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 
20 #include <linux/iio/iio.h>
21 #include <linux/iio/sysfs.h>
22 
23 #define AL3320A_DRV_NAME "al3320a"
24 
25 #define AL3320A_REG_CONFIG		0x00
26 #define AL3320A_REG_STATUS		0x01
27 #define AL3320A_REG_INT			0x02
28 #define AL3320A_REG_WAIT		0x06
29 #define AL3320A_REG_CONFIG_RANGE	0x07
30 #define AL3320A_REG_PERSIST		0x08
31 #define AL3320A_REG_MEAN_TIME		0x09
32 #define AL3320A_REG_ADUMMY		0x0A
33 #define AL3320A_REG_DATA_LOW		0x22
34 
35 #define AL3320A_REG_LOW_THRESH_LOW	0x30
36 #define AL3320A_REG_LOW_THRESH_HIGH	0x31
37 #define AL3320A_REG_HIGH_THRESH_LOW	0x32
38 #define AL3320A_REG_HIGH_THRESH_HIGH	0x33
39 
40 #define AL3320A_CONFIG_DISABLE		0x00
41 #define AL3320A_CONFIG_ENABLE		0x01
42 
43 #define AL3320A_GAIN_MASK		GENMASK(2, 1)
44 
45 /* chip params default values */
46 #define AL3320A_DEFAULT_MEAN_TIME	4
47 #define AL3320A_DEFAULT_WAIT_TIME	0 /* no waiting */
48 
49 #define AL3320A_SCALE_AVAILABLE "0.512 0.128 0.032 0.01"
50 
51 enum al3320a_range {
52 	AL3320A_RANGE_1, /* 33.28 Klx */
53 	AL3320A_RANGE_2, /* 8.32 Klx  */
54 	AL3320A_RANGE_3, /* 2.08 Klx  */
55 	AL3320A_RANGE_4  /* 0.65 Klx  */
56 };
57 
58 static const int al3320a_scales[][2] = {
59 	{0, 512000}, {0, 128000}, {0, 32000}, {0, 10000}
60 };
61 
62 struct al3320a_data {
63 	struct i2c_client *client;
64 };
65 
66 static const struct iio_chan_spec al3320a_channels[] = {
67 	{
68 		.type	= IIO_LIGHT,
69 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
70 				      BIT(IIO_CHAN_INFO_SCALE),
71 	}
72 };
73 
74 static IIO_CONST_ATTR(in_illuminance_scale_available, AL3320A_SCALE_AVAILABLE);
75 
76 static struct attribute *al3320a_attributes[] = {
77 	&iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
78 	NULL,
79 };
80 
81 static const struct attribute_group al3320a_attribute_group = {
82 	.attrs = al3320a_attributes,
83 };
84 
al3320a_set_pwr(struct i2c_client * client,bool pwr)85 static int al3320a_set_pwr(struct i2c_client *client, bool pwr)
86 {
87 	u8 val = pwr ? AL3320A_CONFIG_ENABLE : AL3320A_CONFIG_DISABLE;
88 	return i2c_smbus_write_byte_data(client, AL3320A_REG_CONFIG, val);
89 }
90 
al3320a_set_pwr_off(void * _data)91 static void al3320a_set_pwr_off(void *_data)
92 {
93 	struct al3320a_data *data = _data;
94 
95 	al3320a_set_pwr(data->client, false);
96 }
97 
al3320a_init(struct al3320a_data * data)98 static int al3320a_init(struct al3320a_data *data)
99 {
100 	int ret;
101 
102 	ret = al3320a_set_pwr(data->client, true);
103 
104 	if (ret < 0)
105 		return ret;
106 
107 	ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG_RANGE,
108 					FIELD_PREP(AL3320A_GAIN_MASK,
109 						   AL3320A_RANGE_3));
110 	if (ret < 0)
111 		return ret;
112 
113 	ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_MEAN_TIME,
114 					AL3320A_DEFAULT_MEAN_TIME);
115 	if (ret < 0)
116 		return ret;
117 
118 	ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_WAIT,
119 					AL3320A_DEFAULT_WAIT_TIME);
120 	if (ret < 0)
121 		return ret;
122 
123 	return 0;
124 }
125 
al3320a_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)126 static int al3320a_read_raw(struct iio_dev *indio_dev,
