1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Hardware monitoring driver for Analog Devices LT7182S
4  *
5  * Copyright (c) 2022 Guenter Roeck
6  *
7  */
8 
9 #include <linux/bits.h>
10 #include <linux/err.h>
11 #include <linux/i2c.h>
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16 #include "pmbus.h"
17 
18 #define LT7182S_NUM_PAGES	2
19 
20 #define MFR_READ_EXTVCC		0xcd
21 #define MFR_READ_ITH		0xce
22 #define MFR_CONFIG_ALL_LT7182S	0xd1
23 #define MFR_IOUT_PEAK		0xd7
24 #define MFR_ADC_CONTROL_LT7182S 0xd8
25 
26 #define MFR_DEBUG_TELEMETRY	BIT(0)
27 
28 #define MFR_VOUT_PEAK		0xdd
29 #define MFR_VIN_PEAK		0xde
30 #define MFR_TEMPERATURE_1_PEAK	0xdf
31 #define MFR_CLEAR_PEAKS		0xe3
32 
33 #define MFR_CONFIG_IEEE		BIT(8)
34 
lt7182s_read_word_data(struct i2c_client * client,int page,int phase,int reg)35 static int lt7182s_read_word_data(struct i2c_client *client, int page, int phase, int reg)
36 {
37 	int ret;
38 
39 	switch (reg) {
40 	case PMBUS_VIRT_READ_VMON:
41 		if (page == 0 || page == 1)
42 			ret = pmbus_read_word_data(client, page, phase, MFR_READ_ITH);
43 		else
44 			ret = pmbus_read_word_data(client, 0, phase, MFR_READ_EXTVCC);
45 		break;
46 	case PMBUS_VIRT_READ_IOUT_MAX:
47 		ret = pmbus_read_word_data(client, page, phase, MFR_IOUT_PEAK);
48 		break;
49 	case PMBUS_VIRT_READ_VOUT_MAX:
50 		ret = pmbus_read_word_data(client, page, phase, MFR_VOUT_PEAK);
51 		break;
52 	case PMBUS_VIRT_READ_VIN_MAX:
53 		ret = pmbus_read_word_data(client, page, phase, MFR_VIN_PEAK);
54 		break;
55 	case PMBUS_VIRT_READ_TEMP_MAX:
56 		ret = pmbus_read_word_data(client, page, phase, MFR_TEMPERATURE_1_PEAK);
57 		break;
58 	case PMBUS_VIRT_RESET_VIN_HISTORY:
59 		ret = (page == 0) ? 0 : -ENODATA;
60 		break;
61 	default:
62 		ret = -ENODATA;
63 		break;
64 	}
65 	return ret;
66 }
67 
lt7182s_write_word_data(struct i2c_client * client,int page,int reg,u16 word)68 static int lt7182s_write_word_data(struct i2c_client *client, int page, int reg, u16 word)
69 {
70 	int ret;
71 
72 	switch (reg) {
73 	case PMBUS_VIRT_RESET_VIN_HISTORY:
74 		ret = pmbus_write_byte(client, 0, MFR_CLEAR_PEAKS);
75 		break;
76 	default:
77 		ret = -ENODATA;
78 		break;
79 	}
80 	return ret;
81 }
82 
83 static struct pmbus_driver_info lt7182s_info = {
84 	.pages = LT7182S_NUM_PAGES,
85 	.format[PSC_VOLTAGE_IN] = linear,
86 	.format[PSC_VOLTAGE_OUT] = linear,
87 	.format[PSC_CURRENT_IN] = linear,
88 	.format[PSC_CURRENT_OUT] = linear,
89 	.format[PSC_TEMPERATURE] = linear,
90 	.format[PSC_POWER] = linear,
91 	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT |
92 	  PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT | PMBUS_HAVE_POUT |
93 	  PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_STATUS_IOUT |
94 	  PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_STATUS_TEMP,
95 	.func[1] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT |
96 	  PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT | PMBUS_HAVE_POUT |
97 	  PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_STATUS_IOUT |
