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linux/drivers/hwmon/ntc_thermistor.c
Linus Walleij 4f2d9cced4 hwmon: (ntc_thermistor): try reading processed 
Before trying the custom method of reading the sensor
as raw and then converting, we want to use
iio_read_channel_processed_scale() which first tries to
see if the ADC can provide a processed value directly,
else reads raw and applies scaling inside of IIO
using the scale attributes of the ADC. We need to
multiply the scaled value with 1000 to get to
microvolts from millivolts which is what processed
IIO channels returns.

Keep the code that assumes 12bit ADC around as a
fallback.

This gives correct readings on the AB8500 thermistor
inputs used in the Ux500 HREFP520 platform for reading
battery and board temperature.

Cc: Peter Rosin <peda@axentia.se>
Cc: Chris Lesiak <chris.lesiak@licor.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: linux-iio@vger.kernel.org
Link: https://lore.kernel.org/linux-iio/20201224011607.1059534-1-linus.walleij@linaro.org/
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Chris Lesiak <chris.lesiak@licor.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210308100219.2732156-2-linus.walleij@linaro.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2021-03-25 19:13:51 +00:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* ntc_thermistor.c - NTC Thermistors
*
* Copyright (C) 2010 Samsung Electronics
* MyungJoo Ham <myungjoo.ham@samsung.com>
*/
#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/of.h>
#include <linux/of_device.h>
#include <linux/platform_data/ntc_thermistor.h>
#include <linux/iio/iio.h>
#include <linux/iio/machine.h>
#include <linux/iio/driver.h>
#include <linux/iio/consumer.h>
#include <linux/hwmon.h>
struct ntc_compensation {
int temp_c;
unsigned int ohm;
};
/*
* Used as index in a zero-terminated array, holes not allowed so
* that NTC_LAST is the first empty array entry.
*/
enum {
NTC_B57330V2103,
NTC_B57891S0103,
NTC_NCP03WB473,
NTC_NCP03WF104,
NTC_NCP15WB473,
NTC_NCP15WL333,
NTC_NCP15XH103,
NTC_NCP18WB473,
NTC_NCP21WB473,
NTC_LAST,
};
static const struct platform_device_id ntc_thermistor_id[] = {
[NTC_B57330V2103] = { "b57330v2103", TYPE_B57330V2103 },
[NTC_B57891S0103] = { "b57891s0103", TYPE_B57891S0103 },
[NTC_NCP03WB473] = { "ncp03wb473", TYPE_NCPXXWB473 },
[NTC_NCP03WF104] = { "ncp03wf104", TYPE_NCPXXWF104 },
[NTC_NCP15WB473] = { "ncp15wb473", TYPE_NCPXXWB473 },
[NTC_NCP15WL333] = { "ncp15wl333", TYPE_NCPXXWL333 },
[NTC_NCP15XH103] = { "ncp15xh103", TYPE_NCPXXXH103 },
[NTC_NCP18WB473] = { "ncp18wb473", TYPE_NCPXXWB473 },
[NTC_NCP21WB473] = { "ncp21wb473", TYPE_NCPXXWB473 },
[NTC_LAST] = { },
};
/*
* 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
*/
static 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 },
