![Sachin Kamat](/assets/img/avatar_default.png)
Commit 0998d06310
(device-core: Ensure drvdata = NULL when no
driver is bound) removes the need to set driver data field to
NULL.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
538 lines
14 KiB
C
538 lines
14 KiB
C
/*
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* ntc_thermistor.c - NTC Thermistors
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*
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* Copyright (C) 2010 Samsung Electronics
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* MyungJoo Ham <myungjoo.ham@samsung.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/pm_runtime.h>
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#include <linux/math64.h>
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#include <linux/platform_device.h>
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#include <linux/err.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/platform_data/ntc_thermistor.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/machine.h>
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#include <linux/iio/driver.h>
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#include <linux/iio/consumer.h>
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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struct ntc_compensation {
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int temp_c;
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unsigned int ohm;
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};
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static const struct platform_device_id ntc_thermistor_id[] = {
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{ "ncp15wb473", TYPE_NCPXXWB473 },
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{ "ncp18wb473", TYPE_NCPXXWB473 },
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{ "ncp21wb473", TYPE_NCPXXWB473 },
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{ "ncp03wb473", TYPE_NCPXXWB473 },
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{ "ncp15wl333", TYPE_NCPXXWL333 },
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{ },
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};
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/*
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* A compensation table should be sorted by the values of .ohm
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* in descending order.
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* The following compensation tables are from the specification of Murata NTC
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* Thermistors Datasheet
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*/
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static const struct ntc_compensation ncpXXwb473[] = {
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{ .temp_c = -40, .ohm = 1747920 },
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{ .temp_c = -35, .ohm = 1245428 },
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{ .temp_c = -30, .ohm = 898485 },
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{ .temp_c = -25, .ohm = 655802 },
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{ .temp_c = -20, .ohm = 483954 },
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{ .temp_c = -15, .ohm = 360850 },
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{ .temp_c = -10, .ohm = 271697 },
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{ .temp_c = -5, .ohm = 206463 },
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{ .temp_c = 0, .ohm = 158214 },
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{ .temp_c = 5, .ohm = 122259 },
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{ .temp_c = 10, .ohm = 95227 },
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{ .temp_c = 15, .ohm = 74730 },
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{ .temp_c = 20, .ohm = 59065 },
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{ .temp_c = 25, .ohm = 47000 },
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{ .temp_c = 30, .ohm = 37643 },
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{ .temp_c = 35, .ohm = 30334 },
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{ .temp_c = 40, .ohm = 24591 },
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{ .temp_c = 45, .ohm = 20048 },
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{ .temp_c = 50, .ohm = 16433 },
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{ .temp_c = 55, .ohm = 13539 },
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{ .temp_c = 60, .ohm = 11209 },
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{ .temp_c = 65, .ohm = 9328 },
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{ .temp_c = 70, .ohm = 7798 },
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{ .temp_c = 75, .ohm = 6544 },
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{ .temp_c = 80, .ohm = 5518 },
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{ .temp_c = 85, .ohm = 4674 },
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{ .temp_c = 90, .ohm = 3972 },
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{ .temp_c = 95, .ohm = 3388 },
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{ .temp_c = 100, .ohm = 2902 },
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{ .temp_c = 105, .ohm = 2494 },
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{ .temp_c = 110, .ohm = 2150 },
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{ .temp_c = 115, .ohm = 1860 },
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{ .temp_c = 120, .ohm = 1615 },
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{ .temp_c = 125, .ohm = 1406 },
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};
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static const struct ntc_compensation ncpXXwl333[] = {
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{ .temp_c = -40, .ohm = 1610154 },
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{ .temp_c = -35, .ohm = 1130850 },
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{ .temp_c = -30, .ohm = 802609 },
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{ .temp_c = -25, .ohm = 575385 },
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{ .temp_c = -20, .ohm = 416464 },
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{ .temp_c = -15, .ohm = 304219 },
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{ .temp_c = -10, .ohm = 224193 },
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{ .temp_c = -5, .ohm = 166623 },
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{ .temp_c = 0, .ohm = 124850 },
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{ .temp_c = 5, .ohm = 94287 },
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{ .temp_c = 10, .ohm = 71747 },
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{ .temp_c = 15, .ohm = 54996 },
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{ .temp_c = 20, .ohm = 42455 },
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{ .temp_c = 25, .ohm = 33000 },
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{ .temp_c = 30, .ohm = 25822 },
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{ .temp_c = 35, .ohm = 20335 },
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{ .temp_c = 40, .ohm = 16115 },
