34 struct devfreq_event_dev **edev;
35 unsigned int edev_count;
36 struct mutex lock;
37
38 unsigned long curr_freq;
39
40 struct regulator *regulator;
41 struct clk *clk;
42 unsigned int voltage_tolerance;
43 unsigned int ratio;
44};
45
46/*
47 * Control the devfreq-event device to get the current state of bus
48 */
49#define exynos_bus_ops_edev(ops) \
50static int exynos_bus_##ops(struct exynos_bus *bus) \
51{ \
52 int i, ret; \
53 \
54 for (i = 0; i < bus->edev_count; i++) { \
55 if (!bus->edev[i]) \
56 continue; \
57 ret = devfreq_event_##ops(bus->edev[i]); \
58 if (ret < 0) \
59 return ret; \
60 } \
61 \
62 return 0; \
63}
64exynos_bus_ops_edev(enable_edev);
65exynos_bus_ops_edev(disable_edev);
66exynos_bus_ops_edev(set_event);
67
68static int exynos_bus_get_event(struct exynos_bus *bus,
69 struct devfreq_event_data *edata)
70{
71 struct devfreq_event_data event_data;
72 unsigned long load_count = 0, total_count = 0;
73 int i, ret = 0;
74
75 for (i = 0; i < bus->edev_count; i++) {
76 if (!bus->edev[i])
77 continue;
78
79 ret = devfreq_event_get_event(bus->edev[i], &event_data);
80 if (ret < 0)
81 return ret;
82
83 if (i == 0 || event_data.load_count > load_count) {
84 load_count = event_data.load_count;
85 total_count = event_data.total_count;
86 }
87 }
88
89 edata->load_count = load_count;
90 edata->total_count = total_count;
91
92 return ret;
93}
94
95/*
96 * Must necessary function for devfreq simple-ondemand governor
97 */
98static int exynos_bus_target(struct device *dev, unsigned long *freq, u32 flags)
99{
100 struct exynos_bus *bus = dev_get_drvdata(dev);
101 struct dev_pm_opp *new_opp;
102 unsigned long old_freq, new_freq, new_volt, tol;
103 int ret = 0;
104
105 /* Get new opp-bus instance according to new bus clock */
106 new_opp = devfreq_recommended_opp(dev, freq, flags);
107 if (IS_ERR(new_opp)) {
108 dev_err(dev, "failed to get recommended opp instance\n");
109 return PTR_ERR(new_opp);
110 }
111
112 new_freq = dev_pm_opp_get_freq(new_opp);
113 new_volt = dev_pm_opp_get_voltage(new_opp);
114 dev_pm_opp_put(new_opp);
115
116 old_freq = bus->curr_freq;
117
118 if (old_freq == new_freq)
119 return 0;
120 tol = new_volt * bus->voltage_tolerance / 100;
121
122 /* Change voltage and frequency according to new OPP level */
123 mutex_lock(&bus->lock);
124
125 if (old_freq < new_freq) {
126 ret = regulator_set_voltage_tol(bus->regulator, new_volt, tol);
127 if (ret < 0) {
128 dev_err(bus->dev, "failed to set voltage\n");
129 goto out;
130 }
131 }
132
133 ret = clk_set_rate(bus->clk, new_freq);
134 if (ret < 0) {
135 dev_err(dev, "failed to change clock of bus\n");
136 clk_set_rate(bus->clk, old_freq);
137 goto out;
138 }
139
140 if (old_freq > new_freq) {
141 ret = regulator_set_voltage_tol(bus->regulator, new_volt, tol);
142 if (ret < 0) {
143 dev_err(bus->dev, "failed to set voltage\n");
144 goto out;
145 }
146 }
147 bus->curr_freq = new_freq;
148
149 dev_dbg(dev, "Set the frequency of bus (%luHz -> %luHz, %luHz)\n",
150 old_freq, new_freq, clk_get_rate(bus->clk));
151out:
152 mutex_unlock(&bus->lock);
153
154 return ret;
155}
156
157static int exynos_bus_get_dev_status(struct device *dev,
158 struct devfreq_dev_status *stat)
159{
160 struct exynos_bus *bus = dev_get_drvdata(dev);
161 struct devfreq_event_data edata;
162 int ret;
163
164 stat->current_frequency = bus->curr_freq;
165
166 ret = exynos_bus_get_event(bus, &edata);
167 if (ret < 0) {
168 stat->total_time = stat->busy_time = 0;
169 goto err;
170 }
171
172 stat->busy_time = (edata.load_count * 100) / bus->ratio;
173 stat->total_time = edata.total_count;
174
175 dev_dbg(dev, "Usage of devfreq-event : %lu/%lu\n", stat->busy_time,
176 stat->total_time);
177
