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/regmap.h>
19 #include <linux/mod_devicetable.h>
20 
21 #include <linux/iio/iio.h>
22 #include <linux/iio/sysfs.h>
23 
24 #define AL3320A_REG_CONFIG		0x00
25 #define AL3320A_REG_STATUS		0x01
26 #define AL3320A_REG_INT			0x02
27 #define AL3320A_REG_WAIT		0x06
28 #define AL3320A_REG_CONFIG_RANGE	0x07
29 #define AL3320A_REG_PERSIST		0x08
30 #define AL3320A_REG_MEAN_TIME		0x09
31 #define AL3320A_REG_ADUMMY		0x0A
32 #define AL3320A_REG_DATA_LOW		0x22
33 
34 #define AL3320A_REG_LOW_THRESH_LOW	0x30
35 #define AL3320A_REG_LOW_THRESH_HIGH	0x31
36 #define AL3320A_REG_HIGH_THRESH_LOW	0x32
37 #define AL3320A_REG_HIGH_THRESH_HIGH	0x33
38 
39 #define AL3320A_CONFIG_DISABLE		0x00
40 #define AL3320A_CONFIG_ENABLE		0x01
41 
42 #define AL3320A_GAIN_MASK		GENMASK(2, 1)
43 
44 /* chip params default values */
45 #define AL3320A_DEFAULT_MEAN_TIME	4
46 #define AL3320A_DEFAULT_WAIT_TIME	0 /* no waiting */
47 
48 #define AL3320A_SCALE_AVAILABLE "0.512 0.128 0.032 0.01"
49 
50 enum al3320a_range {
51 	AL3320A_RANGE_1, /* 33.28 Klx */
52 	AL3320A_RANGE_2, /* 8.32 Klx  */
53 	AL3320A_RANGE_3, /* 2.08 Klx  */
54 	AL3320A_RANGE_4  /* 0.65 Klx  */
55 };
56 
57 static const int al3320a_scales[][2] = {
58 	{0, 512000}, {0, 128000}, {0, 32000}, {0, 10000}
59 };
60 
61 static const struct regmap_config al3320a_regmap_config = {
62 	.reg_bits = 8,
63 	.val_bits = 8,
64 	.max_register = AL3320A_REG_HIGH_THRESH_HIGH,
65 };
66 
67 struct al3320a_data {
68 	struct regmap *regmap;
69 };
70 
71 static const struct iio_chan_spec al3320a_channels[] = {
72 	{
73 		.type	= IIO_LIGHT,
74 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
75 				      BIT(IIO_CHAN_INFO_SCALE),
76 	}
77 };
78 
79 static IIO_CONST_ATTR(in_illuminance_scale_available, AL3320A_SCALE_AVAILABLE);
80 
81 static struct attribute *al3320a_attributes[] = {
82 	&iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
83 	NULL,
84 };
85 
86 static const struct attribute_group al3320a_attribute_group = {
87 	.attrs = al3320a_attributes,
88 };
89 
90 static int al3320a_set_pwr_on(struct al3320a_data *data)
91 {
92 	return regmap_write(data->regmap, AL3320A_REG_CONFIG, AL3320A_CONFIG_ENABLE);
93 }
94 
95 static void al3320a_set_pwr_off(void *_data)
96 {
97 	struct al3320a_data *data = _data;
98 	struct device *dev = regmap_get_device(data->regmap);
99 	int ret;
100 
101 	ret = regmap_write(data->regmap, AL3320A_REG_CONFIG, AL3320A_CONFIG_DISABLE);
102 	if (ret)
103 		dev_err(dev, "failed to write system register\n");
104 }
105 
106 static int al3320a_init(struct al3320a_data *data)
107 {
108 	struct device *dev = regmap_get_device(data->regmap);
109 	int ret;
110 
111 	ret = al3320a_set_pwr_on(data);
112 	if (ret)
113 		return ret;
114 
115 	ret = devm_add_action_or_reset(dev, al3320a_set_pwr_off, data);
116 	if (ret)
117 		return ret;
118 
119 	ret = regmap_write(data->regmap, AL3320A_REG_CONFIG_RANGE,
120 			   FIELD_PREP(AL3320A_GAIN_MASK, AL3320A_RANGE_3));
121 	if (ret)
122 		return ret;
123 
124 	ret = regmap_write(data->regmap, AL3320A_REG_MEAN_TIME,
125 			   AL3320A_DEFAULT_MEAN_TIME);
126 	if (ret)
127 		return ret;
128 
129 	return regmap_write(data->regmap, AL3320A_REG_WAIT,
130 			    AL3320A_DEFAULT_WAIT_TIME);
131 }
132 
133 static int al3320a_read_raw(struct iio_dev *indio_dev,
134 			    struct iio_chan_spec const *chan, int *val,
135 			    int *val2, long mask)
136 {
137 	struct al3320a_data *data = iio_priv(indio_dev);
138 	int ret, gain, raw;
139 
140 	switch (mask) {
141 	case IIO_CHAN_INFO_RAW:
142 		/*
143 		 * ALS ADC value is stored in two adjacent registers:
144 		 * - low byte of output is stored at AL3320A_REG_DATA_LOW
145 		 * - high byte of output is stored at AL3320A_REG_DATA_LOW + 1