};
static 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 },
};
static const struct ntc_compensation ncpXXwf104[] = {
{ .temp_c = -40, .ohm = 4397119 },
{ .temp_c = -35, .ohm = 3088599 },
{ .temp_c = -30, .ohm = 2197225 },
{ .temp_c = -25, .ohm = 1581881 },
{ .temp_c = -20, .ohm = 1151037 },
{ .temp_c = -15, .ohm = 846579 },
{ .temp_c = -10, .ohm = 628988 },
{ .temp_c = -5, .ohm = 471632 },
{ .temp_c = 0, .ohm = 357012 },
{ .temp_c = 5, .ohm = 272500 },
{ .temp_c = 10, .ohm = 209710 },
{ .temp_c = 15, .ohm = 162651 },
{ .temp_c = 20, .ohm = 127080 },
{ .temp_c = 25, .ohm = 100000 },
{ .temp_c = 30, .ohm = 79222 },
{ .temp_c = 35, .ohm = 63167 },
{ .temp_c = 40, .ohm = 50677 },
{ .temp_c = 45, .ohm = 40904 },
{ .temp_c = 50, .ohm = 33195 },
{ .temp_c = 55, .ohm = 27091 },
{ .temp_c = 60, .ohm = 22224 },
{ .temp_c = 65, .ohm = 18323 },
{ .temp_c = 70, .ohm = 15184 },
{ .temp_c = 75, .ohm = 12635 },
{ .temp_c = 80, .ohm = 10566 },
{ .temp_c = 85, .ohm = 8873 },
{ .temp_c = 90, .ohm = 7481 },
{ .temp_c = 95, .ohm = 6337 },
{ .temp_c = 100, .ohm = 5384 },
{ .temp_c = 105, .ohm = 4594 },
{ .temp_c = 110, .ohm = 3934 },
{ .temp_c = 115, .ohm = 3380 },
{ .temp_c = 120, .ohm = 2916 },
{ .temp_c = 125, .ohm = 2522 },
};
static const struct ntc_compensation ncpXXxh103[] = {
{ .temp_c = -40, .ohm = 247565 },
{ .temp_c = -35, .ohm = 181742 },
{ .temp_c = -30, .ohm = 135128 },
{ .temp_c = -25, .ohm = 101678 },
{ .temp_c = -20, .ohm = 77373 },
{ .temp_c = -15, .ohm = 59504 },
{ .temp_c = -10, .ohm = 46222 },
{ .temp_c = -5, .ohm = 36244 },
{ .temp_c = 0, .ohm = 28674 },
{ .temp_c = 5, .ohm = 22878 },
{ .temp_c = 10, .ohm = 18399 },
{ .temp_c = 15, .ohm = 14910 },
{ .temp_c = 20, .ohm = 12169 },
{ .temp_c = 25, .ohm = 10000 },
{ .temp_c = 30, .ohm = 8271 },
{ .temp_c = 35, .ohm = 6883 },
{ .temp_c = 40, .ohm = 5762 },
{ .temp_c = 45, .ohm = 4851 },
{ .temp_c = 50, .ohm = 4105 },
{ .temp_c = 55, .ohm = 3492 },
{ .temp_c = 60, .ohm = 2985 },
{ .temp_c = 65, .ohm = 2563 },
{ .temp_c = 70, .ohm = 2211 },
{ .temp_c = 75, .ohm = 1915 },
{ .temp_c = 80, .ohm = 1666 },
{ .temp_c = 85, .ohm = 1454 },
{ .temp_c = 90, .ohm = 1275 },
{ .temp_c = 95, .ohm = 1121 },
{ .temp_c = 100, .ohm = 990 },
{ .temp_c = 105, .ohm = 876 },
{ .temp_c = 110, .ohm = 779 },
{ .temp_c = 115, .ohm = 694 },
{ .temp_c = 120, .ohm = 620 },
{ .temp_c = 125, .ohm = 556 },
};
/*
* The following compensation tables are from the specifications in EPCOS NTC
* Thermistors Datasheets
*/
static const struct ntc_compensation b57330v2103[] = {
{ .temp_c = -40, .ohm = 190030 },
{ .temp_c = -35, .ohm = 145360 },
{ .temp_c = -30, .ohm = 112060 },
{ .temp_c = -25, .ohm = 87041 },
{ .temp_c = -20, .ohm = 68104 },
{ .temp_c = -15, .ohm = 53665 },
