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08da09f028
CLEAR_FAULTS commands can apparently sometimes trigger catastrophic
power output glitches on the ahe-50dc, so block them from being sent
at all.
Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220427035109.3819-1-zev@bewilderbeest.net
Fixes: d387d88ed0 ("hwmon: (pmbus) Add Delta AHE-50DC fan control module driver")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
131 lines
3.8 KiB
C
131 lines
3.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Delta AHE-50DC power shelf fan control module driver
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*
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* Copyright 2021 Zev Weiss <zev@bewilderbeest.net>
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*/
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#include <linux/i2c.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/pmbus.h>
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#include "pmbus.h"
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#define AHE50DC_PMBUS_READ_TEMP4 0xd0
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static int ahe50dc_fan_write_byte(struct i2c_client *client, int page, u8 value)
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{
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/*
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* The CLEAR_FAULTS operation seems to sometimes (unpredictably, perhaps
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* 5% of the time or so) trigger a problematic phenomenon in which the
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* fan speeds surge momentarily and at least some (perhaps all?) of the
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* system's power outputs experience a glitch.
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*
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* However, according to Delta it should be OK to simply not send any
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* CLEAR_FAULTS commands (the device doesn't seem to be capable of
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* reporting any faults anyway), so just blackhole them unconditionally.
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*/
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return value == PMBUS_CLEAR_FAULTS ? -EOPNOTSUPP : -ENODATA;
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}
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static int ahe50dc_fan_read_word_data(struct i2c_client *client, int page, int phase, int reg)
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{
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/* temp1 in (virtual) page 1 is remapped to mfr-specific temp4 */
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if (page == 1) {
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if (reg == PMBUS_READ_TEMPERATURE_1)
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return i2c_smbus_read_word_data(client, AHE50DC_PMBUS_READ_TEMP4);
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return -EOPNOTSUPP;
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}
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/*
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* There's a fairly limited set of commands this device actually
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* supports, so here we block attempts to read anything else (which
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* return 0xffff and would cause confusion elsewhere).
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*/
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switch (reg) {
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case PMBUS_STATUS_WORD:
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case PMBUS_FAN_COMMAND_1:
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case PMBUS_FAN_COMMAND_2:
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case PMBUS_FAN_COMMAND_3:
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case PMBUS_FAN_COMMAND_4:
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case PMBUS_STATUS_FAN_12:
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case PMBUS_STATUS_FAN_34:
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case PMBUS_READ_VIN:
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case PMBUS_READ_TEMPERATURE_1:
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case PMBUS_READ_TEMPERATURE_2:
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case PMBUS_READ_TEMPERATURE_3:
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case PMBUS_READ_FAN_SPEED_1:
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case PMBUS_READ_FAN_SPEED_2:
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case PMBUS_READ_FAN_SPEED_3:
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case PMBUS_READ_FAN_SPEED_4:
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return -ENODATA;
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default:
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return -EOPNOTSUPP;
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}
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}
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static struct pmbus_driver_info ahe50dc_fan_info = {
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.pages = 2,
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.format[PSC_FAN] = direct,
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.format[PSC_TEMPERATURE] = direct,
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.format[PSC_VOLTAGE_IN] = direct,
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.m[PSC_FAN] = 1,
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.b[PSC_FAN] = 0,
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.R[PSC_FAN] = 0,
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.m[PSC_TEMPERATURE] = 1,
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.b[PSC_TEMPERATURE] = 0,
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.R[PSC_TEMPERATURE] = 1,
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.m[PSC_VOLTAGE_IN] = 1,
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.b[PSC_VOLTAGE_IN] = 0,
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.R[PSC_VOLTAGE_IN] = 3,
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.func[0] = PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_TEMP3 |
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PMBUS_HAVE_VIN | PMBUS_HAVE_FAN12 | PMBUS_HAVE_FAN34 |
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PMBUS_HAVE_STATUS_FAN12 | PMBUS_HAVE_STATUS_FAN34 | PMBUS_PAGE_VIRTUAL,
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.func[1] = PMBUS_HAVE_TEMP | PMBUS_PAGE_VIRTUAL,
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.write_byte = ahe50dc_fan_write_byte,
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.read_word_data = ahe50dc_fan_read_word_data,
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};
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/*
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* CAPABILITY returns 0xff, which appears to be this device's way indicating
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* it doesn't support something (and if we enable I2C_CLIENT_PEC on seeing bit
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* 7 being set it generates bad PECs, so let's not go there).
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*/
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static struct pmbus_platform_data ahe50dc_fan_data = {
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.flags = PMBUS_NO_CAPABILITY,
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};
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static int ahe50dc_fan_probe(struct i2c_client *client)
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{
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client->dev.platform_data = &ahe50dc_fan_data;
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return pmbus_do_probe(client, &ahe50dc_fan_info);
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}
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static const struct i2c_device_id ahe50dc_fan_id[] = {
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{ "ahe50dc_fan" },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, ahe50dc_fan_id);
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static const struct of_device_id __maybe_unused ahe50dc_fan_of_match[] = {
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{ .compatible = "delta,ahe50dc-fan" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, ahe50dc_fan_of_match);
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static struct i2c_driver ahe50dc_fan_driver = {
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.driver = {
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.name = "ahe50dc_fan",
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.of_match_table = of_match_ptr(ahe50dc_fan_of_match),
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},
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.probe_new = ahe50dc_fan_probe,
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.id_table = ahe50dc_fan_id,
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};
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module_i2c_driver(ahe50dc_fan_driver);
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MODULE_AUTHOR("Zev Weiss <zev@bewilderbeest.net>");
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MODULE_DESCRIPTION("Driver for Delta AHE-50DC power shelf fan control module");
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MODULE_LICENSE("GPL");
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MODULE_IMPORT_NS(PMBUS);
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