1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Delta AHE-50DC power shelf fan control module driver |
4 | * |
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 0xd0 |
16 | |
17 | static int ahe50dc_fan_write_byte(struct i2c_client *client, int page, u8 value) |
18 | { |
19 | /* |
20 | * The CLEAR_FAULTS operation seems to sometimes (unpredictably, perhaps |
21 | * 5% of the time or so) trigger a problematic phenomenon in which the |
22 | * fan speeds surge momentarily and at least some (perhaps all?) of the |
23 | * system's power outputs experience a glitch. |
24 | * |
25 | * However, according to Delta it should be OK to simply not send any |
26 | * CLEAR_FAULTS commands (the device doesn't seem to be capable of |
27 | * reporting any faults anyway), so just blackhole them unconditionally. |
28 | */ |
29 | return value == PMBUS_CLEAR_FAULTS ? -EOPNOTSUPP : -ENODATA; |
30 | } |
31 | |
32 | static 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 actually |
43 | * supports, so here we block attempts to read anything else (which |
44 | * 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 | |
68 | static 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 indicating |
92 | * it doesn't support something (and if we enable I2C_CLIENT_PEC on seeing bit |
93 | * 7 being set it generates bad PECs, so let's not go there). |
94 | */ |
95 | static struct pmbus_platform_data ahe50dc_fan_data = { |
96 | .flags = PMBUS_NO_CAPABILITY, |
97 | }; |
98 | |
99 | static int ahe50dc_fan_probe(struct i2c_client *client) |
100 | { |
101 | client->dev.platform_data = &ahe50dc_fan_data; |
102 | return pmbus_do_probe(client, info: &ahe50dc_fan_info); |
103 | } |
104 | |
105 | static const struct i2c_device_id ahe50dc_fan_id[] = { |
106 | { "ahe50dc_fan" }, |
107 | { } |
108 | }; |
109 | MODULE_DEVICE_TABLE(i2c, ahe50dc_fan_id); |
110 | |
111 | static const struct of_device_id __maybe_unused ahe50dc_fan_of_match[] = { |
112 | { .compatible = "delta,ahe50dc-fan" }, |
113 | { } |
114 | }; |
115 | MODULE_DEVICE_TABLE(of, ahe50dc_fan_of_match); |
116 | |
117 | static 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 | }; |
125 | module_i2c_driver(ahe50dc_fan_driver); |
126 | |
127 | MODULE_AUTHOR("Zev Weiss <zev@bewilderbeest.net>" ); |
128 | MODULE_DESCRIPTION("Driver for Delta AHE-50DC power shelf fan control module" ); |
129 | MODULE_LICENSE("GPL" ); |
130 | MODULE_IMPORT_NS(PMBUS); |
131 | |