diff options
Diffstat (limited to 'drivers/hwmon/ntc_thermistor.c')
| -rw-r--r-- | drivers/hwmon/ntc_thermistor.c | 552 |
1 files changed, 552 insertions, 0 deletions
diff --git a/drivers/hwmon/ntc_thermistor.c b/drivers/hwmon/ntc_thermistor.c new file mode 100644 index 00000000000..ae66f42c4d6 --- /dev/null +++ b/drivers/hwmon/ntc_thermistor.c @@ -0,0 +1,552 @@ +/* + * ntc_thermistor.c - NTC Thermistors + * + * Copyright (C) 2010 Samsung Electronics + * MyungJoo Ham <myungjoo.ham@samsung.com> + * + * 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 <linux/slab.h> +#include <linux/module.h> +#include <linux/pm_runtime.h> +#include <linux/math64.h> +#include <linux/platform_device.h> +#include <linux/err.h> +#include <linux/of.h> +#include <linux/of_device.h> + +#include <linux/platform_data/ntc_thermistor.h> + +#include <linux/iio/iio.h> +#include <linux/iio/machine.h> +#include <linux/iio/driver.h> +#include <linux/iio/consumer.h> + +#include <linux/hwmon.h> +#include <linux/hwmon-sysfs.h> + +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 }, + { }, +}; + +/* + * 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 }, +}; + +struct ntc_data { + struct device *hwmon_dev; + struct ntc_thermistor_platform_data *pdata; + const struct ntc_compensation *comp; + struct device *dev; + 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; + s64 result; + int val, ret; + + ret = iio_read_channel_raw(channel, &val); + if (ret < 0) { + pr_err("read channel() error: %d\n", ret); + return ret; + } + + /* unit: mV */ + result = pdata->pullup_uv * (s64) val; + result >>= 12; + + return (int)result; +} + +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] }, + + /* 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 platform_device *pdev) +{ + struct iio_channel *chan; + struct device_node *np = pdev->dev.of_node; + struct ntc_thermistor_platform_data *pdata; + + if (!np) + return NULL; + + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); + if (!pdata) + return ERR_PTR(-ENOMEM); + + chan = iio_channel_get(&pdev->dev, NULL); + if (IS_ERR(chan)) + return ERR_CAST(chan); + + 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; +} +static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata) +{ + if (pdata->chan) + iio_channel_release(pdata->chan); +} +#else +static struct ntc_thermistor_platform_data * +ntc_thermistor_parse_dt(struct platform_device *pdev) +{ + return NULL; +} + +#define ntc_match NULL + +static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata) +{ } +#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; + u64 mv = uv / 1000; + u64 pmv = pdata->pullup_uv / 1000; + u64 n, puo, pdo; + puo = pdata->pullup_ohm; + pdo = pdata->pulldown_ohm; + + if (mv == 0) { + if (pdata->connect == NTC_CONNECTED_POSITIVE) + return INT_MAX; + return 0; + } + if (mv >= pmv) + return (pdata->connect == NTC_CONNECTED_POSITIVE) ? + 0 : INT_MAX; + + if (pdata->connect == NTC_CONNECTED_POSITIVE && puo == 0) + n = div64_u64_safe(pdo * (pmv - mv), mv); + else if (pdata->connect == NTC_CONNECTED_GROUND && pdo == 0) + n = div64_u64_safe(puo * mv, pmv - mv); + else if (pdata->connect == NTC_CONNECTED_POSITIVE) + n = div64_u64_safe(pdo * puo * (pmv - mv), + puo * mv - pdo * (pmv - mv)); + else + n = div64_u64_safe(pdo * puo * mv, pdo * (pmv - mv) - puo * mv); + + 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 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 int ntc_thermistor_probe(struct platform_device *pdev) +{ + const struct of_device_id *of_id = + of_match_device(of_match_ptr(ntc_match), &pdev->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(pdev); + if (IS_ERR(pdata)) + return PTR_ERR(pdata); + else if (pdata == NULL) + pdata = dev_get_platdata(&pdev->dev); + + if (!pdata) { + dev_err(&pdev->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(&pdev->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(&pdev->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(&pdev->dev, + "Required data to use read_uv not supplied.\n"); + return -EINVAL; + } + + data = devm_kzalloc(&pdev->dev, sizeof(struct ntc_data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + pdev_id = of_id ? of_id->data : platform_get_device_id(pdev); + + data->dev = &pdev->dev; + 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; + default: + dev_err(&pdev->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(&data->dev->kobj, &ntc_attr_group); + if (ret) { + dev_err(data->dev, "unable to create sysfs files\n"); + return ret; + } + + data->hwmon_dev = hwmon_device_register(data->dev); + if (IS_ERR(data->hwmon_dev)) { + dev_err(data->dev, "unable to register as hwmon device.\n"); + ret = PTR_ERR(data->hwmon_dev); + goto err_after_sysfs; + } + + dev_info(&pdev->dev, "Thermistor type: %s successfully probed.\n", + pdev_id->name); + + return 0; +err_after_sysfs: + sysfs_remove_group(&data->dev->kobj, &ntc_attr_group); + ntc_iio_channel_release(pdata); + return ret; +} + +static int ntc_thermistor_remove(struct platform_device *pdev) +{ + struct ntc_data *data = platform_get_drvdata(pdev); + struct ntc_thermistor_platform_data *pdata = data->pdata; + + hwmon_device_unregister(data->hwmon_dev); + sysfs_remove_group(&data->dev->kobj, &ntc_attr_group); + ntc_iio_channel_release(pdata); + + return 0; +} + +static struct platform_driver ntc_thermistor_driver = { + .driver = { + .name = "ntc-thermistor", + .owner = THIS_MODULE, + .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 from Murata"); +MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:ntc-thermistor"); |