st_uvis25_core.c

  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	if (!iio_device_claim_direct(iio_dev))
121		return -EBUSY;
122
123	switch (mask) {
124	case IIO_CHAN_INFO_PROCESSED: {
125		struct st_uvis25_hw *hw = iio_priv(iio_dev);
126
127		/*
128		 * mask irq line during oneshot read since the sensor
129		 * does not export the capability to disable data-ready line
130		 * in the register map and it is enabled by default.
131		 * If the line is unmasked during read_raw() it will be set
132		 * active and never reset since the trigger is disabled
133		 */
134		if (hw->irq > 0)
135			disable_irq(hw->irq);
136		ret = st_uvis25_read_oneshot(hw, ch->address, val);
137		if (hw->irq > 0)
138			enable_irq(hw->irq);
139		break;
140	}
141	default:
142		ret = -EINVAL;
143		break;
144	}
145
146	iio_device_release_direct(iio_dev);
147
148	return ret;
149}
150
151static irqreturn_t st_uvis25_trigger_handler_thread(int irq, void *private)
152{
153	struct st_uvis25_hw *hw = private;
154	int err, status;
155
156	err = regmap_read(hw->regmap, ST_UVIS25_REG_STATUS_ADDR, &status);
157	if (err < 0)
158		return IRQ_HANDLED;
159
160	if (!(status & ST_UVIS25_REG_UV_DA_MASK))
161		return IRQ_NONE;
162
163	iio_trigger_poll_nested(hw->trig);
164
165	return IRQ_HANDLED;
166}
167
168static int st_uvis25_allocate_trigger(struct iio_dev *iio_dev)
169{
170	struct st_uvis25_hw *hw = iio_priv(iio_dev);
171	struct device *dev = regmap_get_device(hw->regmap);
172	bool irq_active_low = false;
173	unsigned long irq_type;
174	int err;
175
176	irq_type = irq_get_trigger_type(hw->irq);
177	switch (irq_type) {
178	case IRQF_TRIGGER_HIGH:
179	case IRQF_TRIGGER_RISING:
180		break;
181	case IRQF_TRIGGER_LOW:
182	case IRQF_TRIGGER_FALLING:
183		irq_active_low = true;
184		break;
185	default:
186		dev_info(dev, "mode %lx unsupported\n", irq_type);
187		return -EINVAL;
188	}
189
190	err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL3_ADDR,
191				 ST_UVIS25_REG_HL_MASK, irq_active_low);
192	if (err < 0)
193		return err;
194
195	err = devm_request_threaded_irq(dev, hw->irq, NULL,
196					st_uvis25_trigger_handler_thread,
197					irq_type | IRQF_ONESHOT,
198					iio_dev->name, hw);
199	if (err) {
200		dev_err(dev, "failed to request trigger irq %d\n",
201			hw->irq);
202		return err;
203	}
204
205	hw->trig = devm_iio_trigger_alloc(dev, "%s-trigger",
206					  iio_dev->name);
207	if (!hw->trig)
208		return -ENOMEM;
209
210	iio_trigger_set_drvdata(hw->trig, iio_dev);
211
212	return devm_iio_trigger_register(dev, hw->trig);
213}
214
215static int st_uvis25_buffer_preenable(struct iio_dev *iio_dev)
216{
217	return st_uvis25_set_enable(iio_priv(iio_dev), true);
218}
219
220static int st_uvis25_buffer_postdisable(struct iio_dev *iio_dev)
221{
222	return st_uvis25_set_enable(iio_priv(iio_dev), false);
223}
224
225static const struct iio_buffer_setup_ops st_uvis25_buffer_ops = {
226	.preenable = st_uvis25_buffer_preenable,
227	.postdisable = st_uvis25_buffer_postdisable,
228};
229
230static irqreturn_t st_uvis25_buffer_handler_thread(int irq, void *p)
231{
232	struct iio_poll_func *pf = p;
233	struct iio_dev *iio_dev = pf->indio_dev;
