adm1177.c

  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 */
 35struct adm1177_state {
 36	struct i2c_client	*client;
 37	u32			r_sense_uohm;
 38	u64			alert_threshold_ua;
 39	bool			vrange_high;
 40};
 41
 42static int adm1177_read_raw(struct adm1177_state *st, u8 num, u8 *data)
 43{
 44	return i2c_master_recv(st->client, data, num);
 45}
 46
 47static int adm1177_write_cmd(struct adm1177_state *st, u8 cmd)
 48{
 49	return i2c_smbus_write_byte(st->client, cmd);
 50}
 51
 52static 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
 73static 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
123static 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
143static 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
174static 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
182static const struct hwmon_ops adm1177_hwmon_ops = {
183	.is_visible = adm1177_is_visible,
184	.read = adm1177_read,
185	.write = adm1177_write,
186};
187
188static const struct hwmon_chip_info adm1177_chip_info = {
189	.ops = &adm1177_hwmon_ops,
190	.info = adm1177_info,
191};
192
193static 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
248static const struct i2c_device_id adm1177_id[] = {
249	{"adm1177"},
250	{}
251};
252MODULE_DEVICE_TABLE(i2c, adm1177_id);
253
254static const struct of_device_id adm1177_dt_ids[] = {
255	{ .compatible = "adi,adm1177" },
256	{},
257};
258MODULE_DEVICE_TABLE(of, adm1177_dt_ids);
259
260static 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};
268module_i2c_driver(adm1177_driver);
269
270MODULE_AUTHOR("Beniamin Bia <beniamin.bia@analog.com>");
271MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
272MODULE_DESCRIPTION("Analog Devices ADM1177 ADC driver");
273MODULE_LICENSE("GPL v2");