{ .temp_c = -10, .ohm = 42576 },
{ .temp_c = -5, .ohm = 34001 },
{ .temp_c = 0, .ohm = 27326 },
{ .temp_c = 5, .ohm = 22096 },
{ .temp_c = 10, .ohm = 17973 },
{ .temp_c = 15, .ohm = 14703 },
{ .temp_c = 20, .ohm = 12090 },
{ .temp_c = 25, .ohm = 10000 },
{ .temp_c = 30, .ohm = 8311 },
{ .temp_c = 35, .ohm = 6941 },
{ .temp_c = 40, .ohm = 5825 },
{ .temp_c = 45, .ohm = 4911 },
{ .temp_c = 50, .ohm = 4158 },
{ .temp_c = 55, .ohm = 3536 },
{ .temp_c = 60, .ohm = 3019 },
{ .temp_c = 65, .ohm = 2588 },
{ .temp_c = 70, .ohm = 2227 },
{ .temp_c = 75, .ohm = 1924 },
{ .temp_c = 80, .ohm = 1668 },
{ .temp_c = 85, .ohm = 1451 },
{ .temp_c = 90, .ohm = 1266 },
{ .temp_c = 95, .ohm = 1108 },
{ .temp_c = 100, .ohm = 973 },
{ .temp_c = 105, .ohm = 857 },
{ .temp_c = 110, .ohm = 757 },
{ .temp_c = 115, .ohm = 671 },
{ .temp_c = 120, .ohm = 596 },
{ .temp_c = 125, .ohm = 531 },
};
static const struct ntc_compensation b57891s0103[] = {
{ .temp_c = -55.0, .ohm = 878900 },
{ .temp_c = -50.0, .ohm = 617590 },
{ .temp_c = -45.0, .ohm = 439340 },
{ .temp_c = -40.0, .ohm = 316180 },
{ .temp_c = -35.0, .ohm = 230060 },
{ .temp_c = -30.0, .ohm = 169150 },
{ .temp_c = -25.0, .ohm = 125550 },
{ .temp_c = -20.0, .ohm = 94143 },
{ .temp_c = -15.0, .ohm = 71172 },
{ .temp_c = -10.0, .ohm = 54308 },
{ .temp_c = -5.0, .ohm = 41505 },
{ .temp_c = 0.0, .ohm = 32014 },
{ .temp_c = 5.0, .ohm = 25011 },
{ .temp_c = 10.0, .ohm = 19691 },
{ .temp_c = 15.0, .ohm = 15618 },
{ .temp_c = 20.0, .ohm = 12474 },
{ .temp_c = 25.0, .ohm = 10000 },
{ .temp_c = 30.0, .ohm = 8080 },
{ .temp_c = 35.0, .ohm = 6569 },
{ .temp_c = 40.0, .ohm = 5372 },
{ .temp_c = 45.0, .ohm = 4424 },
{ .temp_c = 50.0, .ohm = 3661 },
{ .temp_c = 55.0, .ohm = 3039 },
{ .temp_c = 60.0, .ohm = 2536 },
{ .temp_c = 65.0, .ohm = 2128 },
{ .temp_c = 70.0, .ohm = 1794 },
{ .temp_c = 75.0, .ohm = 1518 },
{ .temp_c = 80.0, .ohm = 1290 },
{ .temp_c = 85.0, .ohm = 1100 },
{ .temp_c = 90.0, .ohm = 942 },
{ .temp_c = 95.0, .ohm = 809 },
{ .temp_c = 100.0, .ohm = 697 },
{ .temp_c = 105.0, .ohm = 604 },
{ .temp_c = 110.0, .ohm = 525 },
{ .temp_c = 115.0, .ohm = 457 },
{ .temp_c = 120.0, .ohm = 400 },
{ .temp_c = 125.0, .ohm = 351 },
{ .temp_c = 130.0, .ohm = 308 },
{ .temp_c = 135.0, .ohm = 272 },
{ .temp_c = 140.0, .ohm = 240 },
{ .temp_c = 145.0, .ohm = 213 },
{ .temp_c = 150.0, .ohm = 189 },
{ .temp_c = 155.0, .ohm = 168 },
};
struct ntc_type {
const struct ntc_compensation *comp;
int n_comp;
};
#define NTC_TYPE(ntc, compensation) \
[(ntc)] = { .comp = (compensation), .n_comp = ARRAY_SIZE(compensation) }
static const struct ntc_type ntc_type[] = {
NTC_TYPE(TYPE_B57330V2103, b57330v2103),
NTC_TYPE(TYPE_B57891S0103, b57891s0103),
NTC_TYPE(TYPE_NCPXXWB473, ncpXXwb473),
NTC_TYPE(TYPE_NCPXXWF104, ncpXXwf104),
