drivers/regulator/max597x-regulator.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Device driver for regulators in MAX5970 and MAX5978 IC
0004  *
0005  * Copyright (c) 2022 9elements GmbH
0006  *
0007  * Author: Patrick Rudolph <patrick.rudolph@9elements.com>
0008  */
0009
0010 #include <linux/bitops.h>
0011 #include <linux/device.h>
0012 #include <linux/err.h>
0013 #include <linux/module.h>
0014 #include <linux/io.h>
0015 #include <linux/of.h>
0016 #include <linux/i2c.h>
0017 #include <linux/regmap.h>
0018 #include <linux/regulator/driver.h>
0019 #include <linux/regulator/machine.h>
0020 #include <linux/regulator/of_regulator.h>
0021 #include <linux/platform_device.h>
0022
0023 #include <linux/mfd/max597x.h>
0024
0025 struct max597x_regulator {
0026     int num_switches, mon_rng, irng, shunt_micro_ohms, lim_uA;
0027     struct regmap *regmap;
0028 };
0029
0030 enum max597x_regulator_id {
0031     MAX597X_SW0,
0032     MAX597X_SW1,
0033 };
0034
0035 static int max597x_uvp_ovp_check_mode(struct regulator_dev *rdev, int severity)
0036 {
0037     int ret, reg;
0038
0039     /* Status1 register contains the soft strap values sampled at POR */
0040     ret = regmap_read(rdev->regmap, MAX5970_REG_STATUS1, &reg);
0041     if (ret)
0042         return ret;
0043
0044     /* Check soft straps match requested mode */
0045     if (severity == REGULATOR_SEVERITY_PROT) {
0046         if (STATUS1_PROT(reg) != STATUS1_PROT_SHUTDOWN)
0047             return -EOPNOTSUPP;
0048
0049         return 0;
0050     }
0051     if (STATUS1_PROT(reg) == STATUS1_PROT_SHUTDOWN)
0052         return -EOPNOTSUPP;
0053
0054     return 0;
0055 }
0056
0057 static int max597x_set_vp(struct regulator_dev *rdev, int lim_uV, int severity,
0058               bool enable, bool overvoltage)
0059 {
0060     int off_h, off_l, reg, ret;
0061     struct max597x_regulator *data = rdev_get_drvdata(rdev);
0062     int channel = rdev_get_id(rdev);
0063
0064     if (overvoltage) {
0065         if (severity == REGULATOR_SEVERITY_WARN) {
0066             off_h = MAX5970_REG_CH_OV_WARN_H(channel);
0067             off_l = MAX5970_REG_CH_OV_WARN_L(channel);
0068         } else {
0069             off_h = MAX5970_REG_CH_OV_CRIT_H(channel);
0070             off_l = MAX5970_REG_CH_OV_CRIT_L(channel);
0071         }
0072     } else {
0073         if (severity == REGULATOR_SEVERITY_WARN) {
0074             off_h = MAX5970_REG_CH_UV_WARN_H(channel);
0075             off_l = MAX5970_REG_CH_UV_WARN_L(channel);
0076         } else {
0077             off_h = MAX5970_REG_CH_UV_CRIT_H(channel);
0078             off_l = MAX5970_REG_CH_UV_CRIT_L(channel);
0079         }
0080     }
0081
0082     if (enable)
0083         /* reg = ADC_MASK * (lim_uV / 1000000) / (data->mon_rng / 1000000) */
0084         reg = ADC_MASK * lim_uV / data->mon_rng;
0085     else
0086         reg = 0;
0087
0088     ret = regmap_write(rdev->regmap, off_h, MAX5970_VAL2REG_H(reg));
0089     if (ret)
0090         return ret;
0091
0092     ret = regmap_write(rdev->regmap, off_l, MAX5970_VAL2REG_L(reg));
0093     if (ret)
0094         return ret;
0095
0096     return 0;
0097 }
0098
0099 static int max597x_set_uvp(struct regulator_dev *rdev, int lim_uV, int severity,
0100                bool enable)
0101 {
0102     int ret;
0103
0104     /*
0105      * MAX5970 has enable control as a special value in limit reg. Can't
0106      * set limit but keep feature disabled or enable W/O given limit.
