linux/drivers/regulator/max8660.c
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   1/*
   2 * max8660.c  --  Voltage regulation for the Maxim 8660/8661
   3 *
   4 * based on max1586.c and wm8400-regulator.c
   5 *
   6 * Copyright (C) 2009 Wolfram Sang, Pengutronix e.K.
   7 *
   8 * This program is free software; you can redistribute it and/or modify it
   9 * under the terms of the GNU General Public License as published by the Free
  10 * Software Foundation; version 2 of the License.
  11 *
  12 * This program is distributed in the hope that it will be useful, but WITHOUT
  13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15 * more details.
  16 *
  17 * You should have received a copy of the GNU General Public License along with
  18 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  19 * Place, Suite 330, Boston, MA  02111-1307  USA
  20 *
  21 * Some info:
  22 *
  23 * Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX8660-MAX8661.pdf
  24 *
  25 * This chip is a bit nasty because it is a write-only device. Thus, the driver
  26 * uses shadow registers to keep track of its values. The main problem appears
  27 * to be the initialization: When Linux boots up, we cannot know if the chip is
  28 * in the default state or not, so we would have to pass such information in
  29 * platform_data. As this adds a bit of complexity to the driver, this is left
  30 * out for now until it is really needed.
  31 *
  32 * [A|S|M]DTV1 registers are currently not used, but [A|S|M]DTV2.
  33 *
  34 * If the driver is feature complete, it might be worth to check if one set of
  35 * functions for V3-V7 is sufficient. For maximum flexibility during
  36 * development, they are separated for now.
  37 *
  38 */
  39
  40#include <linux/module.h>
  41#include <linux/err.h>
  42#include <linux/i2c.h>
  43#include <linux/platform_device.h>
  44#include <linux/regulator/driver.h>
  45#include <linux/slab.h>
  46#include <linux/regulator/max8660.h>
  47#include <linux/of.h>
  48#include <linux/of_device.h>
  49#include <linux/regulator/of_regulator.h>
  50
  51#define MAX8660_DCDC_MIN_UV      725000
  52#define MAX8660_DCDC_MAX_UV     1800000
  53#define MAX8660_DCDC_STEP         25000
  54#define MAX8660_DCDC_MAX_SEL    0x2b
  55
  56#define MAX8660_LDO5_MIN_UV     1700000
  57#define MAX8660_LDO5_MAX_UV     2000000
  58#define MAX8660_LDO5_STEP         25000
  59#define MAX8660_LDO5_MAX_SEL    0x0c
  60
  61#define MAX8660_LDO67_MIN_UV    1800000
  62#define MAX8660_LDO67_MAX_UV    3300000
  63#define MAX8660_LDO67_STEP       100000
  64#define MAX8660_LDO67_MAX_SEL   0x0f
  65
  66enum {
  67        MAX8660_OVER1,
  68        MAX8660_OVER2,
  69        MAX8660_VCC1,
  70        MAX8660_ADTV1,
  71        MAX8660_ADTV2,
  72        MAX8660_SDTV1,
  73        MAX8660_SDTV2,
  74        MAX8660_MDTV1,
  75        MAX8660_MDTV2,
  76        MAX8660_L12VCR,
  77        MAX8660_FPWM,
  78        MAX8660_N_REGS, /* not a real register */
  79};
  80
  81struct max8660 {
  82        struct i2c_client *client;
  83        u8 shadow_regs[MAX8660_N_REGS];         /* as chip is write only */
  84        struct regulator_dev *rdev[];
  85};
  86
  87static int max8660_write(struct max8660 *max8660, u8 reg, u8 mask, u8 val)
  88{
  89        static const u8 max8660_addresses[MAX8660_N_REGS] =
  90          { 0x10, 0x12, 0x20, 0x23, 0x24, 0x29, 0x2a, 0x32, 0x33, 0x39, 0x80 };
  91
  92        int ret;
  93        u8 reg_val = (max8660->shadow_regs[reg] & mask) | val;
  94        dev_vdbg(&max8660->client->dev, "Writing reg %02x with %02x\n",
  95                        max8660_addresses[reg], reg_val);
  96
  97        ret = i2c_smbus_write_byte_data(max8660->client,
  98                        max8660_addresses[reg], reg_val);
  99        if (ret == 0)
 100                max8660->shadow_regs[reg] = reg_val;
 101
 102        return ret;
 103}
 104
 105
 106/*
 107 * DCDC functions
 108 */
 109
 110static int max8660_dcdc_is_enabled(struct regulator_dev *rdev)
 111{
