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/pm_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 u32 *imx6_soc_volt;
  39 static u32 soc_opp_count;
  40
  41 static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index)
  42 {
  43         struct dev_pm_opp *opp;
  44         unsigned long freq_hz, volt, volt_old;
  45         unsigned int old_freq, new_freq;
  46         int ret;
  47
  48         new_freq = freq_table[index].frequency;
  49         freq_hz = new_freq * 1000;
  50         old_freq = clk_get_rate(arm_clk) / 1000;
  51
  52         rcu_read_lock();
  53         opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_hz);
  54         if (IS_ERR(opp)) {
  55                 rcu_read_unlock();
  56                 dev_err(cpu_dev, "failed to find OPP for %ld\n", freq_hz);
  57                 return PTR_ERR(opp);
  58         }
  59
  60         volt = dev_pm_opp_get_voltage(opp);
  61         rcu_read_unlock();
  62         volt_old = regulator_get_voltage(arm_reg);
  63
  64         dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
  65                 old_freq / 1000, volt_old / 1000,
  66                 new_freq / 1000, volt / 1000);
  67
  68         /* scaling up?  scale voltage before frequency */
  69         if (new_freq > old_freq) {
  70                 ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
  71                 if (ret) {
  72                         dev_err(cpu_dev, "failed to scale vddpu up: %d\n", ret);
  73                         return ret;
  74                 }
  75                 ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
  76                 if (ret) {
  77                         dev_err(cpu_dev, "failed to scale vddsoc up: %d\n", ret);
  78                         return ret;
  79                 }
  80                 ret = regulator_set_voltage_tol(arm_reg, volt, 0);
  81                 if (ret) {
  82                         dev_err(cpu_dev,
  83                                 "failed to scale vddarm up: %d\n", ret);
  84                         return ret;
  85                 }
  86         }
  87
  88         /*
  89          * The setpoints are selected per PLL/PDF frequencies, so we need to
  90          * reprogram PLL for frequency scaling.  The procedure of reprogramming
  91          * PLL1 is as below.
  92          *
  93          *  - Enable pll2_pfd2_396m_clk and reparent pll1_sw_clk to it
  94          *  - Reprogram pll1_sys_clk and reparent pll1_sw_clk back to it
  95          *  - Disable pll2_pfd2_396m_clk
  96          */
  97         clk_set_parent(step_clk, pll2_pfd2_396m_clk);
  98         clk_set_parent(pll1_sw_clk, step_clk);
  99         if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk)) {
 100                 clk_set_rate(pll1_sys_clk, new_freq * 1000);
 101                 clk_set_parent(pll1_sw_clk, pll1_sys_clk);
 102         }
 103
 104         /* Ensure the arm clock divider is what we expect */
 105         ret = clk_set_rate(arm_clk, new_freq * 1000);
 106         if (ret) {
 107                 dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
 108                 regulator_set_voltage_tol(arm_reg, volt_old, 0);
 109                 return ret;
 110         }
 111
 112         /* scaling down?  scale voltage after frequency */
 113         if (new_freq < old_freq) {
 114                 ret = regulator_set_voltage_tol(arm_reg, volt, 0);
 115                 if (ret) {
 116                         dev_warn(cpu_dev,
 117                                  "failed to scale vddarm down: %d\n", ret);
 118                         ret = 0;
 119                 }
 120                 ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
 121                 if (ret) {
 122                         dev_warn(cpu_dev, "failed to scale vddsoc down: %d\n", ret);
 123                         ret = 0;
 124                 }
 125                 ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
 126                 if (ret) {
 127                         dev_warn(cpu_dev, "failed to scale vddpu down: %d\n", ret);