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{ .temp_c = 45, .ohm = 12849 },
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{ .temp_c = 50, .ohm = 10306 },
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{ .temp_c = 55, .ohm = 8314 },
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{ .temp_c = 60, .ohm = 6746 },
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{ .temp_c = 65, .ohm = 5503 },
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{ .temp_c = 70, .ohm = 4513 },
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{ .temp_c = 75, .ohm = 3721 },
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{ .temp_c = 80, .ohm = 3084 },
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{ .temp_c = 85, .ohm = 2569 },
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{ .temp_c = 90, .ohm = 2151 },
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{ .temp_c = 95, .ohm = 1809 },
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{ .temp_c = 100, .ohm = 1529 },
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{ .temp_c = 105, .ohm = 1299 },
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{ .temp_c = 110, .ohm = 1108 },
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{ .temp_c = 115, .ohm = 949 },
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{ .temp_c = 120, .ohm = 817 },
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{ .temp_c = 125, .ohm = 707 },
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};
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struct ntc_data {
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struct device *hwmon_dev;
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struct ntc_thermistor_platform_data *pdata;
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const struct ntc_compensation *comp;
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struct device *dev;
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int n_comp;
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char name[PLATFORM_NAME_SIZE];
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};
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#ifdef CONFIG_OF
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static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
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{
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struct iio_channel *channel = pdata->chan;
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unsigned int result;
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int val, ret;
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ret = iio_read_channel_raw(channel, &val);
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if (ret < 0) {
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pr_err("read channel() error: %d\n", ret);
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return ret;
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}
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/* unit: mV */
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result = pdata->pullup_uv * val;
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result >>= 12;
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return result;
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}
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static const struct of_device_id ntc_match[] = {
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{ .compatible = "ntc,ncp15wb473",
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.data = &ntc_thermistor_id[TYPE_NCPXXWB473] },
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{ .compatible = "ntc,ncp18wb473",
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.data = &ntc_thermistor_id[TYPE_NCPXXWB473] },
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{ .compatible = "ntc,ncp21wb473",
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.data = &ntc_thermistor_id[TYPE_NCPXXWB473] },
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{ .compatible = "ntc,ncp03wb473",
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.data = &ntc_thermistor_id[TYPE_NCPXXWB473] },
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{ .compatible = "ntc,ncp15wl333",
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.data = &ntc_thermistor_id[TYPE_NCPXXWL333] },
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{ },
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};
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MODULE_DEVICE_TABLE(of, ntc_match);
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static struct ntc_thermistor_platform_data *
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ntc_thermistor_parse_dt(struct platform_device *pdev)
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{
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struct iio_channel *chan;
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struct device_node *np = pdev->dev.of_node;
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struct ntc_thermistor_platform_data *pdata;
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if (!np)
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return NULL;
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pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
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if (!pdata)
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return ERR_PTR(-ENOMEM);
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chan = iio_channel_get(&pdev->dev, NULL);
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if (IS_ERR(chan))
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return ERR_CAST(chan);
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if (of_property_read_u32(np, "pullup-uv", &pdata->pullup_uv))
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return ERR_PTR(-ENODEV);
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if (of_property_read_u32(np, "pullup-ohm", &pdata->pullup_ohm))
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return ERR_PTR(-ENODEV);
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if (of_property_read_u32(np, "pulldown-ohm", &pdata->pulldown_ohm))
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return ERR_PTR(-ENODEV);
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if (of_find_property(np, "connected-positive", NULL))
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pdata->connect = NTC_CONNECTED_POSITIVE;
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else /* status change should be possible if not always on. */
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pdata->connect = NTC_CONNECTED_GROUND;
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pdata->chan = chan;
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pdata->read_uv = ntc_adc_iio_read;
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return pdata;
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}
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static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata)
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{
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if (pdata->chan)
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iio_channel_release(pdata->chan);
