linux/drivers/regulator/max8660.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * max8660.c  --  Voltage regulation for the Maxim 8660/8661
   4 *
   5 * based on max1586.c and wm8400-regulator.c
   6 *
   7 * Copyright (C) 2009 Wolfram Sang, Pengutronix e.K.
   8 *
   9 * Some info:
  10 *
  11 * Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX8660-MAX8661.pdf
  12 *
  13 * This chip is a bit nasty because it is a write-only device. Thus, the driver
  14 * uses shadow registers to keep track of its values. The main problem appears
  15 * to be the initialization: When Linux boots up, we cannot know if the chip is
  16 * in the default state or not, so we would have to pass such information in
  17 * platform_data. As this adds a bit of complexity to the driver, this is left
  18 * out for now until it is really needed.
  19 *
  20 * [A|S|M]DTV1 registers are currently not used, but [A|S|M]DTV2.
  21 *
  22 * If the driver is feature complete, it might be worth to check if one set of
  23 * functions for V3-V7 is sufficient. For maximum flexibility during
  24 * development, they are separated for now.
  25 */
  26
  27#include <linux/module.h>
  28#include <linux/err.h>
  29#include <linux/i2c.h>
  30#include <linux/platform_device.h>
  31#include <linux/regulator/driver.h>
  32#include <linux/slab.h>
  33#include <linux/regulator/max8660.h>
  34#include <linux/of.h>
  35#include <linux/of_device.h>
  36#include <linux/regulator/of_regulator.h>
  37
  38#define MAX8660_DCDC_MIN_UV      725000
  39#define MAX8660_DCDC_MAX_UV     1800000
  40#define MAX8660_DCDC_STEP         25000
  41#define MAX8660_DCDC_MAX_SEL    0x2b
  42
  43#define MAX8660_LDO5_MIN_UV     1700000
  44#define MAX8660_LDO5_MAX_UV     2000000
  45#define MAX8660_LDO5_STEP         25000
  46#define MAX8660_LDO5_MAX_SEL    0x0c
  47
  48#define MAX8660_LDO67_MIN_UV    1800000
  49#define MAX8660_LDO67_MAX_UV    3300000
  50#define MAX8660_LDO67_STEP       100000
  51#define MAX8660_LDO67_MAX_SEL   0x0f
  52
  53enum {
  54        MAX8660_OVER1,
  55        MAX8660_OVER2,
  56        MAX8660_VCC1,
  57        MAX8660_ADTV1,
  58        MAX8660_ADTV2,
  59        MAX8660_SDTV1,
  60        MAX8660_SDTV2,
  61        MAX8660_MDTV1,
  62        MAX8660_MDTV2,
  63        MAX8660_L12VCR,
  64        MAX8660_FPWM,
  65        MAX8660_N_REGS, /* not a real register */
  66};
  67
  68struct max8660 {
  69        struct i2c_client *client;
  70        u8 shadow_regs[MAX8660_N_REGS];         /* as chip is write only */
  71};
  72
  73static int max8660_write(struct max8660 *max8660, u8 reg, u8 mask, u8 val)
  74{
  75        static const u8 max8660_addresses[MAX8660_N_REGS] = {
  76         0x10, 0x12, 0x20, 0x23, 0x24, 0x29, 0x2a, 0x32, 0x33, 0x39, 0x80
  77        };
  78
  79        int ret;
  80        u8 reg_val = (max8660->shadow_regs[reg] & mask) | val;
  81
  82        dev_vdbg(&max8660->client->dev, "Writing reg %02x with %02x\n",
  83                        max8660_addresses[reg], reg_val);
  84
  85        ret = i2c_smbus_write_byte_data(max8660->client,
  86                        max8660_addresses[reg], reg_val);
  87        if (ret == 0)
  88                max8660->shadow_regs[reg] = reg_val;
  89
  90        return ret;
  91}
  92
  93
  94/*
  95 * DCDC functions
  96 */
  97
  98static int max8660_dcdc_is_enabled(struct regulator_dev *rdev)
  99{
 100        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 101        u8 val = max8660->shadow_regs[MAX8660_OVER1];
 102        u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;
 103
 104        return !!(val & mask);
 105}
 106
 107static int max8660_dcdc_enable(struct regulator_dev *rdev)
 108{
 109        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 110        u8 bit = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;
 111
