diff options
Diffstat (limited to 'drivers/hwmon/pmbus/max31785.c')
| -rw-r--r-- | drivers/hwmon/pmbus/max31785.c | 408 |
1 files changed, 408 insertions, 0 deletions
diff --git a/drivers/hwmon/pmbus/max31785.c b/drivers/hwmon/pmbus/max31785.c new file mode 100644 index 000000000..c9dc8799b --- /dev/null +++ b/drivers/hwmon/pmbus/max31785.c @@ -0,0 +1,408 @@ +/* + * 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 <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/err.h> +#include <linux/i2c.h> +#include "pmbus.h" + +enum max31785_regs { + MFR_REVISION = 0x9b, + MFR_FAN_CONFIG = 0xf1, +}; + +#define MAX31785 0x3030 +#define MAX31785A 0x3040 + +#define MFR_FAN_CONFIG_DUAL_TACH BIT(12) + +#define MAX31785_NR_PAGES 23 +#define MAX31785_NR_FAN_PAGES 6 + +static int max31785_read_byte_data(struct i2c_client *client, int page, + int reg) +{ + if (page < MAX31785_NR_PAGES) + return -ENODATA; + + switch (reg) { + case PMBUS_VOUT_MODE: + return -ENOTSUPP; + case PMBUS_FAN_CONFIG_12: + return pmbus_read_byte_data(client, page - MAX31785_NR_PAGES, + reg); + } + + return -ENODATA; +} + +static int max31785_write_byte(struct i2c_client *client, int page, u8 value) +{ + if (page < MAX31785_NR_PAGES) + return -ENODATA; + + return -ENOTSUPP; +} + +static int max31785_read_long_data(struct i2c_client *client, int page, + int reg, u32 *data) +{ + unsigned char cmdbuf[1]; + unsigned char rspbuf[4]; + int rc; + + struct i2c_msg msg[2] = { + { + .addr = client->addr, + .flags = 0, + .len = sizeof(cmdbuf), + .buf = cmdbuf, + }, + { + .addr = client->addr, + .flags = I2C_M_RD, + .len = sizeof(rspbuf), + .buf = rspbuf, + }, + }; + + cmdbuf[0] = reg; + + rc = pmbus_set_page(client, page); + if (rc < 0) + return rc; + + rc = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg)); + if (rc < 0) + return rc; + + *data = (rspbuf[0] << (0 * 8)) | (rspbuf[1] << (1 * 8)) | + (rspbuf[2] << (2 * 8)) | (rspbuf[3] << (3 * 8)); + + return rc; +} + +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) +{ + u32 val; + int rv; + + switch (reg) { + case PMBUS_READ_FAN_SPEED_1: + if (page < MAX31785_NR_PAGES) + return -ENODATA; + + rv = max31785_read_long_data(client, page - MAX31785_NR_PAGES, + reg, &val); + if (rv < 0) + return rv; + + rv = (val >> 16) & 0xffff; + break; + case PMBUS_FAN_COMMAND_1: + /* + * PMBUS_FAN_COMMAND_x is probed to judge whether or not to + * expose fan control registers. + * + * Don't expose fan_target attribute for virtual pages. + */ + rv = (page >= MAX31785_NR_PAGES) ? -ENOTSUPP : -ENODATA; + break; + 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) + +#define MAX37185_NUM_FAN_PAGES 6 + +static const struct pmbus_driver_info max31785_info = { + .pages = MAX31785_NR_PAGES, + + .write_word_data = max31785_write_word_data, + .read_byte_data = max31785_read_byte_data, + .read_word_data = max31785_read_word_data, + .write_byte = max31785_write_byte, + + /* 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_configure_dual_tach(struct i2c_client *client, + struct pmbus_driver_info *info) +{ + int ret; + int i; + + for (i = 0; i < MAX31785_NR_FAN_PAGES; i++) { + ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, i); + if (ret < 0) + return ret; + + ret = i2c_smbus_read_word_data(client, MFR_FAN_CONFIG); + if (ret < 0) + return ret; + + if (ret & MFR_FAN_CONFIG_DUAL_TACH) { + int virtual = MAX31785_NR_PAGES + i; + + info->pages = virtual + 1; + info->func[virtual] |= PMBUS_HAVE_FAN12; + info->func[virtual] |= PMBUS_PAGE_VIRTUAL; + } + } + + return 0; +} + +static int max31785_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct device *dev = &client->dev; + struct pmbus_driver_info *info; + bool dual_tach = false; + s64 ret; + + if (!i2c_check_functionality(client->adapter, + I2C_FUNC_SMBUS_BYTE_DATA | + I2C_FUNC_SMBUS_WORD_DATA)) + return -ENODEV; + + 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; + + ret = i2c_smbus_read_word_data(client, MFR_REVISION); + if (ret < 0) + return ret; + + if (ret == MAX31785A) { + dual_tach = true; + } else if (ret == MAX31785) { + if (!strcmp("max31785a", id->name)) + dev_warn(dev, "Expected max3175a, found max31785: cannot provide secondary tachometer readings\n"); + } else { + return -ENODEV; + } + + if (dual_tach) { + ret = max31785_configure_dual_tach(client, info); + 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 const struct of_device_id max31785_of_match[] = { + { .compatible = "maxim,max31785" }, + { .compatible = "maxim,max31785a" }, + { }, +}; + +MODULE_DEVICE_TABLE(of, max31785_of_match); + +static struct i2c_driver max31785_driver = { + .driver = { + .name = "max31785", + .of_match_table = max31785_of_match, + }, + .probe = max31785_probe, + .remove = pmbus_do_remove, + .id_table = max31785_id, +}; + +module_i2c_driver(max31785_driver); + +MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>"); +MODULE_DESCRIPTION("PMBus driver for the Maxim MAX31785"); +MODULE_LICENSE("GPL"); |