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1 | /* |
2 | * Copyright (C) 2013 Freescale Semiconductor, Inc. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | */ | |
8 | ||
9 | #include <linux/clk.h> | |
10 | #include <linux/cpufreq.h> | |
11 | #include <linux/delay.h> | |
12 | #include <linux/err.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/of.h> | |
15 | #include <linux/opp.h> | |
16 | #include <linux/platform_device.h> | |
17 | #include <linux/regulator/consumer.h> | |
18 | ||
19 | #define PU_SOC_VOLTAGE_NORMAL 1250000 | |
20 | #define PU_SOC_VOLTAGE_HIGH 1275000 | |
21 | #define FREQ_1P2_GHZ 1200000000 | |
22 | ||
23 | static struct regulator *arm_reg; | |
24 | static struct regulator *pu_reg; | |
25 | static struct regulator *soc_reg; | |
26 | ||
27 | static struct clk *arm_clk; | |
28 | static struct clk *pll1_sys_clk; | |
29 | static struct clk *pll1_sw_clk; | |
30 | static struct clk *step_clk; | |
31 | static struct clk *pll2_pfd2_396m_clk; | |
32 | ||
33 | static struct device *cpu_dev; | |
34 | static struct cpufreq_frequency_table *freq_table; | |
35 | static unsigned int transition_latency; | |
36 | ||
37 | static int imx6q_verify_speed(struct cpufreq_policy *policy) | |
38 | { | |
39 | return cpufreq_frequency_table_verify(policy, freq_table); | |
40 | } | |
41 | ||
42 | static unsigned int imx6q_get_speed(unsigned int cpu) | |
43 | { | |
44 | return clk_get_rate(arm_clk) / 1000; | |
45 | } | |
46 | ||
47 | static int imx6q_set_target(struct cpufreq_policy *policy, | |
48 | unsigned int target_freq, unsigned int relation) | |
49 | { | |
50 | struct cpufreq_freqs freqs; | |
51 | struct opp *opp; | |
52 | unsigned long freq_hz, volt, volt_old; | |
53 | unsigned int index, cpu; | |
54 | int ret; | |
55 | ||
56 | ret = cpufreq_frequency_table_target(policy, freq_table, target_freq, | |
57 | relation, &index); | |
58 | if (ret) { | |
59 | dev_err(cpu_dev, "failed to match target frequency %d: %d\n", | |
60 | target_freq, ret); | |
61 | return ret; | |
62 | } | |
63 | ||
64 | freqs.new = freq_table[index].frequency; | |
65 | freq_hz = freqs.new * 1000; | |
66 | freqs.old = clk_get_rate(arm_clk) / 1000; | |
67 | ||
68 | if (freqs.old == freqs.new) | |
69 | return 0; | |
70 | ||
71 | for_each_online_cpu(cpu) { | |
72 | freqs.cpu = cpu; | |
73 | cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); | |
74 | } | |
75 | ||
76 | rcu_read_lock(); | |
77 | opp = opp_find_freq_ceil(cpu_dev, &freq_hz); | |
78 | if (IS_ERR(opp)) { | |
79 | rcu_read_unlock(); | |
80 | dev_err(cpu_dev, "failed to find OPP for %ld\n", freq_hz); | |
81 | return PTR_ERR(opp); | |
82 | } | |
83 | ||
84 | volt = opp_get_voltage(opp); | |
85 | rcu_read_unlock(); | |
86 | volt_old = regulator_get_voltage(arm_reg); | |
87 | ||
88 | dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n", | |
89 | freqs.old / 1000, volt_old / 1000, | |
