1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * STMicroelectronics uvis25 sensor driver
4  *
5  * Copyright 2017 STMicroelectronics Inc.
6  *
7  * Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
8  */
9 
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/device.h>
13 #include <linux/iio/sysfs.h>
14 #include <linux/delay.h>
15 #include <linux/pm.h>
16 #include <linux/interrupt.h>
17 #include <linux/irqreturn.h>
18 #include <linux/iio/trigger.h>
19 #include <linux/iio/trigger_consumer.h>
20 #include <linux/iio/triggered_buffer.h>
21 #include <linux/iio/buffer.h>
22 #include <linux/regmap.h>
23 
24 #include "st_uvis25.h"
25 
26 #define ST_UVIS25_REG_WHOAMI_ADDR	0x0f
27 #define ST_UVIS25_REG_WHOAMI_VAL	0xca
28 #define ST_UVIS25_REG_CTRL1_ADDR	0x20
29 #define ST_UVIS25_REG_ODR_MASK		BIT(0)
30 #define ST_UVIS25_REG_BDU_MASK		BIT(1)
31 #define ST_UVIS25_REG_CTRL2_ADDR	0x21
32 #define ST_UVIS25_REG_BOOT_MASK		BIT(7)
33 #define ST_UVIS25_REG_CTRL3_ADDR	0x22
34 #define ST_UVIS25_REG_HL_MASK		BIT(7)
35 #define ST_UVIS25_REG_STATUS_ADDR	0x27
36 #define ST_UVIS25_REG_UV_DA_MASK	BIT(0)
37 #define ST_UVIS25_REG_OUT_ADDR		0x28
38 
39 static const struct iio_chan_spec st_uvis25_channels[] = {
40 	{
41 		.type = IIO_UVINDEX,
42 		.address = ST_UVIS25_REG_OUT_ADDR,
43 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
44 		.scan_index = 0,
45 		.scan_type = {
46 			.sign = 'u',
47 			.realbits = 8,
48 			.storagebits = 8,
49 		},
50 	},
51 	IIO_CHAN_SOFT_TIMESTAMP(1),
52 };
53 
54 static int st_uvis25_check_whoami(struct st_uvis25_hw *hw)
55 {
56 	int err, data;
57 
58 	err = regmap_read(hw->regmap, ST_UVIS25_REG_WHOAMI_ADDR, &data);
59 	if (err < 0) {
60 		dev_err(regmap_get_device(hw->regmap),
61 			"failed to read whoami register\n");
62 		return err;
63 	}
64 
65 	if (data != ST_UVIS25_REG_WHOAMI_VAL) {
66 		dev_err(regmap_get_device(hw->regmap),
67 			"wrong whoami {%02x vs %02x}\n",
68 			data, ST_UVIS25_REG_WHOAMI_VAL);
69 		return -ENODEV;
70 	}
71 
72 	return 0;
73 }
74 
75 static int st_uvis25_set_enable(struct st_uvis25_hw *hw, bool enable)
76 {
77 	int err;
78 
79 	err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
80 				 ST_UVIS25_REG_ODR_MASK, enable);
81 	if (err < 0)
82 		return err;
83 
84 	hw->enabled = enable;
85 
86 	return 0;
87 }
88 
89 static int st_uvis25_read_oneshot(struct st_uvis25_hw *hw, u8 addr, int *val)
90 {
91 	int err;
92 
93 	err = st_uvis25_set_enable(hw, true);
94 	if (err < 0)
95 		return err;
96 
97 	msleep(1500);
98 
99 	/*
100 	 * in order to avoid possible race conditions with interrupt
101 	 * generation, disable the sensor first and then poll output
102 	 * register. That sequence guarantees the interrupt will be reset
103 	 * when irq line is unmasked
104 	 */
105 	err = st_uvis25_set_enable(hw, false);
106 	if (err < 0)
107 		return err;
108 
109 	err = regmap_read(hw->regmap, addr, val);
110 
111 	return err < 0 ? err : IIO_VAL_INT;
112 }
113 
114 static int st_uvis25_read_raw(struct iio_dev *iio_dev,
115 			      struct iio_chan_spec const *ch,
116 			      int *val, int *val2, long mask)
117 {
118 	int ret;
119 
120 	ret = iio_device_claim_direct_mode(iio_dev);
121 	if (ret)
122 		return ret;
123 
124 	switch (mask) {
125 	case IIO_CHAN_INFO_PROCESSED: {
126 		struct st_uvis25_hw *hw = iio_priv(iio_dev);
127 
128 		/*
129 		 * mask irq line during oneshot read since the sensor
130 		 * does not export the capability to disable data-ready line
131 		 * in the register map and it is enabled by default.