 112        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 113        u8 val = max8660->shadow_regs[MAX8660_OVER1];
 114        u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;
 115        return !!(val & mask);
 116}
 117
 118static int max8660_dcdc_enable(struct regulator_dev *rdev)
 119{
 120        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 121        u8 bit = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;
 122        return max8660_write(max8660, MAX8660_OVER1, 0xff, bit);
 123}
 124
 125static int max8660_dcdc_disable(struct regulator_dev *rdev)
 126{
 127        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 128        u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? ~1 : ~4;
 129        return max8660_write(max8660, MAX8660_OVER1, mask, 0);
 130}
 131
 132static int max8660_dcdc_get_voltage_sel(struct regulator_dev *rdev)
 133{
 134        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 135
 136        u8 reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
 137        u8 selector = max8660->shadow_regs[reg];
 138        return selector;
 139}
 140
 141static int max8660_dcdc_set_voltage_sel(struct regulator_dev *rdev,
 142                                        unsigned int selector)
 143{
 144        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 145        u8 reg, bits;
 146        int ret;
 147
 148        reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
 149        ret = max8660_write(max8660, reg, 0, selector);
 150        if (ret)
 151                return ret;
 152
 153        /* Select target voltage register and activate regulation */
 154        bits = (rdev_get_id(rdev) == MAX8660_V3) ? 0x03 : 0x30;
 155        return max8660_write(max8660, MAX8660_VCC1, 0xff, bits);
 156}
 157
 158static struct regulator_ops max8660_dcdc_ops = {
 159        .is_enabled = max8660_dcdc_is_enabled,
 160        .list_voltage = regulator_list_voltage_linear,
 161        .map_voltage = regulator_map_voltage_linear,
 162        .set_voltage_sel = max8660_dcdc_set_voltage_sel,
 163        .get_voltage_sel = max8660_dcdc_get_voltage_sel,
 164};
 165
 166
 167/*
 168 * LDO5 functions
 169 */
 170
 171static int max8660_ldo5_get_voltage_sel(struct regulator_dev *rdev)
 172{
 173        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 174
 175        u8 selector = max8660->shadow_regs[MAX8660_MDTV2];
 176        return selector;
 177}
 178
 179static int max8660_ldo5_set_voltage_sel(struct regulator_dev *rdev,
 180                                        unsigned int selector)
 181{
 182        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 183        int ret;
 184
 185        ret = max8660_write(max8660, MAX8660_MDTV2, 0, selector);
 186        if (ret)
 187                return ret;
 188
 189        /* Select target voltage register and activate regulation */
 190        return max8660_write(max8660, MAX8660_VCC1, 0xff, 0xc0);
 191}
 192
 193static struct regulator_ops max8660_ldo5_ops = {
 194        .list_voltage = regulator_list_voltage_linear,
 195        .map_voltage = regulator_map_voltage_linear,
 196        .set_voltage_sel = max8660_ldo5_set_voltage_sel,
 197        .get_voltage_sel = max8660_ldo5_get_voltage_sel,
 198};
 199
 200
 201/*
 202 * LDO67 functions
 203 */
 204
 205static int max8660_ldo67_is_enabled(struct regulator_dev *rdev)
 206{
 207        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 208        u8 val = max8660->shadow_regs[MAX8660_OVER2];
 209        u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;
 210        return !!(val & mask);
 211}
 212
 213static int max8660_ldo67_enable(struct regulator_dev *rdev)
 214{
 215        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 216        u8 bit = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;
 217        return max8660_write(max8660, MAX8660_OVER2, 0xff, bit);
 218}
 219
 220static int max8660_ldo67_disable(struct regulator_dev *rdev)
 221{
