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/err.h>
  13 #include <linux/module.h>
  14 #include <linux/of.h>
  15 #include <linux/pm_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 /* clk used by i.MX6UL */
  34 static struct clk *pll2_bus_clk;
  35 static struct clk *secondary_sel_clk;
  36
  37 static struct device *cpu_dev;
  38 static bool free_opp;
  39 static struct cpufreq_frequency_table *freq_table;
  40 static unsigned int transition_latency;
  41
  42 static u32 *imx6_soc_volt;
  43 static u32 soc_opp_count;
  44
  45 static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index)
  46 {
  47         struct dev_pm_opp *opp;
  48         unsigned long freq_hz, volt, volt_old;
  49         unsigned int old_freq, new_freq;
  50         int ret;
  51
  52         new_freq = freq_table[index].frequency;
  53         freq_hz = new_freq * 1000;
  54         old_freq = clk_get_rate(arm_clk) / 1000;
  55
  56         opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_hz);
  57         if (IS_ERR(opp)) {
  58                 dev_err(cpu_dev, "failed to find OPP for %ld\n", freq_hz);
  59                 return PTR_ERR(opp);
  60         }
  61
  62         volt = dev_pm_opp_get_voltage(opp);
  63         dev_pm_opp_put(opp);
  64
  65         volt_old = regulator_get_voltage(arm_reg);
  66
  67         dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
  68                 old_freq / 1000, volt_old / 1000,
  69                 new_freq / 1000, volt / 1000);
  70
  71         /* scaling up?  scale voltage before frequency */
  72         if (new_freq > old_freq) {
  73                 if (!IS_ERR(pu_reg)) {
  74                         ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
  75                         if (ret) {
  76                                 dev_err(cpu_dev, "failed to scale vddpu up: %d\n", ret);
  77                                 return ret;
  78                         }
  79                 }
  80                 ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
  81                 if (ret) {
  82                         dev_err(cpu_dev, "failed to scale vddsoc up: %d\n", ret);
  83                         return ret;
  84                 }
  85                 ret = regulator_set_voltage_tol(arm_reg, volt, 0);
  86                 if (ret) {
  87                         dev_err(cpu_dev,
  88                                 "failed to scale vddarm up: %d\n", ret);
  89                         return ret;
  90                 }
  91         }
  92
  93         /*
  94          * The setpoints are selected per PLL/PDF frequencies, so we need to
  95          * reprogram PLL for frequency scaling.  The procedure of reprogramming
  96          * PLL1 is as below.
  97          * For i.MX6UL, it has a secondary clk mux, the cpu frequency change
  98          * flow is slightly different from other i.MX6 OSC.
  99          * The cpu frequeny change flow for i.MX6(except i.MX6UL) is as below:
 100          *  - Enable pll2_pfd2_396m_clk and reparent pll1_sw_clk to it
 101          *  - Reprogram pll1_sys_clk and reparent pll1_sw_clk back to it
 102          *  - Disable pll2_pfd2_396m_clk
 103          */
 104         if (of_machine_is_compatible("fsl,imx6ul") ||
 105             of_machine_is_compatible("fsl,imx6ull")) {
 106                 /*
 107                  * When changing pll1_sw_clk's parent to pll1_sys_clk,
 108                  * CPU may run at higher than 528MHz, this will lead to
 109                  * the system unstable if the voltage is lower than the
 110                  * voltage of 528MHz, so lower the CPU frequency to one
 111                  * half before changing CPU frequency.
