root/arch/arm/mach-omap2/vc.c

DEFINITIONS

1. omap_vc_config_channel
2. omap_vc_pre_scale
3. omap_vc_post_scale
4. omap_vc_bypass_scale
5. omap_usec_to_32k
6. omap3_vc_set_pmic_signaling
7. omap3_vc_init_pmic_signaling
8. omap3_init_voltsetup1
9. omap3_set_i2c_timings
10. omap3_set_off_timings
11. omap3_vc_init_channel
12. omap4_calc_volt_ramp
13. omap4_usec_to_val_scrm
14. omap4_set_timings
15. omap4_vc_init_channel
16. omap4_vc_i2c_timing_init
17. omap_vc_i2c_init
18. omap_vc_calc_vsel
19. omap_pm_setup_sr_i2c_pcb_length
20. omap_vc_init_channel

   1 /*
   2  * OMAP Voltage Controller (VC) interface
   3  *
   4  * Copyright (C) 2011 Texas Instruments, Inc.
   5  *
   6  * This file is licensed under the terms of the GNU General Public
   7  * License version 2. This program is licensed "as is" without any
   8  * warranty of any kind, whether express or implied.
   9  */
  10 #include <linux/kernel.h>
  11 #include <linux/delay.h>
  12 #include <linux/init.h>
  13 #include <linux/bug.h>
  14 #include <linux/io.h>
  15 
  16 #include <asm/div64.h>
  17 
  18 #include "iomap.h"
  19 #include "soc.h"
  20 #include "voltage.h"
  21 #include "vc.h"
  22 #include "prm-regbits-34xx.h"
  23 #include "prm-regbits-44xx.h"
  24 #include "prm44xx.h"
  25 #include "pm.h"
  26 #include "scrm44xx.h"
  27 #include "control.h"
  28 
  29 /**
  30  * struct omap_vc_channel_cfg - describe the cfg_channel bitfield
  31  * @sa: bit for slave address
  32  * @rav: bit for voltage configuration register
  33  * @rac: bit for command configuration register
  34  * @racen: enable bit for RAC
  35  * @cmd: bit for command value set selection
  36  *
  37  * Channel configuration bits, common for OMAP3+
  38  * OMAP3 register: PRM_VC_CH_CONF
  39  * OMAP4 register: PRM_VC_CFG_CHANNEL
  40  * OMAP5 register: PRM_VC_SMPS_<voltdm>_CONFIG
  41  */
  42 struct omap_vc_channel_cfg {
  43         u8 sa;
  44         u8 rav;
  45         u8 rac;
  46         u8 racen;
  47         u8 cmd;
  48 };
  49 
  50 static struct omap_vc_channel_cfg vc_default_channel_cfg = {
  51         .sa    = BIT(0),
  52         .rav   = BIT(1),
  53         .rac   = BIT(2),
  54         .racen = BIT(3),
  55         .cmd   = BIT(4),
  56 };
  57 
  58 /*
  59  * On OMAP3+, all VC channels have the above default bitfield
  60  * configuration, except the OMAP4 MPU channel.  This appears
  61  * to be a freak accident as every other VC channel has the
  62  * default configuration, thus creating a mutant channel config.
  63  */
  64 static struct omap_vc_channel_cfg vc_mutant_channel_cfg = {
  65         .sa    = BIT(0),
  66         .rav   = BIT(2),
  67         .rac   = BIT(3),
  68         .racen = BIT(4),
  69         .cmd   = BIT(1),
  70 };
  71 
  72 static struct omap_vc_channel_cfg *vc_cfg_bits;
  73 
  74 /* Default I2C trace length on pcb, 6.3cm. Used for capacitance calculations. */
  75 static u32 sr_i2c_pcb_length = 63;
  76 #define CFG_CHANNEL_MASK 0x1f
  77 
  78 /**
  79  * omap_vc_config_channel - configure VC channel to PMIC mappings
  80  * @voltdm: pointer to voltagdomain defining the desired VC channel
  81  *
  82  * Configures the VC channel to PMIC mappings for the following
  83  * PMIC settings
  84  * - i2c slave address (SA)
  85  * - voltage configuration address (RAV)
  86  * - command configuration address (RAC) and enable bit (RACEN)
  87  * - command values for ON, ONLP, RET and OFF (CMD)
  88  *
  89  * This function currently only allows flexible configuration of the
  90  * non-default channel.  Starting with OMAP4, there are more than 2
  91  * channels, with one defined as the default (on OMAP4, it's MPU.)
  92  * Only the non-default channel can be configured.
  93  */
  94 static int omap_vc_config_channel(struct voltagedomain *voltdm)
  95 {
  96         struct omap_vc_channel *vc = voltdm->vc;
  97 
  98         /*
  99          * For default channel, the only configurable bit is RACEN.