 222        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 223        u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? ~2 : ~4;
 224        return max8660_write(max8660, MAX8660_OVER2, mask, 0);
 225}
 226
 227static int max8660_ldo67_get_voltage_sel(struct regulator_dev *rdev)
 228{
 229        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 230
 231        u8 shift = (rdev_get_id(rdev) == MAX8660_V6) ? 0 : 4;
 232        u8 selector = (max8660->shadow_regs[MAX8660_L12VCR] >> shift) & 0xf;
 233        return selector;
 234}
 235
 236static int max8660_ldo67_set_voltage_sel(struct regulator_dev *rdev,
 237                                         unsigned int selector)
 238{
 239        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 240
 241        if (rdev_get_id(rdev) == MAX8660_V6)
 242                return max8660_write(max8660, MAX8660_L12VCR, 0xf0, selector);
 243        else
 244                return max8660_write(max8660, MAX8660_L12VCR, 0x0f,
 245                                     selector << 4);
 246}
 247
 248static struct regulator_ops max8660_ldo67_ops = {
 249        .is_enabled = max8660_ldo67_is_enabled,
 250        .enable = max8660_ldo67_enable,
 251        .disable = max8660_ldo67_disable,
 252        .list_voltage = regulator_list_voltage_linear,
 253        .map_voltage = regulator_map_voltage_linear,
 254        .get_voltage_sel = max8660_ldo67_get_voltage_sel,
 255        .set_voltage_sel = max8660_ldo67_set_voltage_sel,
 256};
 257
 258static const struct regulator_desc max8660_reg[] = {
 259        {
 260                .name = "V3(DCDC)",
 261                .id = MAX8660_V3,
 262                .ops = &max8660_dcdc_ops,
 263                .type = REGULATOR_VOLTAGE,
 264                .n_voltages = MAX8660_DCDC_MAX_SEL + 1,
 265                .owner = THIS_MODULE,
 266                .min_uV = MAX8660_DCDC_MIN_UV,
 267                .uV_step = MAX8660_DCDC_STEP,
 268        },
 269        {
 270                .name = "V4(DCDC)",
 271                .id = MAX8660_V4,
 272                .ops = &max8660_dcdc_ops,
 273                .type = REGULATOR_VOLTAGE,
 274                .n_voltages = MAX8660_DCDC_MAX_SEL + 1,
 275                .owner = THIS_MODULE,
 276                .min_uV = MAX8660_DCDC_MIN_UV,
 277                .uV_step = MAX8660_DCDC_STEP,
 278        },
 279        {
 280                .name = "V5(LDO)",
 281                .id = MAX8660_V5,
 282                .ops = &max8660_ldo5_ops,
 283                .type = REGULATOR_VOLTAGE,
 284                .n_voltages = MAX8660_LDO5_MAX_SEL + 1,
 285                .owner = THIS_MODULE,
 286                .min_uV = MAX8660_LDO5_MIN_UV,
 287                .uV_step = MAX8660_LDO5_STEP,
 288        },
 289        {
 290                .name = "V6(LDO)",
 291                .id = MAX8660_V6,
 292                .ops = &max8660_ldo67_ops,
 293                .type = REGULATOR_VOLTAGE,
 294                .n_voltages = MAX8660_LDO67_MAX_SEL + 1,
 295                .owner = THIS_MODULE,
 296                .min_uV = MAX8660_LDO67_MIN_UV,
 297                .uV_step = MAX8660_LDO67_STEP,
 298        },
 299        {
 300                .name = "V7(LDO)",
 301                .id = MAX8660_V7,
 302                .ops = &max8660_ldo67_ops,
 303                .type = REGULATOR_VOLTAGE,
 304                .n_voltages = MAX8660_LDO67_MAX_SEL + 1,
 305                .owner = THIS_MODULE,
 306                .min_uV = MAX8660_LDO67_MIN_UV,
 307                .uV_step = MAX8660_LDO67_STEP,
 308        },
 309};
 310
 311enum {
 312        MAX8660 = 0,
 313        MAX8661 = 1,
 314};
 315
 316#ifdef CONFIG_OF
 317static const struct of_device_id max8660_dt_ids[] = {
 318        { .compatible = "maxim,max8660", .data = (void *) MAX8660 },
 319        { .compatible = "maxim,max8661", .data = (void *) MAX8661 },
 320        { }
 321};
 322MODULE_DEVICE_TABLE(of, max8660_dt_ids);
 323
 324static int max8660_pdata_from_dt(struct device *dev,
 325                                 struct device_node **of_node,