146 		 */
147 		ret = regmap_read(data->regmap, AL3320A_REG_DATA_LOW, &raw);
148 		if (ret)
149 			return ret;
150 
151 		*val = raw;
152 
153 		return IIO_VAL_INT;
154 	case IIO_CHAN_INFO_SCALE:
155 		ret = regmap_read(data->regmap, AL3320A_REG_CONFIG_RANGE, &gain);
156 		if (ret)
157 			return ret;
158 
159 		gain = FIELD_GET(AL3320A_GAIN_MASK, gain);
160 		*val = al3320a_scales[gain][0];
161 		*val2 = al3320a_scales[gain][1];
162 
163 		return IIO_VAL_INT_PLUS_MICRO;
164 	}
165 	return -EINVAL;
166 }
167 
168 static int al3320a_write_raw(struct iio_dev *indio_dev,
169 			     struct iio_chan_spec const *chan, int val,
170 			     int val2, long mask)
171 {
172 	struct al3320a_data *data = iio_priv(indio_dev);
173 	unsigned int i;
174 
175 	switch (mask) {
176 	case IIO_CHAN_INFO_SCALE:
177 		for (i = 0; i < ARRAY_SIZE(al3320a_scales); i++) {
178 			if (val != al3320a_scales[i][0] ||
179 			    val2 != al3320a_scales[i][1])
180 				continue;
181 
182 			return regmap_write(data->regmap, AL3320A_REG_CONFIG_RANGE,
183 					    FIELD_PREP(AL3320A_GAIN_MASK, i));
184 		}
185 		break;
186 	}
187 	return -EINVAL;
188 }
189 
190 static const struct iio_info al3320a_info = {
191 	.read_raw	= al3320a_read_raw,
192 	.write_raw	= al3320a_write_raw,
193 	.attrs		= &al3320a_attribute_group,
194 };
195 
196 static int al3320a_probe(struct i2c_client *client)
197 {
198 	struct al3320a_data *data;
199 	struct device *dev = &client->dev;
200 	struct iio_dev *indio_dev;
201 	int ret;
202 
203 	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
204 	if (!indio_dev)
205 		return -ENOMEM;
206 
207 	data = iio_priv(indio_dev);
208 	i2c_set_clientdata(client, indio_dev);
209 
210 	data->regmap = devm_regmap_init_i2c(client, &al3320a_regmap_config);
211 	if (IS_ERR(data->regmap))
212 		return dev_err_probe(dev, PTR_ERR(data->regmap),
213 				     "cannot allocate regmap\n");
214 
215 	indio_dev->info = &al3320a_info;
216 	indio_dev->name = "al3320a";
217 	indio_dev->channels = al3320a_channels;
218 	indio_dev->num_channels = ARRAY_SIZE(al3320a_channels);
219 	indio_dev->modes = INDIO_DIRECT_MODE;
220 
221 	ret = al3320a_init(data);
222 	if (ret < 0) {
223 		dev_err(dev, "al3320a chip init failed\n");
224 		return ret;
225 	}
226 
227 	return devm_iio_device_register(dev, indio_dev);
228 }
229 
230 static int al3320a_suspend(struct device *dev)
231 {
232 	struct al3320a_data *data = iio_priv(dev_get_drvdata(dev));
233 
234 	al3320a_set_pwr_off(data);
235 	return 0;
236 }
237 
238 static int al3320a_resume(struct device *dev)
239 {
240 	struct al3320a_data *data = iio_priv(dev_get_drvdata(dev));
241 
242 	return al3320a_set_pwr_on(data);
243 }
244 
245 static DEFINE_SIMPLE_DEV_PM_OPS(al3320a_pm_ops, al3320a_suspend,
246 				al3320a_resume);
247 
248 static const struct i2c_device_id al3320a_id[] = {
249 	{ "al3320a" },
250 	{ }
251 };
252 MODULE_DEVICE_TABLE(i2c, al3320a_id);
253 
254 static const struct of_device_id al3320a_of_match[] = {
255 	{ .compatible = "dynaimage,al3320a", },
256 	{ }
257 };
258 MODULE_DEVICE_TABLE(of, al3320a_of_match);
259 
260 static const struct acpi_device_id al3320a_acpi_match[] = {
261 	{"CALS0001"},
262 	{ }
263 };
264 MODULE_DEVICE_TABLE(acpi, al3320a_acpi_match);
265 
266 static struct i2c_driver al3320a_driver = {
267 	.driver = {
268 		.name = "al3320a",
269 		.of_match_table = al3320a_of_match,
270 		.pm = pm_sleep_ptr(&al3320a_pm_ops),
271 		.acpi_match_table = al3320a_acpi_match,
272 	},
273 	.probe		= al3320a_probe,
274 	.id_table	= al3320a_id,
275 };
276 
277 module_i2c_driver(al3320a_driver);
278 
279 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
280 MODULE_DESCRIPTION("AL3320A Ambient Light Sensor driver");
281 MODULE_LICENSE("GPL v2");
282