90 | freqs.new / 1000, volt / 1000); | |
91 | ||
92 | /* scaling up? scale voltage before frequency */ | |
93 | if (freqs.new > freqs.old) { | |
94 | ret = regulator_set_voltage_tol(arm_reg, volt, 0); | |
95 | if (ret) { | |
96 | dev_err(cpu_dev, | |
97 | "failed to scale vddarm up: %d\n", ret); | |
98 | return ret; | |
99 | } | |
100 | ||
101 | /* | |
102 | * Need to increase vddpu and vddsoc for safety | |
103 | * if we are about to run at 1.2 GHz. | |
104 | */ | |
105 | if (freqs.new == FREQ_1P2_GHZ / 1000) { | |
106 | regulator_set_voltage_tol(pu_reg, | |
107 | PU_SOC_VOLTAGE_HIGH, 0); | |
108 | regulator_set_voltage_tol(soc_reg, | |
109 | PU_SOC_VOLTAGE_HIGH, 0); | |
110 | } | |
111 | } | |
112 | ||
113 | /* | |
114 | * The setpoints are selected per PLL/PDF frequencies, so we need to | |
115 | * reprogram PLL for frequency scaling. The procedure of reprogramming | |
116 | * PLL1 is as below. | |
117 | * | |
118 | * - Enable pll2_pfd2_396m_clk and reparent pll1_sw_clk to it | |
119 | * - Reprogram pll1_sys_clk and reparent pll1_sw_clk back to it | |
120 | * - Disable pll2_pfd2_396m_clk | |
121 | */ | |
122 | clk_prepare_enable(pll2_pfd2_396m_clk); | |
123 | clk_set_parent(step_clk, pll2_pfd2_396m_clk); | |
124 | clk_set_parent(pll1_sw_clk, step_clk); | |
125 | if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk)) { | |
126 | clk_set_rate(pll1_sys_clk, freqs.new * 1000); | |
127 | /* | |
128 | * If we are leaving 396 MHz set-point, we need to enable | |
129 | * pll1_sys_clk and disable pll2_pfd2_396m_clk to keep | |
130 | * their use count correct. | |
131 | */ | |
132 | if (freqs.old * 1000 <= clk_get_rate(pll2_pfd2_396m_clk)) { | |
133 | clk_prepare_enable(pll1_sys_clk); | |
134 | clk_disable_unprepare(pll2_pfd2_396m_clk); | |
135 | } | |
136 | clk_set_parent(pll1_sw_clk, pll1_sys_clk); | |
137 | clk_disable_unprepare(pll2_pfd2_396m_clk); | |
138 | } else { | |
139 | /* | |
140 | * Disable pll1_sys_clk if pll2_pfd2_396m_clk is sufficient | |
141 | * to provide the frequency. | |
142 | */ | |
143 | clk_disable_unprepare(pll1_sys_clk); | |
144 | } | |
145 | ||
146 | /* Ensure the arm clock divider is what we expect */ | |
147 | ret = clk_set_rate(arm_clk, freqs.new * 1000); | |
148 | if (ret) { | |
149 | dev_err(cpu_dev, "failed to set clock rate: %d\n", ret); | |
150 | regulator_set_voltage_tol(arm_reg, volt_old, 0); | |
151 | return ret; | |
152 | } | |
153 | ||
154 | /* scaling down? scale voltage after frequency */ | |
155 | if (freqs.new < freqs.old) { | |
156 | ret = regulator_set_voltage_tol(arm_reg, volt, 0); | |
157 | if (ret) | |
158 | dev_warn(cpu_dev, | |
159 | "failed to scale vddarm down: %d\n", ret); | |
160 | ||
161 | if (freqs.old == FREQ_1P2_GHZ / 1000) { | |
162 | regulator_set_voltage_tol(pu_reg, | |
163 | PU_SOC_VOLTAGE_NORMAL, 0); | |
164 | regulator_set_voltage_tol(soc_reg, | |
165 | PU_SOC_VOLTAGE_NORMAL, 0); | |
166 | } | |
167 | } | |