 112        return max8660_write(max8660, MAX8660_OVER1, 0xff, bit);
 113}
 114
 115static int max8660_dcdc_disable(struct regulator_dev *rdev)
 116{
 117        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 118        u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? ~1 : ~4;
 119
 120        return max8660_write(max8660, MAX8660_OVER1, mask, 0);
 121}
 122
 123static int max8660_dcdc_get_voltage_sel(struct regulator_dev *rdev)
 124{
 125        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 126        u8 reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
 127        u8 selector = max8660->shadow_regs[reg];
 128
 129        return selector;
 130}
 131
 132static int max8660_dcdc_set_voltage_sel(struct regulator_dev *rdev,
 133                                        unsigned int selector)
 134{
 135        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 136        u8 reg, bits;
 137        int ret;
 138
 139        reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
 140        ret = max8660_write(max8660, reg, 0, selector);
 141        if (ret)
 142                return ret;
 143
 144        /* Select target voltage register and activate regulation */
 145        bits = (rdev_get_id(rdev) == MAX8660_V3) ? 0x03 : 0x30;
 146        return max8660_write(max8660, MAX8660_VCC1, 0xff, bits);
 147}
 148
 149static struct regulator_ops max8660_dcdc_ops = {
 150        .is_enabled = max8660_dcdc_is_enabled,
 151        .list_voltage = regulator_list_voltage_linear,
 152        .map_voltage = regulator_map_voltage_linear,
 153        .set_voltage_sel = max8660_dcdc_set_voltage_sel,
 154        .get_voltage_sel = max8660_dcdc_get_voltage_sel,
 155};
 156
 157
 158/*
 159 * LDO5 functions
 160 */
 161
 162static int max8660_ldo5_get_voltage_sel(struct regulator_dev *rdev)
 163{
 164        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 165
 166        u8 selector = max8660->shadow_regs[MAX8660_MDTV2];
 167        return selector;
 168}
 169
 170static int max8660_ldo5_set_voltage_sel(struct regulator_dev *rdev,
 171                                        unsigned int selector)
 172{
 173        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 174        int ret;
 175
 176        ret = max8660_write(max8660, MAX8660_MDTV2, 0, selector);
 177        if (ret)
 178                return ret;
 179
 180        /* Select target voltage register and activate regulation */
 181        return max8660_write(max8660, MAX8660_VCC1, 0xff, 0xc0);
 182}
 183
 184static const struct regulator_ops max8660_ldo5_ops = {
 185        .list_voltage = regulator_list_voltage_linear,
 186        .map_voltage = regulator_map_voltage_linear,
 187        .set_voltage_sel = max8660_ldo5_set_voltage_sel,
 188        .get_voltage_sel = max8660_ldo5_get_voltage_sel,
 189};
 190
 191
 192/*
 193 * LDO67 functions
 194 */
 195
 196static int max8660_ldo67_is_enabled(struct regulator_dev *rdev)
 197{
 198        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 199        u8 val = max8660->shadow_regs[MAX8660_OVER2];
 200        u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;
 201
 202        return !!(val & mask);
 203}
 204
 205static int max8660_ldo67_enable(struct regulator_dev *rdev)
 206{
 207        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 208        u8 bit = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;
 209
 210        return max8660_write(max8660, MAX8660_OVER2, 0xff, bit);
 211}
 212
 213static int max8660_ldo67_disable(struct regulator_dev *rdev)
 214{
 215        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 216        u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? ~2 : ~4;
 217
 218        return max8660_write(max8660, MAX8660_OVER2, mask, 0);
 219}
 220
 221static int max8660_ldo67_get_voltage_sel(struct regulator_dev *rdev)