 100          * All others must stay at zero (see function comment above.)
 101          */
 102         if (vc->flags & OMAP_VC_CHANNEL_DEFAULT)
 103                 vc->cfg_channel &= vc_cfg_bits->racen;
 104 
 105         voltdm->rmw(CFG_CHANNEL_MASK << vc->cfg_channel_sa_shift,
 106                     vc->cfg_channel << vc->cfg_channel_sa_shift,
 107                     vc->cfg_channel_reg);
 108 
 109         return 0;
 110 }
 111 
 112 /* Voltage scale and accessory APIs */
 113 int omap_vc_pre_scale(struct voltagedomain *voltdm,
 114                       unsigned long target_volt,
 115                       u8 *target_vsel, u8 *current_vsel)
 116 {
 117         struct omap_vc_channel *vc = voltdm->vc;
 118         u32 vc_cmdval;
 119 
 120         /* Check if sufficient pmic info is available for this vdd */
 121         if (!voltdm->pmic) {
 122                 pr_err("%s: Insufficient pmic info to scale the vdd_%s\n",
 123                         __func__, voltdm->name);
 124                 return -EINVAL;
 125         }
 126 
 127         if (!voltdm->pmic->uv_to_vsel) {
 128                 pr_err("%s: PMIC function to convert voltage in uV to vsel not registered. Hence unable to scale voltage for vdd_%s\n",
 129                        __func__, voltdm->name);
 130                 return -ENODATA;
 131         }
 132 
 133         if (!voltdm->read || !voltdm->write) {
 134                 pr_err("%s: No read/write API for accessing vdd_%s regs\n",
 135                         __func__, voltdm->name);
 136                 return -EINVAL;
 137         }
 138 
 139         *target_vsel = voltdm->pmic->uv_to_vsel(target_volt);
 140         *current_vsel = voltdm->pmic->uv_to_vsel(voltdm->nominal_volt);
 141 
 142         /* Setting the ON voltage to the new target voltage */
 143         vc_cmdval = voltdm->read(vc->cmdval_reg);
 144         vc_cmdval &= ~vc->common->cmd_on_mask;
 145         vc_cmdval |= (*target_vsel << vc->common->cmd_on_shift);
 146         voltdm->write(vc_cmdval, vc->cmdval_reg);
 147 
 148         voltdm->vc_param->on = target_volt;
 149 
 150         omap_vp_update_errorgain(voltdm, target_volt);
 151 
 152         return 0;
 153 }
 154 
 155 void omap_vc_post_scale(struct voltagedomain *voltdm,
 156                         unsigned long target_volt,
 157                         u8 target_vsel, u8 current_vsel)
 158 {
 159         u32 smps_steps = 0, smps_delay = 0;
 160 
 161         smps_steps = abs(target_vsel - current_vsel);
 162         /* SMPS slew rate / step size. 2us added as buffer. */
 163         smps_delay = ((smps_steps * voltdm->pmic->step_size) /
 164                         voltdm->pmic->slew_rate) + 2;
 165         udelay(smps_delay);
 166 }
 167 
 168 /* vc_bypass_scale - VC bypass method of voltage scaling */
 169 int omap_vc_bypass_scale(struct voltagedomain *voltdm,
 170                          unsigned long target_volt)
 171 {
 172         struct omap_vc_channel *vc = voltdm->vc;
 173         u32 loop_cnt = 0, retries_cnt = 0;
 174         u32 vc_valid, vc_bypass_val_reg, vc_bypass_value;
 175         u8 target_vsel, current_vsel;
 176         int ret;
 177 
 178         ret = omap_vc_pre_scale(voltdm, target_volt, &target_vsel, &current_vsel);
 179         if (ret)
 180                 return ret;
 181 
 182         vc_valid = vc->common->valid;
 183         vc_bypass_val_reg = vc->common->bypass_val_reg;
 184         vc_bypass_value = (target_vsel << vc->common->data_shift) |
 185                 (vc->volt_reg_addr << vc->common->regaddr_shift) |
 186                 (vc->i2c_slave_addr << vc->common->slaveaddr_shift);
 187 
 188         voltdm->write(vc_bypass_value, vc_bypass_val_reg);
 189         voltdm->write(vc_bypass_value | vc_valid, vc_bypass_val_reg);
 190 
 191         vc_bypass_value = voltdm->read(vc_bypass_val_reg);
 192         /*
 193          * Loop till the bypass command is acknowledged from the SMPS.
 194          * NOTE: This is legacy code. The loop count and retry count needs
 195          * to be revisited.
