arch/arm/mach-omap2/vc.c

   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
  15 #include <plat/cpu.h>
  16
  17 #include "voltage.h"
  18 #include "vc.h"
  19 #include "prm-regbits-34xx.h"
  20 #include "prm-regbits-44xx.h"
  21 #include "prm44xx.h"
  22
  23 /**
  24  * struct omap_vc_channel_cfg - describe the cfg_channel bitfield
  25  * @sa: bit for slave address
  26  * @rav: bit for voltage configuration register
  27  * @rac: bit for command configuration register
  28  * @racen: enable bit for RAC
  29  * @cmd: bit for command value set selection
  30  *
  31  * Channel configuration bits, common for OMAP3+
  32  * OMAP3 register: PRM_VC_CH_CONF
  33  * OMAP4 register: PRM_VC_CFG_CHANNEL
  34  * OMAP5 register: PRM_VC_SMPS_<voltdm>_CONFIG
  35  */
  36 struct omap_vc_channel_cfg {
  37         u8 sa;
  38         u8 rav;
  39         u8 rac;
  40         u8 racen;
  41         u8 cmd;
  42 };
  43
  44 static struct omap_vc_channel_cfg vc_default_channel_cfg = {
  45         .sa    = BIT(0),
  46         .rav   = BIT(1),
  47         .rac   = BIT(2),
  48         .racen = BIT(3),
  49         .cmd   = BIT(4),
  50 };
  51
  52 /*
  53  * On OMAP3+, all VC channels have the above default bitfield
  54  * configuration, except the OMAP4 MPU channel.  This appears
  55  * to be a freak accident as every other VC channel has the
  56  * default configuration, thus creating a mutant channel config.
  57  */
  58 static struct omap_vc_channel_cfg vc_mutant_channel_cfg = {
  59         .sa    = BIT(0),
  60         .rav   = BIT(2),
  61         .rac   = BIT(3),
  62         .racen = BIT(4),
  63         .cmd   = BIT(1),
  64 };
  65
  66 static struct omap_vc_channel_cfg *vc_cfg_bits;
  67 #define CFG_CHANNEL_MASK 0x1f
  68
  69 /**
  70  * omap_vc_config_channel - configure VC channel to PMIC mappings
  71  * @voltdm: pointer to voltagdomain defining the desired VC channel
  72  *
  73  * Configures the VC channel to PMIC mappings for the following
  74  * PMIC settings
  75  * - i2c slave address (SA)
  76  * - voltage configuration address (RAV)
  77  * - command configuration address (RAC) and enable bit (RACEN)
  78  * - command values for ON, ONLP, RET and OFF (CMD)
  79  *
  80  * This function currently only allows flexible configuration of the
  81  * non-default channel.  Starting with OMAP4, there are more than 2
  82  * channels, with one defined as the default (on OMAP4, it's MPU.)
  83  * Only the non-default channel can be configured.
  84  */
  85 static int omap_vc_config_channel(struct voltagedomain *voltdm)
  86 {
  87         struct omap_vc_channel *vc = voltdm->vc;
  88
  89         /*
  90          * For default channel, the only configurable bit is RACEN.
  91          * All others must stay at zero (see function comment above.)
