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
39static 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
54static 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
75static 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
89static 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
114static 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
152static 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
169static 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
217static int st_uvis25_buffer_preenable(struct iio_dev *iio_dev)
218{
219	return st_uvis25_set_enable(iio_priv(iio_dev), true);
220}
221
222static int st_uvis25_buffer_postdisable(struct iio_dev *iio_dev)
223{
224	return st_uvis25_set_enable(iio_priv(iio_dev), false);
225}
226
227static const struct iio_buffer_setup_ops st_uvis25_buffer_ops = {
228	.preenable = st_uvis25_buffer_preenable,
229	.postdisable = st_uvis25_buffer_postdisable,
230};
231
232static 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
249out:
250	iio_trigger_notify_done(hw->trig);
251
252	return IRQ_HANDLED;
253}
254
255static 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
265static const struct iio_info st_uvis25_info = {
266	.read_raw = st_uvis25_read_raw,
267};
268
269static 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
284int 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}
326EXPORT_SYMBOL_NS(st_uvis25_probe, IIO_UVIS25);
327
328static 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
337static 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
349EXPORT_NS_SIMPLE_DEV_PM_OPS(st_uvis25_pm_ops, st_uvis25_suspend, st_uvis25_resume, IIO_UVIS25);
350
351MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>");
352MODULE_DESCRIPTION("STMicroelectronics uvis25 sensor driver");
353MODULE_LICENSE("GPL v2");
354