127 			    struct iio_chan_spec const *chan, int *val,
128 			    int *val2, long mask)
129 {
130 	struct al3320a_data *data = iio_priv(indio_dev);
131 	int ret;
132 
133 	switch (mask) {
134 	case IIO_CHAN_INFO_RAW:
135 		/*
136 		 * ALS ADC value is stored in two adjacent registers:
137 		 * - low byte of output is stored at AL3320A_REG_DATA_LOW
138 		 * - high byte of output is stored at AL3320A_REG_DATA_LOW + 1
139 		 */
140 		ret = i2c_smbus_read_word_data(data->client,
141 					       AL3320A_REG_DATA_LOW);
142 		if (ret < 0)
143 			return ret;
144 		*val = ret;
145 		return IIO_VAL_INT;
146 	case IIO_CHAN_INFO_SCALE:
147 		ret = i2c_smbus_read_byte_data(data->client,
148 					       AL3320A_REG_CONFIG_RANGE);
149 		if (ret < 0)
150 			return ret;
151 
152 		ret = FIELD_GET(AL3320A_GAIN_MASK, ret);
153 		*val = al3320a_scales[ret][0];
154 		*val2 = al3320a_scales[ret][1];
155 
156 		return IIO_VAL_INT_PLUS_MICRO;
157 	}
158 	return -EINVAL;
159 }
160 
al3320a_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)161 static int al3320a_write_raw(struct iio_dev *indio_dev,
162 			     struct iio_chan_spec const *chan, int val,
163 			     int val2, long mask)
164 {
165 	struct al3320a_data *data = iio_priv(indio_dev);
166 	int i;
167 
168 	switch (mask) {
169 	case IIO_CHAN_INFO_SCALE:
170 		for (i = 0; i < ARRAY_SIZE(al3320a_scales); i++) {
171 			if (val != al3320a_scales[i][0] ||
172 			    val2 != al3320a_scales[i][1])
173 				continue;
174 
175 			return i2c_smbus_write_byte_data(data->client,
176 					AL3320A_REG_CONFIG_RANGE,
177 					FIELD_PREP(AL3320A_GAIN_MASK, i));
178 		}
179 		break;
180 	}
181 	return -EINVAL;
182 }
183 
184 static const struct iio_info al3320a_info = {
185 	.read_raw	= al3320a_read_raw,
186 	.write_raw	= al3320a_write_raw,
187 	.attrs		= &al3320a_attribute_group,
188 };
189 
al3320a_probe(struct i2c_client * client,const struct i2c_device_id * id)190 static int al3320a_probe(struct i2c_client *client,
191 			 const struct i2c_device_id *id)
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 __maybe_unused 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 __maybe_unused al3320a_resume(struct device *dev)
232 {
233 	return al3320a_set_pwr(to_i2c_client(dev), true);
234 }
235 
236 static SIMPLE_DEV_PM_OPS(al3320a_pm_ops, al3320a_suspend, al3320a_resume);
237 
238 static const struct i2c_device_id al3320a_id[] = {
239 	{"al3320a", 0},
240 	{}
241 };
242 MODULE_DEVICE_TABLE(i2c, al3320a_id);
243 
244 static const struct of_device_id al3320a_of_match[] = {
245 	{ .compatible = "dynaimage,al3320a", },
246 	{},
247 };
248 MODULE_DEVICE_TABLE(of, al3320a_of_match);
249 
250 static struct i2c_driver al3320a_driver = {
251 	.driver = {
252 		.name = AL3320A_DRV_NAME,
253 		.of_match_table = al3320a_of_match,
254 		.pm = &al3320a_pm_ops,
255 	},
256 	.probe		= al3320a_probe,
257 	.id_table	= al3320a_id,
258 };
259 
260 module_i2c_driver(al3320a_driver);
261 
262 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
263 MODULE_DESCRIPTION("AL3320A Ambient Light Sensor driver");
264 MODULE_LICENSE("GPL v2");
265