1/*
  2 * System Control and Power Interface(SCPI) based hwmon sensor driver
  3 *
  4 * Copyright (C) 2015 ARM Ltd.
  5 * Punit Agrawal <punit.agrawal@arm.com>
  6 *
  7 * This program is free software; you can redistribute it and/or modify
  8 * it under the terms of the GNU General Public License version 2 as
  9 * published by the Free Software Foundation.
 10 *
 11 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 12 * kind, whether express or implied; without even the implied warranty
 13 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 14 * GNU General Public License for more details.
 15 */
 16
 17#include <linux/hwmon.h>
 18#include <linux/module.h>
 19#include <linux/of_device.h>
 20#include <linux/platform_device.h>
 21#include <linux/scpi_protocol.h>
 22#include <linux/slab.h>
 23#include <linux/sysfs.h>
 24#include <linux/thermal.h>
 25
 26struct sensor_data {
 27	unsigned int scale;
 28	struct scpi_sensor_info info;
 29	struct device_attribute dev_attr_input;
 30	struct device_attribute dev_attr_label;
 31	char input[20];
 32	char label[20];
 33};
 34
 35struct scpi_thermal_zone {
 36	int sensor_id;
 37	struct scpi_sensors *scpi_sensors;
 38};
 39
 40struct scpi_sensors {
 41	struct scpi_ops *scpi_ops;
 42	struct sensor_data *data;
 43	struct list_head thermal_zones;
 44	struct attribute **attrs;
 45	struct attribute_group group;
 46	const struct attribute_group *groups[2];
 47};
 48
 49static const u32 gxbb_scpi_scale[] = {
 50	[TEMPERATURE]	= 1,		/* (celsius)		*/
 51	[VOLTAGE]	= 1000,		/* (millivolts)		*/
 52	[CURRENT]	= 1000,		/* (milliamperes)	*/
 53	[POWER]		= 1000000,	/* (microwatts)		*/
 54	[ENERGY]	= 1000000,	/* (microjoules)	*/
 55};
 56
 57static const u32 scpi_scale[] = {
 58	[TEMPERATURE]	= 1000,		/* (millicelsius)	*/
 59	[VOLTAGE]	= 1000,		/* (millivolts)		*/
 60	[CURRENT]	= 1000,		/* (milliamperes)	*/
 61	[POWER]		= 1000000,	/* (microwatts)		*/
 62	[ENERGY]	= 1000000,	/* (microjoules)	*/
 63};
 64
 65static void scpi_scale_reading(u64 *value, struct sensor_data *sensor)
 66{
 67	if (scpi_scale[sensor->info.class] != sensor->scale) {
 68		*value *= scpi_scale[sensor->info.class];
 69		do_div(*value, sensor->scale);
 70	}
 71}
 72
 73static int scpi_read_temp(void *dev, int *temp)
 74{
 75	struct scpi_thermal_zone *zone = dev;
 76	struct scpi_sensors *scpi_sensors = zone->scpi_sensors;
 77	struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops;
 78	struct sensor_data *sensor = &scpi_sensors->data[zone->sensor_id];
 79	u64 value;
 80	int ret;
 81
 82	ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);
 83	if (ret)
 84		return ret;
 85
 86	scpi_scale_reading(&value, sensor);
 87
 88	*temp = value;
 89	return 0;
 90}
 91
 92/* hwmon callback functions */
 93static ssize_t
 94scpi_show_sensor(struct device *dev, struct device_attribute *attr, char *buf)
 95{
 96	struct scpi_sensors *scpi_sensors = dev_get_drvdata(dev);
 97	struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops;
 98	struct sensor_data *sensor;
 99	u64 value;
100	int ret;
101
102	sensor = container_of(attr, struct sensor_data, dev_attr_input);
103
104	ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);
105	if (ret)
106		return ret;
107
108	scpi_scale_reading(&value, sensor);
109
110	return sprintf(buf, "%llu\n", value);
111}
112
113static ssize_t
114scpi_show_label(struct device *dev, struct device_attribute *attr, char *buf)
115{
116	struct sensor_data *sensor;
117
118	sensor = container_of(attr, struct sensor_data, dev_attr_label);
119
120	return sprintf(buf, "%s\n", sensor->info.name);
121}
122
123static const struct thermal_zone_of_device_ops scpi_sensor_ops = {
124	.get_temp = scpi_read_temp,
125};
126
127static const struct of_device_id scpi_of_match[] = {
128	{.compatible = "arm,scpi-sensors", .data = &scpi_scale},
129	{.compatible = "amlogic,meson-gxbb-scpi-sensors", .data = &gxbb_scpi_scale},
130	{},
131};
132MODULE_DEVICE_TABLE(of, scpi_of_match);
133
134static int scpi_hwmon_probe(struct platform_device *pdev)
135{
136	u16 nr_sensors, i;
137	const u32 *scale;
138	int num_temp = 0, num_volt = 0, num_current = 0, num_power = 0;
139	int num_energy = 0;
140	struct scpi_ops *scpi_ops;
141	struct device *hwdev, *dev = &pdev->dev;
142	struct scpi_sensors *scpi_sensors;
143	const struct of_device_id *of_id;
144	int idx, ret;
145
146	scpi_ops = get_scpi_ops();
147	if (!scpi_ops)
148		return -EPROBE_DEFER;
149
150	ret = scpi_ops->sensor_get_capability(&nr_sensors);
151	if (ret)
152		return ret;
153
154	if (!nr_sensors)
155		return -ENODEV;
156
157	scpi_sensors = devm_kzalloc(dev, sizeof(*scpi_sensors), GFP_KERNEL);