 326                                 struct max8660_platform_data *pdata)
 327{
 328        int matched, i;
 329        struct device_node *np;
 330        struct max8660_subdev_data *sub;
 331        struct of_regulator_match rmatch[ARRAY_SIZE(max8660_reg)];
 332
 333        np = of_find_node_by_name(dev->of_node, "regulators");
 334        if (!np) {
 335                dev_err(dev, "missing 'regulators' subnode in DT\n");
 336                return -EINVAL;
 337        }
 338
 339        for (i = 0; i < ARRAY_SIZE(rmatch); i++)
 340                rmatch[i].name = max8660_reg[i].name;
 341
 342        matched = of_regulator_match(dev, np, rmatch, ARRAY_SIZE(rmatch));
 343        if (matched <= 0)
 344                return matched;
 345
 346        pdata->subdevs = devm_kzalloc(dev, sizeof(struct max8660_subdev_data) *
 347                                                matched, GFP_KERNEL);
 348        if (!pdata->subdevs)
 349                return -ENOMEM;
 350
 351        pdata->num_subdevs = matched;
 352        sub = pdata->subdevs;
 353
 354        for (i = 0; i < matched; i++) {
 355                sub->id = i;
 356                sub->name = rmatch[i].name;
 357                sub->platform_data = rmatch[i].init_data;
 358                of_node[i] = rmatch[i].of_node;
 359                sub++;
 360        }
 361
 362        return 0;
 363}
 364#else
 365static inline int max8660_pdata_from_dt(struct device *dev,
 366                                        struct device_node **of_node,
 367                                        struct max8660_platform_data *pdata)
 368{
 369        return 0;
 370}
 371#endif
 372
 373static int max8660_probe(struct i2c_client *client,
 374                                   const struct i2c_device_id *i2c_id)
 375{
 376        struct regulator_dev **rdev;
 377        struct device *dev = &client->dev;
 378        struct max8660_platform_data *pdata = dev_get_platdata(dev);
 379        struct regulator_config config = { };
 380        struct max8660 *max8660;
 381        int boot_on, i, id, ret = -EINVAL;
 382        struct device_node *of_node[MAX8660_V_END];
 383        unsigned long type;
 384
 385        if (dev->of_node && !pdata) {
 386                const struct of_device_id *id;
 387                struct max8660_platform_data pdata_of;
 388
 389                id = of_match_device(of_match_ptr(max8660_dt_ids), dev);
 390                if (!id)
 391                        return -ENODEV;
 392
 393                ret = max8660_pdata_from_dt(dev, of_node, &pdata_of);
 394                if (ret < 0)
 395                        return ret;
 396
 397                pdata = &pdata_of;
 398                type = (unsigned long) id->data;
 399        } else {
 400                type = i2c_id->driver_data;
 401                memset(of_node, 0, sizeof(of_node));
 402        }
 403
 404        if (pdata->num_subdevs > MAX8660_V_END) {
 405                dev_err(dev, "Too many regulators found!\n");
 406                return -EINVAL;
 407        }
 408
 409        max8660 = devm_kzalloc(dev, sizeof(struct max8660) +
 410                        sizeof(struct regulator_dev *) * MAX8660_V_END,
 411                        GFP_KERNEL);
 412        if (!max8660)
 413                return -ENOMEM;
 414
 415        max8660->client = client;
 416        rdev = max8660->rdev;
 417
 418        if (pdata->en34_is_high) {
 419                /* Simulate always on */
 420                max8660->shadow_regs[MAX8660_OVER1] = 5;
 421        } else {
 422                /* Otherwise devices can be toggled via software */
 423                max8660_dcdc_ops.enable = max8660_dcdc_enable;
 424                max8660_dcdc_ops.disable = max8660_dcdc_disable;
 425        }
 426
 427        /*
 428         * First, set up shadow registers to prevent glitches. As some
 429         * registers are shared between regulators, everything must be properly
 430         * set up for all regulators in advance.