178err:
179 ret = exynos_bus_set_event(bus);
180 if (ret < 0) {
181 dev_err(dev, "failed to set event to devfreq-event devices\n");
182 return ret;
183 }
184
185 return ret;
186}
187
188static void exynos_bus_exit(struct device *dev)
189{
190 struct exynos_bus *bus = dev_get_drvdata(dev);
191 int ret;
192
193 ret = exynos_bus_disable_edev(bus);
194 if (ret < 0)
195 dev_warn(dev, "failed to disable the devfreq-event devices\n");
196
197 if (bus->regulator)
198 regulator_disable(bus->regulator);
199
200 dev_pm_opp_of_remove_table(dev);
201 clk_disable_unprepare(bus->clk);
202}
203
204/*
205 * Must necessary function for devfreq passive governor
206 */
207static int exynos_bus_passive_target(struct device *dev, unsigned long *freq,
208 u32 flags)
209{
210 struct exynos_bus *bus = dev_get_drvdata(dev);
211 struct dev_pm_opp *new_opp;
212 unsigned long old_freq, new_freq;
213 int ret = 0;
214
215 /* Get new opp-bus instance according to new bus clock */
216 new_opp = devfreq_recommended_opp(dev, freq, flags);
217 if (IS_ERR(new_opp)) {
218 dev_err(dev, "failed to get recommended opp instance\n");
219 return PTR_ERR(new_opp);
220 }
221
222 new_freq = dev_pm_opp_get_freq(new_opp);
223 dev_pm_opp_put(new_opp);
224
225 old_freq = bus->curr_freq;
226
227 if (old_freq == new_freq)
228 return 0;
229
230 /* Change the frequency according to new OPP level */
231 mutex_lock(&bus->lock);
232
233 ret = clk_set_rate(bus->clk, new_freq);
234 if (ret < 0) {
235 dev_err(dev, "failed to set the clock of bus\n");
236 goto out;
237 }
238
239 *freq = new_freq;
240 bus->curr_freq = new_freq;
241
242 dev_dbg(dev, "Set the frequency of bus (%luHz -> %luHz, %luHz)\n",
243 old_freq, new_freq, clk_get_rate(bus->clk));
244out:
245 mutex_unlock(&bus->lock);
246
247 return ret;
248}
249
250static void exynos_bus_passive_exit(struct device *dev)
251{
252 struct exynos_bus *bus = dev_get_drvdata(dev);
253
254 dev_pm_opp_of_remove_table(dev);
255 clk_disable_unprepare(bus->clk);
256}
257
258static int exynos_bus_parent_parse_of(struct device_node *np,
259 struct exynos_bus *bus)
260{
261 struct device *dev = bus->dev;
262 int i, ret, count, size;
263
264 /* Get the regulator to provide each bus with the power */
265 bus->regulator = devm_regulator_get(dev, "vdd");
266 if (IS_ERR(bus->regulator)) {
267 dev_err(dev, "failed to get VDD regulator\n");
268 return PTR_ERR(bus->regulator);
269 }
270
271 ret = regulator_enable(bus->regulator);
272 if (ret < 0) {
273 dev_err(dev, "failed to enable VDD regulator\n");
274 return ret;
275 }
276
277 /*
278 * Get the devfreq-event devices to get the current utilization of
279 * buses. This raw data will be used in devfreq ondemand governor.
280 */
281 count = devfreq_event_get_edev_count(dev);
282 if (count < 0) {
283 dev_err(dev, "failed to get the count of devfreq-event dev\n");
284 ret = count;
285 goto err_regulator;
286 }
287 bus->edev_count = count;
288
289 size = sizeof(*bus->edev) * count;
290 bus->edev = devm_kzalloc(dev, size, GFP_KERNEL);
291 if (!bus->edev) {
292 ret = -ENOMEM;
293 goto err_regulator;
294 }
295
296 for (i = 0; i < count; i++) {
297 bus->edev[i] = devfreq_event_get_edev_by_phandle(dev, i);
298 if (IS_ERR(bus->edev[i])) {
299 ret = -EPROBE_DEFER;
300 goto err_regulator;
301 }
302 }
303
304 /*
305 * Optionally, Get the saturation ratio according to Exynos SoC
306 * When measuring the utilization of each AXI bus with devfreq-event
307 * devices, the measured real cycle might be much lower than the
308 * total cycle of bus during sampling rate. In result, the devfreq
309 * simple-ondemand governor might not decide to change the current
310 * frequency due to too utilization (= real cycle/total cycle).