 128                         ret = 0;
 129                 }
 130         }
 131
 132         return 0;
 133 }
 134
 135 static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
 136 {
 137         policy->clk = arm_clk;
 138         return cpufreq_generic_init(policy, freq_table, transition_latency);
 139 }
 140
 141 static struct cpufreq_driver imx6q_cpufreq_driver = {
 142         .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 143         .verify = cpufreq_generic_frequency_table_verify,
 144         .target_index = imx6q_set_target,
 145         .get = cpufreq_generic_get,
 146         .init = imx6q_cpufreq_init,
 147         .name = "imx6q-cpufreq",
 148         .attr = cpufreq_generic_attr,
 149 };
 150
 151 static int imx6q_cpufreq_probe(struct platform_device *pdev)
 152 {
 153         struct device_node *np;
 154         struct dev_pm_opp *opp;
 155         unsigned long min_volt, max_volt;
 156         int num, ret;
 157         const struct property *prop;
 158         const __be32 *val;
 159         u32 nr, i, j;
 160
 161         cpu_dev = get_cpu_device(0);
 162         if (!cpu_dev) {
 163                 pr_err("failed to get cpu0 device\n");
 164                 return -ENODEV;
 165         }
 166
 167         np = of_node_get(cpu_dev->of_node);
 168         if (!np) {
 169                 dev_err(cpu_dev, "failed to find cpu0 node\n");
 170                 return -ENOENT;
 171         }
 172
 173         arm_clk = devm_clk_get(cpu_dev, "arm");
 174         pll1_sys_clk = devm_clk_get(cpu_dev, "pll1_sys");
 175         pll1_sw_clk = devm_clk_get(cpu_dev, "pll1_sw");
 176         step_clk = devm_clk_get(cpu_dev, "step");
 177         pll2_pfd2_396m_clk = devm_clk_get(cpu_dev, "pll2_pfd2_396m");
 178         if (IS_ERR(arm_clk) || IS_ERR(pll1_sys_clk) || IS_ERR(pll1_sw_clk) ||
 179             IS_ERR(step_clk) || IS_ERR(pll2_pfd2_396m_clk)) {
 180                 dev_err(cpu_dev, "failed to get clocks\n");
 181                 ret = -ENOENT;
 182                 goto put_node;
 183         }
 184
 185         arm_reg = devm_regulator_get(cpu_dev, "arm");
 186         pu_reg = devm_regulator_get(cpu_dev, "pu");
 187         soc_reg = devm_regulator_get(cpu_dev, "soc");
 188         if (IS_ERR(arm_reg) || IS_ERR(pu_reg) || IS_ERR(soc_reg)) {
 189                 dev_err(cpu_dev, "failed to get regulators\n");
 190                 ret = -ENOENT;
 191                 goto put_node;
 192         }
 193
 194         /*
 195          * We expect an OPP table supplied by platform.
 196          * Just, incase the platform did not supply the OPP
 197          * table, it will try to get it.
 198          */
 199         num = dev_pm_opp_get_opp_count(cpu_dev);
 200         if (num < 0) {
 201                 ret = of_init_opp_table(cpu_dev);
 202                 if (ret < 0) {
 203                         dev_err(cpu_dev, "failed to init OPP table: %d\n", ret);
 204                         goto put_node;
 205                 }
 206
 207                 num = dev_pm_opp_get_opp_count(cpu_dev);
 208                 if (num < 0) {
 209                         ret = num;
 210                         dev_err(cpu_dev, "no OPP table is found: %d\n", ret);
 211                         goto put_node;
 212                 }
 213         }
 214
 215         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 216         if (ret) {
 217                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 218                 goto put_node;
 219         }
 220
 221         /* Make imx6_soc_volt array's size same as arm opp number */
 222         imx6_soc_volt = devm_kzalloc(cpu_dev, sizeof(*imx6_soc_volt) * num, GFP_KERNEL);
 223         if (imx6_soc_volt == NULL) {
 224                 ret = -ENOMEM;
 225                 goto free_freq_table;
 226         }
 227
 228         prop = of_find_property(np, "fsl,soc-operating-points", NULL);
 229         if (!prop || !prop->value)
 230                 goto soc_opp_out;
 231
 232         /*
 233          * Each OPP is a set of tuples consisting of frequency and
 234          * voltage like <freq-kHz vol-uV>.
