drivers/cpufreq/imx6q-cpufreq.c

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