xref: /openbmc/linux/drivers/iio/light/al3320a.c (revision 7cf15f42)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * AL3320A - Dyna Image Ambient Light Sensor
4  *
5  * Copyright (c) 2014, Intel Corporation.
6  *
7  * IIO driver for AL3320A (7-bit I2C slave address 0x1C).
8  *
9  * TODO: interrupt support, thresholds
10  * When the driver will get support for interrupt handling, then interrupt
11  * will need to be disabled before turning sensor OFF in order to avoid
12  * potential races with the interrupt handling.
13  */
14 
15 #include <linux/bitfield.h>
16 #include <linux/i2c.h>
17 #include <linux/module.h>
18 #include <linux/of.h>
19 #include <linux/mod_devicetable.h>
20 
21 #include <linux/iio/iio.h>
22 #include <linux/iio/sysfs.h>
23 
24 #define AL3320A_DRV_NAME "al3320a"
25 
26 #define AL3320A_REG_CONFIG		0x00
27 #define AL3320A_REG_STATUS		0x01
28 #define AL3320A_REG_INT			0x02
29 #define AL3320A_REG_WAIT		0x06
30 #define AL3320A_REG_CONFIG_RANGE	0x07
31 #define AL3320A_REG_PERSIST		0x08
32 #define AL3320A_REG_MEAN_TIME		0x09
33 #define AL3320A_REG_ADUMMY		0x0A
34 #define AL3320A_REG_DATA_LOW		0x22
35 
36 #define AL3320A_REG_LOW_THRESH_LOW	0x30
37 #define AL3320A_REG_LOW_THRESH_HIGH	0x31
38 #define AL3320A_REG_HIGH_THRESH_LOW	0x32
39 #define AL3320A_REG_HIGH_THRESH_HIGH	0x33
40 
41 #define AL3320A_CONFIG_DISABLE		0x00
42 #define AL3320A_CONFIG_ENABLE		0x01
43 
44 #define AL3320A_GAIN_MASK		GENMASK(2, 1)
45 
46 /* chip params default values */
47 #define AL3320A_DEFAULT_MEAN_TIME	4
48 #define AL3320A_DEFAULT_WAIT_TIME	0 /* no waiting */
49 
50 #define AL3320A_SCALE_AVAILABLE "0.512 0.128 0.032 0.01"
51 
52 enum al3320a_range {
53 	AL3320A_RANGE_1, /* 33.28 Klx */
54 	AL3320A_RANGE_2, /* 8.32 Klx  */
55 	AL3320A_RANGE_3, /* 2.08 Klx  */
56 	AL3320A_RANGE_4  /* 0.65 Klx  */
57 };
58 
59 static const int al3320a_scales[][2] = {
60 	{0, 512000}, {0, 128000}, {0, 32000}, {0, 10000}
61 };
62 
63 struct al3320a_data {
64 	struct i2c_client *client;
65 };
66 
67 static const struct iio_chan_spec al3320a_channels[] = {
68 	{
69 		.type	= IIO_LIGHT,
70 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
71 				      BIT(IIO_CHAN_INFO_SCALE),
72 	}
73 };
74 
75 static IIO_CONST_ATTR(in_illuminance_scale_available, AL3320A_SCALE_AVAILABLE);
76 
77 static struct attribute *al3320a_attributes[] = {
78 	&iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
79 	NULL,
80 };
81 
82 static const struct attribute_group al3320a_attribute_group = {
83 	.attrs = al3320a_attributes,
84 };
85 
al3320a_set_pwr(struct i2c_client * client,bool pwr)86 static int al3320a_set_pwr(struct i2c_client *client, bool pwr)
87 {
88 	u8 val = pwr ? AL3320A_CONFIG_ENABLE : AL3320A_CONFIG_DISABLE;
89 	return i2c_smbus_write_byte_data(client, AL3320A_REG_CONFIG, val);
90 }
91 
al3320a_set_pwr_off(void * _data)92 static void al3320a_set_pwr_off(void *_data)
93 {
94 	struct al3320a_data *data = _data;
95 
96 	al3320a_set_pwr(data->client, false);
97 }
98 
al3320a_init(struct al3320a_data * data)99 static int al3320a_init(struct al3320a_data *data)
100 {
101 	int ret;
102 
103 	ret = al3320a_set_pwr(data->client, true);
104 
105 	if (ret < 0)
106 		return ret;
107 
108 	ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG_RANGE,
109 					FIELD_PREP(AL3320A_GAIN_MASK,
110 						   AL3320A_RANGE_3));
111 	if (ret < 0)
112 		return ret;
113 
114 	ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_MEAN_TIME,
115 					AL3320A_DEFAULT_MEAN_TIME);
116 	if (ret < 0)
117 		return ret;
118 
119 	ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_WAIT,
120 					AL3320A_DEFAULT_WAIT_TIME);
121 	if (ret < 0)
122 		return ret;
123 
124 	return 0;
125 }
126 
al3320a_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)127 static int al3320a_read_raw(struct iio_dev *indio_dev,
128 			    struct iio_chan_spec const *chan, int *val,
129 			    int *val2, long mask)
130 {
131 	struct al3320a_data *data = iio_priv(indio_dev);
132 	int ret;
133 
134 	switch (mask) {