NTC_TYPE(TYPE_NCPXXWL333, ncpXXwl333),
NTC_TYPE(TYPE_NCPXXXH103, ncpXXxh103),
};
struct ntc_data {
struct ntc_thermistor_platform_data *pdata;
const struct ntc_compensation *comp;
int n_comp;
};
#if defined(CONFIG_OF) && IS_ENABLED(CONFIG_IIO)
static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
{
struct iio_channel *channel = pdata->chan;
int uv, ret;
ret = iio_read_channel_processed_scale(channel, &uv, 1000);
if (ret < 0) {
int raw;
/*
* This fallback uses a raw read and then
* assumes the ADC is 12 bits, scaling with
* a factor 1000 to get to microvolts.
*/
ret = iio_read_channel_raw(channel, &raw);
if (ret < 0) {
pr_err("read channel() error: %d\n", ret);
return ret;
}
ret = iio_convert_raw_to_processed(channel, raw, &uv, 1000);
if (ret < 0) {
/* Assume 12 bit ADC with vref at pullup_uv */
uv = (pdata->pullup_uv * (s64)raw) >> 12;
}
}
return uv;
}
static const struct of_device_id ntc_match[] = {
{ .compatible = "epcos,b57330v2103",
.data = &ntc_thermistor_id[NTC_B57330V2103]},
{ .compatible = "epcos,b57891s0103",
.data = &ntc_thermistor_id[NTC_B57891S0103] },
{ .compatible = "murata,ncp03wb473",
.data = &ntc_thermistor_id[NTC_NCP03WB473] },
{ .compatible = "murata,ncp03wf104",
.data = &ntc_thermistor_id[NTC_NCP03WF104] },
{ .compatible = "murata,ncp15wb473",
.data = &ntc_thermistor_id[NTC_NCP15WB473] },
{ .compatible = "murata,ncp15wl333",
.data = &ntc_thermistor_id[NTC_NCP15WL333] },
{ .compatible = "murata,ncp15xh103",
.data = &ntc_thermistor_id[NTC_NCP15XH103] },
{ .compatible = "murata,ncp18wb473",
.data = &ntc_thermistor_id[NTC_NCP18WB473] },
{ .compatible = "murata,ncp21wb473",
.data = &ntc_thermistor_id[NTC_NCP21WB473] },
/* Usage of vendor name "ntc" is deprecated */
{ .compatible = "ntc,ncp03wb473",
.data = &ntc_thermistor_id[NTC_NCP03WB473] },
{ .compatible = "ntc,ncp15wb473",
.data = &ntc_thermistor_id[NTC_NCP15WB473] },
{ .compatible = "ntc,ncp15wl333",
.data = &ntc_thermistor_id[NTC_NCP15WL333] },
{ .compatible = "ntc,ncp18wb473",
.data = &ntc_thermistor_id[NTC_NCP18WB473] },
{ .compatible = "ntc,ncp21wb473",
.data = &ntc_thermistor_id[NTC_NCP21WB473] },
{ },
};
MODULE_DEVICE_TABLE(of, ntc_match);
static struct ntc_thermistor_platform_data *
ntc_thermistor_parse_dt(struct device *dev)
{
struct iio_channel *chan;
enum iio_chan_type type;
struct device_node *np = dev->of_node;
struct ntc_thermistor_platform_data *pdata;
int ret;
if (!np)
return NULL;
pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return ERR_PTR(-ENOMEM);
chan = devm_iio_channel_get(dev, NULL);
if (IS_ERR(chan))
return ERR_CAST(chan);
ret = iio_get_channel_type(chan, &type);
if (ret < 0)
return ERR_PTR(ret);
if (type != IIO_VOLTAGE)
return ERR_PTR(-EINVAL);
if (of_property_read_u32(np, "pullup-uv", &pdata->pullup_uv))