 431         */
 432        max8660->shadow_regs[MAX8660_ADTV1] =
 433                max8660->shadow_regs[MAX8660_ADTV2] =
 434                max8660->shadow_regs[MAX8660_SDTV1] =
 435                max8660->shadow_regs[MAX8660_SDTV2] = 0x1b;
 436        max8660->shadow_regs[MAX8660_MDTV1] =
 437                max8660->shadow_regs[MAX8660_MDTV2] = 0x04;
 438
 439        for (i = 0; i < pdata->num_subdevs; i++) {
 440
 441                if (!pdata->subdevs[i].platform_data)
 442                        goto err_out;
 443
 444                boot_on = pdata->subdevs[i].platform_data->constraints.boot_on;
 445
 446                switch (pdata->subdevs[i].id) {
 447                case MAX8660_V3:
 448                        if (boot_on)
 449                                max8660->shadow_regs[MAX8660_OVER1] |= 1;
 450                        break;
 451
 452                case MAX8660_V4:
 453                        if (boot_on)
 454                                max8660->shadow_regs[MAX8660_OVER1] |= 4;
 455                        break;
 456
 457                case MAX8660_V5:
 458                        break;
 459
 460                case MAX8660_V6:
 461                        if (boot_on)
 462                                max8660->shadow_regs[MAX8660_OVER2] |= 2;
 463                        break;
 464
 465                case MAX8660_V7:
 466                        if (type == MAX8661) {
 467                                dev_err(dev, "Regulator not on this chip!\n");
 468                                goto err_out;
 469                        }
 470
 471                        if (boot_on)
 472                                max8660->shadow_regs[MAX8660_OVER2] |= 4;
 473                        break;
 474
 475                default:
 476                        dev_err(dev, "invalid regulator %s\n",
 477                                 pdata->subdevs[i].name);
 478                        goto err_out;
 479                }
 480        }
 481
 482        /* Finally register devices */
 483        for (i = 0; i < pdata->num_subdevs; i++) {
 484
 485                id = pdata->subdevs[i].id;
 486
 487                config.dev = dev;
 488                config.init_data = pdata->subdevs[i].platform_data;
 489                config.of_node = of_node[i];
 490                config.driver_data = max8660;
 491
 492                rdev[i] = regulator_register(&max8660_reg[id], &config);
 493                if (IS_ERR(rdev[i])) {
 494                        ret = PTR_ERR(rdev[i]);
 495                        dev_err(dev, "failed to register %s\n",
 496                                max8660_reg[id].name);
 497                        goto err_unregister;
 498                }
 499        }
 500
 501        i2c_set_clientdata(client, max8660);
 502        return 0;
 503
 504err_unregister:
 505        while (--i >= 0)
 506                regulator_unregister(rdev[i]);
 507err_out:
 508        return ret;
 509}
 510
 511static int max8660_remove(struct i2c_client *client)
 512{
 513        struct max8660 *max8660 = i2c_get_clientdata(client);
 514        int i;
 515
 516        for (i = 0; i < MAX8660_V_END; i++)
 517                regulator_unregister(max8660->rdev[i]);
 518        return 0;
 519}
 520
 521static const struct i2c_device_id max8660_id[] = {
 522        { .name = "max8660", .driver_data = MAX8660 },
 523        { .name = "max8661", .driver_data = MAX8661 },
 524        { }
 525};
 526MODULE_DEVICE_TABLE(i2c, max8660_id);
 527
 528static struct i2c_driver max8660_driver = {
 529        .probe = max8660_probe,
 530        .remove = max8660_remove,
 531        .driver         = {
 532                .name   = "max8660",
 533                .owner  = THIS_MODULE,
 534        },
 535        .id_table       = max8660_id,
 536};
 537
 538static int __init max8660_init(void)
 539{
 540        return i2c_add_driver(&max8660_driver);
 541}
 542subsys_initcall(max8660_init);
 543
 544static void __exit max8660_exit(void)
 545{
 546        i2c_del_driver(&max8660_driver);
 547}
 548module_exit(max8660_exit);
 549
 550/* Module information */
 551MODULE_DESCRIPTION("MAXIM 8660/8661 voltage regulator driver");
 552MODULE_AUTHOR("Wolfram Sang");
 553MODULE_LICENSE("GPL v2");
 554
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