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 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 */
 34struct 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
 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				   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
 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_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
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_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
142static 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
173static 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
181static const struct hwmon_ops adm1177_hwmon_ops = {
182	.is_visible = adm1177_is_visible,
183	.read = adm1177_read,
184	.write = adm1177_write,
185};
186
187static const struct hwmon_chip_info adm1177_chip_info = {
188	.ops = &adm1177_hwmon_ops,
189	.info = adm1177_info,
190};
191
192static void adm1177_remove(void *data)
193{
194	struct adm1177_state *st = data;
195
196	regulator_disable(st->reg);
197}
198
199static int adm1177_probe(struct i2c_client *client,
200			 const struct i2c_device_id *id)
201{
202	struct device *dev = &client->dev;
203	struct device *hwmon_dev;
204	struct adm1177_state *st;
205	u32 alert_threshold_ua;
206	int ret;
207
208	st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
209	if (!st)
210		return -ENOMEM;
211
212	st->client = client;
213
214	st->reg = devm_regulator_get_optional(&client->dev, "vref");
215	if (IS_ERR(st->reg)) {
216		if (PTR_ERR(st->reg) == -EPROBE_DEFER)
217			return -EPROBE_DEFER;
218
219		st->reg = NULL;
220	} else {
221		ret = regulator_enable(st->reg);
222		if (ret)
223			return ret;
224		ret = devm_add_action_or_reset(&client->dev, adm1177_remove,
225					       st);
226		if (ret)
227			return ret;
228	}
229
230	if (device_property_read_u32(dev, "shunt-resistor-micro-ohms",
231				     &st->r_sense_uohm))
232		st->r_sense_uohm = 0;
233	if (device_property_read_u32(dev, "adi,shutdown-threshold-microamp",
234				     &alert_threshold_ua)) {
235		if (st->r_sense_uohm)
236			/*
237			 * set maximum default value from datasheet based on
238			 * shunt-resistor
239			 */
240			alert_threshold_ua = div_u64(105840000000,
241						     st->r_sense_uohm);
242		else
243			alert_threshold_ua = 0;
244	}
245	st->vrange_high = device_property_read_bool(dev,
246						    "adi,vrange-high-enable");
247	if (alert_threshold_ua && st->r_sense_uohm)
248		adm1177_write_alert_thr(st, alert_threshold_ua);
249
250	ret = adm1177_write_cmd(st, ADM1177_CMD_V_CONT |
251				    ADM1177_CMD_I_CONT |
252				    (st->vrange_high ? 0 : ADM1177_CMD_VRANGE));
253	if (ret)
254		return ret;
255
256	hwmon_dev =
257		devm_hwmon_device_register_with_info(dev, client->name, st,
258						     &adm1177_chip_info, NULL);
259	return PTR_ERR_OR_ZERO(hwmon_dev);
260}
261
262static const struct i2c_device_id adm1177_id[] = {
263	{"adm1177", 0},
264	{}
265};
266MODULE_DEVICE_TABLE(i2c, adm1177_id);
267
268static const struct of_device_id adm1177_dt_ids[] = {
269	{ .compatible = "adi,adm1177" },
270	{},
271};
272MODULE_DEVICE_TABLE(of, adm1177_dt_ids);
273
274static struct i2c_driver adm1177_driver = {
275	.class = I2C_CLASS_HWMON,
276	.driver = {
277		.name = "adm1177",
278		.of_match_table = adm1177_dt_ids,
279	},
280	.probe = adm1177_probe,
281	.id_table = adm1177_id,
282};
283module_i2c_driver(adm1177_driver);
284
285MODULE_AUTHOR("Beniamin Bia <beniamin.bia@analog.com>");
286MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
287MODULE_DESCRIPTION("Analog Devices ADM1177 ADC driver");
288MODULE_LICENSE("GPL v2");