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