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1// SPDX-License-Identifier: GPL-2.02/*3 * Delta AHE-50DC power shelf fan control module driver4 *5 * Copyright 2021 Zev Weiss <zev@bewilderbeest.net>6 */7 8#include <linux/i2c.h>9#include <linux/kernel.h>10#include <linux/module.h>11#include <linux/pmbus.h>12 13#include "pmbus.h"14 15#define AHE50DC_PMBUS_READ_TEMP4 0xd016 17static int ahe50dc_fan_write_byte(struct i2c_client *client, int page, u8 value)18{19 /*20 * The CLEAR_FAULTS operation seems to sometimes (unpredictably, perhaps21 * 5% of the time or so) trigger a problematic phenomenon in which the22 * fan speeds surge momentarily and at least some (perhaps all?) of the23 * system's power outputs experience a glitch.24 *25 * However, according to Delta it should be OK to simply not send any26 * CLEAR_FAULTS commands (the device doesn't seem to be capable of27 * reporting any faults anyway), so just blackhole them unconditionally.28 */29 return value == PMBUS_CLEAR_FAULTS ? -EOPNOTSUPP : -ENODATA;30}31 32static int ahe50dc_fan_read_word_data(struct i2c_client *client, int page, int phase, int reg)33{34 /* temp1 in (virtual) page 1 is remapped to mfr-specific temp4 */35 if (page == 1) {36 if (reg == PMBUS_READ_TEMPERATURE_1)37 return i2c_smbus_read_word_data(client, AHE50DC_PMBUS_READ_TEMP4);38 return -EOPNOTSUPP;39 }40 41 /*42 * There's a fairly limited set of commands this device actually43 * supports, so here we block attempts to read anything else (which44 * return 0xffff and would cause confusion elsewhere).45 */46 switch (reg) {47 case PMBUS_STATUS_WORD:48 case PMBUS_FAN_COMMAND_1:49 case PMBUS_FAN_COMMAND_2:50 case PMBUS_FAN_COMMAND_3:51 case PMBUS_FAN_COMMAND_4:52 case PMBUS_STATUS_FAN_12:53 case PMBUS_STATUS_FAN_34:54 case PMBUS_READ_VIN:55 case PMBUS_READ_TEMPERATURE_1:56 case PMBUS_READ_TEMPERATURE_2:57 case PMBUS_READ_TEMPERATURE_3:58 case PMBUS_READ_FAN_SPEED_1:59 case PMBUS_READ_FAN_SPEED_2:60 case PMBUS_READ_FAN_SPEED_3:61 case PMBUS_READ_FAN_SPEED_4:62 return -ENODATA;63 default:64 return -EOPNOTSUPP;65 }66}67 68static struct pmbus_driver_info ahe50dc_fan_info = {69 .pages = 2,70 .format[PSC_FAN] = direct,71 .format[PSC_TEMPERATURE] = direct,72 .format[PSC_VOLTAGE_IN] = direct,73 .m[PSC_FAN] = 1,74 .b[PSC_FAN] = 0,75 .R[PSC_FAN] = 0,76 .m[PSC_TEMPERATURE] = 1,77 .b[PSC_TEMPERATURE] = 0,78 .R[PSC_TEMPERATURE] = 1,79 .m[PSC_VOLTAGE_IN] = 1,80 .b[PSC_VOLTAGE_IN] = 0,81 .R[PSC_VOLTAGE_IN] = 3,82 .func[0] = PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_TEMP3 |83 PMBUS_HAVE_VIN | PMBUS_HAVE_FAN12 | PMBUS_HAVE_FAN34 |84 PMBUS_HAVE_STATUS_FAN12 | PMBUS_HAVE_STATUS_FAN34 | PMBUS_PAGE_VIRTUAL,85 .func[1] = PMBUS_HAVE_TEMP | PMBUS_PAGE_VIRTUAL,86 .write_byte = ahe50dc_fan_write_byte,87 .read_word_data = ahe50dc_fan_read_word_data,88};89 90/*91 * CAPABILITY returns 0xff, which appears to be this device's way indicating92 * it doesn't support something (and if we enable I2C_CLIENT_PEC on seeing bit93 * 7 being set it generates bad PECs, so let's not go there).94 */95static struct pmbus_platform_data ahe50dc_fan_data = {96 .flags = PMBUS_NO_CAPABILITY,97};98 99static int ahe50dc_fan_probe(struct i2c_client *client)100{101 client->dev.platform_data = &ahe50dc_fan_data;102 return pmbus_do_probe(client, &ahe50dc_fan_info);103}104 105static const struct i2c_device_id ahe50dc_fan_id[] = {106 { "ahe50dc_fan" },107 { }108};109MODULE_DEVICE_TABLE(i2c, ahe50dc_fan_id);110 111static const struct of_device_id __maybe_unused ahe50dc_fan_of_match[] = {112 { .compatible = "delta,ahe50dc-fan" },113 { }114};115MODULE_DEVICE_TABLE(of, ahe50dc_fan_of_match);116 117static struct i2c_driver ahe50dc_fan_driver = {118 .driver = {119 .name = "ahe50dc_fan",120 .of_match_table = of_match_ptr(ahe50dc_fan_of_match),121 },122 .probe = ahe50dc_fan_probe,123 .id_table = ahe50dc_fan_id,124};125module_i2c_driver(ahe50dc_fan_driver);126 127MODULE_AUTHOR("Zev Weiss <zev@bewilderbeest.net>");128MODULE_DESCRIPTION("Driver for Delta AHE-50DC power shelf fan control module");129MODULE_LICENSE("GPL");130MODULE_IMPORT_NS(PMBUS);131