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                 /*
 106                  * When changing pll1_sw_clk's parent to pll1_sys_clk,
 107                  * CPU may run at higher than 528MHz, this will lead to
 108                  * the system unstable if the voltage is lower than the
 109                  * voltage of 528MHz, so lower the CPU frequency to one
 110                  * half before changing CPU frequency.
 111                  */
 112                 clk_set_rate(arm_clk, (old_freq >> 1) * 1000);
 113                 clk_set_parent(pll1_sw_clk, pll1_sys_clk);
 114                 if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk))
 115                         clk_set_parent(secondary_sel_clk, pll2_bus_clk);
 116                 else
 117                         clk_set_parent(secondary_sel_clk, pll2_pfd2_396m_clk);
 118                 clk_set_parent(step_clk, secondary_sel_clk);
 119                 clk_set_parent(pll1_sw_clk, step_clk);
 120         } else {
 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, new_freq * 1000);
 125                         clk_set_parent(pll1_sw_clk, pll1_sys_clk);
 126                 }
 127         }
 128
 129         /* Ensure the arm clock divider is what we expect */
 130         ret = clk_set_rate(arm_clk, new_freq * 1000);
 131         if (ret) {
 132                 dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
 133                 regulator_set_voltage_tol(arm_reg, volt_old, 0);
 134                 return ret;
 135         }
 136
 137         /* scaling down?  scale voltage after frequency */
 138         if (new_freq < old_freq) {
 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                 ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
 146                 if (ret) {
 147                         dev_warn(cpu_dev, "failed to scale vddsoc down: %d\n", ret);
 148                         ret = 0;
 149                 }
 150                 if (!IS_ERR(pu_reg)) {
 151                         ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
 152                         if (ret) {
 153                                 dev_warn(cpu_dev, "failed to scale vddpu down: %d\n", ret);
 154                                 ret = 0;
 155                         }
 156                 }
 157         }
 158
 159         return 0;
 160 }
 161
 162 static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
 163 {
 164         policy->clk = arm_clk;
 165         return cpufreq_generic_init(policy, freq_table, transition_latency);
 166 }
 167
 168 static struct cpufreq_driver imx6q_cpufreq_driver = {
 169         .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 170         .verify = cpufreq_generic_frequency_table_verify,
 171         .target_index = imx6q_set_target,
 172         .get = cpufreq_generic_get,
 173         .init = imx6q_cpufreq_init,
 174         .name = "imx6q-cpufreq",
 175         .attr = cpufreq_generic_attr,
 176 };
 177
 178 static int imx6q_cpufreq_probe(struct platform_device *pdev)
 179 {
 180         struct device_node *np;
 181         struct dev_pm_opp *opp;
 182         unsigned long min_volt, max_volt;
 183         int num, ret;
 184         const struct property *prop;
 185         const __be32 *val;
 186         u32 nr, i, j;
 187
 188         cpu_dev = get_cpu_device(0);
 189         if (!cpu_dev) {
 190                 pr_err("failed to get cpu0 device\n");
 191                 return -ENODEV;
 192         }
 193
 194         np = of_node_get(cpu_dev->of_node);
 195         if (!np) {
 196                 dev_err(cpu_dev, "failed to find cpu0 node\n");
 197                 return -ENOENT;
 198         }
 199
 200         arm_clk = clk_get(cpu_dev, "arm");
 201         pll1_sys_clk = clk_get(cpu_dev, "pll1_sys");
 202         pll1_sw_clk = clk_get(cpu_dev, "pll1_sw");
 203         step_clk = clk_get(cpu_dev, "step");
 204         pll2_pfd2_396m_clk = clk_get(cpu_dev, "pll2_pfd2_396m");
 205         if (IS_ERR(arm_clk) || IS_ERR(pll1_sys_clk) || IS_ERR(pll1_sw_clk) ||
 206             IS_ERR(step_clk) || IS_ERR(pll2_pfd2_396m_clk)) {
 207                 dev_err(cpu_dev, "failed to get clocks\n");
 208                 ret = -ENOENT;
 209                 goto put_clk;
 210         }
 211
 212         if (of_machine_is_compatible("fsl,imx6ul")) {
 213                 pll2_bus_clk = clk_get(cpu_dev, "pll2_bus");
 214                 secondary_sel_clk = clk_get(cpu_dev, "secondary_sel");
 215                 if (IS_ERR(pll2_bus_clk) || IS_ERR(secondary_sel_clk)) {
 216                         dev_err(cpu_dev, "failed to get clocks specific to imx6ul\n");
 217                         ret = -ENOENT;
 218                         goto put_clk;
 219                 }
 220         }
 221
 222         arm_reg = regulator_get(cpu_dev, "arm");
 223         pu_reg = regulator_get_optional(cpu_dev, "pu");
 224         soc_reg = regulator_get(cpu_dev, "soc");
 225         if (IS_ERR(arm_reg) || IS_ERR(soc_reg)) {
 226                 dev_err(cpu_dev, "failed to get regulators\n");
 227                 ret = -ENOENT;
 228                 goto put_reg;
 229         }
 230
 231         /*
 232          * We expect an OPP table supplied by platform.
