Hello Kim,
On Wed, Jun 15, 2011 at 10:19 AM, Donggeun Kim <dg77.kim@xxxxxxxxxxx> wrote:
This patch adds support for NTC Thermistor series. In this release, the
following thermistors are supported: NCP15WB473, NCP18WB473, NCP03WB473,
and NCP15WL333. This driver is based on the datasheet of MURATA.
The driver in the patch does conversion from the raw ADC value
(either voltage or resistence) to temperature. In order to use
voltage values as input, the circuit schematics should be provided
with the platform data. A compensation table for each type of thermistor
is provided for the conversion.
Signed-off-by: Donggeun Kim <dg77.kim@xxxxxxxxxxx>
Signed-off-by: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
Signed-off-by: KyungMin Park <kyungmin.park@xxxxxxxxxxx>
--
Updates
v8
- remove compiler warning message
- update Documentation/hwmon/ntc_thermistor
- add EXPERIMENTAL Kconfig dependency
v7
- move header file location
- rename header and driver file
- style fixes
v6
- updated Documentation/hwmon/ntc
- style fixes
v5
- use binary search on sorted table
- removed unnecessary attributes
- style fixes
v4
- put in alphabetic order in Kconfig/Makefile
- handle additional error cases
- remove the exported function
v3
- style fixes
- removed symbol exports
- avoid divide-by-zero
- omitted files added (Kconfig/Makefile)
- removed unnecessary codes
- return error values, not default values for errors.
v2
- added Documentation/hwmon/ntc
- followed hwmon sysfs
- detached the monitoring service
(thank you for the comments, Guenter Roeck)
---
Documentation/hwmon/ntc_thermistor | 93 +++++
drivers/hwmon/Kconfig | 14 +
drivers/hwmon/Makefile | 1 +
drivers/hwmon/ntc_thermistor.c | 477 ++++++++++++++++++++++++++
include/linux/platform_data/ntc_thermistor.h | 53 +++
5 files changed, 638 insertions(+), 0 deletions(-)
create mode 100644 Documentation/hwmon/ntc_thermistor
create mode 100644 drivers/hwmon/ntc_thermistor.c
create mode 100644 include/linux/platform_data/ntc_thermistor.h
<Snip>
+
+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, i;
+
+ 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 = "" 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;
+ }
+
+ data->mintemp = INT_MAX;
+ data->maxtemp = INT_MIN;
+
+ /*
+ * The compensation table is sorted by ohm value. Although it is
+ * normally assumed that the temperature value monotonically
+ * increases or decreases with the ohm value, but there could be
+ * different thermistors.
+ */
+ for (i = 0; i < data->n_comp; i++) {
+ if (data->comp[i].temp_C > data->maxtemp)
+ data->maxtemp = data->comp[i].temp_C;
+ if (data->comp[i].temp_C < data->mintemp)
+ data->mintemp = data->comp[i].temp_C;
+ }
+
+ if (data->mintemp != INT_MAX || data->maxtemp != INT_MIN) {
+ dev_err(data->dev, "error in compensation table\n");
+ ret = -EINVAL;
+ goto err;
+ }
Didnt understand this check. Shouldn't the compensation table allowed to modify this?
+
+ 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 = ""> +
+ 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@xxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ntc-thermistor");
diff --git a/include/linux/platform_data/ntc_thermistor.h b/include/linux/platform_data/ntc_thermistor.h
new file mode 100644
index 0000000..abd2862
--- /dev/null
+++ b/include/linux/platform_data/ntc_thermistor.h
@@ -0,0 +1,53 @@
+/*
+ * ntc_thermistor.h - NTC Thermistors
+ *
+ * Copyright (C) 2010 Samsung Electronics
+ * MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
+ *
+ * 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
+ */
+#ifndef _LINUX_NTC_H
+#define _LINUX_NTC_H
+
+enum ntc_thermistor_type {
+ TYPE_NCPXXWB473,
+ TYPE_NCPXXWL333,
+};
+
+struct ntc_thermistor_platform_data {
+ /*
+ * One (not both) of read_uV and read_ohm should be provided and only
+ * one of the two should be provided.
+ * Both functions should return negative value for an error case.
+ *
+ * pullup_uV, pullup_ohm, pulldown_ohm, and connect are required to use
+ * read_uV()
+ *
+ * How to setup pullup_ohm, pulldown_ohm, and connect is
+ * described at Documentation/hwmon/ntc
+ *
+ * pullup/down_ohm: 0 for infinite / not-connected
+ */
+ int (*read_uV)(void);
+ unsigned int pullup_uV;
+
+ unsigned int pullup_ohm;
+ unsigned int pulldown_ohm;
+ enum { NTC_CONNECTED_POSITIVE, NTC_CONNECTED_GROUND } connect;
+
+ int (*read_ohm)(void);
+};
+
+#endif /* _LINUX_NTC_H */
--
1.7.4.1
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