1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * ACPI Ambient Light Sensor Driver
4 *
5 * Based on ALS driver:
6 * Copyright (C) 2009 Zhang Rui <rui.zhang@intel.com>
7 *
8 * Rework for IIO subsystem:
9 * Copyright (C) 2012-2013 Martin Liska <marxin.liska@gmail.com>
10 *
11 * Final cleanup and debugging:
12 * Copyright (C) 2013-2014 Marek Vasut <marex@denx.de>
13 * Copyright (C) 2015 Gabriele Mazzotta <gabriele.mzt@gmail.com>
14 */
15
16#include <linux/module.h>
17#include <linux/acpi.h>
18#include <linux/err.h>
19#include <linux/irq.h>
20#include <linux/mutex.h>
21
22#include <linux/iio/iio.h>
23#include <linux/iio/buffer.h>
24#include <linux/iio/trigger.h>
25#include <linux/iio/triggered_buffer.h>
26#include <linux/iio/trigger_consumer.h>
27
28#define ACPI_ALS_CLASS "als"
29#define ACPI_ALS_DEVICE_NAME "acpi-als"
30#define ACPI_ALS_NOTIFY_ILLUMINANCE 0x80
31
32/*
33 * So far, there's only one channel in here, but the specification for
34 * ACPI0008 says there can be more to what the block can report. Like
35 * chromaticity and such. We are ready for incoming additions!
36 */
37static const struct iio_chan_spec acpi_als_channels[] = {
38 {
39 .type = IIO_LIGHT,
40 .scan_type = {
41 .sign = 's',
42 .realbits = 32,
43 .storagebits = 32,
44 },
45 /* _RAW is here for backward ABI compatibility */
46 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
47 BIT(IIO_CHAN_INFO_PROCESSED),
48 },
49 IIO_CHAN_SOFT_TIMESTAMP(1),
50};
51
52/*
53 * The event buffer contains timestamp and all the data from
54 * the ACPI0008 block. There are multiple, but so far we only
55 * support _ALI (illuminance): One channel, padding and timestamp.
56 */
57#define ACPI_ALS_EVT_BUFFER_SIZE \
58 (sizeof(s32) + sizeof(s32) + sizeof(s64))
59
60struct acpi_als {
61 struct acpi_device *device;
62 struct mutex lock;
63 struct iio_trigger *trig;
64
65 s32 evt_buffer[ACPI_ALS_EVT_BUFFER_SIZE / sizeof(s32)] __aligned(8);
66};
67
68/*
69 * All types of properties the ACPI0008 block can report. The ALI, ALC, ALT
70 * and ALP can all be handled by acpi_als_read_value() below, while the ALR is
71 * special.
72 *
73 * The _ALR property returns tables that can be used to fine-tune the values
74 * reported by the other props based on the particular hardware type and it's
75 * location (it contains tables for "rainy", "bright inhouse lighting" etc.).
76 *
77 * So far, we support only ALI (illuminance).
78 */
79#define ACPI_ALS_ILLUMINANCE "_ALI"
80#define ACPI_ALS_CHROMATICITY "_ALC"
81#define ACPI_ALS_COLOR_TEMP "_ALT"
82#define ACPI_ALS_POLLING "_ALP"
83#define ACPI_ALS_TABLES "_ALR"
84
85static int acpi_als_read_value(struct acpi_als *als, char *prop, s32 *val)
86{
87 unsigned long long temp_val;
88 acpi_status status;
89
90 status = acpi_evaluate_integer(handle: als->device->handle, pathname: prop, NULL,
91 data: &temp_val);
92
93 if (ACPI_FAILURE(status)) {
94 acpi_evaluation_failure_warn(handle: als->device->handle, name: prop, status);
95 return -EIO;
96 }
97
98 *val = temp_val;
99
100 return 0;
101}
102
103static void acpi_als_notify(struct acpi_device *device, u32 event)
104{
105 struct iio_dev *indio_dev = acpi_driver_data(d: device);
106 struct acpi_als *als = iio_priv(indio_dev);
107
108 if (iio_buffer_enabled(indio_dev) && iio_trigger_using_own(indio_dev)) {
109 switch (event) {
110 case ACPI_ALS_NOTIFY_ILLUMINANCE:
111 iio_trigger_poll_nested(trig: als->trig);
112 break;
113 default:
114 /* Unhandled event */
115 dev_dbg(&device->dev,
116 "Unhandled ACPI ALS event (%08x)!\n",
117 event);
118 }
119 }
120}
121
122static int acpi_als_read_raw(struct iio_dev *indio_dev,
123 struct iio_chan_spec const *chan, int *val,
