2 * Copyright (C) 2013 Freescale Semiconductor, Inc.
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.
10 #include <linux/cpufreq.h>
11 #include <linux/delay.h>
12 #include <linux/err.h>
13 #include <linux/module.h>
15 #include <linux/opp.h>
16 #include <linux/platform_device.h>
17 #include <linux/regulator/consumer.h>
19 #define PU_SOC_VOLTAGE_NORMAL 1250000
20 #define PU_SOC_VOLTAGE_HIGH 1275000
21 #define FREQ_1P2_GHZ 1200000000
23 static struct regulator *arm_reg;
24 static struct regulator *pu_reg;
25 static struct regulator *soc_reg;
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;
33 static struct device *cpu_dev;
34 static struct cpufreq_frequency_table *freq_table;
35 static unsigned int transition_latency;
37 static int imx6q_verify_speed(struct cpufreq_policy *policy)
39 return cpufreq_frequency_table_verify(policy, freq_table);
42 static unsigned int imx6q_get_speed(unsigned int cpu)
44 return clk_get_rate(arm_clk) / 1000;
47 static int imx6q_set_target(struct cpufreq_policy *policy,
48 unsigned int target_freq, unsigned int relation)
50 struct cpufreq_freqs freqs;
52 unsigned long freq_hz, volt, volt_old;
56 ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
59 dev_err(cpu_dev, "failed to match target frequency %d: %d\n",
64 freqs.new = freq_table[index].frequency;
65 freq_hz = freqs.new * 1000;
66 freqs.old = clk_get_rate(arm_clk) / 1000;
68 if (freqs.old == freqs.new)
71 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
74 opp = opp_find_freq_ceil(cpu_dev, &freq_hz);
77 dev_err(cpu_dev, "failed to find OPP for %ld\n", freq_hz);
81 volt = opp_get_voltage(opp);
83 volt_old = regulator_get_voltage(arm_reg);
85 dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
86 freqs.old / 1000, volt_old / 1000,
87 freqs.new / 1000, volt / 1000);
89 /* scaling up? scale voltage before frequency */
90 if (freqs.new > freqs.old) {
91 ret = regulator_set_voltage_tol(arm_reg, volt, 0);
94 "failed to scale vddarm up: %d\n", ret);
99 * Need to increase vddpu and vddsoc for safety
100 * if we are about to run at 1.2 GHz.
102 if (freqs.new == FREQ_1P2_GHZ / 1000) {
103 regulator_set_voltage_tol(pu_reg,
104 PU_SOC_VOLTAGE_HIGH, 0);
105 regulator_set_voltage_tol(soc_reg,
106 PU_SOC_VOLTAGE_HIGH, 0);
111 * The setpoints are selected per PLL/PDF frequencies, so we need to
112 * reprogram PLL for frequency scaling. The procedure of reprogramming
115 * - Enable pll2_pfd2_396m_clk and reparent pll1_sw_clk to it
116 * - Reprogram pll1_sys_clk and reparent pll1_sw_clk back to it
117 * - Disable pll2_pfd2_396m_clk
119 clk_prepare_enable(pll2_pfd2_396m_clk);
120 clk_set_parent(step_clk, pll2_pfd2_396m_clk);
121 clk_set_parent(pll1_sw_clk, step_clk);
122 if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk)) {
123 clk_set_rate(pll1_sys_clk, freqs.new * 1000);
125 * If we are leaving 396 MHz set-point, we need to enable
126 * pll1_sys_clk and disable pll2_pfd2_396m_clk to keep
127 * their use count correct.
129 if (freqs.old * 1000 <= clk_get_rate(pll2_pfd2_396m_clk)) {
130 clk_prepare_enable(pll1_sys_clk);
131 clk_disable_unprepare(pll2_pfd2_396m_clk);
133 clk_set_parent(pll1_sw_clk, pll1_sys_clk);
134 clk_disable_unprepare(pll2_pfd2_396m_clk);
137 * Disable pll1_sys_clk if pll2_pfd2_396m_clk is sufficient
138 * to provide the frequency.