 196          */
 197         while (!(vc_bypass_value & vc_valid)) {
 198                 loop_cnt++;
 199 
 200                 if (retries_cnt > 10) {
 201                         pr_warn("%s: Retry count exceeded\n", __func__);
 202                         return -ETIMEDOUT;
 203                 }
 204 
 205                 if (loop_cnt > 50) {
 206                         retries_cnt++;
 207                         loop_cnt = 0;
 208                         udelay(10);
 209                 }
 210                 vc_bypass_value = voltdm->read(vc_bypass_val_reg);
 211         }
 212 
 213         omap_vc_post_scale(voltdm, target_volt, target_vsel, current_vsel);
 214         return 0;
 215 }
 216 
 217 /* Convert microsecond value to number of 32kHz clock cycles */
 218 static inline u32 omap_usec_to_32k(u32 usec)
 219 {
 220         return DIV_ROUND_UP_ULL(32768ULL * (u64)usec, 1000000ULL);
 221 }
 222 
 223 struct omap3_vc_timings {
 224         u32 voltsetup1;
 225         u32 voltsetup2;
 226 };
 227 
 228 struct omap3_vc {
 229         struct voltagedomain *vd;
 230         u32 voltctrl;
 231         u32 voltsetup1;
 232         u32 voltsetup2;
 233         struct omap3_vc_timings timings[2];
 234 };
 235 static struct omap3_vc vc;
 236 
 237 void omap3_vc_set_pmic_signaling(int core_next_state)
 238 {
 239         struct voltagedomain *vd = vc.vd;
 240         struct omap3_vc_timings *c = vc.timings;
 241         u32 voltctrl, voltsetup1, voltsetup2;
 242 
 243         voltctrl = vc.voltctrl;
 244         voltsetup1 = vc.voltsetup1;
 245         voltsetup2 = vc.voltsetup2;
 246 
 247         switch (core_next_state) {
 248         case PWRDM_POWER_OFF:
 249                 voltctrl &= ~(OMAP3430_PRM_VOLTCTRL_AUTO_RET |
 250                               OMAP3430_PRM_VOLTCTRL_AUTO_SLEEP);
 251                 voltctrl |= OMAP3430_PRM_VOLTCTRL_AUTO_OFF;
 252                 if (voltctrl & OMAP3430_PRM_VOLTCTRL_SEL_OFF)
 253                         voltsetup2 = c->voltsetup2;
 254                 else
 255                         voltsetup1 = c->voltsetup1;
 256                 break;
 257         case PWRDM_POWER_RET:
 258         default:
 259                 c++;
 260                 voltctrl &= ~(OMAP3430_PRM_VOLTCTRL_AUTO_OFF |
 261                               OMAP3430_PRM_VOLTCTRL_AUTO_SLEEP);
 262                 voltctrl |= OMAP3430_PRM_VOLTCTRL_AUTO_RET;
 263                 voltsetup1 = c->voltsetup1;
 264                 break;
 265         }
 266 
 267         if (voltctrl != vc.voltctrl) {
 268                 vd->write(voltctrl, OMAP3_PRM_VOLTCTRL_OFFSET);
 269                 vc.voltctrl = voltctrl;
 270         }
 271         if (voltsetup1 != vc.voltsetup1) {
 272                 vd->write(c->voltsetup1,
 273                           OMAP3_PRM_VOLTSETUP1_OFFSET);
 274                 vc.voltsetup1 = voltsetup1;
 275         }
 276         if (voltsetup2 != vc.voltsetup2) {
 277                 vd->write(c->voltsetup2,
 278                           OMAP3_PRM_VOLTSETUP2_OFFSET);
 279                 vc.voltsetup2 = voltsetup2;
 280         }
 281 }
 282 
 283 /*
 284  * Configure signal polarity for sys_clkreq and sys_off_mode pins
 285  * as the default values are wrong and can cause the system to hang
 286  * if any twl4030 scripts are loaded.
 287  */
 288 static void __init omap3_vc_init_pmic_signaling(struct voltagedomain *voltdm)
 289 {
 290         u32 val;
 291 
 292         if (vc.vd)
 293                 return;
 294 
 295         vc.vd = voltdm;
 296 
 297         val = voltdm->read(OMAP3_PRM_POLCTRL_OFFSET);
 298         if (!(val & OMAP3430_PRM_POLCTRL_CLKREQ_POL) ||
 299             (val & OMAP3430_PRM_POLCTRL_OFFMODE_POL)) {
 300                 val |= OMAP3430_PRM_POLCTRL_CLKREQ_POL;
 301                 val &= ~OMAP3430_PRM_POLCTRL_OFFMODE_POL;
 302                 pr_debug("PM: fixing sys_clkreq and sys_off_mode polarity to 0x%x\n",
 303                          val);
 304                 voltdm->write(val, OMAP3_PRM_POLCTRL_OFFSET);
 305         }
 306 
 307         /*
 308          * By default let's use I2C4 signaling for retention idle
 309          * and sys_off_mode pin signaling for off idle. This way we
 310          * have sys_clk_req pin go down for retention and both
 311          * sys_clk_req and sys_off_mode pins will go down for off
 312          * idle. And we can also scale voltages to zero for off-idle.