 112                  */
 113                 clk_set_rate(arm_clk, (old_freq >> 1) * 1000);
 114                 clk_set_parent(pll1_sw_clk, pll1_sys_clk);
 115                 if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk))
 116                         clk_set_parent(secondary_sel_clk, pll2_bus_clk);
 117                 else
 118                         clk_set_parent(secondary_sel_clk, pll2_pfd2_396m_clk);
 119                 clk_set_parent(step_clk, secondary_sel_clk);
 120                 clk_set_parent(pll1_sw_clk, step_clk);
 121         } else {
 122                 clk_set_parent(step_clk, pll2_pfd2_396m_clk);
 123                 clk_set_parent(pll1_sw_clk, step_clk);
 124                 if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk)) {
 125                         clk_set_rate(pll1_sys_clk, new_freq * 1000);
 126                         clk_set_parent(pll1_sw_clk, pll1_sys_clk);
 127                 }
 128         }
 129
 130         /* Ensure the arm clock divider is what we expect */
 131         ret = clk_set_rate(arm_clk, new_freq * 1000);
 132         if (ret) {
 133                 dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
 134                 regulator_set_voltage_tol(arm_reg, volt_old, 0);
 135                 return ret;
 136         }
 137
 138         /* scaling down?  scale voltage after frequency */
 139         if (new_freq < old_freq) {
 140                 ret = regulator_set_voltage_tol(arm_reg, volt, 0);
 141                 if (ret) {
 142                         dev_warn(cpu_dev,
 143                                  "failed to scale vddarm down: %d\n", ret);
 144                         ret = 0;
 145                 }
 146                 ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
 147                 if (ret) {
 148                         dev_warn(cpu_dev, "failed to scale vddsoc down: %d\n", ret);
 149                         ret = 0;
 150                 }
 151                 if (!IS_ERR(pu_reg)) {
 152                         ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
 153                         if (ret) {
 154                                 dev_warn(cpu_dev, "failed to scale vddpu down: %d\n", ret);
 155                                 ret = 0;
 156                         }
 157                 }
 158         }
 159
 160         return 0;
 161 }
 162
 163 static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
 164 {
 165         int ret;
 166
 167         policy->clk = arm_clk;
 168         ret = cpufreq_generic_init(policy, freq_table, transition_latency);
 169         policy->suspend_freq = policy->max;
 170
 171         return ret;
 172 }
 173
 174 static struct cpufreq_driver imx6q_cpufreq_driver = {
 175         .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 176         .verify = cpufreq_generic_frequency_table_verify,
 177         .target_index = imx6q_set_target,
 178         .get = cpufreq_generic_get,
 179         .init = imx6q_cpufreq_init,
 180         .name = "imx6q-cpufreq",
 181         .attr = cpufreq_generic_attr,
 182         .suspend = cpufreq_generic_suspend,
 183 };
 184
 185 static int imx6q_cpufreq_probe(struct platform_device *pdev)
 186 {
 187         struct device_node *np;
 188         struct dev_pm_opp *opp;
 189         unsigned long min_volt, max_volt;
 190         int num, ret;
 191         const struct property *prop;
 192         const __be32 *val;
 193         u32 nr, i, j;
 194
 195         cpu_dev = get_cpu_device(0);
 196         if (!cpu_dev) {
 197                 pr_err("failed to get cpu0 device\n");
 198                 return -ENODEV;
 199         }
 200
 201         np = of_node_get(cpu_dev->of_node);
 202         if (!np) {
 203                 dev_err(cpu_dev, "failed to find cpu0 node\n");
 204                 return -ENOENT;
 205         }
 206
 207         arm_clk = clk_get(cpu_dev, "arm");
 208         pll1_sys_clk = clk_get(cpu_dev, "pll1_sys");
 209         pll1_sw_clk = clk_get(cpu_dev, "pll1_sw");
 210         step_clk = clk_get(cpu_dev, "step");
 211         pll2_pfd2_396m_clk = clk_get(cpu_dev, "pll2_pfd2_396m");
 212         if (IS_ERR(arm_clk) || IS_ERR(pll1_sys_clk) || IS_ERR(pll1_sw_clk) ||
 213             IS_ERR(step_clk) || IS_ERR(pll2_pfd2_396m_clk)) {
 214                 dev_err(cpu_dev, "failed to get clocks\n");
 215                 ret = -ENOENT;
 216                 goto put_clk;
 217         }
 218
 219         if (of_machine_is_compatible("fsl,imx6ul") ||
 220             of_machine_is_compatible("fsl,imx6ull")) {
 221                 pll2_bus_clk = clk_get(cpu_dev, "pll2_bus");
 222                 secondary_sel_clk = clk_get(cpu_dev, "secondary_sel");
 223                 if (IS_ERR(pll2_bus_clk) || IS_ERR(secondary_sel_clk)) {
 224                         dev_err(cpu_dev, "failed to get clocks specific to imx6ul\n");
 225                         ret = -ENOENT;
 226                         goto put_clk;
 227                 }
 228         }
 229
 230         arm_reg = regulator_get(cpu_dev, "arm");
 231         pu_reg = regulator_get_optional(cpu_dev, "pu");
 232         soc_reg = regulator_get(cpu_dev, "soc");
 233         if (PTR_ERR(arm_reg) == -EPROBE_DEFER ||
 234                         PTR_ERR(soc_reg) == -EPROBE_DEFER ||
 235                         PTR_ERR(pu_reg) == -EPROBE_DEFER) {
 236                 ret = -EPROBE_DEFER;
 237                 dev_dbg(cpu_dev, "regulators not ready, defer\n");
 238                 goto put_reg;
 239         }
 240         if (IS_ERR(arm_reg) || IS_ERR(soc_reg)) {
 241                 dev_err(cpu_dev, "failed to get regulators\n");
 242                 ret = -ENOENT;
 243                 goto put_reg;
 244         }
 245
 246         /*
 247          * We expect an OPP table supplied by platform.
