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(als->device->handle, prop, NULL,
91				       &temp_val);
92
93	if (ACPI_FAILURE(status)) {
94		acpi_evaluation_failure_warn(als->device->handle, 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(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(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, &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);
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, buffer, pf->timestamp);
178out:
179	mutex_unlock(&als->lock);
180	iio_trigger_notify_done(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(dev, 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, 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(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