 313          * Note that no actual voltage scaling during off-idle will
 314          * happen unless the board specific twl4030 PMIC scripts are
 315          * loaded. See also omap_vc_i2c_init for comments regarding
 316          * erratum i531.
 317          */
 318         val = voltdm->read(OMAP3_PRM_VOLTCTRL_OFFSET);
 319         if (!(val & OMAP3430_PRM_VOLTCTRL_SEL_OFF)) {
 320                 val |= OMAP3430_PRM_VOLTCTRL_SEL_OFF;
 321                 pr_debug("PM: setting voltctrl sys_off_mode signaling to 0x%x\n",
 322                          val);
 323                 voltdm->write(val, OMAP3_PRM_VOLTCTRL_OFFSET);
 324         }
 325         vc.voltctrl = val;
 326 
 327         omap3_vc_set_pmic_signaling(PWRDM_POWER_ON);
 328 }
 329 
 330 static void omap3_init_voltsetup1(struct voltagedomain *voltdm,
 331                                   struct omap3_vc_timings *c, u32 idle)
 332 {
 333         unsigned long val;
 334 
 335         val = (voltdm->vc_param->on - idle) / voltdm->pmic->slew_rate;
 336         val *= voltdm->sys_clk.rate / 8 / 1000000 + 1;
 337         val <<= __ffs(voltdm->vfsm->voltsetup_mask);
 338         c->voltsetup1 &= ~voltdm->vfsm->voltsetup_mask;
 339         c->voltsetup1 |= val;
 340 }
 341 
 342 /**
 343  * omap3_set_i2c_timings - sets i2c sleep timings for a channel
 344  * @voltdm: channel to configure
 345  * @off_mode: select whether retention or off mode values used
 346  *
 347  * Calculates and sets up voltage controller to use I2C based
 348  * voltage scaling for sleep modes. This can be used for either off mode
 349  * or retention. Off mode has additionally an option to use sys_off_mode
 350  * pad, which uses a global signal to program the whole power IC to
 351  * off-mode.
 352  *
 353  * Note that pmic is not controlling the voltage scaling during
 354  * retention signaled over I2C4, so we can keep voltsetup2 as 0.
 355  * And the oscillator is not shut off over I2C4, so no need to
 356  * set clksetup.
 357  */
 358 static void omap3_set_i2c_timings(struct voltagedomain *voltdm)
 359 {
 360         struct omap3_vc_timings *c = vc.timings;
 361 
 362         /* Configure PRWDM_POWER_OFF over I2C4 */
 363         omap3_init_voltsetup1(voltdm, c, voltdm->vc_param->off);
 364         c++;
 365         /* Configure PRWDM_POWER_RET over I2C4 */
 366         omap3_init_voltsetup1(voltdm, c, voltdm->vc_param->ret);
 367 }
 368 
 369 /**
 370  * omap3_set_off_timings - sets off-mode timings for a channel
 371  * @voltdm: channel to configure
 372  *
 373  * Calculates and sets up off-mode timings for a channel. Off-mode
 374  * can use either I2C based voltage scaling, or alternatively
 375  * sys_off_mode pad can be used to send a global command to power IC.n,
 376  * sys_off_mode has the additional benefit that voltages can be
 377  * scaled to zero volt level with TWL4030 / TWL5030, I2C can only
 378  * scale to 600mV.
 379  *
 380  * Note that omap is not controlling the voltage scaling during
 381  * off idle signaled by sys_off_mode, so we can keep voltsetup1
 382  * as 0.
 383  */
 384 static void omap3_set_off_timings(struct voltagedomain *voltdm)
 385 {
 386         struct omap3_vc_timings *c = vc.timings;
 387         u32 tstart, tshut, clksetup, voltoffset;
 388 
 389         if (c->voltsetup2)
 390                 return;
 391 
 392         omap_pm_get_oscillator(&tstart, &tshut);
 393         if (tstart == ULONG_MAX) {
 394                 pr_debug("PM: oscillator start-up time not initialized, using 10ms\n");
 395                 clksetup = omap_usec_to_32k(10000);
 396         } else {
 397                 clksetup = omap_usec_to_32k(tstart);
 398         }
 399 
 400         /*
 401          * For twl4030 errata 27, we need to allow minimum ~488.32 us wait to
 402          * switch from HFCLKIN to internal oscillator. That means timings
 403          * have voltoffset fixed to 0xa in rounded up 32 KiHz cycles. And
 404          * that means we can calculate the value based on the oscillator
 405          * start-up time since voltoffset2 = clksetup - voltoffset.