158	if (!scpi_sensors)
159		return -ENOMEM;
160
161	scpi_sensors->data = devm_kcalloc(dev, nr_sensors,
162				   sizeof(*scpi_sensors->data), GFP_KERNEL);
163	if (!scpi_sensors->data)
164		return -ENOMEM;
165
166	scpi_sensors->attrs = devm_kcalloc(dev, (nr_sensors * 2) + 1,
167				   sizeof(*scpi_sensors->attrs), GFP_KERNEL);
168	if (!scpi_sensors->attrs)
169		return -ENOMEM;
170
171	scpi_sensors->scpi_ops = scpi_ops;
172
173	of_id = of_match_device(scpi_of_match, &pdev->dev);
174	if (!of_id) {
175		dev_err(&pdev->dev, "Unable to initialize scpi-hwmon data\n");
176		return -ENODEV;
177	}
178	scale = of_id->data;
179
180	for (i = 0, idx = 0; i < nr_sensors; i++) {
181		struct sensor_data *sensor = &scpi_sensors->data[idx];
182
183		ret = scpi_ops->sensor_get_info(i, &sensor->info);
184		if (ret)
185			return ret;
186
187		switch (sensor->info.class) {
188		case TEMPERATURE:
189			snprintf(sensor->input, sizeof(sensor->input),
190				 "temp%d_input", num_temp + 1);
191			snprintf(sensor->label, sizeof(sensor->input),
192				 "temp%d_label", num_temp + 1);
193			num_temp++;
194			break;
195		case VOLTAGE:
196			snprintf(sensor->input, sizeof(sensor->input),
197				 "in%d_input", num_volt);
198			snprintf(sensor->label, sizeof(sensor->input),
199				 "in%d_label", num_volt);
200			num_volt++;
201			break;
202		case CURRENT:
203			snprintf(sensor->input, sizeof(sensor->input),
204				 "curr%d_input", num_current + 1);
205			snprintf(sensor->label, sizeof(sensor->input),
206				 "curr%d_label", num_current + 1);
207			num_current++;
208			break;
209		case POWER:
210			snprintf(sensor->input, sizeof(sensor->input),
211				 "power%d_input", num_power + 1);
212			snprintf(sensor->label, sizeof(sensor->input),
213				 "power%d_label", num_power + 1);
214			num_power++;
215			break;
216		case ENERGY:
217			snprintf(sensor->input, sizeof(sensor->input),
218				 "energy%d_input", num_energy + 1);
219			snprintf(sensor->label, sizeof(sensor->input),
220				 "energy%d_label", num_energy + 1);
221			num_energy++;
222			break;
223		default:
224			continue;
225		}
226
227		sensor->scale = scale[sensor->info.class];
228
229		sensor->dev_attr_input.attr.mode = S_IRUGO;
230		sensor->dev_attr_input.show = scpi_show_sensor;
231		sensor->dev_attr_input.attr.name = sensor->input;
232
233		sensor->dev_attr_label.attr.mode = S_IRUGO;
234		sensor->dev_attr_label.show = scpi_show_label;
235		sensor->dev_attr_label.attr.name = sensor->label;
236
237		scpi_sensors->attrs[idx << 1] = &sensor->dev_attr_input.attr;
238		scpi_sensors->attrs[(idx << 1) + 1] = &sensor->dev_attr_label.attr;
239
240		sysfs_attr_init(scpi_sensors->attrs[idx << 1]);
241		sysfs_attr_init(scpi_sensors->attrs[(idx << 1) + 1]);
242		idx++;
243	}
244
245	scpi_sensors->group.attrs = scpi_sensors->attrs;
246	scpi_sensors->groups[0] = &scpi_sensors->group;
247
248	platform_set_drvdata(pdev, scpi_sensors);
249
250	hwdev = devm_hwmon_device_register_with_groups(dev,
251			"scpi_sensors", scpi_sensors, scpi_sensors->groups);
252
253	if (IS_ERR(hwdev))
254		return PTR_ERR(hwdev);
255
256	/*
257	 * Register the temperature sensors with the thermal framework
258	 * to allow their usage in setting up the thermal zones from
259	 * device tree.
260	 *
261	 * NOTE: Not all temperature sensors maybe used for thermal
262	 * control
263	 */
264	INIT_LIST_HEAD(&scpi_sensors->thermal_zones);
265	for (i = 0; i < nr_sensors; i++) {
266		struct sensor_data *sensor = &scpi_sensors->data[i];
267		struct thermal_zone_device *z;
268		struct scpi_thermal_zone *zone;
269
270		if (sensor->info.class != TEMPERATURE)
271			continue;
272
273		zone = devm_kzalloc(dev, sizeof(*zone), GFP_KERNEL);
274		if (!zone)
275			return -ENOMEM;
276
277		zone->sensor_id = i;
278		zone->scpi_sensors = scpi_sensors;
279		z = devm_thermal_zone_of_sensor_register(dev,
280							 sensor->info.sensor_id,
281							 zone,
282							 &scpi_sensor_ops);
283		/*
284		 * The call to thermal_zone_of_sensor_register returns
285		 * an error for sensors that are not associated with
286		 * any thermal zones or if the thermal subsystem is
287		 * not configured.
288		 */
289		if (IS_ERR(z)) {
290			devm_kfree(dev, zone);
291			continue;
292		}
293	}
294
295	return 0;
296}
297
298static struct platform_driver scpi_hwmon_platdrv = {
299	.driver = {
300		.name	= "scpi-hwmon",
301		.of_match_table = scpi_of_match,
302	},
303	.probe		= scpi_hwmon_probe,
304};
305module_platform_driver(scpi_hwmon_platdrv);
306
307MODULE_AUTHOR("Punit Agrawal <punit.agrawal@arm.com>");
308MODULE_DESCRIPTION("ARM SCPI HWMON interface driver");
309MODULE_LICENSE("GPL v2");