1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Hardware monitoring driver for LTC3815
4 *
5 * Copyright (c) 2015 Linear Technology
6 * Copyright (c) 2015 Guenter Roeck
7 */
8
9#include <linux/err.h>
10#include <linux/i2c.h>
11#include <linux/init.h>
12#include <linux/jiffies.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include "pmbus.h"
16
17#define LTC3815_MFR_IOUT_PEAK	0xd7
18#define LTC3815_MFR_VOUT_PEAK	0xdd
19#define LTC3815_MFR_VIN_PEAK	0xde
20#define LTC3815_MFR_TEMP_PEAK	0xdf
21#define LTC3815_MFR_IIN_PEAK	0xe1
22#define LTC3815_MFR_SPECIAL_ID	0xe7
23
24#define LTC3815_ID		0x8000
25#define LTC3815_ID_MASK		0xff00
26
27static int ltc3815_read_byte_data(struct i2c_client *client, int page, int reg)
28{
29	int ret;
30
31	switch (reg) {
32	case PMBUS_VOUT_MODE:
33		/*
34		 * The chip returns 0x3e, suggesting VID mode with manufacturer
35		 * specific VID codes. Since the output voltage is reported
36		 * with a LSB of 0.5mV, override and report direct mode with
37		 * appropriate coefficients.
38		 */
39		ret = 0x40;
40		break;
41	default:
42		ret = -ENODATA;
43		break;
44	}
45	return ret;
46}
47
48static int ltc3815_write_byte(struct i2c_client *client, int page, u8 reg)
49{
50	int ret;
51
52	switch (reg) {
53	case PMBUS_CLEAR_FAULTS:
54		/*
55		 * LTC3815 does not support the CLEAR_FAULTS command.
56		 * Emulate it by clearing the status register.
57		 */
58		ret = pmbus_read_word_data(client, 0, 0xff, PMBUS_STATUS_WORD);
59		if (ret > 0) {
60			pmbus_write_word_data(client, 0, PMBUS_STATUS_WORD,
61					      ret);
62			ret = 0;
63		}
64		break;
65	default:
66		ret = -ENODATA;
67		break;
68	}
69	return ret;
70}
71
72static int ltc3815_read_word_data(struct i2c_client *client, int page,
73				  int phase, int reg)
74{
75	int ret;
76
77	switch (reg) {
78	case PMBUS_VIRT_READ_VIN_MAX:
79		ret = pmbus_read_word_data(client, page, phase,
80					   LTC3815_MFR_VIN_PEAK);
81		break;
82	case PMBUS_VIRT_READ_VOUT_MAX:
83		ret = pmbus_read_word_data(client, page, phase,
84					   LTC3815_MFR_VOUT_PEAK);
85		break;
86	case PMBUS_VIRT_READ_TEMP_MAX:
87		ret = pmbus_read_word_data(client, page, phase,
88					   LTC3815_MFR_TEMP_PEAK);
89		break;
90	case PMBUS_VIRT_READ_IOUT_MAX:
91		ret = pmbus_read_word_data(client, page, phase,
92					   LTC3815_MFR_IOUT_PEAK);
93		break;
94	case PMBUS_VIRT_READ_IIN_MAX:
95		ret = pmbus_read_word_data(client, page, phase,
96					   LTC3815_MFR_IIN_PEAK);
97		break;
98	case PMBUS_VIRT_RESET_VOUT_HISTORY:
99	case PMBUS_VIRT_RESET_VIN_HISTORY:
100	case PMBUS_VIRT_RESET_TEMP_HISTORY:
101	case PMBUS_VIRT_RESET_IOUT_HISTORY:
102	case PMBUS_VIRT_RESET_IIN_HISTORY:
103		ret = 0;
104		break;
105	default:
106		ret = -ENODATA;
107		break;
108	}
109	return ret;
110}
111
112static int ltc3815_write_word_data(struct i2c_client *client, int page,