0107      */
0108     if ((lim_uV && !enable) || (!lim_uV && enable))
0109         return -EINVAL;
0110
0111     ret = max597x_uvp_ovp_check_mode(rdev, severity);
0112     if (ret)
0113         return ret;
0114
0115     return max597x_set_vp(rdev, lim_uV, severity, enable, false);
0116 }
0117
0118 static int max597x_set_ovp(struct regulator_dev *rdev, int lim_uV, int severity,
0119                bool enable)
0120 {
0121     int ret;
0122
0123     /*
0124      * MAX5970 has enable control as a special value in limit reg. Can't
0125      * set limit but keep feature disabled or enable W/O given limit.
0126      */
0127     if ((lim_uV && !enable) || (!lim_uV && enable))
0128         return -EINVAL;
0129
0130     ret = max597x_uvp_ovp_check_mode(rdev, severity);
0131     if (ret)
0132         return ret;
0133
0134     return max597x_set_vp(rdev, lim_uV, severity, enable, true);
0135 }
0136
0137 static int max597x_set_ocp(struct regulator_dev *rdev, int lim_uA,
0138                int severity, bool enable)
0139 {
0140     int ret, val, reg;
0141     unsigned int vthst, vthfst;
0142
0143     struct max597x_regulator *data = rdev_get_drvdata(rdev);
0144     int rdev_id = rdev_get_id(rdev);
0145     /*
0146      * MAX5970 doesn't has enable control for ocp.
0147      * If limit is specified but enable is not set then hold the value in
0148      * variable & later use it when ocp needs to be enabled.
0149      */
0150     if (lim_uA != 0 && lim_uA != data->lim_uA)
0151         data->lim_uA = lim_uA;
0152
0153     if (severity != REGULATOR_SEVERITY_PROT)
0154         return -EINVAL;
0155
0156     if (enable) {
0157
0158         /* Calc Vtrip threshold in uV. */
0159         vthst =
0160             div_u64(mul_u32_u32(data->shunt_micro_ohms, data->lim_uA),
0161                 1000000);
0162
0163         /*
0164          * As recommended in datasheed, add 20% margin to avoid
0165          * spurious event & passive component tolerance.
0166          */
0167         vthst = div_u64(mul_u32_u32(vthst, 120), 100);
0168
0169         /* Calc fast Vtrip threshold in uV */
0170         vthfst = vthst * (MAX5970_FAST2SLOW_RATIO / 100);
0171
0172         if (vthfst > data->irng) {
0173             dev_err(&rdev->dev, "Current limit out of range\n");
0174             return -EINVAL;
0175         }
0176         /* Fast trip threshold to be programmed */
0177         val = div_u64(mul_u32_u32(0xFF, vthfst), data->irng);
0178     } else
0179         /*
0180          * Since there is no option to disable ocp, set limit to max
0181          * value
0182          */
0183         val = 0xFF;
0184
0185     reg = MAX5970_REG_DAC_FAST(rdev_id);
0186     ret = regmap_write(rdev->regmap, reg, val);
0187
0188     return ret;
0189 }
0190
0191 static int max597x_get_status(struct regulator_dev *rdev)
0192 {
0193     int val, ret;
0194
0195     ret = regmap_read(rdev->regmap, MAX5970_REG_STATUS3, &val);
0196     if (ret)
0197         return REGULATOR_FAILED_RETRY;
0198
0199     if (val & MAX5970_STATUS3_ALERT)
0200         return REGULATOR_STATUS_ERROR;
0201
0202     ret = regulator_is_enabled_regmap(rdev);
0203     if (ret < 0)
0204         return ret;
0205
0206     if (ret)
0207         return REGULATOR_STATUS_ON;
0208
0209     return REGULATOR_STATUS_OFF;
0210 }
0211
0212 static const struct regulator_ops max597x_switch_ops = {