return ERR_PTR(-ENODEV);
if (of_property_read_u32(np, "pullup-ohm", &pdata->pullup_ohm))
return ERR_PTR(-ENODEV);
if (of_property_read_u32(np, "pulldown-ohm", &pdata->pulldown_ohm))
return ERR_PTR(-ENODEV);
if (of_find_property(np, "connected-positive", NULL))
pdata->connect = NTC_CONNECTED_POSITIVE;
else /* status change should be possible if not always on. */
pdata->connect = NTC_CONNECTED_GROUND;
pdata->chan = chan;
pdata->read_uv = ntc_adc_iio_read;
return pdata;
}
#else
static struct ntc_thermistor_platform_data *
ntc_thermistor_parse_dt(struct device *dev)
{
return NULL;
}
#define ntc_match NULL
#endif
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 int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv)
{
struct ntc_thermistor_platform_data *pdata = data->pdata;
u32 puv = pdata->pullup_uv;
u64 n, puo, pdo;
puo = pdata->pullup_ohm;
pdo = pdata->pulldown_ohm;
if (uv == 0)
return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
INT_MAX : 0;
if (uv >= puv)
return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
0 : INT_MAX;
if (pdata->connect == NTC_CONNECTED_POSITIVE && puo == 0)
n = div_u64(pdo * (puv - uv), uv);
else if (pdata->connect == NTC_CONNECTED_GROUND && pdo == 0)
n = div_u64(puo * uv, puv - uv);
else if (pdata->connect == NTC_CONNECTED_POSITIVE)
n = div64_u64_safe(pdo * puo * (puv - uv),
puo * uv - pdo * (puv - uv));
else
n = div64_u64_safe(pdo * puo * uv, pdo * (puv - uv) - puo * uv);
if (n > INT_MAX)
n = INT_MAX;
return n;
}
static void lookup_comp(struct ntc_data *data, unsigned int ohm,
int *i_low, int *i_high)
{
int start, end, mid;
/*
* Handle special cases: Resistance is higher than or equal to
* resistance in first table entry, or resistance is lower or equal
* to resistance in last table entry.
* In these cases, return i_low == i_high, either pointing to the
* beginning or to the end of the table depending on the condition.
*/
if (ohm >= data->comp[0].ohm) {
*i_low = 0;
*i_high = 0;
return;
}
if (ohm <= data->comp[data->n_comp - 1].ohm) {
*i_low = data->n_comp - 1;
*i_high = data->n_comp - 1;
return;
}
/* Do a binary search on compensation table */
start = 0;
end = data->n_comp;
while (start < end) {
mid = start + (end - start) / 2;
/*
* start <= mid < end
* data->comp[start].ohm > ohm >= data->comp[end].ohm
*
* We could check for "ohm == data->comp[mid].ohm" here, but
* that is a quite unlikely condition, and we would have to
* check again after updating start. Check it at the end instead
* for simplicity.
*/
if (ohm >= data->comp[mid].ohm) {
end = mid;
} else {
start = mid + 1;
/*
* ohm >= data->comp[start].ohm might be true here,
* since we set start to mid + 1. In that case, we are
* done. We could keep going, but the condition is quite
* likely to occur, so it is worth checking for it.
