xref: /openbmc/linux/drivers/iio/light/acpi-als.c (revision f700e55e)
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  */
37 static 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 
60 struct 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 
acpi_als_read_value(struct acpi_als * als,char * prop,s32 * val)85 static 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 
acpi_als_notify(struct acpi_device * device,u32 event)103 static 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 
acpi_als_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)122 static 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 
146 static const struct iio_info acpi_als_info = {
147 	.read_raw		= acpi_als_read_raw,
148 };
149 
acpi_als_trigger_handler(int irq,void * p)150 static 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);
178 out:
179 	mutex_unlock(&als->lock);
180 	iio_trigger_notify_done(indio_dev->trig);
181 
182 	return IRQ_HANDLED;
183 }
184 
acpi_als_add(struct acpi_device * device)185 static 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 
231 static const struct acpi_device_id acpi_als_device_ids[] = {
232 	{"ACPI0008", 0},
233 	{},
234 };
235 
236 MODULE_DEVICE_TABLE(acpi, acpi_als_device_ids);
237 
238 static 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 
248 module_acpi_driver(acpi_als_driver);
249 
250 MODULE_AUTHOR("Zhang Rui <rui.zhang@intel.com>");
251 MODULE_AUTHOR("Martin Liska <marxin.liska@gmail.com>");
252 MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
253 MODULE_DESCRIPTION("ACPI Ambient Light Sensor Driver");
254 MODULE_LICENSE("GPL");
255