 248          * Just, incase the platform did not supply the OPP
 249          * table, it will try to get it.
 250          */
 251         num = dev_pm_opp_get_opp_count(cpu_dev);
 252         if (num < 0) {
 253                 ret = dev_pm_opp_of_add_table(cpu_dev);
 254                 if (ret < 0) {
 255                         dev_err(cpu_dev, "failed to init OPP table: %d\n", ret);
 256                         goto put_reg;
 257                 }
 258
 259                 /* Because we have added the OPPs here, we must free them */
 260                 free_opp = true;
 261
 262                 num = dev_pm_opp_get_opp_count(cpu_dev);
 263                 if (num < 0) {
 264                         ret = num;
 265                         dev_err(cpu_dev, "no OPP table is found: %d\n", ret);
 266                         goto out_free_opp;
 267                 }
 268         }
 269
 270         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 271         if (ret) {
 272                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 273                 goto out_free_opp;
 274         }
 275
 276         /* Make imx6_soc_volt array's size same as arm opp number */
 277         imx6_soc_volt = devm_kzalloc(cpu_dev, sizeof(*imx6_soc_volt) * num, GFP_KERNEL);
 278         if (imx6_soc_volt == NULL) {
 279                 ret = -ENOMEM;
 280                 goto free_freq_table;
 281         }
 282
 283         prop = of_find_property(np, "fsl,soc-operating-points", NULL);
 284         if (!prop || !prop->value)
 285                 goto soc_opp_out;
 286
 287         /*
 288          * Each OPP is a set of tuples consisting of frequency and
 289          * voltage like <freq-kHz vol-uV>.
 290          */
 291         nr = prop->length / sizeof(u32);
 292         if (nr % 2 || (nr / 2) < num)
 293                 goto soc_opp_out;
 294
 295         for (j = 0; j < num; j++) {
 296                 val = prop->value;
 297                 for (i = 0; i < nr / 2; i++) {
 298                         unsigned long freq = be32_to_cpup(val++);
 299                         unsigned long volt = be32_to_cpup(val++);
 300                         if (freq_table[j].frequency == freq) {
 301                                 imx6_soc_volt[soc_opp_count++] = volt;
 302                                 break;
 303                         }
 304                 }
 305         }
 306
 307 soc_opp_out:
 308         /* use fixed soc opp volt if no valid soc opp info found in dtb */
 309         if (soc_opp_count != num) {
 310                 dev_warn(cpu_dev, "can NOT find valid fsl,soc-operating-points property in dtb, use default value!\n");
 311                 for (j = 0; j < num; j++)
 312                         imx6_soc_volt[j] = PU_SOC_VOLTAGE_NORMAL;
 313                 if (freq_table[num - 1].frequency * 1000 == FREQ_1P2_GHZ)
 314                         imx6_soc_volt[num - 1] = PU_SOC_VOLTAGE_HIGH;
 315         }
 316
 317         if (of_property_read_u32(np, "clock-latency", &transition_latency))
 318                 transition_latency = CPUFREQ_ETERNAL;
 319
 320         /*
 321          * Calculate the ramp time for max voltage change in the
 322          * VDDSOC and VDDPU regulators.