  92          */
  93         if (vc->flags & OMAP_VC_CHANNEL_DEFAULT)
  94                 vc->cfg_channel &= vc_cfg_bits->racen;
  95
  96         voltdm->rmw(CFG_CHANNEL_MASK << vc->cfg_channel_sa_shift,
  97                     vc->cfg_channel << vc->cfg_channel_sa_shift,
  98                     vc->cfg_channel_reg);
  99
 100         return 0;
 101 }
 102
 103 /* Voltage scale and accessory APIs */
 104 int omap_vc_pre_scale(struct voltagedomain *voltdm,
 105                       unsigned long target_volt,
 106                       u8 *target_vsel, u8 *current_vsel)
 107 {
 108         struct omap_vc_channel *vc = voltdm->vc;
 109         u32 vc_cmdval;
 110
 111         /* Check if sufficient pmic info is available for this vdd */
 112         if (!voltdm->pmic) {
 113                 pr_err("%s: Insufficient pmic info to scale the vdd_%s\n",
 114                         __func__, voltdm->name);
 115                 return -EINVAL;
 116         }
 117
 118         if (!voltdm->pmic->uv_to_vsel) {
 119                 pr_err("%s: PMIC function to convert voltage in uV to"
 120                         "vsel not registered. Hence unable to scale voltage"
 121                         "for vdd_%s\n", __func__, voltdm->name);
 122                 return -ENODATA;
 123         }
 124
 125         if (!voltdm->read || !voltdm->write) {
 126                 pr_err("%s: No read/write API for accessing vdd_%s regs\n",
 127                         __func__, voltdm->name);
 128                 return -EINVAL;
 129         }
 130
 131         *target_vsel = voltdm->pmic->uv_to_vsel(target_volt);
 132         *current_vsel = voltdm->pmic->uv_to_vsel(voltdm->nominal_volt);
 133
 134         /* Setting the ON voltage to the new target voltage */
 135         vc_cmdval = voltdm->read(vc->cmdval_reg);
 136         vc_cmdval &= ~vc->common->cmd_on_mask;
 137         vc_cmdval |= (*target_vsel << vc->common->cmd_on_shift);
 138         voltdm->write(vc_cmdval, vc->cmdval_reg);
 139
 140         omap_vp_update_errorgain(voltdm, target_volt);
 141
 142         return 0;
 143 }
 144
 145 void omap_vc_post_scale(struct voltagedomain *voltdm,
 146                         unsigned long target_volt,
 147                         u8 target_vsel, u8 current_vsel)
 148 {
 149         u32 smps_steps = 0, smps_delay = 0;
 150
 151         smps_steps = abs(target_vsel - current_vsel);
 152         /* SMPS slew rate / step size. 2us added as buffer. */
 153         smps_delay = ((smps_steps * voltdm->pmic->step_size) /
 154                         voltdm->pmic->slew_rate) + 2;
 155         udelay(smps_delay);
 156 }
 157
 158 /* vc_bypass_scale - VC bypass method of voltage scaling */
 159 int omap_vc_bypass_scale(struct voltagedomain *voltdm,
 160                          unsigned long target_volt)
 161 {
 162         struct omap_vc_channel *vc = voltdm->vc;
 163         u32 loop_cnt = 0, retries_cnt = 0;
 164         u32 vc_valid, vc_bypass_val_reg, vc_bypass_value;
 165         u8 target_vsel, current_vsel;
 166         int ret;
 167
 168         ret = omap_vc_pre_scale(voltdm, target_volt, &target_vsel, &current_vsel);
 169         if (ret)
 170                 return ret;
 171
 172         vc_valid = vc->common->valid;
 173         vc_bypass_val_reg = vc->common->bypass_val_reg;
 174         vc_bypass_value = (target_vsel << vc->common->data_shift) |
 175                 (vc->volt_reg_addr << vc->common->regaddr_shift) |
 176                 (vc->i2c_slave_addr << vc->common->slaveaddr_shift);
 177
 178         voltdm->write(vc_bypass_value, vc_bypass_val_reg);
 179         voltdm->write(vc_bypass_value | vc_valid, vc_bypass_val_reg);
 180
 181         vc_bypass_value = voltdm->read(vc_bypass_val_reg);
 182         /*
 183          * Loop till the bypass command is acknowledged from the SMPS.
 184          * NOTE: This is legacy code. The loop count and retry count needs
 185          * to be revisited.