 406          */
 407         voltoffset = omap_usec_to_32k(488);
 408         c->voltsetup2 = clksetup - voltoffset;
 409         voltdm->write(clksetup, OMAP3_PRM_CLKSETUP_OFFSET);
 410         voltdm->write(voltoffset, OMAP3_PRM_VOLTOFFSET_OFFSET);
 411 }
 412 
 413 static void __init omap3_vc_init_channel(struct voltagedomain *voltdm)
 414 {
 415         omap3_vc_init_pmic_signaling(voltdm);
 416         omap3_set_off_timings(voltdm);
 417         omap3_set_i2c_timings(voltdm);
 418 }
 419 
 420 /**
 421  * omap4_calc_volt_ramp - calculates voltage ramping delays on omap4
 422  * @voltdm: channel to calculate values for
 423  * @voltage_diff: voltage difference in microvolts
 424  *
 425  * Calculates voltage ramp prescaler + counter values for a voltage
 426  * difference on omap4. Returns a field value suitable for writing to
 427  * VOLTSETUP register for a channel in following format:
 428  * bits[8:9] prescaler ... bits[0:5] counter. See OMAP4 TRM for reference.
 429  */
 430 static u32 omap4_calc_volt_ramp(struct voltagedomain *voltdm, u32 voltage_diff)
 431 {
 432         u32 prescaler;
 433         u32 cycles;
 434         u32 time;
 435 
 436         time = voltage_diff / voltdm->pmic->slew_rate;
 437 
 438         cycles = voltdm->sys_clk.rate / 1000 * time / 1000;
 439 
 440         cycles /= 64;
 441         prescaler = 0;
 442 
 443         /* shift to next prescaler until no overflow */
 444 
 445         /* scale for div 256 = 64 * 4 */
 446         if (cycles > 63) {
 447                 cycles /= 4;
 448                 prescaler++;
 449         }
 450 
 451         /* scale for div 512 = 256 * 2 */
 452         if (cycles > 63) {
 453                 cycles /= 2;
 454                 prescaler++;
 455         }
 456 
 457         /* scale for div 2048 = 512 * 4 */
 458         if (cycles > 63) {
 459                 cycles /= 4;
 460                 prescaler++;
 461         }
 462 
 463         /* check for overflow => invalid ramp time */
 464         if (cycles > 63) {
 465                 pr_warn("%s: invalid setuptime for vdd_%s\n", __func__,
 466                         voltdm->name);
 467                 return 0;
 468         }
 469 
 470         cycles++;
 471 
 472         return (prescaler << OMAP4430_RAMP_UP_PRESCAL_SHIFT) |
 473                 (cycles << OMAP4430_RAMP_UP_COUNT_SHIFT);
 474 }
 475 
 476 /**
 477  * omap4_usec_to_val_scrm - convert microsecond value to SCRM module bitfield
 478  * @usec: microseconds
 479  * @shift: number of bits to shift left
 480  * @mask: bitfield mask
 481  *
 482  * Converts microsecond value to OMAP4 SCRM bitfield. Bitfield is
 483  * shifted to requested position, and checked agains the mask value.
 484  * If larger, forced to the max value of the field (i.e. the mask itself.)
 485  * Returns the SCRM bitfield value.
 486  */
 487 static u32 omap4_usec_to_val_scrm(u32 usec, int shift, u32 mask)
 488 {
 489         u32 val;
 490 
 491         val = omap_usec_to_32k(usec) << shift;
 492 
 493         /* Check for overflow, if yes, force to max value */
 494         if (val > mask)
 495                 val = mask;
 496 
 497         return val;
 498 }
 499 
 500 /**
 501  * omap4_set_timings - set voltage ramp timings for a channel
 502  * @voltdm: channel to configure
 503  * @off_mode: whether off-mode values are used
 504  *
 505  * Calculates and sets the voltage ramp up / down values for a channel.
