1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * ADM1177 Hot Swap Controller and Digital Power Monitor with Soft Start Pin
4 *
5 * Copyright 2015-2019 Analog Devices Inc.
6 */
7
8 #include <linux/bits.h>
9 #include <linux/device.h>
10 #include <linux/hwmon.h>
11 #include <linux/i2c.h>
12 #include <linux/init.h>
13 #include <linux/module.h>
14 #include <linux/regulator/consumer.h>
15
16 /* Command Byte Operations */
17 #define ADM1177_CMD_V_CONT BIT(0)
18 #define ADM1177_CMD_I_CONT BIT(2)
19 #define ADM1177_CMD_VRANGE BIT(4)
20
21 /* Extended Register */
22 #define ADM1177_REG_ALERT_TH 2
23
24 #define ADM1177_BITS 12
25
26 /**
27 * struct adm1177_state - driver instance specific data
28 * @client: pointer to i2c client
29 * @r_sense_uohm: current sense resistor value
30 * @alert_threshold_ua: current limit for shutdown
31 * @vrange_high: internal voltage divider
32 */
33 struct adm1177_state {
34 struct i2c_client *client;
35 u32 r_sense_uohm;
36 u32 alert_threshold_ua;
37 bool vrange_high;
38 };
39
adm1177_read_raw(struct adm1177_state * st,u8 num,u8 * data)40 static int adm1177_read_raw(struct adm1177_state *st, u8 num, u8 *data)
41 {
42 return i2c_master_recv(st->client, data, num);
43 }
44
adm1177_write_cmd(struct adm1177_state * st,u8 cmd)45 static int adm1177_write_cmd(struct adm1177_state *st, u8 cmd)
46 {
47 return i2c_smbus_write_byte(st->client, cmd);
48 }
49
adm1177_write_alert_thr(struct adm1177_state * st,u32 alert_threshold_ua)50 static int adm1177_write_alert_thr(struct adm1177_state *st,
51 u32 alert_threshold_ua)
52 {
53 u64 val;
54 int ret;
55
56 val = 0xFFULL * alert_threshold_ua * st->r_sense_uohm;
57 val = div_u64(val, 105840000U);
58 val = div_u64(val, 1000U);
59 if (val > 0xFF)
60 val = 0xFF;
61
62 ret = i2c_smbus_write_byte_data(st->client, ADM1177_REG_ALERT_TH,
63 val);
64 if (ret)
65 return ret;
66
67 st->alert_threshold_ua = alert_threshold_ua;
68 return 0;
69 }
70
adm1177_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * val)71 static int adm1177_read(struct device *dev, enum hwmon_sensor_types type,
72 u32 attr, int channel, long *val)
73 {
74 struct adm1177_state *st = dev_get_drvdata(dev);
75 u8 data[3];
76 long dummy;
77 int ret;
78
79 switch (type) {
80 case hwmon_curr:
81 switch (attr) {
82 case hwmon_curr_input:
83 ret = adm1177_read_raw(st, 3, data);
84 if (ret < 0)
85 return ret;
86 dummy = (data[1] << 4) | (data[2] & 0xF);
87 /*
88 * convert to milliamperes
89 * ((105.84mV / 4096) x raw) / senseResistor(ohm)
90 */
91 *val = div_u64((105840000ull * dummy),
92 4096 * st->r_sense_uohm);
93 return 0;
94 case hwmon_curr_max_alarm:
95 *val = st->alert_threshold_ua;
96 return 0;
97 default:
98 return -EOPNOTSUPP;
99 }
100 case hwmon_in:
101 ret = adm1177_read_raw(st, 3, data);
102 if (ret < 0)
103 return ret;
104 dummy = (data[0] << 4) | (data[2] >> 4);
105 /*
106 * convert to millivolts based on resistor devision
107 * (V_fullscale / 4096) * raw
108 */
109 if (st->vrange_high)
110 dummy *= 26350;
111 else
112 dummy *= 6650;
113
114 *val = DIV_ROUND_CLOSEST(dummy, 4096);
115 return 0;
116 default:
117 return -EOPNOTSUPP;
118 }
119 }
120
adm1177_write(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long val)121 static int adm1177_write(struct device *dev, enum hwmon_sensor_types type,
122 u32 attr, int channel, long val)
123 {
124 struct adm1177_state *st = dev_get_drvdata(dev);
125
126 switch (type) {
127 case hwmon_curr:
128 switch (attr) {
129 case hwmon_curr_max_alarm:
130 adm1177_write_alert_thr(st, val);
