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/mutex.h>
 20
 21#include <linux/iio/iio.h>
 22#include <linux/iio/buffer.h>
 23#include <linux/iio/kfifo_buf.h>
 24
 25#define ACPI_ALS_CLASS			"als"
 26#define ACPI_ALS_DEVICE_NAME		"acpi-als"
 27#define ACPI_ALS_NOTIFY_ILLUMINANCE	0x80
 28
 29ACPI_MODULE_NAME("acpi-als");
 30
 31/*
 32 * So far, there's only one channel in here, but the specification for
 33 * ACPI0008 says there can be more to what the block can report. Like
 34 * chromaticity and such. We are ready for incoming additions!
 35 */
 36static const struct iio_chan_spec acpi_als_channels[] = {
 37	{
 38		.type		= IIO_LIGHT,
 39		.scan_type	= {
 40			.sign		= 's',
 41			.realbits	= 32,
 42			.storagebits	= 32,
 43		},
 44		/* _RAW is here for backward ABI compatibility */
 45		.info_mask_separate	= BIT(IIO_CHAN_INFO_RAW) |
 46					  BIT(IIO_CHAN_INFO_PROCESSED),
 47	},
 48};
 49
 50/*
 51 * The event buffer contains timestamp and all the data from
 52 * the ACPI0008 block. There are multiple, but so far we only
 53 * support _ALI (illuminance). Once someone adds new channels
 54 * to acpi_als_channels[], the evt_buffer below will grow
 55 * automatically.
 56 */
 57#define ACPI_ALS_EVT_NR_SOURCES		ARRAY_SIZE(acpi_als_channels)
 58#define ACPI_ALS_EVT_BUFFER_SIZE		\
 59	(sizeof(s64) + (ACPI_ALS_EVT_NR_SOURCES * sizeof(s32)))
 60
 61struct acpi_als {
 62	struct acpi_device	*device;
 63	struct mutex		lock;
 64
 65	s32			evt_buffer[ACPI_ALS_EVT_BUFFER_SIZE];
 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_EXCEPTION((AE_INFO, status, "Error reading ALS %s", prop));
 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	s32 *buffer = als->evt_buffer;
108	s64 time_ns = iio_get_time_ns(indio_dev);
109	s32 val;
110	int ret;
111
112	mutex_lock(&als->lock);
113
114	memset(buffer, 0, ACPI_ALS_EVT_BUFFER_SIZE);
115
116	switch (event) {
117	case ACPI_ALS_NOTIFY_ILLUMINANCE:
118		ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, &val);
119		if (ret < 0)
120			goto out;
121		*buffer++ = val;
122		break;
123	default:
124		/* Unhandled event */
125		dev_dbg(&device->dev, "Unhandled ACPI ALS event (%08x)!\n",
126			event);
127		goto out;
128	}
129
130	iio_push_to_buffers_with_timestamp(indio_dev, als->evt_buffer, time_ns);
131
132out:
133	mutex_unlock(&als->lock);
134}
135
136static int acpi_als_read_raw(struct iio_dev *indio_dev,
137			     struct iio_chan_spec const *chan, int *val,
138			     int *val2, long mask)
139{
140	struct acpi_als *als = iio_priv(indio_dev);
141	s32 temp_val;
142	int ret;
143
144	if ((mask != IIO_CHAN_INFO_PROCESSED) && (mask != IIO_CHAN_INFO_RAW))
145		return -EINVAL;
146
147	/* we support only illumination (_ALI) so far. */
148	if (chan->type != IIO_LIGHT)
149		return -EINVAL;
150
151	ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, &temp_val);
152	if (ret < 0)
153		return ret;
154
155	*val = temp_val;
156
157	return IIO_VAL_INT;
158}
159
160static const struct iio_info acpi_als_info = {
161	.read_raw		= acpi_als_read_raw,
162};
163
164static int acpi_als_add(struct acpi_device *device)
165{
166	struct acpi_als *als;
167	struct iio_dev *indio_dev;
168	struct iio_buffer *buffer;
169
170	indio_dev = devm_iio_device_alloc(&device->dev, sizeof(*als));
171	if (!indio_dev)
172		return -ENOMEM;
173
174	als = iio_priv(indio_dev);
175
176	device->driver_data = indio_dev;
177	als->device = device;
178	mutex_init(&als->lock);
179
180	indio_dev->name = ACPI_ALS_DEVICE_NAME;
181	indio_dev->info = &acpi_als_info;
182	indio_dev->modes = INDIO_BUFFER_SOFTWARE;
183	indio_dev->channels = acpi_als_channels;
184	indio_dev->num_channels = ARRAY_SIZE(acpi_als_channels);
185
186	buffer = devm_iio_kfifo_allocate(&device->dev);
187	if (!buffer)
188		return -ENOMEM;
189
190	iio_device_attach_buffer(indio_dev, buffer);
191
192	return devm_iio_device_register(&device->dev, indio_dev);
193}
194
195static const struct acpi_device_id acpi_als_device_ids[] = {
196	{"ACPI0008", 0},
197	{},
198};
199
200MODULE_DEVICE_TABLE(acpi, acpi_als_device_ids);
201
202static struct acpi_driver acpi_als_driver = {
203	.name	= "acpi_als",
204	.class	= ACPI_ALS_CLASS,
205	.ids	= acpi_als_device_ids,
206	.ops = {
207		.add	= acpi_als_add,
208		.notify	= acpi_als_notify,
209	},
210};
211
212module_acpi_driver(acpi_als_driver);
213
214MODULE_AUTHOR("Zhang Rui <rui.zhang@intel.com>");
215MODULE_AUTHOR("Martin Liska <marxin.liska@gmail.com>");
216MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
217MODULE_DESCRIPTION("ACPI Ambient Light Sensor Driver");
218MODULE_LICENSE("GPL");