0213     .enable = regulator_enable_regmap,
0214     .disable = regulator_disable_regmap,
0215     .is_enabled = regulator_is_enabled_regmap,
0216     .get_status = max597x_get_status,
0217     .set_over_voltage_protection = max597x_set_ovp,
0218     .set_under_voltage_protection = max597x_set_uvp,
0219     .set_over_current_protection = max597x_set_ocp,
0220 };
0221
0222 static int max597x_dt_parse(struct device_node *np,
0223                 const struct regulator_desc *desc,
0224                 struct regulator_config *cfg)
0225 {
0226     struct max597x_regulator *data = cfg->driver_data;
0227     int ret = 0;
0228
0229     ret =
0230         of_property_read_u32(np, "shunt-resistor-micro-ohms",
0231                  &data->shunt_micro_ohms);
0232     if (ret < 0)
0233         dev_err(cfg->dev,
0234             "property 'shunt-resistor-micro-ohms' not found, err %d\n",
0235             ret);
0236     return ret;
0237
0238 }
0239
0240 #define MAX597X_SWITCH(_ID, _ereg, _chan, _supply) {     \
0241     .name            = #_ID,                         \
0242     .of_match        = of_match_ptr(#_ID),           \
0243     .ops             = &max597x_switch_ops,          \
0244     .regulators_node = of_match_ptr("regulators"),   \
0245     .type            = REGULATOR_VOLTAGE,            \
0246     .id              = MAX597X_##_ID,                \
0247     .owner           = THIS_MODULE,                  \
0248     .supply_name     = _supply,                      \
0249     .enable_reg      = _ereg,                        \
0250     .enable_mask     = CHXEN((_chan)),               \
0251     .of_parse_cb     = max597x_dt_parse,         \
0252 }
0253
0254 static const struct regulator_desc regulators[] = {
0255     MAX597X_SWITCH(SW0, MAX5970_REG_CHXEN, 0, "vss1"),
0256     MAX597X_SWITCH(SW1, MAX5970_REG_CHXEN, 1, "vss2"),
0257 };
0258
0259 static int max597x_regmap_read_clear(struct regmap *map, unsigned int reg,
0260                      unsigned int *val)
0261 {
0262     int ret;
0263
0264     ret = regmap_read(map, reg, val);
0265     if (ret)
0266         return ret;
0267
0268     if (*val)
0269         return regmap_write(map, reg, *val);
0270
0271     return 0;
0272 }
0273
0274 static int max597x_irq_handler(int irq, struct regulator_irq_data *rid,
0275                    unsigned long *dev_mask)
0276 {
0277     struct regulator_err_state *stat;
0278     struct max597x_regulator *d = (struct max597x_regulator *)rid->data;
0279     int val, ret, i;
0280
0281     ret = max597x_regmap_read_clear(d->regmap, MAX5970_REG_FAULT0, &val);
0282     if (ret)
0283         return REGULATOR_FAILED_RETRY;
0284
0285     *dev_mask = 0;
0286     for (i = 0; i < d->num_switches; i++) {
0287         stat = &rid->states[i];
0288         stat->notifs = 0;
0289         stat->errors = 0;
0290     }
0291
0292     for (i = 0; i < d->num_switches; i++) {
0293         stat = &rid->states[i];
0294
0295         if (val & UV_STATUS_CRIT(i)) {
0296             *dev_mask |= 1 << i;
0297             stat->notifs |= REGULATOR_EVENT_UNDER_VOLTAGE;
0298             stat->errors |= REGULATOR_ERROR_UNDER_VOLTAGE;
0299         } else if (val & UV_STATUS_WARN(i)) {
0300             *dev_mask |= 1 << i;
0301             stat->notifs |= REGULATOR_EVENT_UNDER_VOLTAGE_WARN;
0302             stat->errors |= REGULATOR_ERROR_UNDER_VOLTAGE_WARN;
