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/math64.h>
14 #include <linux/minmax.h>
15 #include <linux/module.h>
16 #include <linux/regulator/consumer.h>
17
18 /* Command Byte Operations */
19 #define ADM1177_CMD_V_CONT BIT(0)
20 #define ADM1177_CMD_I_CONT BIT(2)
21 #define ADM1177_CMD_VRANGE BIT(4)
22
23 /* Extended Register */
24 #define ADM1177_REG_ALERT_TH 2
25
26 #define ADM1177_BITS 12
27
28 /**
29 * struct adm1177_state - driver instance specific data
30 * @client: pointer to i2c client
31 * @r_sense_uohm: current sense resistor value
32 * @alert_threshold_ua: current limit for shutdown
33 * @vrange_high: internal voltage divider
34 */
35 struct adm1177_state {
36 struct i2c_client *client;
37 u32 r_sense_uohm;
38 u64 alert_threshold_ua;
39 bool vrange_high;
40 };
41
adm1177_read_raw(struct adm1177_state * st,u8 num,u8 * data)42 static int adm1177_read_raw(struct adm1177_state *st, u8 num, u8 *data)
43 {
44 return i2c_master_recv(st->client, data, num);
45 }
46
adm1177_write_cmd(struct adm1177_state * st,u8 cmd)47 static int adm1177_write_cmd(struct adm1177_state *st, u8 cmd)
48 {
49 return i2c_smbus_write_byte(st->client, cmd);
50 }
51
adm1177_write_alert_thr(struct adm1177_state * st,u64 alert_threshold_ua)52 static int adm1177_write_alert_thr(struct adm1177_state *st,
53 u64 alert_threshold_ua)
54 {
55 u64 val;
56 int ret;
57
58 val = 0xFFULL * alert_threshold_ua * st->r_sense_uohm;
59 val = div_u64(val, 105840000U);
60 val = div_u64(val, 1000U);
61 if (val > 0xFF)
62 val = 0xFF;
63
64 ret = i2c_smbus_write_byte_data(st->client, ADM1177_REG_ALERT_TH,
65 val);
66 if (ret)
67 return ret;
68
69 st->alert_threshold_ua = alert_threshold_ua;
70 return 0;
71 }
72
adm1177_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * val)73 static int adm1177_read(struct device *dev, enum hwmon_sensor_types type,
74 u32 attr, int channel, long *val)
75 {
76 struct adm1177_state *st = dev_get_drvdata(dev);
77 u8 data[3];
78 long dummy;
79 int ret;
80
81 switch (type) {
82 case hwmon_curr:
83 switch (attr) {
84 case hwmon_curr_input:
85 ret = adm1177_read_raw(st, 3, data);
86 if (ret < 0)
87 return ret;
88 dummy = (data[1] << 4) | (data[2] & 0xF);
89 /*
90 * convert to milliamperes
91 * ((105.84mV / 4096) x raw) / senseResistor(ohm)
92 */
93 *val = div_u64((105840000ull * dummy),
94 4096 * st->r_sense_uohm);
95 return 0;
96 case hwmon_curr_max:
97 *val = div_u64(st->alert_threshold_ua, 1000);
98 return 0;
99 default:
100 return -EOPNOTSUPP;
101 }
102 case hwmon_in:
103 ret = adm1177_read_raw(st, 3, data);
104 if (ret < 0)
105 return ret;
106 dummy = (data[0] << 4) | (data[2] >> 4);
107 /*
108 * convert to millivolts based on resistor devision
109 * (V_fullscale / 4096) * raw
110 */
111 if (st->vrange_high)
112 dummy *= 26350;
113 else
114 dummy *= 6650;
115
116 *val = DIV_ROUND_CLOSEST(dummy, 4096);
117 return 0;
118 default:
119 return -EOPNOTSUPP;
120 }
121 }
122
adm1177_write(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long val)123 static int adm1177_write(struct device *dev, enum hwmon_sensor_types type,
124 u32 attr, int channel, long val)
125 {
126 struct adm1177_state *st = dev_get_drvdata(dev);
127
128 switch (type) {
129 case hwmon_curr:
130 switch (attr) {
131 case hwmon_curr_max:
132 val = clamp_val(val, 0,
133 div_u64(105840000ULL, st->r_sense_uohm));
134 return adm1177_write_alert_thr(st, (u64)val * 1000);
135 default:
136 return -EOPNOTSUPP;
137 }
138 default:
