Merge tag 'hwmon-for-v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon updates from Guenter Roeck:
 "New drivers:

   - Driver for the Microchip LAN966x SoC

   - PMBus driver for Infineon Digital Multi-phase xdp152 family
     controllers

  Chip support added to existing drivers:

   - asus-ec-sensors:
      - Support for ROG STRIX X570-E GAMING WIFI II, PRIME X470-PRO, and
        ProArt X570 Creator WIFI
      - External temperature sensor support for ASUS WS X570-ACE

   - nct6775:
      - Support for I2C driver
      - Support for ASUS PRO H410T / PRIME H410M-R /
        ROG X570-E GAMING WIFI II

   - lm75:
      - Support for - Atmel AT30TS74

   - pmbus/max16601:
      - Support for MAX16602

   - aquacomputer_d5next:
      - Support for Aquacomputer Farbwerk
      - Support for Aquacomputer Octo

   - jc42:
      - Support for S-34TS04A

  Kernel API changes / clarifications:

   - The chip parameter of with_info API is now mandatory

   - New hwmon_device_register_for_thermal API call for use by the
     thermal subsystem

  Improvements:

   - PMBus and JC42 drivers now register with thermal subsystem

   - PMBus drivers now support get_voltage/set_voltage power operations

   - The adt7475 driver now supports pin configuration

   - The lm90 driver now supports setting extended range temperatures
     configuration with a devicetree property

   - The dell-smm driver now registers as cooling device

   - The OCC driver delays hwmon registration until requested by
     userspace

  ... and various other minor fixes and improvements"

* tag 'hwmon-for-v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging: (71 commits)
  hwmon: (aquacomputer_d5next) Fix an error handling path in aqc_probe()
  hwmon: (sl28cpld) Fix typo in comment
  hwmon: (pmbus) Check PEC support before reading other registers
  hwmon: (dimmtemp) Fix bitmap handling
  hwmon: (lm90) enable extended range according to DTS node
  dt-bindings: hwmon: lm90: add ti,extended-range-enable property
  dt-bindings: hwmon: lm90: add missing ti,tmp461
  hwmon: (ibmaem) Directly use ida_alloc()/free()
  hwmon: Directly use ida_alloc()/free()
  hwmon: (asus-ec-sensors) fix Formula VIII definition
  dt-bindings: trivial-devices: Add xdp152
  hwmon: (sl28cpld-hwmon) Use HWMON_CHANNEL_INFO macro
  hwmon: (pwm-fan) Use HWMON_CHANNEL_INFO macro
  hwmon: (peci/dimmtemp) Use HWMON_CHANNEL_INFO macro
  hwmon: (peci/cputemp) Use HWMON_CHANNEL_INFO macro
  hwmon: (mr75203) Use HWMON_CHANNEL_INFO macro
  hwmon: (ltc2992) Use HWMON_CHANNEL_INFO macro
  hwmon: (as370-hwmon) Use HWMON_CHANNEL_INFO macro
  hwmon: Make chip parameter for with_info API mandatory
  thermal/drivers/thermal_hwmon: Use hwmon_device_register_for_thermal()
  ...

3 files changed, 113 insertions, 0 deletions

diff --git a/lib/Kconfig b/lib/Kconfig
index 087e06b4cdfd..6a843639814f 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -737,3 +737,6 @@ config PLDMFW
 
 config ASN1_ENCODER
        tristate
+
+config POLYNOMIAL
+       tristate
diff --git a/lib/Makefile b/lib/Makefile
index 6b9ffc1bd1ee..89fcae891361 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -263,6 +263,8 @@ obj-$(CONFIG_MEMREGION) += memregion.o
 obj-$(CONFIG_STMP_DEVICE) += stmp_device.o
 obj-$(CONFIG_IRQ_POLL) += irq_poll.o
 
