1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * cros_ec_baro - Driver for barometer sensor behind CrosEC.
4  *
5  * Copyright (C) 2017 Google, Inc
6  */
7 
8 #include <linux/device.h>
9 #include <linux/iio/buffer.h>
10 #include <linux/iio/common/cros_ec_sensors_core.h>
11 #include <linux/iio/iio.h>
12 #include <linux/iio/kfifo_buf.h>
13 #include <linux/iio/trigger.h>
14 #include <linux/iio/triggered_buffer.h>
15 #include <linux/iio/trigger_consumer.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 #include <linux/platform_data/cros_ec_commands.h>
20 #include <linux/platform_data/cros_ec_proto.h>
21 #include <linux/platform_device.h>
22 
23 /*
24  * One channel for pressure, the other for timestamp.
25  */
26 #define CROS_EC_BARO_MAX_CHANNELS (1 + 1)
27 
28 /* State data for ec_sensors iio driver. */
29 struct cros_ec_baro_state {
30 	/* Shared by all sensors */
31 	struct cros_ec_sensors_core_state core;
32 
33 	struct iio_chan_spec channels[CROS_EC_BARO_MAX_CHANNELS];
34 };
35 
cros_ec_baro_read(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)36 static int cros_ec_baro_read(struct iio_dev *indio_dev,
37 			     struct iio_chan_spec const *chan,
38 			     int *val, int *val2, long mask)
39 {
40 	struct cros_ec_baro_state *st = iio_priv(indio_dev);
41 	u16 data = 0;
42 	int ret;
43 	int idx = chan->scan_index;
44 
45 	mutex_lock(&st->core.cmd_lock);
46 
47 	switch (mask) {
48 	case IIO_CHAN_INFO_RAW:
49 		ret = cros_ec_sensors_read_cmd(indio_dev, 1 << idx,
50 					     (s16 *)&data);
51 		if (ret)
52 			break;
53 
54 		*val = data;
55 		ret = IIO_VAL_INT;
56 		break;
57 	case IIO_CHAN_INFO_SCALE:
58 		st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
59 		st->core.param.sensor_range.data = EC_MOTION_SENSE_NO_VALUE;
60 
61 		ret = cros_ec_motion_send_host_cmd(&st->core, 0);
62 		if (ret)
63 			break;
64 
65 		*val = st->core.resp->sensor_range.ret;
66 
67 		/* scale * in_pressure_raw --> kPa */
68 		*val2 = 10 << CROS_EC_SENSOR_BITS;
69 		ret = IIO_VAL_FRACTIONAL;
70 		break;
71 	default:
72 		ret = cros_ec_sensors_core_read(&st->core, chan, val, val2,
73 						mask);
74 		break;
75 	}
76 
77 	mutex_unlock(&st->core.cmd_lock);
78 
79 	return ret;
80 }
81 
cros_ec_baro_write(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)82 static int cros_ec_baro_write(struct iio_dev *indio_dev,
83 			      struct iio_chan_spec const *chan,
84 			      int val, int val2, long mask)
85 {
86 	struct cros_ec_baro_state *st = iio_priv(indio_dev);
87 	int ret = 0;
88 
89 	mutex_lock(&st->core.cmd_lock);
90 
91 	switch (mask) {
92 	case IIO_CHAN_INFO_SCALE:
93 		st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
94 		st->core.param.sensor_range.data = val;
95 
96 		/* Always roundup, so caller gets at least what it asks for. */
97 		st->core.param.sensor_range.roundup = 1;
98 
99 		ret = cros_ec_motion_send_host_cmd(&st->core, 0);
100 		if (ret == 0) {
101 			st->core.range_updated = true;
102 			st->core.curr_range = val;
103 		}
104 		break;
105 	default:
106 		ret = cros_ec_sensors_core_write(&st->core, chan, val, val2,
107 						 mask);
108 		break;
109 	}
