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