 186          */
 187         while (!(vc_bypass_value & vc_valid)) {
 188                 loop_cnt++;
 189
 190                 if (retries_cnt > 10) {
 191                         pr_warning("%s: Retry count exceeded\n", __func__);
 192                         return -ETIMEDOUT;
 193                 }
 194
 195                 if (loop_cnt > 50) {
 196                         retries_cnt++;
 197                         loop_cnt = 0;
 198                         udelay(10);
 199                 }
 200                 vc_bypass_value = voltdm->read(vc_bypass_val_reg);
 201         }
 202
 203         omap_vc_post_scale(voltdm, target_volt, target_vsel, current_vsel);
 204         return 0;
 205 }
 206
 207 static void __init omap3_vfsm_init(struct voltagedomain *voltdm)
 208 {
 209         /*
 210          * Voltage Manager FSM parameters init
 211          * XXX This data should be passed in from the board file
 212          */
 213         voltdm->write(OMAP3_CLKSETUP, OMAP3_PRM_CLKSETUP_OFFSET);
 214         voltdm->write(OMAP3_VOLTOFFSET, OMAP3_PRM_VOLTOFFSET_OFFSET);
 215         voltdm->write(OMAP3_VOLTSETUP2, OMAP3_PRM_VOLTSETUP2_OFFSET);
 216 }
 217
 218 static void __init omap3_vc_init_channel(struct voltagedomain *voltdm)
 219 {
 220         static bool is_initialized;
 221
 222         if (is_initialized)
 223                 return;
 224
 225         omap3_vfsm_init(voltdm);
 226
 227         is_initialized = true;
 228 }
 229
 230
 231 /* OMAP4 specific voltage init functions */
 232 static void __init omap4_vc_init_channel(struct voltagedomain *voltdm)
 233 {
 234         static bool is_initialized;
 235         u32 vc_val;
 236
 237         if (is_initialized)
 238                 return;
 239
 240         /* XXX These are magic numbers and do not belong! */
 241         vc_val = (0x60 << OMAP4430_SCLL_SHIFT | 0x26 << OMAP4430_SCLH_SHIFT);
 242         voltdm->write(vc_val, OMAP4_PRM_VC_CFG_I2C_CLK_OFFSET);
 243
 244         is_initialized = true;
 245 }
 246
 247 /**
 248  * omap_vc_i2c_init - initialize I2C interface to PMIC
 249  * @voltdm: voltage domain containing VC data
 250  *
 251  * Use PMIC supplied settings for I2C high-speed mode and
 252  * master code (if set) and program the VC I2C configuration
 253  * register.
 254  *
 255  * The VC I2C configuration is common to all VC channels,
 256  * so this function only configures I2C for the first VC
 257  * channel registers.  All other VC channels will use the
 258  * same configuration.
 259  */
 260 static void __init omap_vc_i2c_init(struct voltagedomain *voltdm)
 261 {
 262         struct omap_vc_channel *vc = voltdm->vc;
 263         static bool initialized;
 264         static bool i2c_high_speed;
 265         u8 mcode;
 266
 267         if (initialized) {
 268                 if (voltdm->pmic->i2c_high_speed != i2c_high_speed)
 269                         pr_warn("%s: I2C config for vdd_%s does not match other channels (%u).",
 270                                 __func__, voltdm->name, i2c_high_speed);
 271                 return;
 272         }
 273
 274         i2c_high_speed = voltdm->pmic->i2c_high_speed;
 275         if (i2c_high_speed)
 276                 voltdm->rmw(vc->common->i2c_cfg_hsen_mask,
 277                             vc->common->i2c_cfg_hsen_mask,
 278                             vc->common->i2c_cfg_reg);
 279
 280         mcode = voltdm->pmic->i2c_mcode;
 281         if (mcode)
 282                 voltdm->rmw(vc->common->i2c_mcode_mask,
