1// SPDX-License-Identifier: GPL-2.0-or-later
2
3#include <linux/err.h>
4#include <linux/i2c.h>
5#include <linux/init.h>
6#include <linux/kernel.h>
7#include <linux/module.h>
8#include <linux/pmbus.h>
9#include "pmbus.h"
10
11/* LTC4286 register */
12#define LTC4286_MFR_CONFIG1 0xF2
13
14/* LTC4286 configuration */
15#define VRANGE_SELECT_BIT BIT(1)
16
17#define LTC4286_MFR_ID_SIZE 3
18
19/*
20 * Initialize the MBR as default settings which is referred to LTC4286 datasheet
21 * (March 22, 2022 version) table 3 page 16
22 */
23static struct pmbus_driver_info ltc4286_info = {
24 .pages = 1,
25 .format[PSC_VOLTAGE_IN] = direct,
26 .format[PSC_VOLTAGE_OUT] = direct,
27 .format[PSC_CURRENT_OUT] = direct,
28 .format[PSC_POWER] = direct,
29 .format[PSC_TEMPERATURE] = direct,
30 .m[PSC_VOLTAGE_IN] = 32,
31 .b[PSC_VOLTAGE_IN] = 0,
32 .R[PSC_VOLTAGE_IN] = 1,
33 .m[PSC_VOLTAGE_OUT] = 32,
34 .b[PSC_VOLTAGE_OUT] = 0,
35 .R[PSC_VOLTAGE_OUT] = 1,
36 .m[PSC_CURRENT_OUT] = 1024,
37 .b[PSC_CURRENT_OUT] = 0,
38 /*
39 * The rsense value used in MBR formula in LTC4286 datasheet should be ohm unit.
40 * However, the rsense value that user input is micro ohm.
41 * Thus, the MBR setting which involves rsense should be shifted by 6 digits.
42 */
43 .R[PSC_CURRENT_OUT] = 3 - 6,
44 .m[PSC_POWER] = 1,
45 .b[PSC_POWER] = 0,
46 /*
47 * The rsense value used in MBR formula in LTC4286 datasheet should be ohm unit.
48 * However, the rsense value that user input is micro ohm.
49 * Thus, the MBR setting which involves rsense should be shifted by 6 digits.
50 */
51 .R[PSC_POWER] = 4 - 6,
52 .m[PSC_TEMPERATURE] = 1,
53 .b[PSC_TEMPERATURE] = 273,
54 .R[PSC_TEMPERATURE] = 0,
55 .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
56 PMBUS_HAVE_PIN | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_VOUT |
57 PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_STATUS_TEMP,
58};
59
60static const struct i2c_device_id ltc4286_id[] = {
61 { "ltc4286", },
62 { "ltc4287", },
63 {}
64};
65MODULE_DEVICE_TABLE(i2c, ltc4286_id);
66
67static int ltc4286_probe(struct i2c_client *client)
68{
69 int ret;
70 const struct i2c_device_id *mid;
71 u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1];
72 struct pmbus_driver_info *info;
73 u32 rsense;
74 int vrange_nval, vrange_oval;
75
76 ret = i2c_smbus_read_block_data(client, command: PMBUS_MFR_ID, values: block_buffer);
77 if (ret < 0) {
78 return dev_err_probe(dev: &client->dev, err: ret,
79 fmt: "Failed to read manufacturer id\n");
80 }
81
82 /*
83 * Refer to ltc4286 datasheet page 20
84 * the manufacturer id is LTC
85 */
86 if (ret != LTC4286_MFR_ID_SIZE ||
87 strncmp(block_buffer, "LTC", LTC4286_MFR_ID_SIZE)) {
88 return dev_err_probe(dev: &client->dev, err: -ENODEV,
89 fmt: "Manufacturer id mismatch\n");
90 }
91
92 ret = i2c_smbus_read_block_data(client, command: PMBUS_MFR_MODEL, values: block_buffer);
93 if (ret < 0) {
94 return dev_err_probe(dev: &client->dev, err: ret,
95 fmt: "Failed to read manufacturer model\n");
96 }
97
98 for (mid = ltc4286_id; mid->name[0]; mid++) {
99 if (!strncasecmp(s1: mid->name, s2: block_buffer, strlen(mid->name)))
100 break;
101 }
102 if (!mid->name[0])
103 return dev_err_probe(dev: &client->dev, err: -ENODEV,
104 fmt: "Unsupported device\n");
105
106 if (of_property_read_u32(np: client->dev.of_node,
107 propname: "shunt-resistor-micro-ohms", out_value: &rsense))
108 rsense = 300; /* 0.3 mOhm if not set via DT */
109
110 if (rsense == 0)
111 return -EINVAL;
112
113 /* Check for the latter MBR value won't overflow */
114 if (rsense > (INT_MAX / 1024))
115 return -EINVAL;
116
117 info = devm_kmemdup(dev: &client->dev, src: &ltc4286_info, len: sizeof(*info),
118 GFP_KERNEL);
119 if (!info)
120 return -ENOMEM;
121
122 /* Check MFR1 CONFIG register bit 1 VRANGE_SELECT before driver loading */
123 vrange_oval = i2c_smbus_read_word_data(client, LTC4286_MFR_CONFIG1);
124 if (vrange_oval < 0)
125 return dev_err_probe(dev: &client->dev, err: vrange_oval,
126 fmt: "Failed to read manufacturer configuration one\n");
127 vrange_nval = vrange_oval;
128
129 if (device_property_read_bool(dev: &client->dev, propname: "adi,vrange-low-enable")) {
130 vrange_nval &=
131 ~VRANGE_SELECT_BIT; /* VRANGE_SELECT = 0, 25.6 volts */
132
133 info->m[PSC_VOLTAGE_IN] = 128;
134 info->m[PSC_VOLTAGE_OUT] = 128;
135 info->m[PSC_POWER] = 4 * rsense;
136 } else {
137 vrange_nval |=
138 VRANGE_SELECT_BIT; /* VRANGE_SELECT = 1, 102.4 volts */
139
140 info->m[PSC_POWER] = rsense;
141 }
142 if (vrange_nval != vrange_oval) {
143 /* Set MFR1 CONFIG register bit 1 VRANGE_SELECT */
144 ret = i2c_smbus_write_word_data(client, LTC4286_MFR_CONFIG1,
145 value: vrange_nval);
146 if (ret < 0)
147 return dev_err_probe(dev: &client->dev, err: ret,
148 fmt: "Failed to set vrange\n");
149 }
150
151 info->m[PSC_CURRENT_OUT] = 1024 * rsense;
152
153 return pmbus_do_probe(client, info);
154}
155
156static const struct of_device_id ltc4286_of_match[] = {
157 { .compatible = "lltc,ltc4286" },
158 { .compatible = "lltc,ltc4287" },
159 {}
160};
161
162static struct i2c_driver ltc4286_driver = {
163 .driver = {
164 .name = "ltc4286",
165 .of_match_table = ltc4286_of_match,
166 },
167 .probe = ltc4286_probe,
168 .id_table = ltc4286_id,
169};
170
171module_i2c_driver(ltc4286_driver);
172
173MODULE_AUTHOR("Delphine CC Chiu <Delphine_CC_Chiu@wiwynn.com>");
174MODULE_DESCRIPTION("PMBUS driver for LTC4286 and compatibles");
175MODULE_LICENSE("GPL");
176

source code of linux/drivers/hwmon/pmbus/ltc4286.c