 506  */
 507 static void omap4_set_timings(struct voltagedomain *voltdm, bool off_mode)
 508 {
 509         u32 val;
 510         u32 ramp;
 511         int offset;
 512         u32 tstart, tshut;
 513 
 514         if (off_mode) {
 515                 ramp = omap4_calc_volt_ramp(voltdm,
 516                         voltdm->vc_param->on - voltdm->vc_param->off);
 517                 offset = voltdm->vfsm->voltsetup_off_reg;
 518         } else {
 519                 ramp = omap4_calc_volt_ramp(voltdm,
 520                         voltdm->vc_param->on - voltdm->vc_param->ret);
 521                 offset = voltdm->vfsm->voltsetup_reg;
 522         }
 523 
 524         if (!ramp)
 525                 return;
 526 
 527         val = voltdm->read(offset);
 528 
 529         val |= ramp << OMAP4430_RAMP_DOWN_COUNT_SHIFT;
 530 
 531         val |= ramp << OMAP4430_RAMP_UP_COUNT_SHIFT;
 532 
 533         voltdm->write(val, offset);
 534 
 535         omap_pm_get_oscillator(&tstart, &tshut);
 536 
 537         val = omap4_usec_to_val_scrm(tstart, OMAP4_SETUPTIME_SHIFT,
 538                 OMAP4_SETUPTIME_MASK);
 539         val |= omap4_usec_to_val_scrm(tshut, OMAP4_DOWNTIME_SHIFT,
 540                 OMAP4_DOWNTIME_MASK);
 541 
 542         writel_relaxed(val, OMAP4_SCRM_CLKSETUPTIME);
 543 }
 544 
 545 /* OMAP4 specific voltage init functions */
 546 static void __init omap4_vc_init_channel(struct voltagedomain *voltdm)
 547 {
 548         omap4_set_timings(voltdm, true);
 549         omap4_set_timings(voltdm, false);
 550 }
 551 
 552 struct i2c_init_data {
 553         u8 loadbits;
 554         u8 load;
 555         u8 hsscll_38_4;
 556         u8 hsscll_26;
 557         u8 hsscll_19_2;
 558         u8 hsscll_16_8;
 559         u8 hsscll_12;
 560 };
 561 
 562 static const struct i2c_init_data omap4_i2c_timing_data[] __initconst = {
 563         {
 564                 .load = 50,
 565                 .loadbits = 0x3,
 566                 .hsscll_38_4 = 13,
 567                 .hsscll_26 = 11,
 568                 .hsscll_19_2 = 9,
 569                 .hsscll_16_8 = 9,
 570                 .hsscll_12 = 8,
 571         },
 572         {
 573                 .load = 25,
 574                 .loadbits = 0x2,
 575                 .hsscll_38_4 = 13,
 576                 .hsscll_26 = 11,
 577                 .hsscll_19_2 = 9,
 578                 .hsscll_16_8 = 9,
 579                 .hsscll_12 = 8,
 580         },
 581         {
 582                 .load = 12,
 583                 .loadbits = 0x1,
 584                 .hsscll_38_4 = 11,
 585                 .hsscll_26 = 10,
 586                 .hsscll_19_2 = 9,
 587                 .hsscll_16_8 = 9,
 588                 .hsscll_12 = 8,
 589         },
 590         {
 591                 .load = 0,
 592                 .loadbits = 0x0,
 593                 .hsscll_38_4 = 12,
 594                 .hsscll_26 = 10,
 595                 .hsscll_19_2 = 9,
 596                 .hsscll_16_8 = 8,
 597                 .hsscll_12 = 8,
 598         },
 599 };
 600 
 601 /**
 602  * omap4_vc_i2c_timing_init - sets up board I2C timing parameters
 603  * @voltdm: voltagedomain pointer to get data from
 604  *
 605  * Use PMIC + board supplied settings for calculating the total I2C
 606  * channel capacitance and set the timing parameters based on this.
 607  * Pre-calculated values are provided in data tables, as it is not
 608  * too straightforward to calculate these runtime.