*/
if (ohm >= data->comp[start].ohm)
end = start;
}
/*
* start <= end
* data->comp[start].ohm >= ohm >= data->comp[end].ohm
*/
}
/*
* start == end
* ohm >= data->comp[end].ohm
*/
*i_low = end;
if (ohm == data->comp[end].ohm)
*i_high = end;
else
*i_high = end - 1;
}
static int get_temp_mc(struct ntc_data *data, unsigned int ohm)
{
int low, high;
int temp;
lookup_comp(data, ohm, &low, &high);
if (low == high) {
/* Unable to use linear approximation */
temp = data->comp[low].temp_c * 1000;
} 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 temp;
}
static int ntc_thermistor_get_ohm(struct ntc_data *data)
{
int read_uv;
if (data->pdata->read_ohm)
return data->pdata->read_ohm();
if (data->pdata->read_uv) {
read_uv = data->pdata->read_uv(data->pdata);
if (read_uv < 0)
return read_uv;
return get_ohm_of_thermistor(data, read_uv);
}
return -EINVAL;
}
static int ntc_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *val)
{
struct ntc_data *data = dev_get_drvdata(dev);
int ohm;
switch (type) {
case hwmon_temp:
switch (attr) {
case hwmon_temp_input:
ohm = ntc_thermistor_get_ohm(data);
if (ohm < 0)
return ohm;
*val = get_temp_mc(data, ohm);
return 0;
case hwmon_temp_type:
*val = 4;
return 0;
default:
break;
}
break;
default:
break;
}
return -EINVAL;
}
static umode_t ntc_is_visible(const void *data, enum hwmon_sensor_types type,
u32 attr, int channel)
{
if (type == hwmon_temp) {
switch (attr) {
case hwmon_temp_input:
case hwmon_temp_type:
return 0444;
default:
break;
}
}
return 0;
}
static const struct hwmon_channel_info *ntc_info[] = {
HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_TYPE),
NULL
};
static const struct hwmon_ops ntc_hwmon_ops = {
.is_visible = ntc_is_visible,
.read = ntc_read,
};
static const struct hwmon_chip_info ntc_chip_info = {
.ops = &ntc_hwmon_ops,
.info = ntc_info,
};
static int ntc_thermistor_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
const struct of_device_id *of_id =
of_match_device(of_match_ptr(ntc_match), dev);
const struct platform_device_id *pdev_id;
struct ntc_thermistor_platform_data *pdata;
struct device *hwmon_dev;
struct ntc_data *data;
pdata = ntc_thermistor_parse_dt(dev);
if (IS_ERR(pdata))
return PTR_ERR(pdata);
else if (pdata == NULL)
pdata = dev_get_platdata(dev);
if (!pdata) {
dev_err(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(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(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(dev, "Required data to use read_uv not supplied.\n");
return -EINVAL;
}
data = devm_kzalloc(dev, sizeof(struct ntc_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
pdev_id = of_id ? of_id->data : platform_get_device_id(pdev);
data->pdata = pdata;
if (pdev_id->driver_data >= ARRAY_SIZE(ntc_type)) {
dev_err(dev, "Unknown device type: %lu(%s)\n",
pdev_id->driver_data, pdev_id->name);
return -EINVAL;
}
data->comp = ntc_type[pdev_id->driver_data].comp;
data->n_comp = ntc_type[pdev_id->driver_data].n_comp;
hwmon_dev = devm_hwmon_device_register_with_info(dev, pdev_id->name,
data, &ntc_chip_info,
NULL);
if (IS_ERR(hwmon_dev)) {
dev_err(dev, "unable to register as hwmon device.\n");
return PTR_ERR(hwmon_dev);
}
dev_info(dev, "Thermistor type: %s successfully probed.\n",
pdev_id->name);
return 0;
}
static struct platform_driver ntc_thermistor_driver = {
.driver = {
.name = "ntc-thermistor",
.of_match_table = of_match_ptr(ntc_match),
},
.probe = ntc_thermistor_probe,
.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");
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