+obj-$(CONFIG_POLYNOMIAL) += polynomial.o
+
 # stackdepot.c should not be instrumented or call instrumented functions.
 # Prevent the compiler from calling builtins like memcmp() or bcmp() from this
 # file.
diff --git a/lib/polynomial.c b/lib/polynomial.c
new file mode 100644
index 000000000000..66d383445fec
--- /dev/null
+++ b/lib/polynomial.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic polynomial calculation using integer coefficients.
+ *
+ * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
+ *
+ * Authors:
+ *   Maxim Kaurkin <maxim.kaurkin@baikalelectronics.ru>
+ *   Serge Semin <Sergey.Semin@baikalelectronics.ru>
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/polynomial.h>
+
+/*
+ * Originally this was part of drivers/hwmon/bt1-pvt.c.
+ * There the following conversion is used and should serve as an example here:
+ *
+ * The original translation formulae of the temperature (in degrees of Celsius)
+ * to PVT data and vice-versa are following:
+ *
+ * N = 1.8322e-8*(T^4) + 2.343e-5*(T^3) + 8.7018e-3*(T^2) + 3.9269*(T^1) +
+ *     1.7204e2
+ * T = -1.6743e-11*(N^4) + 8.1542e-8*(N^3) + -1.8201e-4*(N^2) +
+ *     3.1020e-1*(N^1) - 4.838e1
+ *
+ * where T = [-48.380, 147.438]C and N = [0, 1023].
+ *
+ * They must be accordingly altered to be suitable for the integer arithmetics.
+ * The technique is called 'factor redistribution', which just makes sure the
+ * multiplications and divisions are made so to have a result of the operations
+ * within the integer numbers limit. In addition we need to translate the
+ * formulae to accept millidegrees of Celsius. Here what they look like after
+ * the alterations:
+ *
+ * N = (18322e-20*(T^4) + 2343e-13*(T^3) + 87018e-9*(T^2) + 39269e-3*T +
+ *     17204e2) / 1e4
+ * T = -16743e-12*(D^4) + 81542e-9*(D^3) - 182010e-6*(D^2) + 310200e-3*D -
+ *     48380
+ * where T = [-48380, 147438] mC and N = [0, 1023].
+ *
+ * static const struct polynomial poly_temp_to_N = {
+ *         .total_divider = 10000,
+ *         .terms = {
+ *                 {4, 18322, 10000, 10000},
+ *                 {3, 2343, 10000, 10},
+ *                 {2, 87018, 10000, 10},
+ *                 {1, 39269, 1000, 1},
+ *                 {0, 1720400, 1, 1}
+ *         }
+ * };
+ *
+ * static const struct polynomial poly_N_to_temp = {
+ *         .total_divider = 1,
+ *         .terms = {
+ *                 {4, -16743, 1000, 1},
+ *                 {3, 81542, 1000, 1},
+ *                 {2, -182010, 1000, 1},
+ *                 {1, 310200, 1000, 1},
+ *                 {0, -48380, 1, 1}
+ *         }
+ * };
+ */
+
+/**
+ * polynomial_calc - calculate a polynomial using integer arithmetic
+ *
+ * @poly: pointer to the descriptor of the polynomial
+ * @data: input value of the polynimal
+ *
+ * Calculate the result of a polynomial using only integer arithmetic. For
+ * this to work without too much loss of precision the coefficients has to
+ * be altered. This is called factor redistribution.
+ *
+ * Returns the result of the polynomial calculation.
+ */
+long polynomial_calc(const struct polynomial *poly, long data)
+{
+	const struct polynomial_term *term = poly->terms;
+	long total_divider = poly->total_divider ?: 1;
+	long tmp, ret = 0;
+	int deg;
+
+	/*
+	 * Here is the polynomial calculation function, which performs the
+	 * redistributed terms calculations. It's pretty straightforward.
+	 * We walk over each degree term up to the free one, and perform
+	 * the redistributed multiplication of the term coefficient, its
+	 * divider (as for the rationale fraction representation), data
+	 * power and the rational fraction divider leftover. Then all of
+	 * this is collected in a total sum variable, which value is
+	 * normalized by the total divider before being returned.
+	 */
+	do {
+		tmp = term->coef;
+		for (deg = 0; deg < term->deg; ++deg)
+			tmp = mult_frac(tmp, data, term->divider);
+		ret += tmp / term->divider_leftover;
+	} while ((term++)->deg);
+
+	return ret / total_divider;
+}
+EXPORT_SYMBOL_GPL(polynomial_calc);
+
+MODULE_DESCRIPTION("Generic polynomial calculations");
+MODULE_LICENSE("GPL");