311 * So, this property is used to adjust the utilization when calculating
312 * the busy_time in exynos_bus_get_dev_status().
313 */
314 if (of_property_read_u32(np, "exynos,saturation-ratio", &bus->ratio))
315 bus->ratio = DEFAULT_SATURATION_RATIO;
316
317 if (of_property_read_u32(np, "exynos,voltage-tolerance",
318 &bus->voltage_tolerance))
319 bus->voltage_tolerance = DEFAULT_VOLTAGE_TOLERANCE;
320
321 return 0;
322
323err_regulator:
324 regulator_disable(bus->regulator);
325
326 return ret;
327}
328
329static int exynos_bus_parse_of(struct device_node *np,
330 struct exynos_bus *bus)
331{
332 struct device *dev = bus->dev;
333 struct dev_pm_opp *opp;
334 unsigned long rate;
335 int ret;
336
337 /* Get the clock to provide each bus with source clock */
338 bus->clk = devm_clk_get(dev, "bus");
339 if (IS_ERR(bus->clk)) {
340 dev_err(dev, "failed to get bus clock\n");
341 return PTR_ERR(bus->clk);
342 }
343
344 ret = clk_prepare_enable(bus->clk);
345 if (ret < 0) {
346 dev_err(dev, "failed to get enable clock\n");
347 return ret;
348 }
349
350 /* Get the freq and voltage from OPP table to scale the bus freq */
351 ret = dev_pm_opp_of_add_table(dev);
352 if (ret < 0) {
353 dev_err(dev, "failed to get OPP table\n");
354 goto err_clk;
355 }
356
357 rate = clk_get_rate(bus->clk);
358
359 opp = devfreq_recommended_opp(dev, &rate, 0);
360 if (IS_ERR(opp)) {
361 dev_err(dev, "failed to find dev_pm_opp\n");
362 ret = PTR_ERR(opp);
363 goto err_opp;
364 }
365 bus->curr_freq = dev_pm_opp_get_freq(opp);
366 dev_pm_opp_put(opp);
367
368 return 0;
369
370err_opp:
371 dev_pm_opp_of_remove_table(dev);
372err_clk:
373 clk_disable_unprepare(bus->clk);
374
375 return ret;
376}
377
378static int exynos_bus_probe(struct platform_device *pdev)
379{
380 struct device *dev = &pdev->dev;
381 struct device_node *np = dev->of_node, *node;
382 struct devfreq_dev_profile *profile;
383 struct devfreq_simple_ondemand_data *ondemand_data;
384 struct devfreq_passive_data *passive_data;
385 struct devfreq *parent_devfreq;
386 struct exynos_bus *bus;
387 int ret, max_state;
388 unsigned long min_freq, max_freq;
389
390 if (!np) {
391 dev_err(dev, "failed to find devicetree node\n");
392 return -EINVAL;
393 }
394
395 bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
396 if (!bus)
397 return -ENOMEM;
398 mutex_init(&bus->lock);
399 bus->dev = &pdev->dev;
400 platform_set_drvdata(pdev, bus);
401
402 /* Parse the device-tree to get the resource information */
403 ret = exynos_bus_parse_of(np, bus);
404 if (ret < 0)
405 return ret;
406
407 profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
408 if (!profile) {
409 ret = -ENOMEM;
410 goto err;
411 }
412
413 node = of_parse_phandle(dev->of_node, "devfreq", 0);
414 if (node) {
415 of_node_put(node);
416 goto passive;
417 } else {
418 ret = exynos_bus_parent_parse_of(np, bus);
419 }
420
421 if (ret < 0)
422 goto err;
423
424 /* Initialize the struct profile and governor data for parent device */
425 profile->polling_ms = 50;
426 profile->target = exynos_bus_target;
427 profile->get_dev_status = exynos_bus_get_dev_status;
428 profile->exit = exynos_bus_exit;
429
430 ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL);
431 if (!ondemand_data) {
432 ret = -ENOMEM;
433 goto err;
434 }
435 ondemand_data->upthreshold = 40;
436 ondemand_data->downdifferential = 5;
437
438 /* Add devfreq device to monitor and handle the exynos bus */
439 bus->devfreq = devm_devfreq_add_device(dev, profile,
440 DEVFREQ_GOV_SIMPLE_ONDEMAND,
441 ondemand_data);
442 if (IS_ERR(bus->devfreq)) {
443 dev_err(dev, "failed to add devfreq device\n");
444 ret = PTR_ERR(bus->devfreq);
445 goto err;
446 }
447
448 /* Register opp_notifier to catch the change of OPP */
449 ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq);
450 if (ret < 0) {
451 dev_err(dev, "failed to register opp notifier\n");
452 goto err;
453 }
454
455 /*
456 * Enable devfreq-event to get raw data which is used to determine
457 * current bus load.
