/* * ntc_thermistor.c - NTC Thermistors * * Copyright (C) 2010 Samsung Electronics * MyungJoo Ham * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include struct ntc_compensation { int temp_c; unsigned int ohm; }; /* Order matters, ntc_match references the entries by index */ static const struct platform_device_id ntc_thermistor_id[] = { { "ncp15wb473", TYPE_NCPXXWB473 }, { "ncp18wb473", TYPE_NCPXXWB473 }, { "ncp21wb473", TYPE_NCPXXWB473 }, { "ncp03wb473", TYPE_NCPXXWB473 }, { "ncp15wl333", TYPE_NCPXXWL333 }, { "b57330v2103", TYPE_B57330V2103}, { "ncp03wf104", TYPE_NCPXXWF104 }, { "ncp15xh103", TYPE_NCPXXXH103 }, { }, }; /* * A compensation table should be sorted by the values of .ohm * in descending order. * The following compensation tables are from the specification of Murata NTC * Thermistors Datasheet */ static const struct ntc_compensation ncpXXwb473[] = { { .temp_c = -40, .ohm = 1747920 }, { .temp_c = -35, .ohm = 1245428 }, { .temp_c = -30, .ohm = 898485 }, { .temp_c = -25, .ohm = 655802 }, { .temp_c = -20, .ohm = 483954 }, { .temp_c = -15, .ohm = 360850 }, { .temp_c = -10, .ohm = 271697 }, { .temp_c = -5, .ohm = 206463 }, { .temp_c = 0, .ohm = 158214 }, { .temp_c = 5, .ohm = 122259 }, { .temp_c = 10, .ohm = 95227 }, { .temp_c = 15, .ohm = 74730 }, { .temp_c = 20, .ohm = 59065 }, { .temp_c = 25, .ohm = 47000 }, { .temp_c = 30, .ohm = 37643 }, { .temp_c = 35, .ohm = 30334 }, { .temp_c = 40, .ohm = 24591 }, { .temp_c = 45, .ohm = 20048 }, { .temp_c = 50, .ohm = 16433 }, { .temp_c = 55, .ohm = 13539 }, { .temp_c = 60, .ohm = 11209 }, { .temp_c = 65, .ohm = 9328 }, { .temp_c = 70, .ohm = 7798 }, { .temp_c = 75, .ohm = 6544 }, { .temp_c = 80, .ohm = 5518 }, { .temp_c = 85, .ohm = 4674 }, { .temp_c = 90, .ohm = 3972 }, { .temp_c = 95, .ohm = 3388 }, { .temp_c = 100, .ohm = 2902 }, { .temp_c = 105, .ohm = 2494 }, { .temp_c = 110, .ohm = 2150 }, { .temp_c = 115, .ohm = 1860 }, { .temp_c = 120, .ohm = 1615 }, { .temp_c = 125, .ohm = 1406 }, }; static const struct ntc_compensation ncpXXwl333[] = { { .temp_c = -40, .ohm = 1610154 }, { .temp_c = -35, .ohm = 1130850 }, { .temp_c = -30, .ohm = 802609 }, { .temp_c = -25, .ohm = 575385 }, { .temp_c = -20, .ohm = 416464 }, { .temp_c = -15, .ohm = 304219 }, { .temp_c = -10, .ohm = 224193 }, { .temp_c = -5, .ohm = 166623 }, { .temp_c = 0, .ohm = 124850 }, { .temp_c = 5, .ohm = 94287 }, { .temp_c = 10, .ohm = 71747 }, { .temp_c = 15, .ohm = 54996 }, { .temp_c = 20, .ohm = 42455 }, { .temp_c = 25, .ohm = 33000 }, { .temp_c = 30, .ohm = 25822 }, { .temp_c = 35, .ohm = 20335 }, { .temp_c = 40, .ohm = 16115 }, { .temp_c = 45, .ohm = 12849 }, { .temp_c = 50, .ohm = 10306 }, { .temp_c = 55, .ohm = 8314 }, { .temp_c = 60, .ohm = 6746 }, { .temp_c = 65, .ohm = 5503 }, { .temp_c = 70, .ohm = 4513 }, { .temp_c = 75, .ohm = 3721 }, { .temp_c = 80, .ohm = 3084 }, { .temp_c = 85, .ohm = 2569 }, { .temp_c = 90, .ohm = 2151 }, { .temp_c = 95, .ohm = 