/* * Copyright (C) 2017 IBM Corp. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */ #include #include #include #include #include #include "pmbus.h" enum max31785_regs { MFR_REVISION = 0x9b, }; #define MAX31785_NR_PAGES 23 static int max31785_get_pwm(struct i2c_client *client, int page) { int rv; rv = pmbus_get_fan_rate_device(client, page, 0, percent); if (rv < 0) return rv; else if (rv >= 0x8000) return 0; else if (rv >= 0x2711) return 0x2710; return rv; } static int max31785_get_pwm_mode(struct i2c_client *client, int page) { int config; int command; config = pmbus_read_byte_data(client, page, PMBUS_FAN_CONFIG_12); if (config < 0) return config; command = pmbus_read_word_data(client, page, PMBUS_FAN_COMMAND_1); if (command < 0) return command; if (config & PB_FAN_1_RPM) return (command >= 0x8000) ? 3 : 2; if (command >= 0x8000) return 3; else if (command >= 0x2711) return 0; return 1; } static int max31785_read_word_data(struct i2c_client *client, int page, int reg) { int rv; switch (reg) { case PMBUS_VIRT_PWM_1: rv = max31785_get_pwm(client, page); break; case PMBUS_VIRT_PWM_ENABLE_1: rv = max31785_get_pwm_mode(client, page); break; default: rv = -ENODATA; break; } return rv; } static inline u32 max31785_scale_pwm(u32 sensor_val) { /* * The datasheet describes the accepted value range for manual PWM as * [0, 0x2710], while the hwmon pwmX sysfs interface accepts values in * [0, 255]. The MAX31785 uses DIRECT mode to scale the FAN_COMMAND * registers and in PWM mode the coefficients are m=1, b=0, R=2. The * important observation here is that 0x2710 == 10000 == 100 * 100. * * R=2 (== 10^2 == 100) accounts for scaling the value provided at the * sysfs interface into the required hardware resolution, but it does * not yet yield a value that we can write to the device (this initial * scaling is handled by pmbus_data2reg()). Multiplying by 100 below * translates the parameter value into the percentage units required by * PMBus, and then we scale back by 255 as required by the hwmon pwmX * interface to yield the percentage value at the appropriate * resolution for hardware. */ return (sensor_val * 100) / 255; } static int max31785_pwm_enable(struct i2c_client *client, int page, u16 word) { int config = 0; int rate; switch (word) { case 0: rate = 0x7fff; break; case 1: rate = pmbus_get_fan_rate_cached(client, page, 0, percent); if (rate < 0) return rate; rate = max31785_scale_pwm(rate); break; case 2: config = PB_FAN_1_RPM; rate = pmbus_get_fan_rate_cached(client, page, 0, rpm); if (rate < 0) return rate; break; case 3: rate = 0xffff; break; default: return -EINVAL; } return pmbus_update_fan(client, page, 0, config, PB_FAN_1_RPM, rate); } static int max31785_write_word_data(struct i2c_client *client, int page, int reg, u16 word) { switch (reg) { case PMBUS_VIRT_PWM_1: return pmbus_update_fan(client, page, 0, 0, PB_FAN_1_RPM, max31785_scale_pwm(word)); case PMBUS_VIRT_PWM_ENABLE_1: return max31785_pwm_enable(client, page, word); default: break; } return -ENODATA; } #define MAX31785_FAN_FUNCS \ (PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12 | PMBUS_HAVE_PWM12) #define MAX31785_TEMP_FUNCS \ (PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP) #define MAX31785_VOUT_FUNCS \ (PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT) static const struct pmbus_driver_info max31785_info = { .pages = MAX31785_NR_PAGES, .write_word_data = max31785_write_word_data, .read_word_data = max31785_read_word_data, /* RPM */ .format[PSC_FAN] = direct, .m[PSC_FAN] = 1, .b[PSC_FAN] = 0, .R[PSC_FAN] = 0, /* PWM */ .format[PSC_PWM] = direct, .m[PSC_PWM] = 1, .b[PSC_PWM] = 0, .R[PSC_PWM] = 2, .func[0] = MAX31785_FAN_FUNCS, .func[1] = MAX31785_FAN_FUNCS, .func[2] = MAX31785_FAN_FUNCS, .func[3] = MAX31785_FAN_FUNCS, .func[4] = MAX31785_FAN_FUNCS, .func[5] = MAX31785_FAN_FUNCS, .format[PSC_TEMPERATURE] = direct, .m[PSC_TEMPERATURE] = 1, .b[PSC_TEMPERATURE] = 0, .R[PSC_TEMPERATURE] = 2, .func[6] = MAX31785_TEMP_FUNCS, .func[7] = MAX31785_TEMP_FUNCS, .func[8] = MAX31785_TEMP_FUNCS, .func[9] = MAX31785_TEMP_FUNCS, .func[10] = MAX31785_TEMP_FUNCS, .func[11] = MAX31785_TEMP_FUNCS, .func[12] = MAX31785_TEMP_FUNCS, .func[13] = MAX31785_TEMP_FUNCS, .func[14] = MAX31785_TEMP_FUNCS, .func[15] = MAX31785_TEMP_FUNCS, .func[16] = MAX31785_TEMP_FUNCS, .format[PSC_VOLTAGE_OUT] = direct, .m[PSC_VOLTAGE_OUT] = 1, .b[PSC_VOLTAGE_OUT] = 0, .R[PSC_VOLTAGE_OUT] = 0, .func[17] = MAX31785_VOUT_FUNCS, .func[18] = MAX31785_VOUT_FUNCS, .func[19] = MAX31785_VOUT_FUNCS, .func[20] = MAX31785_VOUT_FUNCS, .func[21] = MAX31785_VOUT_FUNCS, .func[22] = MAX31785_VOUT_FUNCS, }; static int max31785_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct device *dev = &client->dev; struct pmbus_driver_info *info; s64 ret; info = devm_kzalloc(dev, sizeof(struct pmbus_driver_info), GFP_KERNEL); if (!info) return -ENOMEM; *info = max31785_info; ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 255); if (ret < 0) return ret; return pmbus_do_probe(client, id, info); } static const struct i2c_device_id max31785_id[] = { { "max31785", 0 }, { "max31785a", 0 }, { }, }; MODULE_DEVICE_TABLE(i2c, max31785_id); static struct i2c_driver max31785_driver = { .driver = { .name = "max31785", }, .probe = max31785_probe, .remove = pmbus_do_remove, .id_table = max31785_id, }; module_i2c_driver(max31785_driver); MODULE_AUTHOR("Andrew Jeffery "); MODULE_DESCRIPTION("PMBus driver for the Maxim MAX31785"); MODULE_LICENSE("GPL");