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}
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#else
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static struct ntc_thermistor_platform_data *
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ntc_thermistor_parse_dt(struct platform_device *pdev)
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{
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return NULL;
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}
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static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata)
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{ }
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#endif
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static inline u64 div64_u64_safe(u64 dividend, u64 divisor)
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{
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if (divisor == 0 && dividend == 0)
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return 0;
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if (divisor == 0)
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return UINT_MAX;
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return div64_u64(dividend, divisor);
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}
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static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv)
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{
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struct ntc_thermistor_platform_data *pdata = data->pdata;
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u64 mv = uv / 1000;
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u64 pmv = pdata->pullup_uv / 1000;
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u64 n, puo, pdo;
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puo = pdata->pullup_ohm;
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pdo = pdata->pulldown_ohm;
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if (mv == 0) {
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if (pdata->connect == NTC_CONNECTED_POSITIVE)
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return INT_MAX;
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return 0;
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}
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if (mv >= pmv)
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return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
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0 : INT_MAX;
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if (pdata->connect == NTC_CONNECTED_POSITIVE && puo == 0)
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n = div64_u64_safe(pdo * (pmv - mv), mv);
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else if (pdata->connect == NTC_CONNECTED_GROUND && pdo == 0)
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n = div64_u64_safe(puo * mv, pmv - mv);
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else if (pdata->connect == NTC_CONNECTED_POSITIVE)
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n = div64_u64_safe(pdo * puo * (pmv - mv),
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puo * mv - pdo * (pmv - mv));
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else
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n = div64_u64_safe(pdo * puo * mv, pdo * (pmv - mv) - puo * mv);
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if (n > INT_MAX)
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n = INT_MAX;
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return n;
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}
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static void lookup_comp(struct ntc_data *data, unsigned int ohm,
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int *i_low, int *i_high)
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{
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int start, end, mid;
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/*
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* Handle special cases: Resistance is higher than or equal to
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* resistance in first table entry, or resistance is lower or equal
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* to resistance in last table entry.
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* In these cases, return i_low == i_high, either pointing to the
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* beginning or to the end of the table depending on the condition.
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*/
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if (ohm >= data->comp[0].ohm) {
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*i_low = 0;
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*i_high = 0;
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return;
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}
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if (ohm <= data->comp[data->n_comp - 1].ohm) {
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*i_low = data->n_comp - 1;
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*i_high = data->n_comp - 1;
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return;
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}
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/* Do a binary search on compensation table */
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start = 0;
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end = data->n_comp;
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while (start < end) {
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mid = start + (end - start) / 2;
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/*
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* start <= mid < end
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* data->comp[start].ohm > ohm >= data->comp[end].ohm
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*
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* We could check for "ohm == data->comp[mid].ohm" here, but
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* that is a quite unlikely condition, and we would have to
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* check again after updating start. Check it at the end instead
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* for simplicity.
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*/
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if (ohm >= data->comp[mid].ohm) {
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end = mid;
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} else {
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start = mid + 1;
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/*
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* ohm >= data->comp[start].ohm might be true here,
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* since we set start to mid + 1. In that case, we are
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* done. We could keep going, but the condition is quite
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* likely to occur, so it is worth checking for it.