 283                             mcode << __ffs(vc->common->i2c_mcode_mask),
 284                             vc->common->i2c_cfg_reg);
 285
 286         initialized = true;
 287 }
 288
 289 void __init omap_vc_init_channel(struct voltagedomain *voltdm)
 290 {
 291         struct omap_vc_channel *vc = voltdm->vc;
 292         u8 on_vsel, onlp_vsel, ret_vsel, off_vsel;
 293         u32 val;
 294
 295         if (!voltdm->pmic || !voltdm->pmic->uv_to_vsel) {
 296                 pr_err("%s: No PMIC info for vdd_%s\n", __func__, voltdm->name);
 297                 return;
 298         }
 299
 300         if (!voltdm->read || !voltdm->write) {
 301                 pr_err("%s: No read/write API for accessing vdd_%s regs\n",
 302                         __func__, voltdm->name);
 303                 return;
 304         }
 305
 306         vc->cfg_channel = 0;
 307         if (vc->flags & OMAP_VC_CHANNEL_CFG_MUTANT)
 308                 vc_cfg_bits = &vc_mutant_channel_cfg;
 309         else
 310                 vc_cfg_bits = &vc_default_channel_cfg;
 311
 312         /* get PMIC/board specific settings */
 313         vc->i2c_slave_addr = voltdm->pmic->i2c_slave_addr;
 314         vc->volt_reg_addr = voltdm->pmic->volt_reg_addr;
 315         vc->cmd_reg_addr = voltdm->pmic->cmd_reg_addr;
 316         vc->setup_time = voltdm->pmic->volt_setup_time;
 317
 318         /* Configure the i2c slave address for this VC */
 319         voltdm->rmw(vc->smps_sa_mask,
 320                     vc->i2c_slave_addr << __ffs(vc->smps_sa_mask),
 321                     vc->smps_sa_reg);
 322         vc->cfg_channel |= vc_cfg_bits->sa;
 323
 324         /*
 325          * Configure the PMIC register addresses.
 326          */
 327         voltdm->rmw(vc->smps_volra_mask,
 328                     vc->volt_reg_addr << __ffs(vc->smps_volra_mask),
 329                     vc->smps_volra_reg);
 330         vc->cfg_channel |= vc_cfg_bits->rav;
 331
 332         if (vc->cmd_reg_addr) {
 333                 voltdm->rmw(vc->smps_cmdra_mask,
 334                             vc->cmd_reg_addr << __ffs(vc->smps_cmdra_mask),
 335                             vc->smps_cmdra_reg);
 336                 vc->cfg_channel |= vc_cfg_bits->rac | vc_cfg_bits->racen;
 337         }
 338
 339         /* Set up the on, inactive, retention and off voltage */
 340         on_vsel = voltdm->pmic->uv_to_vsel(voltdm->pmic->on_volt);
 341         onlp_vsel = voltdm->pmic->uv_to_vsel(voltdm->pmic->onlp_volt);
 342         ret_vsel = voltdm->pmic->uv_to_vsel(voltdm->pmic->ret_volt);
 343         off_vsel = voltdm->pmic->uv_to_vsel(voltdm->pmic->off_volt);
 344         val = ((on_vsel << vc->common->cmd_on_shift) |
 345                (onlp_vsel << vc->common->cmd_onlp_shift) |
 346                (ret_vsel << vc->common->cmd_ret_shift) |
 347                (off_vsel << vc->common->cmd_off_shift));
 348         voltdm->write(val, vc->cmdval_reg);
 349         vc->cfg_channel |= vc_cfg_bits->cmd;
 350
 351         /* Channel configuration */
 352         omap_vc_config_channel(voltdm);
 353
 354         /* Configure the setup times */
 355         voltdm->rmw(voltdm->vfsm->voltsetup_mask,
 356                     vc->setup_time << __ffs(voltdm->vfsm->voltsetup_mask),
 357                     voltdm->vfsm->voltsetup_reg);
 358
 359         omap_vc_i2c_init(voltdm);
 360
 361         if (cpu_is_omap34xx())
 362                 omap3_vc_init_channel(voltdm);
 363         else if (cpu_is_omap44xx())
 364                 omap4_vc_init_channel(voltdm);
 365 }
 366