 609  */
 610 static void __init omap4_vc_i2c_timing_init(struct voltagedomain *voltdm)
 611 {
 612         u32 capacitance;
 613         u32 val;
 614         u16 hsscll;
 615         const struct i2c_init_data *i2c_data;
 616 
 617         if (!voltdm->pmic->i2c_high_speed) {
 618                 pr_warn("%s: only high speed supported!\n", __func__);
 619                 return;
 620         }
 621 
 622         /* PCB trace capacitance, 0.125pF / mm => mm / 8 */
 623         capacitance = DIV_ROUND_UP(sr_i2c_pcb_length, 8);
 624 
 625         /* OMAP pad capacitance */
 626         capacitance += 4;
 627 
 628         /* PMIC pad capacitance */
 629         capacitance += voltdm->pmic->i2c_pad_load;
 630 
 631         /* Search for capacitance match in the table */
 632         i2c_data = omap4_i2c_timing_data;
 633 
 634         while (i2c_data->load > capacitance)
 635                 i2c_data++;
 636 
 637         /* Select proper values based on sysclk frequency */
 638         switch (voltdm->sys_clk.rate) {
 639         case 38400000:
 640                 hsscll = i2c_data->hsscll_38_4;
 641                 break;
 642         case 26000000:
 643                 hsscll = i2c_data->hsscll_26;
 644                 break;
 645         case 19200000:
 646                 hsscll = i2c_data->hsscll_19_2;
 647                 break;
 648         case 16800000:
 649                 hsscll = i2c_data->hsscll_16_8;
 650                 break;
 651         case 12000000:
 652                 hsscll = i2c_data->hsscll_12;
 653                 break;
 654         default:
 655                 pr_warn("%s: unsupported sysclk rate: %d!\n", __func__,
 656                         voltdm->sys_clk.rate);
 657                 return;
 658         }
 659 
 660         /* Loadbits define pull setup for the I2C channels */
 661         val = i2c_data->loadbits << 25 | i2c_data->loadbits << 29;
 662 
 663         /* Write to SYSCTRL_PADCONF_WKUP_CTRL_I2C_2 to setup I2C pull */
 664         writel_relaxed(val, OMAP2_L4_IO_ADDRESS(OMAP4_CTRL_MODULE_PAD_WKUP +
 665                                 OMAP4_CTRL_MODULE_PAD_WKUP_CONTROL_I2C_2));
 666 
 667         /* HSSCLH can always be zero */
 668         val = hsscll << OMAP4430_HSSCLL_SHIFT;
 669         val |= (0x28 << OMAP4430_SCLL_SHIFT | 0x2c << OMAP4430_SCLH_SHIFT);
 670 
 671         /* Write setup times to I2C config register */
 672         voltdm->write(val, OMAP4_PRM_VC_CFG_I2C_CLK_OFFSET);
 673 }
 674 
 675 
 676 
 677 /**
 678  * omap_vc_i2c_init - initialize I2C interface to PMIC
 679  * @voltdm: voltage domain containing VC data
 680  *
 681  * Use PMIC supplied settings for I2C high-speed mode and
 682  * master code (if set) and program the VC I2C configuration
 683  * register.
 684  *
 685  * The VC I2C configuration is common to all VC channels,
 686  * so this function only configures I2C for the first VC
 687  * channel registers.  All other VC channels will use the
 688  * same configuration.
 689  */
 690 static void __init omap_vc_i2c_init(struct voltagedomain *voltdm)
 691 {
 692         struct omap_vc_channel *vc = voltdm->vc;
 693         static bool initialized;
 694         static bool i2c_high_speed;
 695         u8 mcode;
 696 
 697         if (initialized) {
 698                 if (voltdm->pmic->i2c_high_speed != i2c_high_speed)
 699                         pr_warn("%s: I2C config for vdd_%s does not match other channels (%u).\n",
 700                                 __func__, voltdm->name, i2c_high_speed);
 701                 return;
 702         }
 703 
 704         /*
 705          * Note that for omap3 OMAP3430_SREN_MASK clears SREN to work around
 706          * erratum i531 "Extra Power Consumed When Repeated Start Operation
 707          * Mode Is Enabled on I2C Interface Dedicated for Smart Reflex (I2C4)".
 708          * Otherwise I2C4 eventually leads into about 23mW extra power being
 709          * consumed even during off idle using VMODE.
 710          */
 711         i2c_high_speed = voltdm->pmic->i2c_high_speed;
 712         if (i2c_high_speed)
 713                 voltdm->rmw(vc->common->i2c_cfg_clear_mask,
 714                             vc->common->i2c_cfg_hsen_mask,
 715                             vc->common->i2c_cfg_reg);
 716 
 717         mcode = voltdm->pmic->i2c_mcode;
 718         if (mcode)
 719                 voltdm->rmw(vc->common->i2c_mcode_mask,
 720                             mcode << __ffs(vc->common->i2c_mcode_mask),
 721                             vc->common->i2c_cfg_reg);
 722 
 723         if (cpu_is_omap44xx())
 724                 omap4_vc_i2c_timing_init(voltdm);
 725 
 726         initialized = true;
 727 }
 728 
 729 /**
 730  * omap_vc_calc_vsel - calculate vsel value for a channel
 731  * @voltdm: channel to calculate value for
 732  * @uvolt: microvolt value to convert to vsel
 733  *
 734  * Converts a microvolt value to vsel value for the used PMIC.
 735  * This checks whether the microvolt value is out of bounds, and
 736  * adjusts the value accordingly. If unsupported value detected,
 737  * warning is thrown.
