1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Support for ON Semiconductor NOA1305 ambient light sensor
4  *
5  * Copyright (C) 2016 Emcraft Systems
6  * Copyright (C) 2019 Collabora Ltd.
7  */
8 
9 #include <linux/delay.h>
10 #include <linux/err.h>
11 #include <linux/i2c.h>
12 #include <linux/iio/iio.h>
13 #include <linux/iio/sysfs.h>
14 #include <linux/module.h>
15 #include <linux/regmap.h>
16 #include <linux/regulator/consumer.h>
17 
18 #define NOA1305_REG_POWER_CONTROL	0x0
19 #define   NOA1305_POWER_CONTROL_DOWN	0x00
20 #define   NOA1305_POWER_CONTROL_ON	0x08
21 #define NOA1305_REG_RESET		0x1
22 #define   NOA1305_RESET_RESET		0x10
23 #define NOA1305_REG_INTEGRATION_TIME	0x2
24 #define   NOA1305_INTEGR_TIME_800MS	0x00
25 #define   NOA1305_INTEGR_TIME_400MS	0x01
26 #define   NOA1305_INTEGR_TIME_200MS	0x02
27 #define   NOA1305_INTEGR_TIME_100MS	0x03
28 #define   NOA1305_INTEGR_TIME_50MS	0x04
29 #define   NOA1305_INTEGR_TIME_25MS	0x05
30 #define   NOA1305_INTEGR_TIME_12_5MS	0x06
31 #define   NOA1305_INTEGR_TIME_6_25MS	0x07
32 #define NOA1305_REG_INT_SELECT		0x3
33 #define   NOA1305_INT_SEL_ACTIVE_HIGH	0x01
34 #define   NOA1305_INT_SEL_ACTIVE_LOW	0x02
35 #define   NOA1305_INT_SEL_INACTIVE	0x03
36 #define NOA1305_REG_INT_THRESH_LSB	0x4
37 #define NOA1305_REG_INT_THRESH_MSB	0x5
38 #define NOA1305_REG_ALS_DATA_LSB	0x6
39 #define NOA1305_REG_ALS_DATA_MSB	0x7
40 #define NOA1305_REG_DEVICE_ID_LSB	0x8
41 #define NOA1305_REG_DEVICE_ID_MSB	0x9
42 
43 #define NOA1305_DEVICE_ID	0x0519
44 #define NOA1305_DRIVER_NAME	"noa1305"
45 
46 struct noa1305_priv {
47 	struct i2c_client *client;
48 	struct regmap *regmap;
49 	struct regulator *vin_reg;
50 };
51 
noa1305_measure(struct noa1305_priv * priv)52 static int noa1305_measure(struct noa1305_priv *priv)
53 {
54 	__le16 data;
55 	int ret;
56 
57 	ret = regmap_bulk_read(priv->regmap, NOA1305_REG_ALS_DATA_LSB, &data,
58 			       2);
59 	if (ret < 0)
60 		return ret;
61 
62 	return le16_to_cpu(data);
63 }
64 
noa1305_scale(struct noa1305_priv * priv,int * val,int * val2)65 static int noa1305_scale(struct noa1305_priv *priv, int *val, int *val2)
66 {
67 	int data;
68 	int ret;
69 
70 	ret = regmap_read(priv->regmap, NOA1305_REG_INTEGRATION_TIME, &data);
71 	if (ret < 0)
72 		return ret;
73 
74 	/*
75 	 * Lux = count / (<Integration Constant> * <Integration Time>)
76 	 *
77 	 * Integration Constant = 7.7
78 	 * Integration Time in Seconds
79 	 */
80 	switch (data) {
81 	case NOA1305_INTEGR_TIME_800MS:
82 		*val = 100;
83 		*val2 = 77 * 8;
84 		break;
85 	case NOA1305_INTEGR_TIME_400MS:
86 		*val = 100;
87 		*val2 = 77 * 4;
88 		break;
89 	case NOA1305_INTEGR_TIME_200MS:
90 		*val = 100;
91 		*val2 = 77 * 2;
92 		break;
93 	case NOA1305_INTEGR_TIME_100MS:
94 		*val = 100;
95 		*val2 = 77;
96 		break;
97 	case NOA1305_INTEGR_TIME_50MS:
98 		*val = 1000;
99 		*val2 = 77 * 5;
100 		break;
101 	case NOA1305_INTEGR_TIME_25MS:
102 		*val = 10000;