0303         }
0304     }
0305
0306     ret = max597x_regmap_read_clear(d->regmap, MAX5970_REG_FAULT1, &val);
0307     if (ret)
0308         return REGULATOR_FAILED_RETRY;
0309
0310     for (i = 0; i < d->num_switches; i++) {
0311         stat = &rid->states[i];
0312
0313         if (val & OV_STATUS_CRIT(i)) {
0314             *dev_mask |= 1 << i;
0315             stat->notifs |= REGULATOR_EVENT_REGULATION_OUT;
0316             stat->errors |= REGULATOR_ERROR_REGULATION_OUT;
0317         } else if (val & OV_STATUS_WARN(i)) {
0318             *dev_mask |= 1 << i;
0319             stat->notifs |= REGULATOR_EVENT_OVER_VOLTAGE_WARN;
0320             stat->errors |= REGULATOR_ERROR_OVER_VOLTAGE_WARN;
0321         }
0322     }
0323
0324     ret = max597x_regmap_read_clear(d->regmap, MAX5970_REG_FAULT2, &val);
0325     if (ret)
0326         return REGULATOR_FAILED_RETRY;
0327
0328     for (i = 0; i < d->num_switches; i++) {
0329         stat = &rid->states[i];
0330
0331         if (val & OC_STATUS_WARN(i)) {
0332             *dev_mask |= 1 << i;
0333             stat->notifs |= REGULATOR_EVENT_OVER_CURRENT_WARN;
0334             stat->errors |= REGULATOR_ERROR_OVER_CURRENT_WARN;
0335         }
0336     }
0337
0338     ret = regmap_read(d->regmap, MAX5970_REG_STATUS0, &val);
0339     if (ret)
0340         return REGULATOR_FAILED_RETRY;
0341
0342     for (i = 0; i < d->num_switches; i++) {
0343         stat = &rid->states[i];
0344
0345         if ((val & MAX5970_CB_IFAULTF(i))
0346             || (val & MAX5970_CB_IFAULTS(i))) {
0347             *dev_mask |= 1 << i;
0348             stat->notifs |=
0349                 REGULATOR_EVENT_OVER_CURRENT |
0350                 REGULATOR_EVENT_DISABLE;
0351             stat->errors |=
0352                 REGULATOR_ERROR_OVER_CURRENT | REGULATOR_ERROR_FAIL;
0353
0354             /* Clear the sub-IRQ status */
0355             regulator_disable_regmap(stat->rdev);
0356         }
0357     }
0358     return 0;
0359 }
0360
0361 static const struct regmap_config max597x_regmap_config = {
0362     .reg_bits = 8,
0363     .val_bits = 8,
0364     .max_register = MAX_REGISTERS,
0365 };
0366
0367 static int max597x_adc_range(struct regmap *regmap, const int ch,
0368                  u32 *irng, u32 *mon_rng)
0369 {
0370     unsigned int reg;
0371     int ret;
0372
0373     /* Decode current ADC range */
0374     ret = regmap_read(regmap, MAX5970_REG_STATUS2, &reg);
0375     if (ret)
0376         return ret;
0377     switch (MAX5970_IRNG(reg, ch)) {
0378     case 0:
0379         *irng = 100000; /* 100 mV */
0380         break;
0381     case 1:
0382         *irng = 50000;  /* 50 mV */
0383         break;
0384     case 2:
0385         *irng = 25000;  /* 25 mV */
0386         break;
0387     default:
0388         return -EINVAL;
0389     }
0390
0391     /* Decode current voltage monitor range */
0392     ret = regmap_read(regmap, MAX5970_REG_MON_RANGE, &reg);
0393     if (ret)
0394         return ret;
0395
0396     *mon_rng = MAX5970_MON_MAX_RANGE_UV >> MAX5970_MON(reg, ch);
0397
0398     return 0;
0399 }
0400
0401 static int max597x_setup_irq(struct device *dev,
0402                  int irq,
0403                  struct regulator_dev *rdevs[MAX5970_NUM_SWITCHES],
0404                  int num_switches, struct max597x_regulator *data)
0405 {