168 | ||
169 | for_each_online_cpu(cpu) { | |
170 | freqs.cpu = cpu; | |
171 | cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); | |
172 | } | |
173 | ||
174 | return 0; | |
175 | } | |
176 | ||
177 | static int imx6q_cpufreq_init(struct cpufreq_policy *policy) | |
178 | { | |
179 | int ret; | |
180 | ||
181 | ret = cpufreq_frequency_table_cpuinfo(policy, freq_table); | |
182 | if (ret) { | |
183 | dev_err(cpu_dev, "invalid frequency table: %d\n", ret); | |
184 | return ret; | |
185 | } | |
186 | ||
187 | policy->cpuinfo.transition_latency = transition_latency; | |
188 | policy->cur = clk_get_rate(arm_clk) / 1000; | |
189 | cpumask_setall(policy->cpus); | |
190 | cpufreq_frequency_table_get_attr(freq_table, policy->cpu); | |
191 | ||
192 | return 0; | |
193 | } | |
194 | ||
195 | static int imx6q_cpufreq_exit(struct cpufreq_policy *policy) | |
196 | { | |
197 | cpufreq_frequency_table_put_attr(policy->cpu); | |
198 | return 0; | |
199 | } | |
200 | ||
201 | static struct freq_attr *imx6q_cpufreq_attr[] = { | |
202 | &cpufreq_freq_attr_scaling_available_freqs, | |
203 | NULL, | |
204 | }; | |
205 | ||
206 | static struct cpufreq_driver imx6q_cpufreq_driver = { | |
207 | .verify = imx6q_verify_speed, | |
208 | .target = imx6q_set_target, | |
209 | .get = imx6q_get_speed, | |
210 | .init = imx6q_cpufreq_init, | |
211 | .exit = imx6q_cpufreq_exit, | |
212 | .name = "imx6q-cpufreq", | |
213 | .attr = imx6q_cpufreq_attr, | |
214 | }; | |
215 | ||
216 | static int imx6q_cpufreq_probe(struct platform_device *pdev) | |
217 | { | |
218 | struct device_node *np; | |
219 | struct opp *opp; | |
220 | unsigned long min_volt, max_volt; | |
221 | int num, ret; | |
222 | ||
223 | cpu_dev = &pdev->dev; | |
224 | ||
225 | np = of_find_node_by_path("/cpus/cpu@0"); | |
226 | if (!np) { | |
227 | dev_err(cpu_dev, "failed to find cpu0 node\n"); | |
228 | return -ENOENT; | |
229 | } | |
230 | ||
231 | cpu_dev->of_node = np; | |
232 | ||
233 | arm_clk = devm_clk_get(cpu_dev, "arm"); | |
234 | pll1_sys_clk = devm_clk_get(cpu_dev, "pll1_sys"); | |
235 | pll1_sw_clk = devm_clk_get(cpu_dev, "pll1_sw"); | |
236 | step_clk = devm_clk_get(cpu_dev, "step"); | |
237 | pll2_pfd2_396m_clk = devm_clk_get(cpu_dev, "pll2_pfd2_396m"); | |
238 | if (IS_ERR(arm_clk) || IS_ERR(pll1_sys_clk) || IS_ERR(pll1_sw_clk) || | |
239 | IS_ERR(step_clk) || IS_ERR(pll2_pfd2_396m_clk)) { | |
240 | dev_err(cpu_dev, "failed to get clocks\n"); | |
241 | ret = -ENOENT; | |
242 | goto put_node; | |
243 | } | |
244 | ||
245 | arm_reg = devm_regulator_get(cpu_dev, "arm"); | |
246 | pu_reg = devm_regulator_get(cpu_dev, "pu"); | |
247 | soc_reg = devm_regulator_get(cpu_dev, "soc"); | |
248 | if (!arm_reg || !pu_reg || !soc_reg) { | |
249 | dev_err(cpu_dev, "failed to get regulators\n"); | |
250 | ret = -ENOENT; | |
251 | goto put_node; | |
252 | } | |
253 | ||
254 | /* We expect an OPP table supplied by platform */ | |