1809 }, { .temp_c = 100, .ohm = 1529 }, { .temp_c = 105, .ohm = 1299 }, { .temp_c = 110, .ohm = 1108 }, { .temp_c = 115, .ohm = 949 }, { .temp_c = 120, .ohm = 817 }, { .temp_c = 125, .ohm = 707 }, }; static const struct ntc_compensation ncpXXwf104[] = { { .temp_c = -40, .ohm = 4397119 }, { .temp_c = -35, .ohm = 3088599 }, { .temp_c = -30, .ohm = 2197225 }, { .temp_c = -25, .ohm = 1581881 }, { .temp_c = -20, .ohm = 1151037 }, { .temp_c = -15, .ohm = 846579 }, { .temp_c = -10, .ohm = 628988 }, { .temp_c = -5, .ohm = 471632 }, { .temp_c = 0, .ohm = 357012 }, { .temp_c = 5, .ohm = 272500 }, { .temp_c = 10, .ohm = 209710 }, { .temp_c = 15, .ohm = 162651 }, { .temp_c = 20, .ohm = 127080 }, { .temp_c = 25, .ohm = 100000 }, { .temp_c = 30, .ohm = 79222 }, { .temp_c = 35, .ohm = 63167 }, { .temp_c = 40, .ohm = 50677 }, { .temp_c = 45, .ohm = 40904 }, { .temp_c = 50, .ohm = 33195 }, { .temp_c = 55, .ohm = 27091 }, { .temp_c = 60, .ohm = 22224 }, { .temp_c = 65, .ohm = 18323 }, { .temp_c = 70, .ohm = 15184 }, { .temp_c = 75, .ohm = 12635 }, { .temp_c = 80, .ohm = 10566 }, { .temp_c = 85, .ohm = 8873 }, { .temp_c = 90, .ohm = 7481 }, { .temp_c = 95, .ohm = 6337 }, { .temp_c = 100, .ohm = 5384 }, { .temp_c = 105, .ohm = 4594 }, { .temp_c = 110, .ohm = 3934 }, { .temp_c = 115, .ohm = 3380 }, { .temp_c = 120, .ohm = 2916 }, { .temp_c = 125, .ohm = 2522 }, }; static const struct ntc_compensation ncpXXxh103[] = { { .temp_c = -40, .ohm = 247565 }, { .temp_c = -35, .ohm = 181742 }, { .temp_c = -30, .ohm = 135128 }, { .temp_c = -25, .ohm = 101678 }, { .temp_c = -20, .ohm = 77373 }, { .temp_c = -15, .ohm = 59504 }, { .temp_c = -10, .ohm = 46222 }, { .temp_c = -5, .ohm = 36244 }, { .temp_c = 0, .ohm = 28674 }, { .temp_c = 5, .ohm = 22878 }, { .temp_c = 10, .ohm = 18399 }, { .temp_c = 15, .ohm = 14910 }, { .temp_c = 20, .ohm = 12169 }, { .temp_c = 25, .ohm = 10000 }, { .temp_c = 30, .ohm = 8271 }, { .temp_c = 35, .ohm = 6883 }, { .temp_c = 40, .ohm = 5762 }, { .temp_c = 45, .ohm = 4851 }, { .temp_c = 50, .ohm = 4105 }, { .temp_c = 55, .ohm = 3492 }, { .temp_c = 60, .ohm = 2985 }, { .temp_c = 65, .ohm = 2563 }, { .temp_c = 70, .ohm = 2211 }, { .temp_c = 75, .ohm = 1915 }, { .temp_c = 80, .ohm = 1666 }, { .temp_c = 85, .ohm = 1454 }, { .temp_c = 90, .ohm = 1275 }, { .temp_c = 95, .ohm = 1121 }, { .temp_c = 100, .ohm = 990 }, { .temp_c = 105, .ohm = 876 }, { .temp_c = 110, .ohm = 779 }, { .temp_c = 115, .ohm = 694 }, { .temp_c = 120, .ohm = 620 }, { .temp_c = 125, .ohm = 556 }, }; /* * The following compensation table is from the specification of EPCOS NTC * Thermistors Datasheet */ static const struct ntc_compensation b57330v2103[] = { { .temp_c = -40, .ohm = 190030 }, { .temp_c = -35, .ohm = 145360 }, { .temp_c = -30, .ohm = 112060 }, { .temp_c = -25, .ohm = 87041 }, { .temp_c = -20, .ohm = 68104 }, { .temp_c = -15, .ohm = 53665 }, { .temp_c = -10, .ohm = 42576 }, { .temp_c = -5, .ohm = 34001 }, { .temp_c = 0, .ohm = 27326 }, { .temp_c = 5, .ohm = 22096 }, { .temp_c = 10, .ohm = 17973 }, { .temp_c = 15, .ohm = 14703 }, { .temp_c = 20, .ohm = 12090 }, { .temp_c = 25, .ohm = 10000 }, { .temp_c = 30, .ohm = 8311 }, { .temp_c = 35, .ohm = 6941 }, { .temp_c = 40, .ohm = 5825 }, { .temp_c = 45, .ohm = 4911 }, { .temp_c = 50, .ohm = 4158 }, { .temp_c = 55, .ohm = 3536 }, { .temp_c = 60, .ohm = 3019 }, { .temp_c = 65, .ohm = 2588 }, { .temp_c = 70, .ohm = 2227 }, { .temp_c = 75, .ohm = 1924 }, { .temp_c = 80, .ohm = 1668 }, { .temp_c = 85, .ohm = 1451 }, { .temp_c = 90, .ohm = 1266 }, { .temp_c = 95, .ohm = 1108 }, { .temp_c = 100, .ohm = 973 }, { .temp_c = 105, .ohm = 857 }, { .temp_c = 110, .ohm = 757 }, { .temp_c = 115, .ohm = 671 }, { .temp_c = 120, .ohm = 596 }, { .temp_c = 125, .ohm = 531 }, }; struct ntc_data { struct device *hwmon_dev; struct ntc_thermistor_platform_data *pdata; const struct ntc_compensation *comp; int n_comp; char name[PLATFORM_NAME_SIZE]; }; #if defined(CONFIG_OF) && IS_ENABLED(CONFIG_IIO) static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata) { struct iio_channel *channel = pdata->chan; int raw, uv, ret; ret = iio_read_channel_raw(channel, &raw); if (ret < 0) { pr_err("read channel() error: %d\n", ret); return ret; } ret = iio_convert_raw_to_processed(channel, raw, &uv, 1000); if (ret < 0) { /* Assume 12 bit ADC with vref at pullup_uv */ uv = (pdata->pullup_uv * (s64)raw) >> 12; } return uv; } static const struct of_device_id ntc_match[] = { { .compatible = "murata,ncp15wb473", .data = &ntc_thermistor_id[0] }, { .compatible = "murata,ncp18wb473", .data = &ntc_thermistor_id[1] }, { .compatible = "murata,ncp21wb473", .data = &ntc_thermistor_id[2] }, { .compatible = "murata,ncp03wb473", .data = &ntc_thermistor_id[3] }, { .compatible = "murata,ncp15wl333", .data = &ntc_thermistor_id[4] }, { .compatible = "epcos,b57330v2103", .data = &ntc_thermistor_id[5]}, { .compatible = "murata,ncp03wf104", .data = &ntc_thermistor_id[6] }, { .compatible = "murata,ncp15xh103", .data = &ntc_thermistor_id[7] }, /* Usage of vendor name "ntc" is deprecated */ { .compatible = "ntc,ncp15wb473", .data = &ntc_thermistor_id[0] }, { .compatible = "ntc,ncp18wb473", .data = &ntc_thermistor_id[1] }, { .compatible = "ntc,ncp21wb473", .data = &ntc_thermistor_id[2] }, { .compatible = "ntc,ncp03wb473", .data = &ntc_thermistor_id[3] }, { .compatible = "ntc,ncp15wl333", .data = &ntc_thermistor_id[4] }, { }, }; MODULE_DEVICE_TABLE(of, ntc_match); static struct ntc_thermistor_platform_data * ntc_thermistor_parse_dt(struct device *dev) { struct iio_channel *chan; enum iio_chan_type type; struct device_node *np = dev->of_node; struct ntc_thermistor_platform_data *pdata; int ret; if (!np) return NULL; pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); if (!pdata) return ERR_PTR(-ENOMEM); chan = devm_iio_channel_get(dev, NULL); if (IS_ERR(chan)) return ERR_CAST(chan); ret = iio_get_channel_type(chan, &type); if (ret < 0) return ERR_PTR(ret); if (type != IIO_VOLTAGE) return ERR_PTR(-EINVAL); if (of_property_read_u32(np, "pullup-uv", &pdata->pullup_uv)) return ERR_PTR(-ENODEV); if (of_property_read_u32(np, "pullup-ohm", &pdata->pullup_ohm)) return ERR_PTR(-ENODEV); if (of_property_read_u32(np, "pulldown-ohm", &pdata->pulldown_ohm)) return ERR_PTR(-ENODEV); if (of_find_property(np, "connected-positive", NULL)) pdata->connect = NTC_CONNECTED_POSITIVE; else /* status change should be possible if not always on. */ pdata->connect = NTC_CONNECTED_GROUND; pdata->chan = chan; pdata->read_uv = ntc_adc_iio_read; return pdata; } #else static struct ntc_thermistor_platform_data * ntc_thermistor_parse_dt(struct device *dev) { return NULL; } #define ntc_match NULL #endif static inline u64 div64_u64_safe(u64 dividend, u64 divisor) { if (divisor == 0 && dividend == 0) return 0; if (divisor == 0) return UINT_MAX; return div64_u64(dividend, divisor); } static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv) { struct ntc_thermistor_platform_data *pdata = data->pdata; u32 puv = pdata->pullup_uv; u64 n, puo, pdo; puo = pdata->pullup_ohm; pdo = pdata->pulldown_ohm; if (uv == 0) return (pdata->connect == NTC_CONNECTED_POSITIVE) ? INT_MAX : 0; if (uv >= puv) return (pdata->connect == NTC_CONNECTED_POSITIVE) ? 0 : INT_MAX; if (pdata->connect == NTC_CONNECTED_POSITIVE && puo == 0) n = div_u64(pdo * (puv - uv), uv); else if (pdata->connect == NTC_CONNECTED_GROUND && pdo == 0) n = div_u64(puo * uv, puv - uv); else if (pdata->connect == NTC_CONNECTED_POSITIVE) n = div64_u64_safe(pdo * puo * (puv - uv), puo * uv - pdo * (puv - uv)); else n = div64_u64_safe(pdo * puo * uv, pdo * (puv - uv) - puo * uv); if (n > INT_MAX) n = INT_MAX; return n; } static void lookup_comp(struct ntc_data *data, unsigned int ohm, int *i_low, int *i_high) { int start, end, mid; /* * Handle special cases: Resistance is higher than or equal to * resistance in first table entry, or resistance is lower or equal * to resistance in last table entry. * In these cases, return i_low == i_high, either pointing to the * beginning or to the end of the table depending on the condition. */ if (ohm >= data->comp[0].ohm) { *i_low = 0; *i_high = 0; return; } if (ohm <= data->comp[data->n_comp - 1].ohm) { *i_low = data->n_comp - 1; *i_high = data->n_comp - 1; return; } /* Do a binary search on compensation table */ start = 0; end = data->n_comp; while (start < end) { mid = start + (end - start) / 2; /* * start <= mid < end * data->comp[start].ohm > ohm >= data->comp[end].ohm * * We could check for "ohm == data->comp[mid].ohm" here, but * that is a quite unlikely condition, and we would have to * check again after updating start. Check it at the end instead * for simplicity. */ if (ohm >= data->comp[mid].ohm) { end = mid; } else { start = mid + 1; /* * ohm >= data->comp[start].ohm might be true here, * since we set start to