// SPDX-License-Identifier: GPL-2.0-or-later /* * sbtsi_temp.c - hwmon driver for a SBI Temperature Sensor Interface (SB-TSI) * compliant AMD SoC temperature device. * * Copyright (c) 2020, Google Inc. * Copyright (c) 2020, Kun Yi <[email protected]> */ #include <linux/err.h> #include <linux/i2c.h> #include <linux/init.h> #include <linux/hwmon.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/of.h> /* * SB-TSI registers only support SMBus byte data access. "_INT" registers are * the integer part of a temperature value or limit, and "_DEC" registers are * corresponding decimal parts. */ #define SBTSI_REG_TEMP_INT … #define SBTSI_REG_STATUS … #define SBTSI_REG_CONFIG … #define SBTSI_REG_TEMP_HIGH_INT … #define SBTSI_REG_TEMP_LOW_INT … #define SBTSI_REG_TEMP_DEC … #define SBTSI_REG_TEMP_HIGH_DEC … #define SBTSI_REG_TEMP_LOW_DEC … #define SBTSI_CONFIG_READ_ORDER_SHIFT … #define SBTSI_TEMP_MIN … #define SBTSI_TEMP_MAX … /* Each client has this additional data */ struct sbtsi_data { … }; /* * From SB-TSI spec: CPU temperature readings and limit registers encode the * temperature in increments of 0.125 from 0 to 255.875. The "high byte" * register encodes the base-2 of the integer portion, and the upper 3 bits of * the "low byte" encode in base-2 the decimal portion. * * e.g. INT=0x19, DEC=0x20 represents 25.125 degrees Celsius * * Therefore temperature in millidegree Celsius = * (INT + DEC / 256) * 1000 = (INT * 8 + DEC / 32) * 125 */ static inline int sbtsi_reg_to_mc(s32 integer, s32 decimal) { … } /* * Inversely, given temperature in millidegree Celsius * INT = (TEMP / 125) / 8 * DEC = ((TEMP / 125) % 8) * 32 * Caller have to make sure temp doesn't exceed 255875, the max valid value. */ static inline void sbtsi_mc_to_reg(s32 temp, u8 *integer, u8 *decimal) { … } static int sbtsi_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long *val) { … } static int sbtsi_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long val) { … } static umode_t sbtsi_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, int channel) { … } static const struct hwmon_channel_info * const sbtsi_info[] = …; static const struct hwmon_ops sbtsi_hwmon_ops = …; static const struct hwmon_chip_info sbtsi_chip_info = …; static int sbtsi_probe(struct i2c_client *client) { … } static const struct i2c_device_id sbtsi_id[] = …; MODULE_DEVICE_TABLE(i2c, sbtsi_id); static const struct of_device_id __maybe_unused sbtsi_of_match[] = …; MODULE_DEVICE_TABLE(of, sbtsi_of_match); static struct i2c_driver sbtsi_driver = …; module_i2c_driver(…) …; MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
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