 222{
 223        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 224        u8 shift = (rdev_get_id(rdev) == MAX8660_V6) ? 0 : 4;
 225        u8 selector = (max8660->shadow_regs[MAX8660_L12VCR] >> shift) & 0xf;
 226
 227        return selector;
 228}
 229
 230static int max8660_ldo67_set_voltage_sel(struct regulator_dev *rdev,
 231                                         unsigned int selector)
 232{
 233        struct max8660 *max8660 = rdev_get_drvdata(rdev);
 234
 235        if (rdev_get_id(rdev) == MAX8660_V6)
 236                return max8660_write(max8660, MAX8660_L12VCR, 0xf0, selector);
 237        else
 238                return max8660_write(max8660, MAX8660_L12VCR, 0x0f,
 239                                     selector << 4);
 240}
 241
 242static const struct regulator_ops max8660_ldo67_ops = {
 243        .is_enabled = max8660_ldo67_is_enabled,
 244        .enable = max8660_ldo67_enable,
 245        .disable = max8660_ldo67_disable,
 246        .list_voltage = regulator_list_voltage_linear,
 247        .map_voltage = regulator_map_voltage_linear,
 248        .get_voltage_sel = max8660_ldo67_get_voltage_sel,
 249        .set_voltage_sel = max8660_ldo67_set_voltage_sel,
 250};
 251
 252static const struct regulator_desc max8660_reg[] = {
 253        {
 254                .name = "V3(DCDC)",
 255                .id = MAX8660_V3,
 256                .ops = &max8660_dcdc_ops,
 257                .type = REGULATOR_VOLTAGE,
 258                .n_voltages = MAX8660_DCDC_MAX_SEL + 1,
 259                .owner = THIS_MODULE,
 260                .min_uV = MAX8660_DCDC_MIN_UV,
 261                .uV_step = MAX8660_DCDC_STEP,
 262        },
 263        {
 264                .name = "V4(DCDC)",
 265                .id = MAX8660_V4,
 266                .ops = &max8660_dcdc_ops,
 267                .type = REGULATOR_VOLTAGE,
 268                .n_voltages = MAX8660_DCDC_MAX_SEL + 1,
 269                .owner = THIS_MODULE,
 270                .min_uV = MAX8660_DCDC_MIN_UV,
 271                .uV_step = MAX8660_DCDC_STEP,
 272        },
 273        {
 274                .name = "V5(LDO)",
 275                .id = MAX8660_V5,
 276                .ops = &max8660_ldo5_ops,
 277                .type = REGULATOR_VOLTAGE,
 278                .n_voltages = MAX8660_LDO5_MAX_SEL + 1,
 279                .owner = THIS_MODULE,
 280                .min_uV = MAX8660_LDO5_MIN_UV,
 281                .uV_step = MAX8660_LDO5_STEP,
 282        },
 283        {
 284                .name = "V6(LDO)",
 285                .id = MAX8660_V6,
 286                .ops = &max8660_ldo67_ops,
 287                .type = REGULATOR_VOLTAGE,
 288                .n_voltages = MAX8660_LDO67_MAX_SEL + 1,
 289                .owner = THIS_MODULE,
 290                .min_uV = MAX8660_LDO67_MIN_UV,
 291                .uV_step = MAX8660_LDO67_STEP,
 292        },
 293        {
 294                .name = "V7(LDO)",
 295                .id = MAX8660_V7,
 296                .ops = &max8660_ldo67_ops,
 297                .type = REGULATOR_VOLTAGE,
 298                .n_voltages = MAX8660_LDO67_MAX_SEL + 1,
 299                .owner = THIS_MODULE,
 300                .min_uV = MAX8660_LDO67_MIN_UV,
 301                .uV_step = MAX8660_LDO67_STEP,
 302        },
 303};
 304
 305enum {
 306        MAX8660 = 0,
 307        MAX8661 = 1,
 308};
 309
 310#ifdef CONFIG_OF
 311static const struct of_device_id max8660_dt_ids[] = {
 312        { .compatible = "maxim,max8660", .data = (void *) MAX8660 },
 313        { .compatible = "maxim,max8661", .data = (void *) MAX8661 },
 314        { }
 315};
 316MODULE_DEVICE_TABLE(of, max8660_dt_ids);
 317
 318static int max8660_pdata_from_dt(struct device *dev,
 319                                 struct device_node **of_node,
