xref: /openbmc/linux/drivers/iio/light/acpi-als.c (revision 8ffdff6a)
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 ACPI_MODULE_NAME("acpi-als");
33 
34 /*
35  * So far, there's only one channel in here, but the specification for
36  * ACPI0008 says there can be more to what the block can report. Like
37  * chromaticity and such. We are ready for incoming additions!
38  */
39 static const struct iio_chan_spec acpi_als_channels[] = {
40 	{
41 		.type		= IIO_LIGHT,
42 		.scan_type	= {
43 			.sign		= 's',
44 			.realbits	= 32,
45 			.storagebits	= 32,
46 		},
47 		/* _RAW is here for backward ABI compatibility */
48 		.info_mask_separate	= BIT(IIO_CHAN_INFO_RAW) |
49 					  BIT(IIO_CHAN_INFO_PROCESSED),
50 	},
51 	IIO_CHAN_SOFT_TIMESTAMP(1),
52 };
53 
54 /*
55  * The event buffer contains timestamp and all the data from
56  * the ACPI0008 block. There are multiple, but so far we only
57  * support _ALI (illuminance): One channel, padding and timestamp.
58  */
59 #define ACPI_ALS_EVT_BUFFER_SIZE		\
60 	(sizeof(s32) + sizeof(s32) + sizeof(s64))
61 
62 struct acpi_als {
63 	struct acpi_device	*device;
64 	struct mutex		lock;
65 	struct iio_trigger	*trig;
66 
67 	s32 evt_buffer[ACPI_ALS_EVT_BUFFER_SIZE / sizeof(s32)]  __aligned(8);
68 };
69 
70 /*
71  * All types of properties the ACPI0008 block can report. The ALI, ALC, ALT
72  * and ALP can all be handled by acpi_als_read_value() below, while the ALR is
73  * special.
74  *
75  * The _ALR property returns tables that can be used to fine-tune the values
76  * reported by the other props based on the particular hardware type and it's
77  * location (it contains tables for "rainy", "bright inhouse lighting" etc.).
78  *
79  * So far, we support only ALI (illuminance).
80  */
81 #define ACPI_ALS_ILLUMINANCE	"_ALI"
82 #define ACPI_ALS_CHROMATICITY	"_ALC"
83 #define ACPI_ALS_COLOR_TEMP	"_ALT"
84 #define ACPI_ALS_POLLING	"_ALP"
85 #define ACPI_ALS_TABLES		"_ALR"
86 
87 static int acpi_als_read_value(struct acpi_als *als, char *prop, s32 *val)
88 {
89 	unsigned long long temp_val;
90 	acpi_status status;
91 
92 	status = acpi_evaluate_integer(als->device->handle, prop, NULL,
93 				       &temp_val);
94 
95 	if (ACPI_FAILURE(status)) {
96 		ACPI_EXCEPTION((AE_INFO, status, "Error reading ALS %s", prop));
97 		return -EIO;
98 	}
99 
100 	*val = temp_val;
101 
102 	return 0;
103 }
104 
105 static void acpi_als_notify(struct acpi_device *device, u32 event)
106 {
107 	struct iio_dev *indio_dev = acpi_driver_data(device);
108 	struct acpi_als *als = iio_priv(indio_dev);
109 
110 	if (iio_buffer_enabled(indio_dev) && iio_trigger_using_own(indio_dev)) {
111 		switch (event) {
112 		case ACPI_ALS_NOTIFY_ILLUMINANCE:
113 			iio_trigger_poll_chained(als->trig);
114 			break;
115 		default:
116 			/* Unhandled event */
117 			dev_dbg(&device->dev,
118 				"Unhandled ACPI ALS event (%08x)!\n",
119 				event);
120 		}
121 	}
122 }
123 
124 static int acpi_als_read_raw(struct iio_dev *indio_dev,
125 			     struct iio_chan_spec const *chan, int *val,
126 			     int *val2, long mask)
127 {
128 	struct acpi_als *als = iio_priv(indio_dev);
129 	s32 temp_val;
130 	int ret;
131 
132 	if ((mask != IIO_CHAN_INFO_PROCESSED) && (mask != IIO_CHAN_INFO_RAW))
133 		return -EINVAL;
134 
135 	/* we support only illumination (_ALI) so far. */
136 	if (chan->type != IIO_LIGHT)
137 		return -EINVAL;
138 
139 	ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, &temp_val);
140 	if (ret < 0)
141 		return ret;
142 
143 	*val = temp_val;
144 
145 	return IIO_VAL_INT;
146 }
147 
148 static const struct iio_info acpi_als_info = {
149 	.read_raw		= acpi_als_read_raw,
150 };
151 
152 static irqreturn_t acpi_als_trigger_handler(int irq, void *p)
153 {
154 	struct iio_poll_func *pf = p;
155 	struct iio_dev *indio_dev = pf->indio_dev;
156 	struct acpi_als *als = iio_priv(indio_dev);
157 	s32 *buffer = als->evt_buffer;
158 	s32 val;
159 	int ret;
160 
161 	mutex_lock(&als->lock);
162 
163 	ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, &val);
164 	if (ret < 0)
165 		goto out;
166 	*buffer = val;
167 
168 	/*
169 	 * When coming from own trigger via polls, set polling function
170 	 * timestamp here. Given ACPI notifier is already in a thread and call
171 	 * function directly, there is no need to set the timestamp in the
172 	 * notify function.
