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1// SPDX-License-Identifier: GPL-2.0+2/*3 * Hardware monitoring driver for EMC2305 fan controller4 *5 * Copyright (C) 2022 Nvidia Technologies Ltd.6 */7 8#include <linux/err.h>9#include <linux/hwmon.h>10#include <linux/i2c.h>11#include <linux/module.h>12#include <linux/platform_data/emc2305.h>13#include <linux/thermal.h>14 15#define EMC2305_REG_DRIVE_FAIL_STATUS 0x2716#define EMC2305_REG_VENDOR 0xfe17#define EMC2305_FAN_MAX 0xff18#define EMC2305_FAN_MIN 0x0019#define EMC2305_FAN_MAX_STATE 1020#define EMC2305_DEVICE 0x3421#define EMC2305_VENDOR 0x5d22#define EMC2305_REG_PRODUCT_ID 0xfd23#define EMC2305_TACH_REGS_UNUSE_BITS 324#define EMC2305_TACH_CNT_MULTIPLIER 0x0225#define EMC2305_TACH_RANGE_MIN 48026 27#define EMC2305_PWM_DUTY2STATE(duty, max_state, pwm_max) \28 DIV_ROUND_CLOSEST((duty) * (max_state), (pwm_max))29#define EMC2305_PWM_STATE2DUTY(state, max_state, pwm_max) \30 DIV_ROUND_CLOSEST((state) * (pwm_max), (max_state))31 32/*33 * Factor by equations [2] and [3] from data sheet; valid for fans where the number of edges34 * equal (poles * 2 + 1).35 */36#define EMC2305_RPM_FACTOR 393216037 38#define EMC2305_REG_FAN_DRIVE(n) (0x30 + 0x10 * (n))39#define EMC2305_REG_FAN_MIN_DRIVE(n) (0x38 + 0x10 * (n))40#define EMC2305_REG_FAN_TACH(n) (0x3e + 0x10 * (n))41 42enum emc230x_product_id {43 EMC2305 = 0x34,44 EMC2303 = 0x35,45 EMC2302 = 0x36,46 EMC2301 = 0x37,47};48 49static const struct i2c_device_id emc2305_ids[] = {50 { "emc2305" },51 { "emc2303" },52 { "emc2302" },53 { "emc2301" },54 { }55};56MODULE_DEVICE_TABLE(i2c, emc2305_ids);57 58/**59 * struct emc2305_cdev_data - device-specific cooling device state60 * @cdev: cooling device61 * @cur_state: cooling current state62 * @last_hwmon_state: last cooling state updated by hwmon subsystem63 * @last_thermal_state: last cooling state updated by thermal subsystem64 *65 * The 'last_hwmon_state' and 'last_thermal_state' fields are provided to support fan low limit66 * speed feature. The purpose of this feature is to provides ability to limit fan speed67 * according to some system wise considerations, like absence of some replaceable units (PSU or68 * line cards), high system ambient temperature, unreliable transceivers temperature sensing or69 * some other factors which indirectly impacts system's airflow70 * Fan low limit feature is supported through 'hwmon' interface: 'hwmon' 'pwm' attribute is71 * used for setting low limit for fan speed in case 'thermal' subsystem is configured in72 * kernel. In this case setting fan speed through 'hwmon' will never let the 'thermal'73 * subsystem to select a lower duty cycle than the duty cycle selected with the 'pwm'74 * attribute.75 * From other side, fan speed is to be updated in hardware through 'pwm' only in case the76 * requested fan speed is above last speed set by 'thermal' subsystem, otherwise requested fan77 * speed will be just stored with no PWM update.78 */79struct emc2305_cdev_data {80 struct thermal_cooling_device *cdev;81 unsigned int cur_state;82 unsigned long last_hwmon_state;83 unsigned long last_thermal_state;84};85 86/**87 * struct emc2305_data - device-specific data88 * @client: i2c client89 * @hwmon_dev: hwmon device90 * @max_state: maximum cooling state of the