 320                                 struct max8660_platform_data *pdata)
 321{
 322        int matched, i;
 323        struct device_node *np;
 324        struct max8660_subdev_data *sub;
 325        struct of_regulator_match rmatch[ARRAY_SIZE(max8660_reg)] = { };
 326
 327        np = of_get_child_by_name(dev->of_node, "regulators");
 328        if (!np) {
 329                dev_err(dev, "missing 'regulators' subnode in DT\n");
 330                return -EINVAL;
 331        }
 332
 333        for (i = 0; i < ARRAY_SIZE(rmatch); i++)
 334                rmatch[i].name = max8660_reg[i].name;
 335
 336        matched = of_regulator_match(dev, np, rmatch, ARRAY_SIZE(rmatch));
 337        of_node_put(np);
 338        if (matched <= 0)
 339                return matched;
 340
 341        pdata->subdevs = devm_kcalloc(dev,
 342                                      matched,
 343                                      sizeof(struct max8660_subdev_data),
 344                                      GFP_KERNEL);
 345        if (!pdata->subdevs)
 346                return -ENOMEM;
 347
 348        pdata->num_subdevs = matched;
 349        sub = pdata->subdevs;
 350
 351        for (i = 0; i < matched; i++) {
 352                sub->id = i;
 353                sub->name = rmatch[i].name;
 354                sub->platform_data = rmatch[i].init_data;
 355                of_node[i] = rmatch[i].of_node;
 356                sub++;
 357        }
 358
 359        return 0;
 360}
 361#else
 362static inline int max8660_pdata_from_dt(struct device *dev,
 363                                        struct device_node **of_node,
 364                                        struct max8660_platform_data *pdata)
 365{
 366        return 0;
 367}
 368#endif
 369
 370static int max8660_probe(struct i2c_client *client,
 371                                   const struct i2c_device_id *i2c_id)
 372{
 373        struct device *dev = &client->dev;
 374        struct max8660_platform_data pdata_of, *pdata = dev_get_platdata(dev);
 375        struct regulator_config config = { };
 376        struct max8660 *max8660;
 377        int boot_on, i, id, ret = -EINVAL;
 378        struct device_node *of_node[MAX8660_V_END];
 379        unsigned long type;
 380
 381        if (dev->of_node && !pdata) {
 382                const struct of_device_id *id;
 383
 384                id = of_match_device(of_match_ptr(max8660_dt_ids), dev);
 385                if (!id)
 386                        return -ENODEV;
 387
 388                ret = max8660_pdata_from_dt(dev, of_node, &pdata_of);
 389                if (ret < 0)
 390                        return ret;
 391
 392                pdata = &pdata_of;
 393                type = (unsigned long) id->data;
 394        } else {
 395                type = i2c_id->driver_data;
 396                memset(of_node, 0, sizeof(of_node));
 397        }
 398
 399        if (pdata->num_subdevs > MAX8660_V_END) {
 400                dev_err(dev, "Too many regulators found!\n");
 401                return -EINVAL;
 402        }
 403
 404        max8660 = devm_kzalloc(dev, sizeof(struct max8660), GFP_KERNEL);
 405        if (!max8660)
 406                return -ENOMEM;
 407
 408        max8660->client = client;
 409
 410        if (pdata->en34_is_high) {
 411                /* Simulate always on */
 412                max8660->shadow_regs[MAX8660_OVER1] = 5;
 413        } else {
 414                /* Otherwise devices can be toggled via software */
 415                max8660_dcdc_ops.enable = max8660_dcdc_enable;
 416                max8660_dcdc_ops.disable = max8660_dcdc_disable;
 417        }
 418
 419        /*
 420         * First, set up shadow registers to prevent glitches. As some
 421         * registers are shared between regulators, everything must be properly
 422         * set up for all regulators in advance.