0406     struct regulator_irq_desc max597x_notif = {
0407         .name = "max597x-irq",
0408         .map_event = max597x_irq_handler,
0409         .data = data,
0410     };
0411     int errs = REGULATOR_ERROR_UNDER_VOLTAGE |
0412         REGULATOR_ERROR_UNDER_VOLTAGE_WARN |
0413         REGULATOR_ERROR_OVER_VOLTAGE_WARN |
0414         REGULATOR_ERROR_REGULATION_OUT |
0415         REGULATOR_ERROR_OVER_CURRENT |
0416         REGULATOR_ERROR_OVER_CURRENT_WARN | REGULATOR_ERROR_FAIL;
0417     void *irq_helper;
0418
0419     /* Register notifiers - can fail if IRQ is not given */
0420     irq_helper = devm_regulator_irq_helper(dev, &max597x_notif,
0421                            irq, 0, errs, NULL,
0422                            &rdevs[0], num_switches);
0423     if (IS_ERR(irq_helper)) {
0424         if (PTR_ERR(irq_helper) == -EPROBE_DEFER)
0425             return -EPROBE_DEFER;
0426
0427         dev_warn(dev, "IRQ disabled %pe\n", irq_helper);
0428     }
0429
0430     return 0;
0431 }
0432
0433 static int max597x_regulator_probe(struct platform_device *pdev)
0434 {
0435
0436
0437     struct max597x_data *max597x = dev_get_drvdata(pdev->dev.parent);
0438     struct max597x_regulator *data;
0439
0440     struct regulator_config config = { };
0441     struct regulator_dev *rdev;
0442     struct regulator_dev *rdevs[MAX5970_NUM_SWITCHES];
0443     int num_switches = max597x->num_switches;
0444     int ret, i;
0445
0446     for (i = 0; i < num_switches; i++) {
0447         data =
0448             devm_kzalloc(max597x->dev, sizeof(struct max597x_regulator),
0449                  GFP_KERNEL);
0450         if (!data)
0451             return -ENOMEM;
0452
0453         data->num_switches = num_switches;
0454         data->regmap = max597x->regmap;
0455
0456         ret = max597x_adc_range(data->regmap, i, &max597x->irng[i], &max597x->mon_rng[i]);
0457         if (ret < 0)
0458             return ret;
0459
0460         data->irng = max597x->irng[i];
0461         data->mon_rng = max597x->mon_rng[i];
0462
0463         config.dev = max597x->dev;
0464         config.driver_data = (void *)data;
0465         config.regmap = data->regmap;
0466         rdev = devm_regulator_register(max597x->dev,
0467                            &regulators[i], &config);
0468         if (IS_ERR(rdev)) {
0469             dev_err(max597x->dev, "failed to register regulator %s\n",
0470                 regulators[i].name);
0471             return PTR_ERR(rdev);
0472         }
0473         rdevs[i] = rdev;
0474         max597x->shunt_micro_ohms[i] = data->shunt_micro_ohms;
0475     }
0476
0477     if (max597x->irq) {
0478         ret =
0479             max597x_setup_irq(max597x->dev, max597x->irq, rdevs, num_switches,
0480                       data);
0481         if (ret) {
0482             dev_err(max597x->dev, "IRQ setup failed");
0483             return ret;
0484         }
0485     }
0486
0487     return ret;
0488 }
0489
0490 static struct platform_driver max597x_regulator_driver = {
0491     .driver = {
0492         .name = "max597x-regulator",
0493     },
0494     .probe = max597x_regulator_probe,
0495 };
0496
0497 module_platform_driver(max597x_regulator_driver);
0498
0499
0500 MODULE_AUTHOR("Patrick Rudolph <patrick.rudolph@9elements.com>");
0501 MODULE_DESCRIPTION("MAX5970_hot-swap controller driver");
0502 MODULE_LICENSE("GPL v2");