 235          */
 236         nr = prop->length / sizeof(u32);
 237         if (nr % 2 || (nr / 2) < num)
 238                 goto soc_opp_out;
 239
 240         for (j = 0; j < num; j++) {
 241                 val = prop->value;
 242                 for (i = 0; i < nr / 2; i++) {
 243                         unsigned long freq = be32_to_cpup(val++);
 244                         unsigned long volt = be32_to_cpup(val++);
 245                         if (freq_table[j].frequency == freq) {
 246                                 imx6_soc_volt[soc_opp_count++] = volt;
 247                                 break;
 248                         }
 249                 }
 250         }
 251
 252 soc_opp_out:
 253         /* use fixed soc opp volt if no valid soc opp info found in dtb */
 254         if (soc_opp_count != num) {
 255                 dev_warn(cpu_dev, "can NOT find valid fsl,soc-operating-points property in dtb, use default value!\n");
 256                 for (j = 0; j < num; j++)
 257                         imx6_soc_volt[j] = PU_SOC_VOLTAGE_NORMAL;
 258                 if (freq_table[num - 1].frequency * 1000 == FREQ_1P2_GHZ)
 259                         imx6_soc_volt[num - 1] = PU_SOC_VOLTAGE_HIGH;
 260         }
 261
 262         if (of_property_read_u32(np, "clock-latency", &transition_latency))
 263                 transition_latency = CPUFREQ_ETERNAL;
 264
 265         /*
 266          * Calculate the ramp time for max voltage change in the
 267          * VDDSOC and VDDPU regulators.
 268          */
 269         ret = regulator_set_voltage_time(soc_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
 270         if (ret > 0)
 271                 transition_latency += ret * 1000;
 272         ret = regulator_set_voltage_time(pu_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
 273         if (ret > 0)
 274                 transition_latency += ret * 1000;
 275
 276         /*
 277          * OPP is maintained in order of increasing frequency, and
 278          * freq_table initialised from OPP is therefore sorted in the
 279          * same order.
 280          */
 281         rcu_read_lock();
 282         opp = dev_pm_opp_find_freq_exact(cpu_dev,
 283                                   freq_table[0].frequency * 1000, true);
 284         min_volt = dev_pm_opp_get_voltage(opp);
 285         opp = dev_pm_opp_find_freq_exact(cpu_dev,
 286                                   freq_table[--num].frequency * 1000, true);
 287         max_volt = dev_pm_opp_get_voltage(opp);
 288         rcu_read_unlock();
 289         ret = regulator_set_voltage_time(arm_reg, min_volt, max_volt);
 290         if (ret > 0)
 291                 transition_latency += ret * 1000;
 292
 293         ret = cpufreq_register_driver(&imx6q_cpufreq_driver);
 294         if (ret) {
 295                 dev_err(cpu_dev, "failed register driver: %d\n", ret);
 296                 goto free_freq_table;
 297         }
 298
 299         of_node_put(np);
 300         return 0;
 301
 302 free_freq_table:
 303         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 304 put_node:
 305         of_node_put(np);
 306         return ret;
 307 }
 308
 309 static int imx6q_cpufreq_remove(struct platform_device *pdev)
 310 {
 311         cpufreq_unregister_driver(&imx6q_cpufreq_driver);
 312         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 313
 314         return 0;
 315 }
 316
 317 static struct platform_driver imx6q_cpufreq_platdrv = {
 318         .driver = {
 319                 .name   = "imx6q-cpufreq",
 320                 .owner  = THIS_MODULE,
 321         },
 322         .probe          = imx6q_cpufreq_probe,
 323         .remove         = imx6q_cpufreq_remove,
 324 };
 325 module_platform_driver(imx6q_cpufreq_platdrv);
 326
 327 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 328 MODULE_DESCRIPTION("Freescale i.MX6Q cpufreq driver");
 329 MODULE_LICENSE("GPL");