 233          * Just, incase the platform did not supply the OPP
 234          * table, it will try to get it.
 235          */
 236         num = dev_pm_opp_get_opp_count(cpu_dev);
 237         if (num < 0) {
 238                 ret = dev_pm_opp_of_add_table(cpu_dev);
 239                 if (ret < 0) {
 240                         dev_err(cpu_dev, "failed to init OPP table: %d\n", ret);
 241                         goto put_reg;
 242                 }
 243
 244                 /* Because we have added the OPPs here, we must free them */
 245                 free_opp = true;
 246
 247                 num = dev_pm_opp_get_opp_count(cpu_dev);
 248                 if (num < 0) {
 249                         ret = num;
 250                         dev_err(cpu_dev, "no OPP table is found: %d\n", ret);
 251                         goto out_free_opp;
 252                 }
 253         }
 254
 255         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 256         if (ret) {
 257                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 258                 goto put_reg;
 259         }
 260
 261         /* Make imx6_soc_volt array's size same as arm opp number */
 262         imx6_soc_volt = devm_kzalloc(cpu_dev, sizeof(*imx6_soc_volt) * num, GFP_KERNEL);
 263         if (imx6_soc_volt == NULL) {
 264                 ret = -ENOMEM;
 265                 goto free_freq_table;
 266         }
 267
 268         prop = of_find_property(np, "fsl,soc-operating-points", NULL);
 269         if (!prop || !prop->value)
 270                 goto soc_opp_out;
 271
 272         /*
 273          * Each OPP is a set of tuples consisting of frequency and
 274          * voltage like <freq-kHz vol-uV>.
 275          */
 276         nr = prop->length / sizeof(u32);
 277         if (nr % 2 || (nr / 2) < num)
 278                 goto soc_opp_out;
 279
 280         for (j = 0; j < num; j++) {
 281                 val = prop->value;
 282                 for (i = 0; i < nr / 2; i++) {
 283                         unsigned long freq = be32_to_cpup(val++);
 284                         unsigned long volt = be32_to_cpup(val++);
 285                         if (freq_table[j].frequency == freq) {
 286                                 imx6_soc_volt[soc_opp_count++] = volt;
 287                                 break;
 288                         }
 289                 }
 290         }
 291
 292 soc_opp_out:
 293         /* use fixed soc opp volt if no valid soc opp info found in dtb */
 294         if (soc_opp_count != num) {
 295                 dev_warn(cpu_dev, "can NOT find valid fsl,soc-operating-points property in dtb, use default value!\n");
 296                 for (j = 0; j < num; j++)
 297                         imx6_soc_volt[j] = PU_SOC_VOLTAGE_NORMAL;
 298                 if (freq_table[num - 1].frequency * 1000 == FREQ_1P2_GHZ)
 299                         imx6_soc_volt[num - 1] = PU_SOC_VOLTAGE_HIGH;
 300         }
 301
 302         if (of_property_read_u32(np, "clock-latency", &transition_latency))
 303                 transition_latency = CPUFREQ_ETERNAL;
 304
 305         /*
 306          * Calculate the ramp time for max voltage change in the
 307          * VDDSOC and VDDPU regulators.
