1 files changed, 453 insertions, 0 deletions

diff --git a/drivers/hwmon/ntc_thermistor.c b/drivers/hwmon/ntc_thermistor.c
new file mode 100644
index 000000000000..d7926f4336b5
--- /dev/null
+++ b/drivers/hwmon/ntc_thermistor.c
@@ -0,0 +1,453 @@
+/*
+ * 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");