131 return 0;
132 default:
133 return -EOPNOTSUPP;
134 }
135 default:
136 return -EOPNOTSUPP;
137 }
138 }
139
adm1177_is_visible(const void * data,enum hwmon_sensor_types type,u32 attr,int channel)140 static umode_t adm1177_is_visible(const void *data,
141 enum hwmon_sensor_types type,
142 u32 attr, int channel)
143 {
144 const struct adm1177_state *st = data;
145
146 switch (type) {
147 case hwmon_in:
148 switch (attr) {
149 case hwmon_in_input:
150 return 0444;
151 }
152 break;
153 case hwmon_curr:
154 switch (attr) {
155 case hwmon_curr_input:
156 if (st->r_sense_uohm)
157 return 0444;
158 return 0;
159 case hwmon_curr_max_alarm:
160 if (st->r_sense_uohm)
161 return 0644;
162 return 0;
163 }
164 break;
165 default:
166 break;
167 }
168 return 0;
169 }
170
171 static const struct hwmon_channel_info * const adm1177_info[] = {
172 HWMON_CHANNEL_INFO(curr,
173 HWMON_C_INPUT | HWMON_C_MAX_ALARM),
174 HWMON_CHANNEL_INFO(in,
175 HWMON_I_INPUT),
176 NULL
177 };
178
179 static const struct hwmon_ops adm1177_hwmon_ops = {
180 .is_visible = adm1177_is_visible,
181 .read = adm1177_read,
182 .write = adm1177_write,
183 };
184
185 static const struct hwmon_chip_info adm1177_chip_info = {
186 .ops = &adm1177_hwmon_ops,
187 .info = adm1177_info,
188 };
189
adm1177_probe(struct i2c_client * client)190 static int adm1177_probe(struct i2c_client *client)
191 {
192 struct device *dev = &client->dev;
193 struct device *hwmon_dev;
194 struct adm1177_state *st;
195 u32 alert_threshold_ua;
196 int ret;
197
198 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
199 if (!st)
200 return -ENOMEM;
201
202 st->client = client;
203
204 ret = devm_regulator_get_enable_optional(&client->dev, "vref");
205 if (ret == -EPROBE_DEFER)
206 return -EPROBE_DEFER;
207
208 if (device_property_read_u32(dev, "shunt-resistor-micro-ohms",
209 &st->r_sense_uohm))
210 st->r_sense_uohm = 0;
211 if (device_property_read_u32(dev, "adi,shutdown-threshold-microamp",
212 &alert_threshold_ua)) {
213 if (st->r_sense_uohm)
214 /*
215 * set maximum default value from datasheet based on
216 * shunt-resistor
217 */
218 alert_threshold_ua = div_u64(105840000000,
219 st->r_sense_uohm);
220 else
221 alert_threshold_ua = 0;
222 }
223 st->vrange_high = device_property_read_bool(dev,
224 "adi,vrange-high-enable");
225 if (alert_threshold_ua && st->r_sense_uohm)
226 adm1177_write_alert_thr(st, alert_threshold_ua);
227
228 ret = adm1177_write_cmd(st, ADM1177_CMD_V_CONT |
229 ADM1177_CMD_I_CONT |
230 (st->vrange_high ? 0 : ADM1177_CMD_VRANGE));
231 if (ret)
232 return ret;
233
234 hwmon_dev =
235 devm_hwmon_device_register_with_info(dev, client->name, st,
236 &adm1177_chip_info, NULL);
237 return PTR_ERR_OR_ZERO(hwmon_dev);
238 }
239
240 static const struct i2c_device_id adm1177_id[] = {
241 {"adm1177", 0},
242 {}
243 };
244 MODULE_DEVICE_TABLE(i2c, adm1177_id);
245
246 static const struct of_device_id adm1177_dt_ids[] = {
247 { .compatible = "adi,adm1177" },
248 {},
249 };
250 MODULE_DEVICE_TABLE(of, adm1177_dt_ids);
251
252 static struct i2c_driver adm1177_driver = {
253 .class = I2C_CLASS_HWMON,
254 .driver = {
255 .name = "adm1177",
256 .of_match_table = adm1177_dt_ids,
257 },
258 .probe = adm1177_probe,
259 .id_table = adm1177_id,
260 };
261 module_i2c_driver(adm1177_driver);
262
263 MODULE_AUTHOR("Beniamin Bia <beniamin.bia@analog.com>");
264 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
265 MODULE_DESCRIPTION("Analog Devices ADM1177 ADC driver");
266 MODULE_LICENSE("GPL v2");
267