103 		*val2 = 77 * 25;
104 		break;
105 	case NOA1305_INTEGR_TIME_12_5MS:
106 		*val = 100000;
107 		*val2 = 77 * 125;
108 		break;
109 	case NOA1305_INTEGR_TIME_6_25MS:
110 		*val = 1000000;
111 		*val2 = 77 * 625;
112 		break;
113 	default:
114 		return -EINVAL;
115 	}
116 
117 	return IIO_VAL_FRACTIONAL;
118 }
119 
120 static const struct iio_chan_spec noa1305_channels[] = {
121 	{
122 		.type = IIO_LIGHT,
123 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
124 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
125 	}
126 };
127 
noa1305_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)128 static int noa1305_read_raw(struct iio_dev *indio_dev,
129 				struct iio_chan_spec const *chan,
130 				int *val, int *val2, long mask)
131 {
132 	int ret = -EINVAL;
133 	struct noa1305_priv *priv = iio_priv(indio_dev);
134 
135 	switch (mask) {
136 	case IIO_CHAN_INFO_RAW:
137 		switch (chan->type) {
138 		case IIO_LIGHT:
139 			ret = noa1305_measure(priv);
140 			if (ret < 0)
141 				return ret;
142 			*val = ret;
143 			return IIO_VAL_INT;
144 		default:
145 			break;
146 		}
147 		break;
148 	case IIO_CHAN_INFO_SCALE:
149 		switch (chan->type) {
150 		case IIO_LIGHT:
151 			return noa1305_scale(priv, val, val2);
152 		default:
153 			break;
154 		}
155 		break;
156 	default:
157 		break;
158 	}
159 
160 	return ret;
161 }
162 
163 static const struct iio_info noa1305_info = {
164 	.read_raw = noa1305_read_raw,
165 };
166 
noa1305_writable_reg(struct device * dev,unsigned int reg)167 static bool noa1305_writable_reg(struct device *dev, unsigned int reg)
168 {
169 	switch (reg) {
170 	case NOA1305_REG_POWER_CONTROL:
171 	case NOA1305_REG_RESET:
172 	case NOA1305_REG_INTEGRATION_TIME:
173 	case NOA1305_REG_INT_SELECT:
174 	case NOA1305_REG_INT_THRESH_LSB:
175 	case NOA1305_REG_INT_THRESH_MSB:
176 		return true;
177 	default:
178 		return false;
179 	}
180 }
181 
182 static const struct regmap_config noa1305_regmap_config = {
183 	.name = NOA1305_DRIVER_NAME,
184 	.reg_bits = 8,
185 	.val_bits = 8,
186 	.max_register = NOA1305_REG_DEVICE_ID_MSB,
187 	.writeable_reg = noa1305_writable_reg,
188 };
189 
noa1305_reg_remove(void * data)190 static void noa1305_reg_remove(void *data)
191 {
192 	struct noa1305_priv *priv = data;
193 
194 	regulator_disable(priv->vin_reg);
195 }
196 
noa1305_probe(struct i2c_client * client,const struct i2c_device_id * id)197 static int noa1305_probe(struct i2c_client *client,
198 			 const struct i2c_device_id *id)
199 {
200 	struct noa1305_priv *priv;
201 	struct iio_dev *indio_dev;
202 	struct regmap *regmap;
203 	__le16 data;
204 	unsigned int dev_id;
205 	int ret;
206 
207 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*priv));
208 	if (!indio_dev)
209 		return -ENOMEM;
210 
211 	regmap = devm_regmap_init_i2c(client, &noa1305_regmap_config);
212 	if (IS_ERR(regmap)) {
213 		dev_err(&client->dev, "Regmap initialization failed.\n");