 323          */
 324         ret = regulator_set_voltage_time(soc_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
 325         if (ret > 0)
 326                 transition_latency += ret * 1000;
 327         if (!IS_ERR(pu_reg)) {
 328                 ret = regulator_set_voltage_time(pu_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
 329                 if (ret > 0)
 330                         transition_latency += ret * 1000;
 331         }
 332
 333         /*
 334          * OPP is maintained in order of increasing frequency, and
 335          * freq_table initialised from OPP is therefore sorted in the
 336          * same order.
 337          */
 338         opp = dev_pm_opp_find_freq_exact(cpu_dev,
 339                                   freq_table[0].frequency * 1000, true);
 340         min_volt = dev_pm_opp_get_voltage(opp);
 341         dev_pm_opp_put(opp);
 342         opp = dev_pm_opp_find_freq_exact(cpu_dev,
 343                                   freq_table[--num].frequency * 1000, true);
 344         max_volt = dev_pm_opp_get_voltage(opp);
 345         dev_pm_opp_put(opp);
 346
 347         ret = regulator_set_voltage_time(arm_reg, min_volt, max_volt);
 348         if (ret > 0)
 349                 transition_latency += ret * 1000;
 350
 351         ret = cpufreq_register_driver(&imx6q_cpufreq_driver);
 352         if (ret) {
 353                 dev_err(cpu_dev, "failed register driver: %d\n", ret);
 354                 goto free_freq_table;
 355         }
 356
 357         of_node_put(np);
 358         return 0;
 359
 360 free_freq_table:
 361         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 362 out_free_opp:
 363         if (free_opp)
 364                 dev_pm_opp_of_remove_table(cpu_dev);
 365 put_reg:
 366         if (!IS_ERR(arm_reg))
 367                 regulator_put(arm_reg);
 368         if (!IS_ERR(pu_reg))
 369                 regulator_put(pu_reg);
 370         if (!IS_ERR(soc_reg))
 371                 regulator_put(soc_reg);
 372 put_clk:
 373         if (!IS_ERR(arm_clk))
 374                 clk_put(arm_clk);
 375         if (!IS_ERR(pll1_sys_clk))
 376                 clk_put(pll1_sys_clk);
 377         if (!IS_ERR(pll1_sw_clk))
 378                 clk_put(pll1_sw_clk);
 379         if (!IS_ERR(step_clk))
 380                 clk_put(step_clk);
 381         if (!IS_ERR(pll2_pfd2_396m_clk))
 382                 clk_put(pll2_pfd2_396m_clk);
 383         if (!IS_ERR(pll2_bus_clk))
 384                 clk_put(pll2_bus_clk);
 385         if (!IS_ERR(secondary_sel_clk))
 386                 clk_put(secondary_sel_clk);
 387         of_node_put(np);
 388         return ret;
 389 }
 390
 391 static int imx6q_cpufreq_remove(struct platform_device *pdev)
 392 {
 393         cpufreq_unregister_driver(&imx6q_cpufreq_driver);
 394         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 395         if (free_opp)
 396                 dev_pm_opp_of_remove_table(cpu_dev);
 397         regulator_put(arm_reg);
 398         if (!IS_ERR(pu_reg))
 399                 regulator_put(pu_reg);
 400         regulator_put(soc_reg);
 401         clk_put(arm_clk);
 402         clk_put(pll1_sys_clk);
 403         clk_put(pll1_sw_clk);
 404         clk_put(step_clk);
 405         clk_put(pll2_pfd2_396m_clk);
 406         clk_put(pll2_bus_clk);
 407         clk_put(secondary_sel_clk);
 408
 409         return 0;
 410 }
 411
 412 static struct platform_driver imx6q_cpufreq_platdrv = {
 413         .driver = {
 414                 .name   = "imx6q-cpufreq",
 415         },
 416         .probe          = imx6q_cpufreq_probe,
 417         .remove         = imx6q_cpufreq_remove,
 418 };
 419 module_platform_driver(imx6q_cpufreq_platdrv);
 420
 421 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 422 MODULE_DESCRIPTION("Freescale i.MX6Q cpufreq driver");
 423 MODULE_LICENSE("GPL");