139 return -EOPNOTSUPP;
140 }
141 }
142
adm1177_is_visible(const void * data,enum hwmon_sensor_types type,u32 attr,int channel)143 static umode_t adm1177_is_visible(const void *data,
144 enum hwmon_sensor_types type,
145 u32 attr, int channel)
146 {
147 const struct adm1177_state *st = data;
148
149 switch (type) {
150 case hwmon_in:
151 switch (attr) {
152 case hwmon_in_input:
153 return 0444;
154 }
155 break;
156 case hwmon_curr:
157 switch (attr) {
158 case hwmon_curr_input:
159 if (st->r_sense_uohm)
160 return 0444;
161 return 0;
162 case hwmon_curr_max:
163 if (st->r_sense_uohm)
164 return 0644;
165 return 0;
166 }
167 break;
168 default:
169 break;
170 }
171 return 0;
172 }
173
174 static const struct hwmon_channel_info * const adm1177_info[] = {
175 HWMON_CHANNEL_INFO(curr,
176 HWMON_C_INPUT | HWMON_C_MAX),
177 HWMON_CHANNEL_INFO(in,
178 HWMON_I_INPUT),
179 NULL
180 };
181
182 static const struct hwmon_ops adm1177_hwmon_ops = {
183 .is_visible = adm1177_is_visible,
184 .read = adm1177_read,
185 .write = adm1177_write,
186 };
187
188 static const struct hwmon_chip_info adm1177_chip_info = {
189 .ops = &adm1177_hwmon_ops,
190 .info = adm1177_info,
191 };
192
adm1177_probe(struct i2c_client * client)193 static int adm1177_probe(struct i2c_client *client)
194 {
195 struct device *dev = &client->dev;
196 struct device *hwmon_dev;
197 struct adm1177_state *st;
198 u64 alert_threshold_ua;
199 u32 prop;
200 int ret;
201
202 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
203 if (!st)
204 return -ENOMEM;
205
206 st->client = client;
207
208 ret = devm_regulator_get_enable_optional(&client->dev, "vref");
209 if (ret == -EPROBE_DEFER)
210 return -EPROBE_DEFER;
211
212 if (device_property_read_u32(dev, "shunt-resistor-micro-ohms",
213 &st->r_sense_uohm))
214 st->r_sense_uohm = 0;
215 if (!device_property_read_u32(dev, "adi,shutdown-threshold-microamp",
216 &prop)) {
217 alert_threshold_ua = prop;
218 } else if (st->r_sense_uohm) {
219 /*
220 * set maximum default value from datasheet based on
221 * shunt-resistor
222 */
223 alert_threshold_ua = div_u64(105840000000ULL,
224 st->r_sense_uohm);
225 } else {
226 alert_threshold_ua = 0;
227 }
228 st->vrange_high = device_property_read_bool(dev,
229 "adi,vrange-high-enable");
230 if (alert_threshold_ua && st->r_sense_uohm) {
231 ret = adm1177_write_alert_thr(st, alert_threshold_ua);
232 if (ret)
233 return ret;
234 }
235
236 ret = adm1177_write_cmd(st, ADM1177_CMD_V_CONT |
237 ADM1177_CMD_I_CONT |
238 (st->vrange_high ? 0 : ADM1177_CMD_VRANGE));
239 if (ret)
240 return ret;
241
242 hwmon_dev =
243 devm_hwmon_device_register_with_info(dev, client->name, st,
244 &adm1177_chip_info, NULL);
245 return PTR_ERR_OR_ZERO(hwmon_dev);
246 }
247
248 static const struct i2c_device_id adm1177_id[] = {
249 {"adm1177"},
250 {}
251 };
252 MODULE_DEVICE_TABLE(i2c, adm1177_id);
253
254 static const struct of_device_id adm1177_dt_ids[] = {
255 { .compatible = "adi,adm1177" },
256 {},
257 };
258 MODULE_DEVICE_TABLE(of, adm1177_dt_ids);
259
260 static struct i2c_driver adm1177_driver = {
261 .driver = {
262 .name = "adm1177",
263 .of_match_table = adm1177_dt_ids,
264 },
265 .probe = adm1177_probe,
266 .id_table = adm1177_id,
267 };
268 module_i2c_driver(adm1177_driver);
269
270 MODULE_AUTHOR("Beniamin Bia <beniamin.bia@analog.com>");
271 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
272 MODULE_DESCRIPTION("Analog Devices ADM1177 ADC driver");
273 MODULE_LICENSE("GPL v2");
274