110 
111 	mutex_unlock(&st->core.cmd_lock);
112 
113 	return ret;
114 }
115 
116 static const struct iio_info cros_ec_baro_info = {
117 	.read_raw = &cros_ec_baro_read,
118 	.write_raw = &cros_ec_baro_write,
119 	.read_avail = &cros_ec_sensors_core_read_avail,
120 };
121 
cros_ec_baro_probe(struct platform_device * pdev)122 static int cros_ec_baro_probe(struct platform_device *pdev)
123 {
124 	struct device *dev = &pdev->dev;
125 	struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
126 	struct iio_dev *indio_dev;
127 	struct cros_ec_baro_state *state;
128 	struct iio_chan_spec *channel;
129 	int ret;
130 
131 	if (!ec_dev || !ec_dev->ec_dev) {
132 		dev_warn(dev, "No CROS EC device found.\n");
133 		return -EINVAL;
134 	}
135 
136 	indio_dev = devm_iio_device_alloc(dev, sizeof(*state));
137 	if (!indio_dev)
138 		return -ENOMEM;
139 
140 	ret = cros_ec_sensors_core_init(pdev, indio_dev, true,
141 					cros_ec_sensors_capture,
142 					cros_ec_sensors_push_data);
143 	if (ret)
144 		return ret;
145 
146 	indio_dev->info = &cros_ec_baro_info;
147 	state = iio_priv(indio_dev);
148 	state->core.type = state->core.resp->info.type;
149 	state->core.loc = state->core.resp->info.location;
150 	channel = state->channels;
151 	/* Common part */
152 	channel->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
153 	channel->info_mask_shared_by_all =
154 		BIT(IIO_CHAN_INFO_SCALE) |
155 		BIT(IIO_CHAN_INFO_SAMP_FREQ);
156 	channel->info_mask_shared_by_all_available =
157 		BIT(IIO_CHAN_INFO_SAMP_FREQ);
158 	channel->scan_type.realbits = CROS_EC_SENSOR_BITS;
159 	channel->scan_type.storagebits = CROS_EC_SENSOR_BITS;
160 	channel->scan_type.shift = 0;
161 	channel->scan_index = 0;
162 	channel->ext_info = cros_ec_sensors_ext_info;
163 	channel->scan_type.sign = 'u';
164 
165 	/* Sensor specific */
166 	switch (state->core.type) {
167 	case MOTIONSENSE_TYPE_BARO:
168 		channel->type = IIO_PRESSURE;
169 		break;
170 	default:
171 		dev_warn(dev, "Unknown motion sensor\n");
172 		return -EINVAL;
173 	}
174 
175 	/* Timestamp */
176 	channel++;
177 	channel->type = IIO_TIMESTAMP;
178 	channel->channel = -1;
179 	channel->scan_index = 1;
180 	channel->scan_type.sign = 's';
181 	channel->scan_type.realbits = 64;
182 	channel->scan_type.storagebits = 64;
183 
184 	indio_dev->channels = state->channels;
185 	indio_dev->num_channels = CROS_EC_BARO_MAX_CHANNELS;
186 
187 	state->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;
188 
189 	return devm_iio_device_register(dev, indio_dev);
190 }
191 
192 static const struct platform_device_id cros_ec_baro_ids[] = {
193 	{
194 		.name = "cros-ec-baro",
195 	},
196 	{ /* sentinel */ }
197 };
198 MODULE_DEVICE_TABLE(platform, cros_ec_baro_ids);
199 
200 static struct platform_driver cros_ec_baro_platform_driver = {
201 	.driver = {
202 		.name	= "cros-ec-baro",
203 		.pm	= &cros_ec_sensors_pm_ops,
204 	},
205 	.probe		= cros_ec_baro_probe,
206 	.id_table	= cros_ec_baro_ids,
207 };
208 module_platform_driver(cros_ec_baro_platform_driver);
209 
210 MODULE_DESCRIPTION("ChromeOS EC barometer sensor driver");
211 MODULE_LICENSE("GPL v2");
212