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