173 	 *
174 	 * If the timestamp was actually 0, the timestamp is set one more time.
175 	 */
176 	if (!pf->timestamp)
177 		pf->timestamp = iio_get_time_ns(indio_dev);
178 
179 	iio_push_to_buffers_with_timestamp(indio_dev, buffer, pf->timestamp);
180 out:
181 	mutex_unlock(&als->lock);
182 	iio_trigger_notify_done(indio_dev->trig);
183 
184 	return IRQ_HANDLED;
185 }
186 
187 static int acpi_als_add(struct acpi_device *device)
188 {
189 	struct device *dev = &device->dev;
190 	struct iio_dev *indio_dev;
191 	struct acpi_als *als;
192 	int ret;
193 
194 	indio_dev = devm_iio_device_alloc(dev, sizeof(*als));
195 	if (!indio_dev)
196 		return -ENOMEM;
197 
198 	als = iio_priv(indio_dev);
199 
200 	device->driver_data = indio_dev;
201 	als->device = device;
202 	mutex_init(&als->lock);
203 
204 	indio_dev->name = ACPI_ALS_DEVICE_NAME;
205 	indio_dev->info = &acpi_als_info;
206 	indio_dev->channels = acpi_als_channels;
207 	indio_dev->num_channels = ARRAY_SIZE(acpi_als_channels);
208 
209 	als->trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name, indio_dev->id);
210 	if (!als->trig)
211 		return -ENOMEM;
212 
213 	ret = devm_iio_trigger_register(dev, als->trig);
214 	if (ret)
215 		return ret;
216 	/*
217 	 * Set hardware trigger by default to let events flow when
218 	 * BIOS support notification.
219 	 */
220 	indio_dev->trig = iio_trigger_get(als->trig);
221 
222 	ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
223 					      iio_pollfunc_store_time,
224 					      acpi_als_trigger_handler,
225 					      NULL);
226 	if (ret)
227 		return ret;
228 
229 	return devm_iio_device_register(dev, indio_dev);
230 }
231 
232 static const struct acpi_device_id acpi_als_device_ids[] = {
233 	{"ACPI0008", 0},
234 	{},
235 };
236 
237 MODULE_DEVICE_TABLE(acpi, acpi_als_device_ids);
238 
239 static struct acpi_driver acpi_als_driver = {
240 	.name	= "acpi_als",
241 	.class	= ACPI_ALS_CLASS,
242 	.ids	= acpi_als_device_ids,
243 	.ops = {
244 		.add	= acpi_als_add,
245 		.notify	= acpi_als_notify,
246 	},
247 };
248 
249 module_acpi_driver(acpi_als_driver);
250 
251 MODULE_AUTHOR("Zhang Rui <rui.zhang@intel.com>");
252 MODULE_AUTHOR("Martin Liska <marxin.liska@gmail.com>");
253 MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
254 MODULE_DESCRIPTION("ACPI Ambient Light Sensor Driver");
255 MODULE_LICENSE("GPL");
256