458 */
459 ret = exynos_bus_enable_edev(bus);
460 if (ret < 0) {
461 dev_err(dev, "failed to enable devfreq-event devices\n");
462 goto err;
463 }
464
465 ret = exynos_bus_set_event(bus);
466 if (ret < 0) {
467 dev_err(dev, "failed to set event to devfreq-event devices\n");
468 goto err;
469 }
470
471 goto out;
472passive:
473 /* Initialize the struct profile and governor data for passive device */
474 profile->target = exynos_bus_passive_target;
475 profile->exit = exynos_bus_passive_exit;
476
477 /* Get the instance of parent devfreq device */
478 parent_devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
479 if (IS_ERR(parent_devfreq)) {
480 ret = -EPROBE_DEFER;
481 goto err;
482 }
483
484 passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
485 if (!passive_data) {
486 ret = -ENOMEM;
487 goto err;
488 }
489 passive_data->parent = parent_devfreq;
490
491 /* Add devfreq device for exynos bus with passive governor */
492 bus->devfreq = devm_devfreq_add_device(dev, profile, DEVFREQ_GOV_PASSIVE,
493 passive_data);
494 if (IS_ERR(bus->devfreq)) {
495 dev_err(dev,
496 "failed to add devfreq dev with passive governor\n");
497 ret = PTR_ERR(bus->devfreq);
498 goto err;
499 }
500
501out:
502 max_state = bus->devfreq->profile->max_state;
503 min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
504 max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
505 pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
506 dev_name(dev), min_freq, max_freq);
507
508 return 0;
509
510err:
511 dev_pm_opp_of_remove_table(dev);
512 clk_disable_unprepare(bus->clk);
513
514 return ret;
515}
516
517#ifdef CONFIG_PM_SLEEP
518static int exynos_bus_resume(struct device *dev)
519{
520 struct exynos_bus *bus = dev_get_drvdata(dev);
521 int ret;
522
523 ret = exynos_bus_enable_edev(bus);
524 if (ret < 0) {
525 dev_err(dev, "failed to enable the devfreq-event devices\n");
526 return ret;
527 }
528
529 return 0;
530}
531
532static int exynos_bus_suspend(struct device *dev)
533{
534 struct exynos_bus *bus = dev_get_drvdata(dev);
535 int ret;
536
537 ret = exynos_bus_disable_edev(bus);
538 if (ret < 0) {
539 dev_err(dev, "failed to disable the devfreq-event devices\n");
540 return ret;
541 }
542
543 return 0;
544}
545#endif
546
547static const struct dev_pm_ops exynos_bus_pm = {
548 SET_SYSTEM_SLEEP_PM_OPS(exynos_bus_suspend, exynos_bus_resume)
549};
550
551static const struct of_device_id exynos_bus_of_match[] = {
552 { .compatible = "samsung,exynos-bus", },
553 { /* sentinel */ },
554};
555MODULE_DEVICE_TABLE(of, exynos_bus_of_match);
556
557static struct platform_driver exynos_bus_platdrv = {
558 .probe = exynos_bus_probe,
559 .driver = {
560 .name = "exynos-bus",
561 .pm = &exynos_bus_pm,
562 .of_match_table = of_match_ptr(exynos_bus_of_match),
563 },
564};
565module_platform_driver(exynos_bus_platdrv);
566
567MODULE_DESCRIPTION("Generic Exynos Bus frequency driver");
568MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
569MODULE_LICENSE("GPL v2");