140 clk_disable_unprepare(pll1_sys_clk);
143 /* Ensure the arm clock divider is what we expect */
144 ret = clk_set_rate(arm_clk, freqs.new * 1000);
146 dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
147 regulator_set_voltage_tol(arm_reg, volt_old, 0);
151 /* scaling down? scale voltage after frequency */
152 if (freqs.new < freqs.old) {
153 ret = regulator_set_voltage_tol(arm_reg, volt, 0);
156 "failed to scale vddarm down: %d\n", ret);
158 if (freqs.old == FREQ_1P2_GHZ / 1000) {
159 regulator_set_voltage_tol(pu_reg,
160 PU_SOC_VOLTAGE_NORMAL, 0);
161 regulator_set_voltage_tol(soc_reg,
162 PU_SOC_VOLTAGE_NORMAL, 0);
166 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
171 static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
175 ret = cpufreq_frequency_table_cpuinfo(policy, freq_table);
177 dev_err(cpu_dev, "invalid frequency table: %d\n", ret);
181 policy->cpuinfo.transition_latency = transition_latency;
182 policy->cur = clk_get_rate(arm_clk) / 1000;
183 cpumask_setall(policy->cpus);
184 cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
189 static int imx6q_cpufreq_exit(struct cpufreq_policy *policy)
191 cpufreq_frequency_table_put_attr(policy->cpu);
195 static struct freq_attr *imx6q_cpufreq_attr[] = {
196 &cpufreq_freq_attr_scaling_available_freqs,
200 static struct cpufreq_driver imx6q_cpufreq_driver = {
201 .verify = imx6q_verify_speed,
202 .target = imx6q_set_target,
203 .get = imx6q_get_speed,
204 .init = imx6q_cpufreq_init,
205 .exit = imx6q_cpufreq_exit,
206 .name = "imx6q-cpufreq",
207 .attr = imx6q_cpufreq_attr,
210 static int imx6q_cpufreq_probe(struct platform_device *pdev)
212 struct device_node *np;
214 unsigned long min_volt, max_volt;
217 cpu_dev = &pdev->dev;
219 np = of_find_node_by_path("/cpus/cpu@0");
221 dev_err(cpu_dev, "failed to find cpu0 node\n");
225 cpu_dev->of_node = np;
227 arm_clk = devm_clk_get(cpu_dev, "arm");
228 pll1_sys_clk = devm_clk_get(cpu_dev, "pll1_sys");
229 pll1_sw_clk = devm_clk_get(cpu_dev, "pll1_sw");
230 step_clk = devm_clk_get(cpu_dev, "step");
231 pll2_pfd2_396m_clk = devm_clk_get(cpu_dev, "pll2_pfd2_396m");
232 if (IS_ERR(arm_clk) || IS_ERR(pll1_sys_clk) || IS_ERR(pll1_sw_clk) ||
233 IS_ERR(step_clk) || IS_ERR(pll2_pfd2_396m_clk)) {
234 dev_err(cpu_dev, "failed to get clocks\n");
239 arm_reg = devm_regulator_get(cpu_dev, "arm");
240 pu_reg = devm_regulator_get(cpu_dev, "pu");
241 soc_reg = devm_regulator_get(cpu_dev, "soc");
242 if (IS_ERR(arm_reg) || IS_ERR(pu_reg) || IS_ERR(soc_reg)) {
243 dev_err(cpu_dev, "failed to get regulators\n");
248 /* We expect an OPP table supplied by platform */
249 num = opp_get_opp_count(cpu_dev);
252 dev_err(cpu_dev, "no OPP table is found: %d\n", ret);
256 ret = opp_init_cpufreq_table(cpu_dev, &freq_table);
258 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
262 if (of_property_read_u32(np, "clock-latency", &transition_latency))
263 transition_latency = CPUFREQ_ETERNAL;
266 * OPP is maintained in order of increasing frequency, and
267 * freq_table initialised from OPP is therefore sorted in the
271 opp = opp_find_freq_exact(cpu_dev,
272 freq_table[0].frequency * 1000, true);
273 min_volt = opp_get_voltage(opp);
274 opp = opp_find_freq_exact(cpu_dev,
275 freq_table[--num].frequency * 1000, true);
276 max_volt = opp_get_voltage(opp);
278 ret = regulator_set_voltage_time(arm_reg, min_volt, max_volt);
280 transition_latency += ret * 1000;
282 /* Count vddpu and vddsoc latency in for 1.2 GHz support */
283 if (freq_table[num].frequency == FREQ_1P2_GHZ / 1000) {
284 ret = regulator_set_voltage_time(pu_reg, PU_SOC_VOLTAGE_NORMAL,
285 PU_SOC_VOLTAGE_HIGH);
287 transition_latency += ret * 1000;
288 ret = regulator_set_voltage_time(soc_reg, PU_SOC_VOLTAGE_NORMAL,
289 PU_SOC_VOLTAGE_HIGH);
291 transition_latency += ret * 1000;
294 ret = cpufreq_register_driver(&imx6q_cpufreq_driver);
296 dev_err(cpu_dev, "failed register driver: %d\n", ret);
297 goto free_freq_table;
304 opp_free_cpufreq_table(cpu_dev, &freq_table);
310 static int imx6q_cpufreq_remove(struct platform_device *pdev)
312 cpufreq_unregister_driver(&imx6q_cpufreq_driver);
313 opp_free_cpufreq_table(cpu_dev, &freq_table);
318 static struct platform_driver imx6q_cpufreq_platdrv = {
320 .name = "imx6q-cpufreq",
321 .owner = THIS_MODULE,
323 .probe = imx6q_cpufreq_probe,
324 .remove = imx6q_cpufreq_remove,
326 module_platform_driver(imx6q_cpufreq_platdrv);
328 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
329 MODULE_DESCRIPTION("Freescale i.MX6Q cpufreq driver");
330 MODULE_LICENSE("GPL");