 738  */
 739 static u8 omap_vc_calc_vsel(struct voltagedomain *voltdm, u32 uvolt)
 740 {
 741         if (voltdm->pmic->vddmin > uvolt)
 742                 uvolt = voltdm->pmic->vddmin;
 743         if (voltdm->pmic->vddmax < uvolt) {
 744                 WARN(1, "%s: voltage not supported by pmic: %u vs max %u\n",
 745                         __func__, uvolt, voltdm->pmic->vddmax);
 746                 /* Lets try maximum value anyway */
 747                 uvolt = voltdm->pmic->vddmax;
 748         }
 749 
 750         return voltdm->pmic->uv_to_vsel(uvolt);
 751 }
 752 
 753 #ifdef CONFIG_PM
 754 /**
 755  * omap_pm_setup_sr_i2c_pcb_length - set length of SR I2C traces on PCB
 756  * @mm: length of the PCB trace in millimetres
 757  *
 758  * Sets the PCB trace length for the I2C channel. By default uses 63mm.
 759  * This is needed for properly calculating the capacitance value for
 760  * the PCB trace, and for setting the SR I2C channel timing parameters.
 761  */
 762 void __init omap_pm_setup_sr_i2c_pcb_length(u32 mm)
 763 {
 764         sr_i2c_pcb_length = mm;
 765 }
 766 #endif
 767 
 768 void __init omap_vc_init_channel(struct voltagedomain *voltdm)
 769 {
 770         struct omap_vc_channel *vc = voltdm->vc;
 771         u8 on_vsel, onlp_vsel, ret_vsel, off_vsel;
 772         u32 val;
 773 
 774         if (!voltdm->pmic || !voltdm->pmic->uv_to_vsel) {
 775                 pr_err("%s: No PMIC info for vdd_%s\n", __func__, voltdm->name);
 776                 return;
 777         }
 778 
 779         if (!voltdm->read || !voltdm->write) {
 780                 pr_err("%s: No read/write API for accessing vdd_%s regs\n",
 781                         __func__, voltdm->name);
 782                 return;
 783         }
 784 
 785         vc->cfg_channel = 0;
 786         if (vc->flags & OMAP_VC_CHANNEL_CFG_MUTANT)
 787                 vc_cfg_bits = &vc_mutant_channel_cfg;
 788         else
 789                 vc_cfg_bits = &vc_default_channel_cfg;
 790 
 791         /* get PMIC/board specific settings */
 792         vc->i2c_slave_addr = voltdm->pmic->i2c_slave_addr;
 793         vc->volt_reg_addr = voltdm->pmic->volt_reg_addr;
 794         vc->cmd_reg_addr = voltdm->pmic->cmd_reg_addr;
 795 
 796         /* Configure the i2c slave address for this VC */
 797         voltdm->rmw(vc->smps_sa_mask,
 798                     vc->i2c_slave_addr << __ffs(vc->smps_sa_mask),
 799                     vc->smps_sa_reg);
 800         vc->cfg_channel |= vc_cfg_bits->sa;
 801 
 802         /*
 803          * Configure the PMIC register addresses.
 804          */
 805         voltdm->rmw(vc->smps_volra_mask,
 806                     vc->volt_reg_addr << __ffs(vc->smps_volra_mask),
 807                     vc->smps_volra_reg);
 808         vc->cfg_channel |= vc_cfg_bits->rav;
 809 
 810         if (vc->cmd_reg_addr) {
 811                 voltdm->rmw(vc->smps_cmdra_mask,
 812                             vc->cmd_reg_addr << __ffs(vc->smps_cmdra_mask),
 813                             vc->smps_cmdra_reg);
 814                 vc->cfg_channel |= vc_cfg_bits->rac;
 815         }
 816 
 817         if (vc->cmd_reg_addr == vc->volt_reg_addr)
 818                 vc->cfg_channel |= vc_cfg_bits->racen;
 819 
 820         /* Set up the on, inactive, retention and off voltage */
 821         on_vsel = omap_vc_calc_vsel(voltdm, voltdm->vc_param->on);
 822         onlp_vsel = omap_vc_calc_vsel(voltdm, voltdm->vc_param->onlp);
 823         ret_vsel = omap_vc_calc_vsel(voltdm, voltdm->vc_param->ret);
 824         off_vsel = omap_vc_calc_vsel(voltdm, voltdm->vc_param->off);
 825 
 826         val = ((on_vsel << vc->common->cmd_on_shift) |
 827                (onlp_vsel << vc->common->cmd_onlp_shift) |
 828                (ret_vsel << vc->common->cmd_ret_shift) |
 829                (off_vsel << vc->common->cmd_off_shift));
 830         voltdm->write(val, vc->cmdval_reg);
 831         vc->cfg_channel |= vc_cfg_bits->cmd;
 832 
 833         /* Channel configuration */
 834         omap_vc_config_channel(voltdm);
 835 
 836         omap_vc_i2c_init(voltdm);
 837 
 838         if (cpu_is_omap34xx())
 839                 omap3_vc_init_channel(voltdm);
 840         else if (cpu_is_omap44xx())
 841                 omap4_vc_init_channel(voltdm);
 842 }
 843