1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Hardware monitoring driver for Maxim MAX15301
4 *
5 * Copyright (c) 2021 Flextronics International Sweden AB
6 *
7 * Even though the specification does not specifically mention it,
8 * extensive empirical testing has revealed that auto-detection of
9 * limit-registers will fail in a random fashion unless the delay
10 * parameter is set to above about 80us. The default delay is set
11 * to 100us to include some safety margin.
12 */
13
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/err.h>
18 #include <linux/slab.h>
19 #include <linux/i2c.h>
20 #include <linux/ktime.h>
21 #include <linux/delay.h>
22 #include <linux/pmbus.h>
23 #include "pmbus.h"
24
25 static const struct i2c_device_id max15301_id[] = {
26 { "bmr461" },
27 { "max15301" },
28 { "max15303" },
29 {}
30 };
31 MODULE_DEVICE_TABLE(i2c, max15301_id);
32
33 struct max15301_data {
34 int id;
35 struct pmbus_driver_info info;
36 };
37
38 #define to_max15301_data(x) container_of(x, struct max15301_data, info)
39
40 #define MAX15301_WAIT_TIME 100 /* us */
41
42 static ushort delay = MAX15301_WAIT_TIME;
43 module_param(delay, ushort, 0644);
44 MODULE_PARM_DESC(delay, "Delay between chip accesses in us");
45
46 static struct max15301_data max15301_data = {
47 .info = {
48 .pages = 1,
49 .func[0] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
50 | PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
51 | PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2
52 | PMBUS_HAVE_STATUS_TEMP
53 | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT,
54 }
55 };
56
max15301_probe(struct i2c_client * client)57 static int max15301_probe(struct i2c_client *client)
58 {
59 int status;
60 u8 device_id[I2C_SMBUS_BLOCK_MAX + 1];
61 const struct i2c_device_id *mid;
62 struct pmbus_driver_info *info = &max15301_data.info;
63
64 if (!i2c_check_functionality(client->adapter,
65 I2C_FUNC_SMBUS_READ_BYTE_DATA
66 | I2C_FUNC_SMBUS_BLOCK_DATA))
67 return -ENODEV;
68
69 status = i2c_smbus_read_block_data(client, PMBUS_IC_DEVICE_ID, device_id);
70 if (status < 0) {
71 dev_err(&client->dev, "Failed to read Device Id\n");
72 return status;
73 }
74 for (mid = max15301_id; mid->name[0]; mid++) {
75 if (!strncasecmp(mid->name, device_id, strlen(mid->name)))
76 break;
77 }
78 if (!mid->name[0]) {
79 dev_err(&client->dev, "Unsupported device\n");
80 return -ENODEV;
81 }
82
83 info->access_delay = delay;
84
85 return pmbus_do_probe(client, info);
86 }
87
88 static struct i2c_driver max15301_driver = {
89 .driver = {
90 .name = "max15301",
91 },
92 .probe = max15301_probe,
93 .id_table = max15301_id,
94 };
95
96 module_i2c_driver(max15301_driver);
97
98 MODULE_AUTHOR("Erik Rosen <erik.rosen@metormote.com>");
99 MODULE_DESCRIPTION("PMBus driver for Maxim MAX15301");
100 MODULE_LICENSE("GPL");
101 MODULE_IMPORT_NS("PMBUS");
102