135 	case IIO_CHAN_INFO_RAW:
136 		/*
137 		 * ALS ADC value is stored in two adjacent registers:
138 		 * - low byte of output is stored at AL3320A_REG_DATA_LOW
139 		 * - high byte of output is stored at AL3320A_REG_DATA_LOW + 1
140 		 */
141 		ret = i2c_smbus_read_word_data(data->client,
142 					       AL3320A_REG_DATA_LOW);
143 		if (ret < 0)
144 			return ret;
145 		*val = ret;
146 		return IIO_VAL_INT;
147 	case IIO_CHAN_INFO_SCALE:
148 		ret = i2c_smbus_read_byte_data(data->client,
149 					       AL3320A_REG_CONFIG_RANGE);
150 		if (ret < 0)
151 			return ret;
152 
153 		ret = FIELD_GET(AL3320A_GAIN_MASK, ret);
154 		*val = al3320a_scales[ret][0];
155 		*val2 = al3320a_scales[ret][1];
156 
157 		return IIO_VAL_INT_PLUS_MICRO;
158 	}
159 	return -EINVAL;
160 }
161 
al3320a_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)162 static int al3320a_write_raw(struct iio_dev *indio_dev,
163 			     struct iio_chan_spec const *chan, int val,
164 			     int val2, long mask)
165 {
166 	struct al3320a_data *data = iio_priv(indio_dev);
167 	int i;
168 
169 	switch (mask) {
170 	case IIO_CHAN_INFO_SCALE:
171 		for (i = 0; i < ARRAY_SIZE(al3320a_scales); i++) {
172 			if (val != al3320a_scales[i][0] ||
173 			    val2 != al3320a_scales[i][1])
174 				continue;
175 
176 			return i2c_smbus_write_byte_data(data->client,
177 					AL3320A_REG_CONFIG_RANGE,
178 					FIELD_PREP(AL3320A_GAIN_MASK, i));
179 		}
180 		break;
181 	}
182 	return -EINVAL;
183 }
184 
185 static const struct iio_info al3320a_info = {
186 	.read_raw	= al3320a_read_raw,
187 	.write_raw	= al3320a_write_raw,
188 	.attrs		= &al3320a_attribute_group,
189 };
190 
al3320a_probe(struct i2c_client * client)191 static int al3320a_probe(struct i2c_client *client)
192 {
193 	struct al3320a_data *data;
194 	struct iio_dev *indio_dev;
195 	int ret;
196 
197 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
198 	if (!indio_dev)
199 		return -ENOMEM;
200 
201 	data = iio_priv(indio_dev);
202 	i2c_set_clientdata(client, indio_dev);
203 	data->client = client;
204 
205 	indio_dev->info = &al3320a_info;
206 	indio_dev->name = AL3320A_DRV_NAME;
207 	indio_dev->channels = al3320a_channels;
208 	indio_dev->num_channels = ARRAY_SIZE(al3320a_channels);
209 	indio_dev->modes = INDIO_DIRECT_MODE;
210 
211 	ret = al3320a_init(data);
212 	if (ret < 0) {
213 		dev_err(&client->dev, "al3320a chip init failed\n");
214 		return ret;
215 	}
216 
217 	ret = devm_add_action_or_reset(&client->dev,
218 					al3320a_set_pwr_off,
219 					data);
220 	if (ret < 0)
221 		return ret;
222 
223 	return devm_iio_device_register(&client->dev, indio_dev);
224 }
225 
al3320a_suspend(struct device * dev)226 static int al3320a_suspend(struct device *dev)
227 {
228 	return al3320a_set_pwr(to_i2c_client(dev), false);
229 }
230 
al3320a_resume(struct device * dev)231 static int al3320a_resume(struct device *dev)
232 {
233 	return al3320a_set_pwr(to_i2c_client(dev), true);
234 }
235 
236 static DEFINE_SIMPLE_DEV_PM_OPS(al3320a_pm_ops, al3320a_suspend,
237 				al3320a_resume);
238 
239 static const struct i2c_device_id al3320a_id[] = {
240 	{"al3320a", 0},
241 	{}
242 };
243 MODULE_DEVICE_TABLE(i2c, al3320a_id);
244 
245 static const struct of_device_id al3320a_of_match[] = {
246 	{ .compatible = "dynaimage,al3320a", },
247 	{},
248 };
249 MODULE_DEVICE_TABLE(of, al3320a_of_match);
250 
251 static const struct acpi_device_id al3320a_acpi_match[] = {
252 	{"CALS0001"},
253 	{ },
254 };
255 MODULE_DEVICE_TABLE(acpi, al3320a_acpi_match);
256 
257 static struct i2c_driver al3320a_driver = {
258 	.driver = {
259 		.name = AL3320A_DRV_NAME,
260 		.of_match_table = al3320a_of_match,
261 		.pm = pm_sleep_ptr(&al3320a_pm_ops),
262 		.acpi_match_table = al3320a_acpi_match,
263 	},
264 	.probe		= al3320a_probe,
265 	.id_table	= al3320a_id,
266 };
267 
268 module_i2c_driver(al3320a_driver);
269 
270 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
271 MODULE_DESCRIPTION("AL3320A Ambient Light Sensor driver");
272 MODULE_LICENSE("GPL v2");
273