mid + 1. In that case, we are * done. We could keep going, but the condition is quite * likely to occur, so it is worth checking for it. */ if (ohm >= data->comp[start].ohm) end = start; } /* * start <= end * data->comp[start].ohm >= ohm >= data->comp[end].ohm */ } /* * start == end * ohm >= data->comp[end].ohm */ *i_low = end; if (ohm == data->comp[end].ohm) *i_high = end; else *i_high = end - 1; } static int get_temp_mc(struct ntc_data *data, unsigned int ohm) { int low, high; int temp; lookup_comp(data, ohm, &low, &high); if (low == high) { /* Unable to use linear approximation */ temp = data->comp[low].temp_c * 1000; } else { temp = data->comp[low].temp_c * 1000 + ((data->comp[high].temp_c - data->comp[low].temp_c) * 1000 * ((int)ohm - (int)data->comp[low].ohm)) / ((int)data->comp[high].ohm - (int)data->comp[low].ohm); } return temp; } static int ntc_thermistor_get_ohm(struct ntc_data *data) { int read_uv; if (data->pdata->read_ohm) return data->pdata->read_ohm(); if (data->pdata->read_uv) { read_uv = data->pdata->read_uv(data->pdata); if (read_uv < 0) return read_uv; return get_ohm_of_thermistor(data, read_uv); } return -EINVAL; } static int ntc_read_temp(void *dev, int *temp) { struct ntc_data *data = dev_get_drvdata(dev); int ohm; ohm = ntc_thermistor_get_ohm(data); if (ohm < 0) return ohm; *temp = get_temp_mc(data, ohm); return 0; } static ssize_t ntc_show_name(struct device *dev, struct device_attribute *attr, char *buf) { struct ntc_data *data = dev_get_drvdata(dev); return sprintf(buf, "%s\n", data->name); } static ssize_t ntc_show_type(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "4\n"); } static ssize_t ntc_show_temp(struct device *dev, struct device_attribute *attr, char *buf) { struct ntc_data *data = dev_get_drvdata(dev); int ohm; ohm = ntc_thermistor_get_ohm(data); if (ohm < 0) return ohm; return sprintf(buf, "%d\n", get_temp_mc(data, ohm)); } static SENSOR_DEVICE_ATTR(temp1_type, S_IRUGO, ntc_show_type, NULL, 0); static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ntc_show_temp, NULL, 0); static DEVICE_ATTR(name, S_IRUGO, ntc_show_name, NULL); static struct attribute *ntc_attributes[] = { &dev_attr_name.attr, &sensor_dev_attr_temp1_type.dev_attr.attr, &sensor_dev_attr_temp1_input.dev_attr.attr, NULL, }; static const struct attribute_group ntc_attr_group = { .attrs = ntc_attributes, }; static const struct thermal_zone_of_device_ops ntc_of_thermal_ops = { .get_temp = ntc_read_temp, }; static int ntc_thermistor_probe(struct platform_device *pdev) { struct thermal_zone_device *tz; struct device *dev = &pdev->dev; const struct of_device_id *of_id = of_match_device(of_match_ptr(ntc_match), dev); const struct platform_device_id *pdev_id; struct ntc_thermistor_platform_data *pdata; struct ntc_data *data; int ret; pdata = ntc_thermistor_parse_dt(dev); if (IS_ERR(pdata)) return PTR_ERR(pdata); else if (pdata == NULL) pdata = dev_get_platdata(dev); if (!pdata) { dev_err(dev, "No platform init data supplied.