113				   int reg, u16 word)
114{
115	int ret;
116
117	switch (reg) {
118	case PMBUS_VIRT_RESET_IIN_HISTORY:
119		ret = pmbus_write_word_data(client, page,
120					    LTC3815_MFR_IIN_PEAK, 0);
121		break;
122	case PMBUS_VIRT_RESET_IOUT_HISTORY:
123		ret = pmbus_write_word_data(client, page,
124					    LTC3815_MFR_IOUT_PEAK, 0);
125		break;
126	case PMBUS_VIRT_RESET_VOUT_HISTORY:
127		ret = pmbus_write_word_data(client, page,
128					    LTC3815_MFR_VOUT_PEAK, 0);
129		break;
130	case PMBUS_VIRT_RESET_VIN_HISTORY:
131		ret = pmbus_write_word_data(client, page,
132					    LTC3815_MFR_VIN_PEAK, 0);
133		break;
134	case PMBUS_VIRT_RESET_TEMP_HISTORY:
135		ret = pmbus_write_word_data(client, page,
136					    LTC3815_MFR_TEMP_PEAK, 0);
137		break;
138	default:
139		ret = -ENODATA;
140		break;
141	}
142	return ret;
143}
144
145static const struct i2c_device_id ltc3815_id[] = {
146	{"ltc3815", 0},
147	{ }
148};
149MODULE_DEVICE_TABLE(i2c, ltc3815_id);
150
151static struct pmbus_driver_info ltc3815_info = {
152	.pages = 1,
153	.format[PSC_VOLTAGE_IN] = direct,
154	.format[PSC_VOLTAGE_OUT] = direct,
155	.format[PSC_CURRENT_IN] = direct,
156	.format[PSC_CURRENT_OUT] = direct,
157	.format[PSC_TEMPERATURE] = direct,
158	.m[PSC_VOLTAGE_IN] = 250,
159	.b[PSC_VOLTAGE_IN] = 0,
160	.R[PSC_VOLTAGE_IN] = 0,
161	.m[PSC_VOLTAGE_OUT] = 2,
162	.b[PSC_VOLTAGE_OUT] = 0,
163	.R[PSC_VOLTAGE_OUT] = 3,
164	.m[PSC_CURRENT_IN] = 1,
165	.b[PSC_CURRENT_IN] = 0,
166	.R[PSC_CURRENT_IN] = 2,
167	.m[PSC_CURRENT_OUT] = 1,
168	.b[PSC_CURRENT_OUT] = 0,
169	.R[PSC_CURRENT_OUT] = 2,
170	.m[PSC_TEMPERATURE] = 1,
171	.b[PSC_TEMPERATURE] = 0,
172	.R[PSC_TEMPERATURE] = 0,
173	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN | PMBUS_HAVE_VOUT |
174		PMBUS_HAVE_IOUT | PMBUS_HAVE_TEMP,
175	.read_byte_data = ltc3815_read_byte_data,
176	.read_word_data = ltc3815_read_word_data,
177	.write_byte = ltc3815_write_byte,
178	.write_word_data = ltc3815_write_word_data,
179};
180
181static int ltc3815_probe(struct i2c_client *client)
182{
183	int chip_id;
184
185	if (!i2c_check_functionality(client->adapter,
186				     I2C_FUNC_SMBUS_READ_WORD_DATA))
187		return -ENODEV;
188
189	chip_id = i2c_smbus_read_word_data(client, LTC3815_MFR_SPECIAL_ID);
190	if (chip_id < 0)
191		return chip_id;
192	if ((chip_id & LTC3815_ID_MASK) != LTC3815_ID)
193		return -ENODEV;
194
195	return pmbus_do_probe(client, &ltc3815_info);
196}
197
198static struct i2c_driver ltc3815_driver = {
199	.driver = {
200		   .name = "ltc3815",
201		   },
202	.probe_new = ltc3815_probe,
203	.remove = pmbus_do_remove,
204	.id_table = ltc3815_id,
205};
206
207module_i2c_driver(ltc3815_driver);
208
209MODULE_AUTHOR("Guenter Roeck");
210MODULE_DESCRIPTION("PMBus driver for LTC3815");
211MODULE_LICENSE("GPL");
212