--- /dev/null
+/*
+ * 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/platform_data/ntc_thermistor.h>
+
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+
+struct ntc_compensation {
+ int temp_C;
+ unsigned int ohm;
+};
+
+/*
+ * 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
+ */
+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 },
+};
+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];
+};
+
+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 unsigned 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 UINT_MAX;
+ return 0;
+ }
+ if (mV >= pmV)
+ return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
+ 0 : UINT_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);
+
+ return (unsigned int) N;
+}
+
+static int lookup_comp(struct ntc_data *data,
+ unsigned int ohm, int *i_low, int *i_high)
+{
+ int start, end, mid = -1;
+
+ /* Do a binary search on compensation table */
+ start = 0;
+ end = data->n_comp;
+
+ while (end > start) {
+ mid = start + (end - start) / 2;
+ if (data->comp[mid].ohm < ohm)
+ end = mid;
+ else if (data->comp[mid].ohm > ohm)
+ start = mid + 1;
+ else
+ break;
+ }
+
+ if (mid == 0) {
+ if (data->comp[mid].ohm > ohm) {
+ *i_high = mid;
+ *i_low = mid + 1;
+ return 0;
+ } else {
+ *i_low = mid;
+ *i_high = -1;
+ return -EINVAL;
+ }
+ }
+ if (mid == (data->n_comp - 1)) {
+ if (data->comp[mid].ohm <= ohm) {
+ *i_low = mid;
+ *i_high = mid - 1;
+ return 0;
+ } else {
+ *i_low = -1;
+ *i_high = mid;
+ return -EINVAL;
+ }
+ }
+
+ if (data->comp[mid].ohm <= ohm) {
+ *i_low = mid;
+ *i_high = mid - 1;
+ }
+ if (data->comp[mid].ohm > ohm) {
+ *i_low = mid + 1;
+ *i_high = mid;
+ }
+
+ return 0;
+}
+
+static int get_temp_mC(struct ntc_data *data, unsigned int ohm, int *temp)
+{
+ int low, high;
+ int ret;
+
+ ret = lookup_comp(data, ohm, &low, &high);
+ if (ret) {
+ /* Unable to use linear approximation */
+ if (low != -1)
+ *temp = data->comp[low].temp_C * 1000;
+ else if (high != -1)
+ *temp = data->comp[high].temp_C * 1000;
+ else
+ return ret;
+ } 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 0;
+}
+
+static int ntc_thermistor_read(struct ntc_data *data, int *temp)
+{
+ int ret;
+ int read_ohm, read_uV;
+ unsigned int ohm = 0;
+
+ if (data->pdata->read_ohm) {
+ read_ohm = data->pdata->read_ohm();
+ if (read_ohm < 0)
+ return read_ohm;
+ ohm = (unsigned int)read_ohm;
+ }
+
+ if (data->pdata->read_uV) {
+ read_uV = data->pdata->read_uV();
+ if (read_uV < 0)
+ return read_uV;
+ ohm = get_ohm_of_thermistor(data, (unsigned int)read_uV);
+ }
+
+ ret = get_temp_mC(data, ohm, temp);
+ if (ret) {
+ dev_dbg(data->dev, "Sensor reading function not available.\n");
+ return ret;
+ }
+
+ 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 temp, ret;
+
+ ret = ntc_thermistor_read(data, &temp);
+ if (ret)
+ return ret;
+ return sprintf(buf, "%d\n", temp);
+}
+
+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 __devinit ntc_thermistor_probe(struct platform_device *pdev)
+{
+ struct ntc_data *data;
+ struct ntc_thermistor_platform_data *pdata = pdev->dev.platform_data;
+ int ret = 0;
+
+ 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 = kzalloc(sizeof(struct ntc_data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->dev = &pdev->dev;
+ data->pdata = pdata;
+ strncpy(data->name, pdev->id_entry->name, PLATFORM_NAME_SIZE);
+
+ switch (pdev->id_entry->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_entry->driver_data,
+ pdev->id_entry->name);
+ ret = -EINVAL;
+ goto err;
+ }
+
+ 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");
+ goto err;
+ }
+
+ data->hwmon_dev = hwmon_device_register(data->dev);
+ if (IS_ERR_OR_NULL(data->hwmon_dev)) {
+ dev_err(data->dev, "unable to register as hwmon device.\n");
+ ret = -EINVAL;
+ goto err_after_sysfs;
+ }
+
+ dev_info(&pdev->dev, "Thermistor %s:%d (type: %s/%lu) successfully probed.\n",
+ pdev->name, pdev->id, pdev->id_entry->name,
+ pdev->id_entry->driver_data);
+ return 0;
+err_after_sysfs:
+ sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
+err:
+ kfree(data);
+ return ret;
+}
+
+static int __devexit ntc_thermistor_remove(struct platform_device *pdev)
+{
+ struct ntc_data *data = platform_get_drvdata(pdev);
+
+ hwmon_device_unregister(data->hwmon_dev);
+ sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
+ platform_set_drvdata(pdev, NULL);
+
+ kfree(data);
+
+ return 0;
+}
+
+static const struct platform_device_id ntc_thermistor_id[] = {
+ { "ncp15wb473", TYPE_NCPXXWB473 },
+ { "ncp18wb473", TYPE_NCPXXWB473 },
+ { "ncp21wb473", TYPE_NCPXXWB473 },
+ { "ncp03wb473", TYPE_NCPXXWB473 },
+ { "ncp15wl333", TYPE_NCPXXWL333 },
+ { },
+};
+
+static struct platform_driver ntc_thermistor_driver = {
+ .driver = {
+ .name = "ntc-thermistor",
+ .owner = THIS_MODULE,
+ },
+ .probe = ntc_thermistor_probe,
+ .remove = __devexit_p(ntc_thermistor_remove),
+ .id_table = ntc_thermistor_id,
+};
+
+static int __init ntc_thermistor_init(void)
+{
+ return platform_driver_register(&ntc_thermistor_driver);
+}
+
+module_init(ntc_thermistor_init);
+
+static void __exit ntc_thermistor_cleanup(void)
+{
+ platform_driver_unregister(&ntc_thermistor_driver);
+}
+
+module_exit(ntc_thermistor_cleanup);
+
+MODULE_DESCRIPTION("NTC Thermistor Driver");
+MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ntc-thermistor");
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