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*/
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if (ohm >= data->comp[start].ohm)
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end = start;
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}
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/*
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* start <= end
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* data->comp[start].ohm >= ohm >= data->comp[end].ohm
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*/
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}
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/*
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* start == end
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* ohm >= data->comp[end].ohm
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*/
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*i_low = end;
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if (ohm == data->comp[end].ohm)
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*i_high = end;
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else
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*i_high = end - 1;
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}
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static int get_temp_mc(struct ntc_data *data, unsigned int ohm)
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{
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int low, high;
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int temp;
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lookup_comp(data, ohm, &low, &high);
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if (low == high) {
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/* Unable to use linear approximation */
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temp = data->comp[low].temp_c * 1000;
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} else {
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temp = data->comp[low].temp_c * 1000 +
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((data->comp[high].temp_c - data->comp[low].temp_c) *
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1000 * ((int)ohm - (int)data->comp[low].ohm)) /
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((int)data->comp[high].ohm - (int)data->comp[low].ohm);
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}
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return temp;
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}
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static int ntc_thermistor_get_ohm(struct ntc_data *data)
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{
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int read_uv;
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if (data->pdata->read_ohm)
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return data->pdata->read_ohm();
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if (data->pdata->read_uv) {
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read_uv = data->pdata->read_uv(data->pdata);
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if (read_uv < 0)
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return read_uv;
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return get_ohm_of_thermistor(data, read_uv);
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}
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return -EINVAL;
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}
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static ssize_t ntc_show_name(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct ntc_data *data = dev_get_drvdata(dev);
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return sprintf(buf, "%s\n", data->name);
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}
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static ssize_t ntc_show_type(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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return sprintf(buf, "4\n");
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}
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static ssize_t ntc_show_temp(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct ntc_data *data = dev_get_drvdata(dev);
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int ohm;
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ohm = ntc_thermistor_get_ohm(data);
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if (ohm < 0)
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return ohm;
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return sprintf(buf, "%d\n", get_temp_mc(data, ohm));
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}
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static SENSOR_DEVICE_ATTR(temp1_type, S_IRUGO, ntc_show_type, NULL, 0);
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static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ntc_show_temp, NULL, 0);
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static DEVICE_ATTR(name, S_IRUGO, ntc_show_name, NULL);
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static struct attribute *ntc_attributes[] = {
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&dev_attr_name.attr,
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&sensor_dev_attr_temp1_type.dev_attr.attr,
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&sensor_dev_attr_temp1_input.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group ntc_attr_group = {
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.attrs = ntc_attributes,
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};
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static int ntc_thermistor_probe(struct platform_device *pdev)
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{
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const struct of_device_id *of_id =
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of_match_device(of_match_ptr(ntc_match), &pdev->dev);
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const struct platform_device_id *pdev_id;
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struct ntc_thermistor_platform_data *pdata;
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struct ntc_data *data;
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int ret;
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pdata = ntc_thermistor_parse_dt(pdev);
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if (IS_ERR(pdata))
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return PTR_ERR(pdata);
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else if (pdata == NULL)
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pdata = pdev->dev.platform_data;
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if (!pdata) {
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dev_err(&pdev->dev, "No platform init data supplied.\n");
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return -ENODEV;
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}
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/* Either one of the two is required. */
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if (!pdata->read_uv && !pdata->read_ohm) {
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dev_err(&pdev->dev,
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"Both read_uv and read_ohm missing. Need either one of the two.\n");
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return -EINVAL;
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}
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if (pdata->read_uv && pdata->read_ohm) {
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dev_warn(&pdev->dev,
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"Only one of read_uv and read_ohm is needed; ignoring read_uv.\n");
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pdata->read_uv = NULL;
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}
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if (pdata->read_uv && (pdata->pullup_uv == 0 ||
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(pdata->pullup_ohm == 0 && pdata->connect ==
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NTC_CONNECTED_GROUND) ||
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(pdata->pulldown_ohm == 0 && pdata->connect ==
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NTC_CONNECTED_POSITIVE) ||
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(pdata->connect != NTC_CONNECTED_POSITIVE &&
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pdata->connect != NTC_CONNECTED_GROUND))) {
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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->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");
|
|
MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("platform:ntc-thermistor");
|