214 		return PTR_ERR(regmap);
215 	}
216 
217 	priv = iio_priv(indio_dev);
218 
219 	priv->vin_reg = devm_regulator_get(&client->dev, "vin");
220 	if (IS_ERR(priv->vin_reg))
221 		return dev_err_probe(&client->dev, PTR_ERR(priv->vin_reg),
222 				     "get regulator vin failed\n");
223 
224 	ret = regulator_enable(priv->vin_reg);
225 	if (ret) {
226 		dev_err(&client->dev, "enable regulator vin failed\n");
227 		return ret;
228 	}
229 
230 	ret = devm_add_action_or_reset(&client->dev, noa1305_reg_remove, priv);
231 	if (ret) {
232 		dev_err(&client->dev, "addition of devm action failed\n");
233 		return ret;
234 	}
235 
236 	i2c_set_clientdata(client, indio_dev);
237 	priv->client = client;
238 	priv->regmap = regmap;
239 
240 	ret = regmap_bulk_read(regmap, NOA1305_REG_DEVICE_ID_LSB, &data, 2);
241 	if (ret < 0) {
242 		dev_err(&client->dev, "ID reading failed: %d\n", ret);
243 		return ret;
244 	}
245 
246 	dev_id = le16_to_cpu(data);
247 	if (dev_id != NOA1305_DEVICE_ID) {
248 		dev_err(&client->dev, "Unknown device ID: 0x%x\n", dev_id);
249 		return -ENODEV;
250 	}
251 
252 	ret = regmap_write(regmap, NOA1305_REG_POWER_CONTROL,
253 			   NOA1305_POWER_CONTROL_ON);
254 	if (ret < 0) {
255 		dev_err(&client->dev, "Enabling power control failed\n");
256 		return ret;
257 	}
258 
259 	ret = regmap_write(regmap, NOA1305_REG_RESET, NOA1305_RESET_RESET);
260 	if (ret < 0) {
261 		dev_err(&client->dev, "Device reset failed\n");
262 		return ret;
263 	}
264 
265 	ret = regmap_write(regmap, NOA1305_REG_INTEGRATION_TIME,
266 			   NOA1305_INTEGR_TIME_800MS);
267 	if (ret < 0) {
268 		dev_err(&client->dev, "Setting integration time failed\n");
269 		return ret;
270 	}
271 
272 	indio_dev->info = &noa1305_info;
273 	indio_dev->channels = noa1305_channels;
274 	indio_dev->num_channels = ARRAY_SIZE(noa1305_channels);
275 	indio_dev->name = NOA1305_DRIVER_NAME;
276 	indio_dev->modes = INDIO_DIRECT_MODE;
277 
278 	ret = devm_iio_device_register(&client->dev, indio_dev);
279 	if (ret)
280 		dev_err(&client->dev, "registering device failed\n");
281 
282 	return ret;
283 }
284 
285 static const struct of_device_id noa1305_of_match[] = {
286 	{ .compatible = "onnn,noa1305" },
287 	{ }
288 };
289 MODULE_DEVICE_TABLE(of, noa1305_of_match);
290 
291 static const struct i2c_device_id noa1305_ids[] = {
292 	{ "noa1305", 0 },
293 	{ }
294 };
295 MODULE_DEVICE_TABLE(i2c, noa1305_ids);
296 
297 static struct i2c_driver noa1305_driver = {
298 	.driver = {
299 		.name		= NOA1305_DRIVER_NAME,
300 		.of_match_table	= noa1305_of_match,
301 	},
302 	.probe		= noa1305_probe,
303 	.id_table	= noa1305_ids,
304 };
305 
306 module_i2c_driver(noa1305_driver);
307 
308 MODULE_AUTHOR("Sergei Miroshnichenko <sergeimir@emcraft.com>");
309 MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.com");
310 MODULE_DESCRIPTION("ON Semiconductor NOA1305 ambient light sensor");
311 MODULE_LICENSE("GPL");
312