Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 708 insertions, 0 deletions

diff --git a/drivers/hwmon/ntc_thermistor.c b/drivers/hwmon/ntc_thermistor.c
new file mode 100644
index 0000000000..ef75b63f58
--- /dev/null
+++ b/drivers/hwmon/ntc_thermistor.c
@@ -0,0 +1,708 @@
+// 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/math64.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/err.h>
+#include <linux/fixp-arith.h>
+#include <linux/iio/consumer.h>
+#include <linux/hwmon.h>
+
+enum ntc_thermistor_type {
+	TYPE_B57330V2103,
+	TYPE_B57891S0103,
+	TYPE_NCPXXWB473,
+	TYPE_NCPXXWF104,
+	TYPE_NCPXXWL333,
+	TYPE_NCPXXXH103,
+};
+
+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_SSG1404001221,
+	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_SSG1404001221]   = { "ssg1404_001221",  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),
+};
+
+/*
+ * pullup_uV, pullup_ohm, pulldown_ohm, and connect are required.
+ *
+ * How to setup pullup_ohm, pulldown_ohm, and connect is
+ * described at Documentation/hwmon/ntc_thermistor.rst
+ *
+ * pullup/down_ohm: 0 for infinite / not-connected
+ *
+ * chan: iio_channel pointer to communicate with the ADC which the
+ * thermistor is using for conversion of the analog values.
+ */
+struct ntc_data {
+	const struct ntc_compensation *comp;
+	int n_comp;
+	unsigned int pullup_uv;
+	unsigned int pullup_ohm;
+	unsigned int pulldown_ohm;
+	enum { NTC_CONNECTED_POSITIVE, NTC_CONNECTED_GROUND } connect;
+	struct iio_channel *chan;
+};
+
+static int ntc_adc_iio_read(struct ntc_data *data)
+{
+	struct iio_channel *channel = data->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 = (data->pullup_uv * (s64)raw) >> 12;
+		}
+	}
+
+	return uv;
+}
+
+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)
+{
+	u32 puv = data->pullup_uv;
+	u64 n, puo, pdo;
+	puo = data->pullup_ohm;
+	pdo = data->pulldown_ohm;
+
+	if (uv == 0)
+		return (data->connect == NTC_CONNECTED_POSITIVE) ?
+			INT_MAX : 0;
+	if (uv >= puv)
+		return (data->connect == NTC_CONNECTED_POSITIVE) ?
+			0 : INT_MAX;
+
+	if (data->connect == NTC_CONNECTED_POSITIVE && puo == 0)
+		n = div_u64(pdo * (puv - uv), uv);
+	else if (data->connect == NTC_CONNECTED_GROUND && pdo == 0)
+		n = div_u64(puo * uv, puv - uv);
+	else if (data->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);
+	/*
+	 * First multiplying the table temperatures with 1000 to get to
+	 * millicentigrades (which is what we want) and then interpolating
+	 * will give the best precision.
+	 */
+	temp = fixp_linear_interpolate(data->comp[low].ohm,
+				       data->comp[low].temp_c * 1000,
+				       data->comp[high].ohm,
+				       data->comp[high].temp_c * 1000,
+				       ohm);
+	return temp;
+}
+
+static int ntc_thermistor_get_ohm(struct ntc_data *data)
+{
+	int read_uv;
+
+	read_uv = ntc_adc_iio_read(data);
+	if (read_uv < 0)
+		return read_uv;
+	return get_ohm_of_thermistor(data, read_uv);
+}
+
+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 * const 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_parse_props(struct device *dev,
+				      struct ntc_data *data)
+{
+	struct iio_channel *chan;
+	enum iio_chan_type type;
+	int ret;
+
+	chan = devm_iio_channel_get(dev, NULL);
+	if (IS_ERR(chan))
+		return PTR_ERR(chan);
+
+	ret = iio_get_channel_type(chan, &type);
+	if (ret < 0)
+		return ret;
+
+	if (type != IIO_VOLTAGE)
+		return -EINVAL;
+
+	ret = device_property_read_u32(dev, "pullup-uv", &data->pullup_uv);
+	if (ret)
+		return dev_err_probe(dev,  ret, "pullup-uv not specified\n");
+
+	ret = device_property_read_u32(dev, "pullup-ohm", &data->pullup_ohm);
+	if (ret)
+		return dev_err_probe(dev,  ret, "pullup-ohm not specified\n");
+
+	ret = device_property_read_u32(dev, "pulldown-ohm", &data->pulldown_ohm);
+	if (ret)
+		return dev_err_probe(dev,  ret, "pulldown-ohm not specified\n");
+
+	if (device_property_read_bool(dev, "connected-positive"))
+		data->connect = NTC_CONNECTED_POSITIVE;
+	else /* status change should be possible if not always on. */
+		data->connect = NTC_CONNECTED_GROUND;
+
+	data->chan = chan;
+
+	return 0;
+}
+
+static int ntc_thermistor_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const struct platform_device_id *pdev_id;
+	struct device *hwmon_dev;
+	struct ntc_data *data;
+	int ret;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	ret = ntc_thermistor_parse_props(dev, data);
+	if (ret)
+		return ret;
+
+	if (data->pullup_uv == 0 ||
+	    (data->pullup_ohm == 0 && data->connect ==
+	     NTC_CONNECTED_GROUND) ||
+	    (data->pulldown_ohm == 0 && data->connect ==
+	     NTC_CONNECTED_POSITIVE) ||
+	    (data->connect != NTC_CONNECTED_POSITIVE &&
+	     data->connect != NTC_CONNECTED_GROUND)) {
+		dev_err(dev, "Required data to use NTC driver not supplied.\n");
+		return -EINVAL;
+	}
+
+	pdev_id = device_get_match_data(dev);
+
+	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 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] },
+	{ .compatible = "samsung,1404-001221",
+		.data = &ntc_thermistor_id[NTC_SSG1404001221] },
+
+	/* 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 platform_driver ntc_thermistor_driver = {
+	.driver = {
+		.name = "ntc-thermistor",
+		.of_match_table = 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");