 308          */
 309         ret = regulator_set_voltage_time(soc_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
 310         if (ret > 0)
 311                 transition_latency += ret * 1000;
 312         if (!IS_ERR(pu_reg)) {
 313                 ret = regulator_set_voltage_time(pu_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
 314                 if (ret > 0)
 315                         transition_latency += ret * 1000;
 316         }
 317
 318         /*
 319          * OPP is maintained in order of increasing frequency, and
 320          * freq_table initialised from OPP is therefore sorted in the
 321          * same order.
 322          */
 323         opp = dev_pm_opp_find_freq_exact(cpu_dev,
 324                                   freq_table[0].frequency * 1000, true);
 325         min_volt = dev_pm_opp_get_voltage(opp);
 326         dev_pm_opp_put(opp);
 327         opp = dev_pm_opp_find_freq_exact(cpu_dev,
 328                                   freq_table[--num].frequency * 1000, true);
 329         max_volt = dev_pm_opp_get_voltage(opp);
 330         dev_pm_opp_put(opp);
 331
 332         ret = regulator_set_voltage_time(arm_reg, min_volt, max_volt);
 333         if (ret > 0)
 334                 transition_latency += ret * 1000;
 335
 336         ret = cpufreq_register_driver(&imx6q_cpufreq_driver);
 337         if (ret) {
 338                 dev_err(cpu_dev, "failed register driver: %d\n", ret);
 339                 goto free_freq_table;
 340         }
 341
 342         of_node_put(np);
 343         return 0;
 344
 345 free_freq_table:
 346         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 347 out_free_opp:
 348         if (free_opp)
 349                 dev_pm_opp_of_remove_table(cpu_dev);
 350 put_reg:
 351         if (!IS_ERR(arm_reg))
 352                 regulator_put(arm_reg);
 353         if (!IS_ERR(pu_reg))
 354                 regulator_put(pu_reg);
 355         if (!IS_ERR(soc_reg))
 356                 regulator_put(soc_reg);
 357 put_clk:
 358         if (!IS_ERR(arm_clk))
 359                 clk_put(arm_clk);
 360         if (!IS_ERR(pll1_sys_clk))
 361                 clk_put(pll1_sys_clk);
 362         if (!IS_ERR(pll1_sw_clk))
 363                 clk_put(pll1_sw_clk);
 364         if (!IS_ERR(step_clk))
 365                 clk_put(step_clk);
 366         if (!IS_ERR(pll2_pfd2_396m_clk))
 367                 clk_put(pll2_pfd2_396m_clk);
 368         if (!IS_ERR(pll2_bus_clk))
 369                 clk_put(pll2_bus_clk);
 370         if (!IS_ERR(secondary_sel_clk))
 371                 clk_put(secondary_sel_clk);
 372         of_node_put(np);
 373         return ret;
 374 }
 375
 376 static int imx6q_cpufreq_remove(struct platform_device *pdev)
 377 {
 378         cpufreq_unregister_driver(&imx6q_cpufreq_driver);
 379         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 380         if (free_opp)
 381                 dev_pm_opp_of_remove_table(cpu_dev);
 382         regulator_put(arm_reg);
 383         if (!IS_ERR(pu_reg))
 384                 regulator_put(pu_reg);
 385         regulator_put(soc_reg);
 386         clk_put(arm_clk);
 387         clk_put(pll1_sys_clk);
 388         clk_put(pll1_sw_clk);
 389         clk_put(step_clk);
 390         clk_put(pll2_pfd2_396m_clk);
 391         clk_put(pll2_bus_clk);
 392         clk_put(secondary_sel_clk);
 393
 394         return 0;
 395 }
 396
 397 static struct platform_driver imx6q_cpufreq_platdrv = {
 398         .driver = {
 399                 .name   = "imx6q-cpufreq",
 400         },
 401         .probe          = imx6q_cpufreq_probe,
 402         .remove         = imx6q_cpufreq_remove,
 403 };
 404 module_platform_driver(imx6q_cpufreq_platdrv);
 405
 406 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 407 MODULE_DESCRIPTION("Freescale i.MX6Q cpufreq driver");
 408 MODULE_LICENSE("GPL");