 423         */
 424        max8660->shadow_regs[MAX8660_ADTV1] =
 425                max8660->shadow_regs[MAX8660_ADTV2] =
 426                max8660->shadow_regs[MAX8660_SDTV1] =
 427                max8660->shadow_regs[MAX8660_SDTV2] = 0x1b;
 428        max8660->shadow_regs[MAX8660_MDTV1] =
 429                max8660->shadow_regs[MAX8660_MDTV2] = 0x04;
 430
 431        for (i = 0; i < pdata->num_subdevs; i++) {
 432
 433                if (!pdata->subdevs[i].platform_data)
 434                        boot_on = false;
 435                else
 436                        boot_on = pdata->subdevs[i].platform_data->constraints.boot_on;
 437
 438                switch (pdata->subdevs[i].id) {
 439                case MAX8660_V3:
 440                        if (boot_on)
 441                                max8660->shadow_regs[MAX8660_OVER1] |= 1;
 442                        break;
 443
 444                case MAX8660_V4:
 445                        if (boot_on)
 446                                max8660->shadow_regs[MAX8660_OVER1] |= 4;
 447                        break;
 448
 449                case MAX8660_V5:
 450                        break;
 451
 452                case MAX8660_V6:
 453                        if (boot_on)
 454                                max8660->shadow_regs[MAX8660_OVER2] |= 2;
 455                        break;
 456
 457                case MAX8660_V7:
 458                        if (type == MAX8661) {
 459                                dev_err(dev, "Regulator not on this chip!\n");
 460                                return -EINVAL;
 461                        }
 462
 463                        if (boot_on)
 464                                max8660->shadow_regs[MAX8660_OVER2] |= 4;
 465                        break;
 466
 467                default:
 468                        dev_err(dev, "invalid regulator %s\n",
 469                                 pdata->subdevs[i].name);
 470                        return ret;
 471                }
 472        }
 473
 474        /* Finally register devices */
 475        for (i = 0; i < pdata->num_subdevs; i++) {
 476                struct regulator_dev *rdev;
 477
 478                id = pdata->subdevs[i].id;
 479
 480                config.dev = dev;
 481                config.init_data = pdata->subdevs[i].platform_data;
 482                config.of_node = of_node[i];
 483                config.driver_data = max8660;
 484
 485                rdev = devm_regulator_register(&client->dev,
 486                                                  &max8660_reg[id], &config);
 487                if (IS_ERR(rdev)) {
 488                        dev_err(&client->dev, "failed to register %s\n",
 489                                max8660_reg[id].name);
 490                        return PTR_ERR(rdev);
 491                }
 492        }
 493
 494        i2c_set_clientdata(client, max8660);
 495        return 0;
 496}
 497
 498static const struct i2c_device_id max8660_id[] = {
 499        { .name = "max8660", .driver_data = MAX8660 },
 500        { .name = "max8661", .driver_data = MAX8661 },
 501        { }
 502};
 503MODULE_DEVICE_TABLE(i2c, max8660_id);
 504
 505static struct i2c_driver max8660_driver = {
 506        .probe = max8660_probe,
 507        .driver         = {
 508                .name   = "max8660",
 509        },
 510        .id_table       = max8660_id,
 511};
 512
 513static int __init max8660_init(void)
 514{
 515        return i2c_add_driver(&max8660_driver);
 516}
 517subsys_initcall(max8660_init);
 518
 519static void __exit max8660_exit(void)
 520{
 521        i2c_del_driver(&max8660_driver);
 522}
 523module_exit(max8660_exit);
 524
 525/* Module information */
 526MODULE_DESCRIPTION("MAXIM 8660/8661 voltage regulator driver");
 527MODULE_AUTHOR("Wolfram Sang");
 528MODULE_LICENSE("GPL v2");
 529