\n"); return -ENODEV; } /* Either one of the two is required. */ if (!pdata->read_uv && !pdata->read_ohm) { dev_err(dev, "Both read_uv and read_ohm missing. Need either one of the two.\n"); return -EINVAL; } if (pdata->read_uv && pdata->read_ohm) { dev_warn(dev, "Only one of read_uv and read_ohm is needed; ignoring read_uv.\n"); pdata->read_uv = NULL; } if (pdata->read_uv && (pdata->pullup_uv == 0 || (pdata->pullup_ohm == 0 && pdata->connect == NTC_CONNECTED_GROUND) || (pdata->pulldown_ohm == 0 && pdata->connect == NTC_CONNECTED_POSITIVE) || (pdata->connect != NTC_CONNECTED_POSITIVE && pdata->connect != NTC_CONNECTED_GROUND))) { dev_err(dev, "Required data to use read_uv not supplied.\n"); return -EINVAL; } data = devm_kzalloc(dev, sizeof(struct ntc_data), GFP_KERNEL); if (!data) return -ENOMEM; pdev_id = of_id ? of_id->data : platform_get_device_id(pdev); data->pdata = pdata; strlcpy(data->name, pdev_id->name, sizeof(data->name)); switch (pdev_id->driver_data) { case TYPE_NCPXXWB473: data->comp = ncpXXwb473; data->n_comp = ARRAY_SIZE(ncpXXwb473); break; case TYPE_NCPXXWL333: data->comp = ncpXXwl333; data->n_comp = ARRAY_SIZE(ncpXXwl333); break; case TYPE_B57330V2103: data->comp = b57330v2103; data->n_comp = ARRAY_SIZE(b57330v2103); break; case TYPE_NCPXXWF104: data->comp = ncpXXwf104; data->n_comp = ARRAY_SIZE(ncpXXwf104); break; case TYPE_NCPXXXH103: data->comp = ncpXXxh103; data->n_comp = ARRAY_SIZE(ncpXXxh103); break; default: dev_err(dev, "Unknown device type: %lu(%s)\n", pdev_id->driver_data, pdev_id->name); return -EINVAL; } platform_set_drvdata(pdev, data); ret = sysfs_create_group(&dev->kobj, &ntc_attr_group); if (ret) { dev_err(dev, "unable to create sysfs files\n"); return ret; } data->hwmon_dev = hwmon_device_register(dev); if (IS_ERR(data->hwmon_dev)) { dev_err(dev, "unable to register as hwmon device.\n"); ret = PTR_ERR(data->hwmon_dev); goto err_after_sysfs; } dev_info(dev, "Thermistor type: %s successfully probed.\n", pdev_id->name); tz = devm_thermal_zone_of_sensor_register(dev, 0, dev, &ntc_of_thermal_ops); if (IS_ERR(tz)) dev_dbg(dev, "Failed to register to thermal fw.\n"); return 0; err_after_sysfs: sysfs_remove_group(&dev->kobj, &ntc_attr_group); return ret; } static int ntc_thermistor_remove(struct platform_device *pdev) { struct ntc_data *data = platform_get_drvdata(pdev); hwmon_device_unregister(data->hwmon_dev); sysfs_remove_group(&pdev->dev.kobj, &ntc_attr_group); return 0; } static struct platform_driver ntc_thermistor_driver = { .driver = { .name = "ntc-thermistor", .of_match_table = of_match_ptr(ntc_match), }, .probe = ntc_thermistor_probe, .remove = ntc_thermistor_remove, .id_table = ntc_thermistor_id, }; module_platform_driver(ntc_thermistor_driver); MODULE_DESCRIPTION("NTC Thermistor Driver"); MODULE_AUTHOR("MyungJoo Ham "); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:ntc-thermistor");