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![Guenter Roeck](/assets/img/avatar_default.png)
Fix Coverity warning: Calling strncpy with a maximum size argument of 20 bytes on destination array "data->name" of size 20 bytes might leave the destination string unterminated. Fix by replacing strncpy() with strlcpy() and by using sizeof() to determine the maximum string length. Signed-off-by: Guenter Roeck <linux@roeck-us.net> Acked-by: Jean Delvare <khali@linux-fr.org>
431 lines
12 KiB
C
431 lines
12 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/platform_data/ntc_thermistor.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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/*
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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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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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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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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();
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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 __devinit ntc_thermistor_probe(struct platform_device *pdev)
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{
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struct ntc_data *data;
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struct ntc_thermistor_platform_data *pdata = pdev->dev.platform_data;
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int ret = 0;
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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,
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"Required data to use read_uV not supplied.\n");
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return -EINVAL;
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}
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data = devm_kzalloc(&pdev->dev, sizeof(struct ntc_data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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data->dev = &pdev->dev;
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data->pdata = pdata;
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strlcpy(data->name, pdev->id_entry->name, sizeof(data->name));
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switch (pdev->id_entry->driver_data) {
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case TYPE_NCPXXWB473:
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data->comp = ncpXXwb473;
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data->n_comp = ARRAY_SIZE(ncpXXwb473);
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break;
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case TYPE_NCPXXWL333:
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data->comp = ncpXXwl333;
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data->n_comp = ARRAY_SIZE(ncpXXwl333);
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break;
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default:
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dev_err(&pdev->dev, "Unknown device type: %lu(%s)\n",
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pdev->id_entry->driver_data,
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pdev->id_entry->name);
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return -EINVAL;
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}
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platform_set_drvdata(pdev, data);
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ret = sysfs_create_group(&data->dev->kobj, &ntc_attr_group);
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if (ret) {
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dev_err(data->dev, "unable to create sysfs files\n");
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return ret;
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}
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data->hwmon_dev = hwmon_device_register(data->dev);
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if (IS_ERR(data->hwmon_dev)) {
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dev_err(data->dev, "unable to register as hwmon device.\n");
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ret = PTR_ERR(data->hwmon_dev);
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goto err_after_sysfs;
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}
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dev_info(&pdev->dev, "Thermistor %s:%d (type: %s/%lu) successfully probed.\n",
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pdev->name, pdev->id, pdev->id_entry->name,
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pdev->id_entry->driver_data);
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return 0;
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err_after_sysfs:
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sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
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return ret;
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}
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static int __devexit ntc_thermistor_remove(struct platform_device *pdev)
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{
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struct ntc_data *data = platform_get_drvdata(pdev);
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hwmon_device_unregister(data->hwmon_dev);
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sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
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platform_set_drvdata(pdev, NULL);
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return 0;
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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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static struct platform_driver ntc_thermistor_driver = {
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.driver = {
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.name = "ntc-thermistor",
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.owner = THIS_MODULE,
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},
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.probe = ntc_thermistor_probe,
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.remove = __devexit_p(ntc_thermistor_remove),
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.id_table = ntc_thermistor_id,
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};
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module_platform_driver(ntc_thermistor_driver);
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MODULE_DESCRIPTION("NTC Thermistor Driver");
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MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:ntc-thermistor");
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