124 int *val2, long mask)
125{
126 struct acpi_als *als = iio_priv(indio_dev);
127 s32 temp_val;
128 int ret;
129
130 if ((mask != IIO_CHAN_INFO_PROCESSED) && (mask != IIO_CHAN_INFO_RAW))
131 return -EINVAL;
132
133 /* we support only illumination (_ALI) so far. */
134 if (chan->type != IIO_LIGHT)
135 return -EINVAL;
136
137 ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, val: &temp_val);
138 if (ret < 0)
139 return ret;
140
141 *val = temp_val;
142
143 return IIO_VAL_INT;
144}
145
146static const struct iio_info acpi_als_info = {
147 .read_raw = acpi_als_read_raw,
148};
149
150static irqreturn_t acpi_als_trigger_handler(int irq, void *p)
151{
152 struct iio_poll_func *pf = p;
153 struct iio_dev *indio_dev = pf->indio_dev;
154 struct acpi_als *als = iio_priv(indio_dev);
155 s32 *buffer = als->evt_buffer;
156 s32 val;
157 int ret;
158
159 mutex_lock(&als->lock);
160
161 ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, val: &val);
162 if (ret < 0)
163 goto out;
164 *buffer = val;
165
166 /*
167 * When coming from own trigger via polls, set polling function
168 * timestamp here. Given ACPI notifier is already in a thread and call
169 * function directly, there is no need to set the timestamp in the
170 * notify function.
171 *
172 * If the timestamp was actually 0, the timestamp is set one more time.
173 */
174 if (!pf->timestamp)
175 pf->timestamp = iio_get_time_ns(indio_dev);
176
177 iio_push_to_buffers_with_timestamp(indio_dev, data: buffer, timestamp: pf->timestamp);
178out:
179 mutex_unlock(lock: &als->lock);
180 iio_trigger_notify_done(trig: indio_dev->trig);
181
182 return IRQ_HANDLED;
183}
184
185static int acpi_als_add(struct acpi_device *device)
186{
187 struct device *dev = &device->dev;
188 struct iio_dev *indio_dev;
189 struct acpi_als *als;
190 int ret;
191
192 indio_dev = devm_iio_device_alloc(parent: dev, sizeof_priv: sizeof(*als));
193 if (!indio_dev)
194 return -ENOMEM;
195
196 als = iio_priv(indio_dev);
197
198 device->driver_data = indio_dev;
199 als->device = device;
200 mutex_init(&als->lock);
201
202 indio_dev->name = ACPI_ALS_DEVICE_NAME;
203 indio_dev->info = &acpi_als_info;
204 indio_dev->channels = acpi_als_channels;
205 indio_dev->num_channels = ARRAY_SIZE(acpi_als_channels);
206
207 als->trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name,
208 iio_device_id(indio_dev));
209 if (!als->trig)
210 return -ENOMEM;
211
212 ret = devm_iio_trigger_register(dev, trig_info: als->trig);
213 if (ret)
214 return ret;
215 /*
216 * Set hardware trigger by default to let events flow when
217 * BIOS support notification.
218 */
219 indio_dev->trig = iio_trigger_get(trig: als->trig);
220
221 ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
222 iio_pollfunc_store_time,
223 acpi_als_trigger_handler,
224 NULL);
225 if (ret)
226 return ret;
227
228 return devm_iio_device_register(dev, indio_dev);
229}
230
231static const struct acpi_device_id acpi_als_device_ids[] = {
232 {"ACPI0008", 0},
233 {},
234};
235
236MODULE_DEVICE_TABLE(acpi, acpi_als_device_ids);
237
238static struct acpi_driver acpi_als_driver = {
239 .name = "acpi_als",
240 .class = ACPI_ALS_CLASS,
241 .ids = acpi_als_device_ids,
242 .ops = {
243 .add = acpi_als_add,
244 .notify = acpi_als_notify,
245 },
246};
247
248module_acpi_driver(acpi_als_driver);
249
250MODULE_AUTHOR("Zhang Rui <rui.zhang@intel.com>");
251MODULE_AUTHOR("Martin Liska <marxin.liska@gmail.com>");
252MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
253MODULE_DESCRIPTION("ACPI Ambient Light Sensor Driver");
254MODULE_LICENSE("GPL");
255

source code of linux/drivers/iio/light/acpi-als.c