132 		 * If the line is unmasked during read_raw() it will be set
133 		 * active and never reset since the trigger is disabled
134 		 */
135 		if (hw->irq > 0)
136 			disable_irq(hw->irq);
137 		ret = st_uvis25_read_oneshot(hw, ch->address, val);
138 		if (hw->irq > 0)
139 			enable_irq(hw->irq);
140 		break;
141 	}
142 	default:
143 		ret = -EINVAL;
144 		break;
145 	}
146 
147 	iio_device_release_direct_mode(iio_dev);
148 
149 	return ret;
150 }
151 
152 static irqreturn_t st_uvis25_trigger_handler_thread(int irq, void *private)
153 {
154 	struct st_uvis25_hw *hw = private;
155 	int err, status;
156 
157 	err = regmap_read(hw->regmap, ST_UVIS25_REG_STATUS_ADDR, &status);
158 	if (err < 0)
159 		return IRQ_HANDLED;
160 
161 	if (!(status & ST_UVIS25_REG_UV_DA_MASK))
162 		return IRQ_NONE;
163 
164 	iio_trigger_poll_nested(hw->trig);
165 
166 	return IRQ_HANDLED;
167 }
168 
169 static int st_uvis25_allocate_trigger(struct iio_dev *iio_dev)
170 {
171 	struct st_uvis25_hw *hw = iio_priv(iio_dev);
172 	struct device *dev = regmap_get_device(hw->regmap);
173 	bool irq_active_low = false;
174 	unsigned long irq_type;
175 	int err;
176 
177 	irq_type = irqd_get_trigger_type(irq_get_irq_data(hw->irq));
178 
179 	switch (irq_type) {
180 	case IRQF_TRIGGER_HIGH:
181 	case IRQF_TRIGGER_RISING:
182 		break;
183 	case IRQF_TRIGGER_LOW:
184 	case IRQF_TRIGGER_FALLING:
185 		irq_active_low = true;
186 		break;
187 	default:
188 		dev_info(dev, "mode %lx unsupported\n", irq_type);
189 		return -EINVAL;
190 	}
191 
192 	err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL3_ADDR,
193 				 ST_UVIS25_REG_HL_MASK, irq_active_low);
194 	if (err < 0)
195 		return err;
196 
197 	err = devm_request_threaded_irq(dev, hw->irq, NULL,
198 					st_uvis25_trigger_handler_thread,
199 					irq_type | IRQF_ONESHOT,
200 					iio_dev->name, hw);
201 	if (err) {
202 		dev_err(dev, "failed to request trigger irq %d\n",
203 			hw->irq);
204 		return err;
205 	}
206 
207 	hw->trig = devm_iio_trigger_alloc(dev, "%s-trigger",
208 					  iio_dev->name);
209 	if (!hw->trig)
210 		return -ENOMEM;
211 
212 	iio_trigger_set_drvdata(hw->trig, iio_dev);
213 
214 	return devm_iio_trigger_register(dev, hw->trig);
215 }
216 
217 static int st_uvis25_buffer_preenable(struct iio_dev *iio_dev)
218 {
219 	return st_uvis25_set_enable(iio_priv(iio_dev), true);
220 }
221 
222 static int st_uvis25_buffer_postdisable(struct iio_dev *iio_dev)
223 {
224 	return st_uvis25_set_enable(iio_priv(iio_dev), false);
225 }
226 
227 static const struct iio_buffer_setup_ops st_uvis25_buffer_ops = {
228 	.preenable = st_uvis25_buffer_preenable,
229 	.postdisable = st_uvis25_buffer_postdisable,
230 };
231 
232 static irqreturn_t st_uvis25_buffer_handler_thread(int irq, void *p)
233 {
234 	struct iio_poll_func *pf = p;
235 	struct iio_dev *iio_dev = pf->indio_dev;
236 	struct st_uvis25_hw *hw = iio_priv(iio_dev);
237 	unsigned int val;
238 	int err;
239 
240 	err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, &val);
241 	if (err < 0)
242 		goto out;