cooling device91 * @pwm_num: number of PWM channels92 * @pwm_separate: separate PWM settings for every channel93 * @pwm_min: array of minimum PWM per channel94 * @cdev_data: array of cooling devices data95 */96struct emc2305_data {97 struct i2c_client *client;98 struct device *hwmon_dev;99 u8 max_state;100 u8 pwm_num;101 bool pwm_separate;102 u8 pwm_min[EMC2305_PWM_MAX];103 struct emc2305_cdev_data cdev_data[EMC2305_PWM_MAX];104};105 106static char *emc2305_fan_name[] = {107 "emc2305_fan",108 "emc2305_fan1",109 "emc2305_fan2",110 "emc2305_fan3",111 "emc2305_fan4",112 "emc2305_fan5",113};114 115static void emc2305_unset_tz(struct device *dev);116 117static int emc2305_get_max_channel(const struct emc2305_data *data)118{119 return data->pwm_num;120}121 122static int emc2305_get_cdev_idx(struct thermal_cooling_device *cdev)123{124 struct emc2305_data *data = cdev->devdata;125 size_t len = strlen(cdev->type);126 int ret;127 128 if (len <= 0)129 return -EINVAL;130 131 /*132 * Returns index of cooling device 0..4 in case of separate PWM setting.133 * Zero index is used in case of one common PWM setting.134 * If the mode is not set as pwm_separate, all PWMs are to be bound135 * to the common thermal zone and should work at the same speed136 * to perform cooling for the same thermal junction.137 * Otherwise, return specific channel that will be used in bound138 * related PWM to the thermal zone.139 */140 if (!data->pwm_separate)141 return 0;142 143 ret = cdev->type[len - 1];144 switch (ret) {145 case '1' ... '5':146 return ret - '1';147 default:148 break;149 }150 return -EINVAL;151}152 153static int emc2305_get_cur_state(struct thermal_cooling_device *cdev, unsigned long *state)154{155 int cdev_idx;156 struct emc2305_data *data = cdev->devdata;157 158 cdev_idx = emc2305_get_cdev_idx(cdev);159 if (cdev_idx < 0)160 return cdev_idx;161 162 *state = data->cdev_data[cdev_idx].cur_state;163 return 0;164}165 166static int emc2305_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state)167{168 struct emc2305_data *data = cdev->devdata;169 *state = data->max_state;170 return 0;171}172 173static int __emc2305_set_cur_state(struct emc2305_data *data, int cdev_idx, unsigned long state)174{175 int ret;176 struct i2c_client *client = data->client;177 u8 val, i;178 179 state = max_t(unsigned long, state, data->cdev_data[cdev_idx].last_hwmon_state);180 181 val = EMC2305_PWM_STATE2DUTY(state, data->max_state, EMC2305_FAN_MAX);182 183 data->cdev_data[cdev_idx].cur_state = state;184 if (data->pwm_separate) {185 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(cdev_idx), val);186 if (ret < 0)187 return ret;188 } else {189 /*190 * Set the same PWM value in all channels191 * if common PWM channel is used.192 */193 for (i = 0; i < data->pwm_num; i++) {194 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(i), val);195 if (ret < 0)196 return ret;197 }198 }199 200 return 0;201}202 203static int emc2305_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)204{205 int cdev_idx, ret;206 struct emc2305_data *data = cdev->devdata;207 208 if (state > data->max_state)209 return -EINVAL;210 211 cdev_idx = emc2305_get_cdev_idx(cdev);212 if (cdev_idx < 0)213 return cdev_idx;214 215 /* Save thermal state. */216 data->cdev_data[cdev_idx].last_thermal_state = state;217 ret = __emc2305_set_cur_state(data, cdev_idx, state);218 if (ret < 0)219 return ret;220 221 return 0;222}223 224static const struct thermal_cooling_device_ops emc2305_cooling_ops = {225 .get_max_state = emc2305_get_max_state,226 .get_cur_state = emc2305_get_cur_state,227 .set_cur_state = emc2305_set_cur_state,228};229 230static int emc2305_show_fault(struct device *dev, int channel)231{232 struct emc2305_data *data = dev_get_drvdata(dev);233 struct i2c_client *client = data->client;234 int status_reg;235 236 status_reg = i2c_smbus_read_byte_data(client, EMC2305_REG_DRIVE_FAIL_STATUS);237 if (status_reg < 0)238 return status_reg;239 240 return status_reg & (1 << channel) ? 1 : 0;241}242 243static int emc2305_show_fan(struct device *dev, int channel)244{245 struct emc2305_data *data = dev_get_drvdata(dev);246 struct i2c_client *client = data->client;247 int ret;248 249 ret = i2c_smbus_read_word_swapped(client, EMC2305_REG_FAN_TACH(channel));250 if (ret <= 0)251 return ret;252 253 ret = ret >> EMC2305_TACH_REGS_UNUSE_BITS;254 ret = EMC2305_RPM_FACTOR / ret;255 if (ret <= EMC2305_TACH_RANGE_MIN)256 return 0;257 258 return ret * EMC2305_TACH_CNT_MULTIPLIER;259}260 261static int emc2305_show_pwm(struct device *dev, int channel)262{263 struct emc2305_data *data = dev_get_drvdata(dev);264 struct i2c_client *client = data->client;265 266 return i2c_smbus_read_byte_data(client, EMC2305_REG_FAN_DRIVE(channel));267}268 269static int emc2305_set_pwm(struct device *dev, long val, int channel)270{271 struct emc2305_data *data = dev_get_drvdata(dev);272 struct i2c_client *client = data->client;273 int ret;274 275 if (val < data->pwm_min[channel] || val > EMC2305_FAN_MAX)276 return -EINVAL;277 278 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(channel), val);279 if (ret < 0)280 return ret;281 data->cdev_data[channel].cur_state = EMC2305_PWM_DUTY2STATE(val, data->max_state,282 EMC2305_FAN_MAX);283 return 0;284}285 286static int emc2305_set_single_tz(struct device *dev, int idx)287{288 struct emc2305_data *data = dev_get_drvdata(dev);289 long pwm;290 int i, cdev_idx, ret;291 292 cdev_idx = (idx) ? idx - 1 : 0;293 pwm = data->pwm_min[cdev_idx];294 295 data->cdev_data[cdev_idx].cdev =296 thermal_cooling_device_register(emc2305_fan_name[idx], data,297 &emc2305_cooling_ops);298 299 if (IS_ERR(data->cdev_data[cdev_idx].cdev)) {300 dev_err(dev, "Failed to register cooling device %s\n", emc2305_fan_name[idx]);301 return PTR_ERR(data->cdev_data[cdev_idx].cdev);302 }303 /* Set minimal PWM speed. */304 if (data->pwm_separate) {305 ret = emc2305_set_pwm(dev, pwm, cdev_idx);306 if (ret < 0)307 return ret;308 } else {309 for (i = 0; i < data->pwm_num; i++) {310 ret = emc2305_set_pwm(dev, pwm, i);311 if (ret < 0)312 return ret;313 }314 }315 data->cdev_data[cdev_idx].cur_state =316 EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state,317 EMC2305_FAN_MAX);318 data->cdev_data[cdev_idx].last_hwmon_state =319 EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state,320 EMC2305_FAN_MAX);321 return 0;322}323 324static int emc2305_set_tz(struct device *dev)325{326 struct emc2305_data *data = dev_get_drvdata(dev);327 int i, ret;328 329 if (!data->pwm_separate)330 return emc2305_set_single_tz(dev, 0);331 332 for (i = 0; i < data->pwm_num; i++) {333 ret = emc2305_set_single_tz(dev, i + 1);334 if (ret)335 goto thermal_cooling_device_register_fail;336 }337 return 0;338 339thermal_cooling_device_register_fail:340 emc2305_unset_tz(dev);341 return ret;342}343 344static void emc2305_unset_tz(struct device *dev)345{346 struct emc2305_data *data = dev_get_drvdata(dev);347 int i;348 349 /* Unregister cooling device. */350 for (i = 0; i < EMC2305_PWM_MAX; i++)351 if (data->cdev_data[i].cdev)352 thermal_cooling_device_unregister(data->cdev_data[i].cdev);353}354 355static umode_t356emc2305_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, int channel)357{358 int max_channel = emc2305_get_max_channel(data);359 360 /* Don't show channels which are not physically connected. */361 if (channel >= max_channel)362 return 0;363 switch (type) {364 case hwmon_fan:365 switch (attr) {366 case hwmon_fan_input:367 return 0444;368 case hwmon_fan_fault:369 return 0444;370 default:371 break;372 }373 break;374 case hwmon_pwm:375 switch (attr) {376 case hwmon_pwm_input:377 return 0644;378 default:379 break;380 }381 break;382 default:383 break;384 }385 386 return 0;387};388 389static int390emc2305_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long val)391{392 struct emc2305_data *data = dev_get_drvdata(dev);393 int cdev_idx;394 395 switch (type) {396 case hwmon_pwm:397 switch (attr) {398 case hwmon_pwm_input:399 /* If thermal is configured - handle PWM limit setting. */400 if (IS_REACHABLE(CONFIG_THERMAL)) {401 if (data->pwm_separate)402 cdev_idx = channel;403 else404 cdev_idx = 0;405 data->cdev_data[cdev_idx].last_hwmon_state =406 EMC2305_PWM_DUTY2STATE(val, data->max_state,407 EMC2305_FAN_MAX);408 /*409 * Update PWM only in case requested state is not less than the410 * last thermal state.411 */412 if (data->cdev_data[cdev_idx].last_hwmon_state >=413 data->cdev_data[cdev_idx].last_thermal_state)414 return __emc2305_set_cur_state(data, cdev_idx,415 data->cdev_data[cdev_idx].last_hwmon_state);416 return 0;417 }418 return emc2305_set_pwm(dev, val, channel);419 default:420 break;421 }422 break;423 default:424 break;425 }426 427 return -EOPNOTSUPP;428};429 430static int431emc2305_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long *val)432{433 int ret;434 435 switch (type) {436 case hwmon_fan:437 switch (attr) {438 case hwmon_fan_input:439 ret = emc2305_show_fan(dev, channel);440 if (ret < 0)441 return ret;442 *val = ret;443 return 0;444 case hwmon_fan_fault:445 ret = emc2305_show_fault(dev, channel);446 if (ret < 0)447 return ret;448 *val = ret;449 return 0;450 default:451 break;452 }453 break;454 case hwmon_pwm:455 switch (attr) {456 case hwmon_pwm_input:457 ret = emc2305_show_pwm(dev, channel);458 if (ret < 0)459 return ret;460 *val = ret;461 return 0;462 default:463 break;464 }465 break;466 default:467 break;468 }469 470 return -EOPNOTSUPP;471};472 473static const struct hwmon_ops emc2305_ops = {474 .is_visible = emc2305_is_visible,475 .read = emc2305_read,476 .write = emc2305_write,477};478 479static const struct hwmon_channel_info * const emc2305_info[] = {480 HWMON_CHANNEL_INFO(fan,481 HWMON_F_INPUT | HWMON_F_FAULT,482 HWMON_F_INPUT | HWMON_F_FAULT,483 HWMON_F_INPUT | HWMON_F_FAULT,484 HWMON_F_INPUT | HWMON_F_FAULT,485 HWMON_F_INPUT | HWMON_F_FAULT),486 HWMON_CHANNEL_INFO(pwm,487 HWMON_PWM_INPUT,488 HWMON_PWM_INPUT,489 HWMON_PWM_INPUT,490 HWMON_PWM_INPUT,491 HWMON_PWM_INPUT),492 NULL493};494 495static const struct hwmon_chip_info emc2305_chip_info = {496 .ops = &emc2305_ops,497 .info = emc2305_info,498};499 500static int emc2305_identify(struct device *dev)501{502 struct i2c_client *client = to_i2c_client(dev);503 struct emc2305_data *data = i2c_get_clientdata(client);504 int ret;505 506 ret = i2c_smbus_read_byte_data(client, EMC2305_REG_PRODUCT_ID);507 if (ret < 0)508 return ret;509 510 switch (ret) {511 case EMC2305:512 data->pwm_num = 5;513 break;514 case EMC2303:515 data->pwm_num = 3;516 break;517 case EMC2302:518 data->pwm_num = 2;519 break;520 case EMC2301:521 data->pwm_num = 1;522 break;523 default:524 return -ENODEV;525 }526 527 return 0;528}529 530static int emc2305_probe(struct i2c_client *client)531{532 struct i2c_adapter *adapter = client->adapter;533 struct device *dev = &client->dev;534 struct emc2305_data *data;535 struct emc2305_platform_data *pdata;536 int vendor;537 int ret;538 int i;539 540 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))541 return -ENODEV;542 543 vendor = i2c_smbus_read_byte_data(client, EMC2305_REG_VENDOR);544 if (vendor != EMC2305_VENDOR)545 return -ENODEV;546 547 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);548 if (!data)549 return -ENOMEM;550 551 i2c_set_clientdata(client, data);552 data->client = client;553 554 ret = emc2305_identify(dev);555 if (ret)556 return ret;557 558 pdata = dev_get_platdata(&client->dev);559 if (pdata) {560 if (!pdata->max_state || pdata->max_state > EMC2305_FAN_MAX_STATE)561 return -EINVAL;562 data->max_state = pdata->max_state;563 /*564 * Validate a number of active PWM channels. Note that565 * configured number can be less than the actual maximum566 * supported by the device.567 */568 if (!pdata->pwm_num || pdata->pwm_num > EMC2305_PWM_MAX)569 return -EINVAL;570 data->pwm_num = pdata->pwm_num;571 data->pwm_separate = pdata->pwm_separate;572 for (i = 0; i < EMC2305_PWM_MAX; i++)573 data->pwm_min[i] = pdata->pwm_min[i];574 } else {575 data->max_state = EMC2305_FAN_MAX_STATE;576 data->pwm_separate = false;577 for (i = 0; i < EMC2305_PWM_MAX; i++)578 data->pwm_min[i] = EMC2305_FAN_MIN;579 }580 581 data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "emc2305", data,582 &emc2305_chip_info, NULL);583 if (IS_ERR(data->hwmon_dev))584 return PTR_ERR(data->hwmon_dev);585 586 if (IS_REACHABLE(CONFIG_THERMAL)) {587 ret = emc2305_set_tz(dev);588 if (ret != 0)589 return ret;590 }591 592 for (i = 0; i < data->pwm_num; i++) {593 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_MIN_DRIVE(i),594 data->pwm_min[i]);595 if (ret < 0)596 return ret;597 }598 599 return 0;600}601 602static void emc2305_remove(struct i2c_client *client)603{604 struct device *dev = &client->dev;605 606 if (IS_REACHABLE(CONFIG_THERMAL))607 emc2305_unset_tz(dev);608}609 610static struct i2c_driver emc2305_driver = {611 .driver = {612 .name = "emc2305",613 },614 .probe = emc2305_probe,615 .remove = emc2305_remove,616 .id_table = emc2305_ids,617};618 619module_i2c_driver(emc2305_driver);620 621MODULE_AUTHOR("Nvidia");622MODULE_DESCRIPTION("Microchip EMC2305 fan controller driver");623MODULE_LICENSE("GPL");624