98 	  PMBUS_HAVE_STATUS_INPUT,
99 	.read_word_data = lt7182s_read_word_data,
100 	.write_word_data = lt7182s_write_word_data,
101 };
102 
lt7182s_probe(struct i2c_client * client)103 static int lt7182s_probe(struct i2c_client *client)
104 {
105 	struct device *dev = &client->dev;
106 	struct pmbus_driver_info *info;
107 	u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
108 	int ret;
109 
110 	if (!i2c_check_functionality(client->adapter,
111 				     I2C_FUNC_SMBUS_READ_BYTE_DATA |
112 				     I2C_FUNC_SMBUS_READ_WORD_DATA |
113 				     I2C_FUNC_SMBUS_READ_BLOCK_DATA))
114 		return -ENODEV;
115 
116 	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, buf);
117 	if (ret < 0) {
118 		dev_err(dev, "Failed to read PMBUS_MFR_ID\n");
119 		return ret;
120 	}
121 	if (ret != 3 || strncmp(buf, "ADI", 3)) {
122 		buf[ret] = '\0';
123 		dev_err(dev, "Manufacturer '%s' not supported\n", buf);
124 		return -ENODEV;
125 	}
126 
127 	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
128 	if (ret < 0) {
129 		dev_err(dev, "Failed to read PMBUS_MFR_MODEL\n");
130 		return ret;
131 	}
132 	if (ret != 7 || strncmp(buf, "LT7182S", 7)) {
133 		buf[ret] = '\0';
134 		dev_err(dev, "Model '%s' not supported\n", buf);
135 		return -ENODEV;
136 	}
137 
138 	info = devm_kmemdup(dev, &lt7182s_info,
139 			    sizeof(struct pmbus_driver_info), GFP_KERNEL);
140 	if (!info)
141 		return -ENOMEM;
142 
143 	/* Set data format to IEEE754 if configured */
144 	ret = i2c_smbus_read_word_data(client, MFR_CONFIG_ALL_LT7182S);
145 	if (ret < 0)
146 		return ret;
147 	if (ret & MFR_CONFIG_IEEE) {
148 		info->format[PSC_VOLTAGE_IN] = ieee754;
149 		info->format[PSC_VOLTAGE_OUT] = ieee754;
150 		info->format[PSC_CURRENT_IN] = ieee754;
151 		info->format[PSC_CURRENT_OUT] = ieee754;
152 		info->format[PSC_TEMPERATURE] = ieee754;
153 		info->format[PSC_POWER] = ieee754;
154 	}
155 
156 	/* Enable VMON output if configured */
157 	ret = i2c_smbus_read_byte_data(client, MFR_ADC_CONTROL_LT7182S);
158 	if (ret < 0)
159 		return ret;
160 	if (ret & MFR_DEBUG_TELEMETRY) {
161 		info->pages = 3;
162 		info->func[0] |= PMBUS_HAVE_VMON;
163 		info->func[1] |= PMBUS_HAVE_VMON;
164 		info->func[2] = PMBUS_HAVE_VMON;
165 	}
166 
167 	return pmbus_do_probe(client, info);
168 }
169 
170 static const struct i2c_device_id lt7182s_id[] = {
171 	{ "lt7182s", 0 },
172 	{}
173 };
174 MODULE_DEVICE_TABLE(i2c, lt7182s_id);
175 
176 static const struct of_device_id __maybe_unused lt7182s_of_match[] = {
177 	{ .compatible = "adi,lt7182s" },
178 	{}
179 };
180 
181 static struct i2c_driver lt7182s_driver = {
182 	.driver = {
183 		.name = "lt7182s",
184 		.of_match_table = of_match_ptr(lt7182s_of_match),
185 	},
186 	.probe_new = lt7182s_probe,
187 	.id_table = lt7182s_id,
188 };
189 
190 module_i2c_driver(lt7182s_driver);
191 
192 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
193 MODULE_DESCRIPTION("PMBus driver for Analog Devices LT7182S");
194 MODULE_LICENSE("GPL");
195 MODULE_IMPORT_NS(PMBUS);
196