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  * @reg:		regulator info for the power supply of the device
30  * @r_sense_uohm:	current sense resistor value
31  * @alert_threshold_ua:	current limit for shutdown
32  * @vrange_high:	internal voltage divider
33  */
34 struct adm1177_state {
35 	struct i2c_client	*client;
36 	struct regulator	*reg;
37 	u32			r_sense_uohm;
38 	u32			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,u32 alert_threshold_ua)52 static int adm1177_write_alert_thr(struct adm1177_state *st,
53 				   u32 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_alarm:
97 			*val = st->alert_threshold_ua;
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_alarm:
132 			adm1177_write_alert_thr(st, val);
133 			return 0;
134 		default:
135 			return -EOPNOTSUPP;
136 		}
137 	default:
138 		return -EOPNOTSUPP;
139 	}
140 }
141 
adm1177_is_visible(const void * data,enum hwmon_sensor_types type,u32 attr,int channel)142 static umode_t adm1177_is_visible(const void *data,
143 				  enum hwmon_sensor_types type,
144 				  u32 attr, int channel)
145 {
146 	const struct adm1177_state *st = data;
147 
148 	switch (type) {
149 	case hwmon_in:
150 		switch (attr) {
151 		case hwmon_in_input:
152 			return 0444;
153 		}
154 		break;
155 	case hwmon_curr:
156 		switch (attr) {
157 		case hwmon_curr_input:
158 			if (st->r_sense_uohm)
159 				return 0444;
160 			return 0;
161 		case hwmon_curr_max_alarm:
162 			if (st->r_sense_uohm)
163 				return 0644;
164 			return 0;
165 		}
166 		break;
167 	default:
168 		break;
169 	}
170 	return 0;
171 }
172 
173 static const struct hwmon_channel_info *adm1177_info[] = {
174 	HWMON_CHANNEL_INFO(curr,
175 			   HWMON_C_INPUT | HWMON_C_MAX_ALARM),
176 	HWMON_CHANNEL_INFO(in,
177 			   HWMON_I_INPUT),
178 	NULL
179 };
180 
181 static const struct hwmon_ops adm1177_hwmon_ops = {
182 	.is_visible = adm1177_is_visible,
183 	.read = adm1177_read,
184 	.write = adm1177_write,
185 };
186 
187 static const struct hwmon_chip_info adm1177_chip_info = {
188 	.ops = &adm1177_hwmon_ops,
189 	.info = adm1177_info,
190 };
191 
adm1177_remove(void * data)192 static void adm1177_remove(void *data)
193 {
194 	struct adm1177_state *st = data;
195 
196 	regulator_disable(st->reg);
197 }
198 
adm1177_probe(struct i2c_client * client)199 static int adm1177_probe(struct i2c_client *client)
200 {
201 	struct device *dev = &client->dev;
202 	struct device *hwmon_dev;
203 	struct adm1177_state *st;
204 	u32 alert_threshold_ua;
205 	int ret;
206 
207 	st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
208 	if (!st)
209 		return -ENOMEM;
210 
211 	st->client = client;
212 
213 	st->reg = devm_regulator_get_optional(&client->dev, "vref");
214 	if (IS_ERR(st->reg)) {
215 		if (PTR_ERR(st->reg) == -EPROBE_DEFER)
216 			return -EPROBE_DEFER;
217 
218 		st->reg = NULL;
219 	} else {
220 		ret = regulator_enable(st->reg);
221 		if (ret)
222 			return ret;
223 		ret = devm_add_action_or_reset(&client->dev, adm1177_remove,
224 					       st);
225 		if (ret)
226 			return ret;
227 	}
228 
229 	if (device_property_read_u32(dev, "shunt-resistor-micro-ohms",
230 				     &st->r_sense_uohm))
231 		st->r_sense_uohm = 0;
232 	if (device_property_read_u32(dev, "adi,shutdown-threshold-microamp",
233 				     &alert_threshold_ua)) {
234 		if (st->r_sense_uohm)
235 			/*
236 			 * set maximum default value from datasheet based on
237 			 * shunt-resistor
238 			 */
239 			alert_threshold_ua = div_u64(105840000000,
240 						     st->r_sense_uohm);
241 		else
242 			alert_threshold_ua = 0;
243 	}
244 	st->vrange_high = device_property_read_bool(dev,
245 						    "adi,vrange-high-enable");
246 	if (alert_threshold_ua && st->r_sense_uohm)
247 		adm1177_write_alert_thr(st, alert_threshold_ua);
248 
249 	ret = adm1177_write_cmd(st, ADM1177_CMD_V_CONT |
250 				    ADM1177_CMD_I_CONT |
251 				    (st->vrange_high ? 0 : ADM1177_CMD_VRANGE));
252 	if (ret)
253 		return ret;
254 
255 	hwmon_dev =
256 		devm_hwmon_device_register_with_info(dev, client->name, st,
257 						     &adm1177_chip_info, NULL);
258 	return PTR_ERR_OR_ZERO(hwmon_dev);
259 }
260 
261 static const struct i2c_device_id adm1177_id[] = {
262 	{"adm1177", 0},
263 	{}
264 };
265 MODULE_DEVICE_TABLE(i2c, adm1177_id);
266 
267 static const struct of_device_id adm1177_dt_ids[] = {
268 	{ .compatible = "adi,adm1177" },
269 	{},
270 };
271 MODULE_DEVICE_TABLE(of, adm1177_dt_ids);
272 
273 static struct i2c_driver adm1177_driver = {
274 	.class = I2C_CLASS_HWMON,
275 	.driver = {
276 		.name = "adm1177",
277 		.of_match_table = adm1177_dt_ids,
278 	},
279 	.probe_new = adm1177_probe,
280 	.id_table = adm1177_id,
281 };
282 module_i2c_driver(adm1177_driver);
283 
284 MODULE_AUTHOR("Beniamin Bia <beniamin.bia@analog.com>");
285 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
286 MODULE_DESCRIPTION("Analog Devices ADM1177 ADC driver");
287 MODULE_LICENSE("GPL v2");
288