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 {}
29 };
30 MODULE_DEVICE_TABLE(i2c, max15301_id);
31
32 struct max15301_data {
33 int id;
34 struct pmbus_driver_info info;
35 };
36
37 #define to_max15301_data(x) container_of(x, struct max15301_data, info)
38
39 #define MAX15301_WAIT_TIME 100 /* us */
40
41 static ushort delay = MAX15301_WAIT_TIME;
42 module_param(delay, ushort, 0644);
43 MODULE_PARM_DESC(delay, "Delay between chip accesses in us");
44
45 static struct max15301_data max15301_data = {
46 .info = {
47 .pages = 1,
48 .func[0] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
49 | PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
50 | PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2
51 | PMBUS_HAVE_STATUS_TEMP
52 | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT,
53 }
54 };
55
max15301_probe(struct i2c_client * client)56 static int max15301_probe(struct i2c_client *client)
57 {
58 int status;
59 u8 device_id[I2C_SMBUS_BLOCK_MAX + 1];
60 const struct i2c_device_id *mid;
61 struct pmbus_driver_info *info = &max15301_data.info;
62
63 if (!i2c_check_functionality(client->adapter,
64 I2C_FUNC_SMBUS_READ_BYTE_DATA
65 | I2C_FUNC_SMBUS_BLOCK_DATA))
66 return -ENODEV;
67
68 status = i2c_smbus_read_block_data(client, PMBUS_IC_DEVICE_ID, device_id);
69 if (status < 0) {
70 dev_err(&client->dev, "Failed to read Device Id\n");
71 return status;
72 }
73 for (mid = max15301_id; mid->name[0]; mid++) {
74 if (!strncasecmp(mid->name, device_id, strlen(mid->name)))
75 break;
76 }
77 if (!mid->name[0]) {
78 dev_err(&client->dev, "Unsupported device\n");
79 return -ENODEV;
80 }
81
82 info->access_delay = delay;
83
84 return pmbus_do_probe(client, info);
85 }
86
87 static struct i2c_driver max15301_driver = {
88 .driver = {
89 .name = "max15301",
90 },
91 .probe = max15301_probe,
92 .id_table = max15301_id,
93 };
94
95 module_i2c_driver(max15301_driver);
96
97 MODULE_AUTHOR("Erik Rosen <erik.rosen@metormote.com>");
98 MODULE_DESCRIPTION("PMBus driver for Maxim MAX15301");
99 MODULE_LICENSE("GPL");
100 MODULE_IMPORT_NS(PMBUS);
101