243 
244 	hw->scan.chan = val;
245 
246 	iio_push_to_buffers_with_timestamp(iio_dev, &hw->scan,
247 					   iio_get_time_ns(iio_dev));
248 
249 out:
250 	iio_trigger_notify_done(hw->trig);
251 
252 	return IRQ_HANDLED;
253 }
254 
255 static int st_uvis25_allocate_buffer(struct iio_dev *iio_dev)
256 {
257 	struct st_uvis25_hw *hw = iio_priv(iio_dev);
258 
259 	return devm_iio_triggered_buffer_setup(regmap_get_device(hw->regmap),
260 					       iio_dev, NULL,
261 					       st_uvis25_buffer_handler_thread,
262 					       &st_uvis25_buffer_ops);
263 }
264 
265 static const struct iio_info st_uvis25_info = {
266 	.read_raw = st_uvis25_read_raw,
267 };
268 
269 static int st_uvis25_init_sensor(struct st_uvis25_hw *hw)
270 {
271 	int err;
272 
273 	err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL2_ADDR,
274 				 ST_UVIS25_REG_BOOT_MASK, 1);
275 	if (err < 0)
276 		return err;
277 
278 	msleep(2000);
279 
280 	return regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
281 				  ST_UVIS25_REG_BDU_MASK, 1);
282 }
283 
284 int st_uvis25_probe(struct device *dev, int irq, struct regmap *regmap)
285 {
286 	struct st_uvis25_hw *hw;
287 	struct iio_dev *iio_dev;
288 	int err;
289 
290 	iio_dev = devm_iio_device_alloc(dev, sizeof(*hw));
291 	if (!iio_dev)
292 		return -ENOMEM;
293 
294 	dev_set_drvdata(dev, (void *)iio_dev);
295 
296 	hw = iio_priv(iio_dev);
297 	hw->irq = irq;
298 	hw->regmap = regmap;
299 
300 	err = st_uvis25_check_whoami(hw);
301 	if (err < 0)
302 		return err;
303 
304 	iio_dev->modes = INDIO_DIRECT_MODE;
305 	iio_dev->channels = st_uvis25_channels;
306 	iio_dev->num_channels = ARRAY_SIZE(st_uvis25_channels);
307 	iio_dev->name = ST_UVIS25_DEV_NAME;
308 	iio_dev->info = &st_uvis25_info;
309 
310 	err = st_uvis25_init_sensor(hw);
311 	if (err < 0)
312 		return err;
313 
314 	if (hw->irq > 0) {
315 		err = st_uvis25_allocate_buffer(iio_dev);
316 		if (err < 0)
317 			return err;
318 
319 		err = st_uvis25_allocate_trigger(iio_dev);
320 		if (err)
321 			return err;
322 	}
323 
324 	return devm_iio_device_register(dev, iio_dev);
325 }
326 EXPORT_SYMBOL_NS(st_uvis25_probe, IIO_UVIS25);
327 
328 static int st_uvis25_suspend(struct device *dev)
329 {
330 	struct iio_dev *iio_dev = dev_get_drvdata(dev);
331 	struct st_uvis25_hw *hw = iio_priv(iio_dev);
332 
333 	return regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
334 				  ST_UVIS25_REG_ODR_MASK, 0);
335 }
336 
337 static int st_uvis25_resume(struct device *dev)
338 {
339 	struct iio_dev *iio_dev = dev_get_drvdata(dev);
340 	struct st_uvis25_hw *hw = iio_priv(iio_dev);
341 
342 	if (hw->enabled)
343 		return regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
344 					  ST_UVIS25_REG_ODR_MASK, 1);
345 
346 	return 0;
347 }
348 
349 EXPORT_NS_SIMPLE_DEV_PM_OPS(st_uvis25_pm_ops, st_uvis25_suspend, st_uvis25_resume, IIO_UVIS25);
350 
351 MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>");
352 MODULE_DESCRIPTION("STMicroelectronics uvis25 sensor driver");
353 MODULE_LICENSE("GPL v2");
354