255 | num = opp_get_opp_count(cpu_dev); | |
256 | if (num < 0) { | |
257 | ret = num; | |
258 | dev_err(cpu_dev, "no OPP table is found: %d\n", ret); | |
259 | goto put_node; | |
260 | } | |
261 | ||
262 | ret = opp_init_cpufreq_table(cpu_dev, &freq_table); | |
263 | if (ret) { | |
264 | dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret); | |
265 | goto put_node; | |
266 | } | |
267 | ||
268 | if (of_property_read_u32(np, "clock-latency", &transition_latency)) | |
269 | transition_latency = CPUFREQ_ETERNAL; | |
270 | ||
271 | /* | |
272 | * OPP is maintained in order of increasing frequency, and | |
273 | * freq_table initialised from OPP is therefore sorted in the | |
274 | * same order. | |
275 | */ | |
276 | rcu_read_lock(); | |
277 | opp = opp_find_freq_exact(cpu_dev, | |
278 | freq_table[0].frequency * 1000, true); | |
279 | min_volt = opp_get_voltage(opp); | |
280 | opp = opp_find_freq_exact(cpu_dev, | |
281 | freq_table[--num].frequency * 1000, true); | |
282 | max_volt = opp_get_voltage(opp); | |
283 | rcu_read_unlock(); | |
284 | ret = regulator_set_voltage_time(arm_reg, min_volt, max_volt); | |
285 | if (ret > 0) | |
286 | transition_latency += ret * 1000; | |
287 | ||
288 | /* Count vddpu and vddsoc latency in for 1.2 GHz support */ | |
289 | if (freq_table[num].frequency == FREQ_1P2_GHZ / 1000) { | |
290 | ret = regulator_set_voltage_time(pu_reg, PU_SOC_VOLTAGE_NORMAL, | |
291 | PU_SOC_VOLTAGE_HIGH); | |
292 | if (ret > 0) | |
293 | transition_latency += ret * 1000; | |
294 | ret = regulator_set_voltage_time(soc_reg, PU_SOC_VOLTAGE_NORMAL, | |
295 | PU_SOC_VOLTAGE_HIGH); | |
296 | if (ret > 0) | |
297 | transition_latency += ret * 1000; | |
298 | } | |
299 | ||
300 | ret = cpufreq_register_driver(&imx6q_cpufreq_driver); | |
301 | if (ret) { | |
302 | dev_err(cpu_dev, "failed register driver: %d\n", ret); | |
303 | goto free_freq_table; | |
304 | } | |
305 | ||
306 | of_node_put(np); | |
307 | return 0; | |
308 | ||
309 | free_freq_table: | |
310 | opp_free_cpufreq_table(cpu_dev, &freq_table); | |
311 | put_node: | |
312 | of_node_put(np); | |
313 | return ret; | |
314 | } | |
315 | ||
316 | static int imx6q_cpufreq_remove(struct platform_device *pdev) | |
317 | { | |
318 | cpufreq_unregister_driver(&imx6q_cpufreq_driver); | |
319 | opp_free_cpufreq_table(cpu_dev, &freq_table); | |
320 | ||
321 | return 0; | |
322 | } | |
323 | ||
324 | static struct platform_driver imx6q_cpufreq_platdrv = { | |
325 | .driver = { | |
326 | .name = "imx6q-cpufreq", | |
327 | .owner = THIS_MODULE, | |
328 | }, | |
329 | .probe = imx6q_cpufreq_probe, | |
330 | .remove = imx6q_cpufreq_remove, | |
331 | }; | |
332 | module_platform_driver(imx6q_cpufreq_platdrv); | |
333 | ||
334 | MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>"); | |
335 | MODULE_DESCRIPTION("Freescale i.MX6Q cpufreq driver"); | |
336 | MODULE_LICENSE("GPL"); |