234	struct st_uvis25_hw *hw = iio_priv(iio_dev);
235	unsigned int val;
236	int err;
237	/* Ensure timestamp is naturally aligned */
238	struct {
239		u8 chan;
240		aligned_s64 ts;
241	} scan = { };
242
243
244	err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, &val);
245	if (err < 0)
246		goto out;
247
248	scan.chan = val;
249
250	iio_push_to_buffers_with_ts(iio_dev, &scan, sizeof(scan),
251				    iio_get_time_ns(iio_dev));
252
253out:
254	iio_trigger_notify_done(hw->trig);
255
256	return IRQ_HANDLED;
257}
258
259static int st_uvis25_allocate_buffer(struct iio_dev *iio_dev)
260{
261	struct st_uvis25_hw *hw = iio_priv(iio_dev);
262
263	return devm_iio_triggered_buffer_setup(regmap_get_device(hw->regmap),
264					       iio_dev, NULL,
265					       st_uvis25_buffer_handler_thread,
266					       &st_uvis25_buffer_ops);
267}
268
269static const struct iio_info st_uvis25_info = {
270	.read_raw = st_uvis25_read_raw,
271};
272
273static int st_uvis25_init_sensor(struct st_uvis25_hw *hw)
274{
275	int err;
276
277	err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL2_ADDR,
278				 ST_UVIS25_REG_BOOT_MASK, 1);
279	if (err < 0)
280		return err;
281
282	msleep(2000);
283
284	return regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
285				  ST_UVIS25_REG_BDU_MASK, 1);
286}
287
288int st_uvis25_probe(struct device *dev, int irq, struct regmap *regmap)
289{
290	struct st_uvis25_hw *hw;
291	struct iio_dev *iio_dev;
292	int err;
293
294	iio_dev = devm_iio_device_alloc(dev, sizeof(*hw));
295	if (!iio_dev)
296		return -ENOMEM;
297
298	dev_set_drvdata(dev, iio_dev);
299
300	hw = iio_priv(iio_dev);
301	hw->irq = irq;
302	hw->regmap = regmap;
303
304	err = st_uvis25_check_whoami(hw);
305	if (err < 0)
306		return err;
307
308	iio_dev->modes = INDIO_DIRECT_MODE;
309	iio_dev->channels = st_uvis25_channels;
310	iio_dev->num_channels = ARRAY_SIZE(st_uvis25_channels);
311	iio_dev->name = ST_UVIS25_DEV_NAME;
312	iio_dev->info = &st_uvis25_info;
313
314	err = st_uvis25_init_sensor(hw);
315	if (err < 0)
316		return err;
317
318	if (hw->irq > 0) {
319		err = st_uvis25_allocate_buffer(iio_dev);
320		if (err < 0)
321			return err;
322
323		err = st_uvis25_allocate_trigger(iio_dev);
324		if (err)
325			return err;
326	}
327
328	return devm_iio_device_register(dev, iio_dev);
329}
330EXPORT_SYMBOL_NS(st_uvis25_probe, "IIO_UVIS25");
331
332static int st_uvis25_suspend(struct device *dev)
333{
334	struct iio_dev *iio_dev = dev_get_drvdata(dev);
335	struct st_uvis25_hw *hw = iio_priv(iio_dev);
336
337	return regmap_clear_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
338				 ST_UVIS25_REG_ODR_MASK);
339}
340
341static int st_uvis25_resume(struct device *dev)
342{
343	struct iio_dev *iio_dev = dev_get_drvdata(dev);
344	struct st_uvis25_hw *hw = iio_priv(iio_dev);
345
346	if (hw->enabled)
347		return regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
348					  ST_UVIS25_REG_ODR_MASK, 1);
349
350	return 0;
351}
352
353EXPORT_NS_SIMPLE_DEV_PM_OPS(st_uvis25_pm_ops, st_uvis25_suspend, st_uvis25_resume, IIO_UVIS25);
354
355MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>");
356MODULE_DESCRIPTION("STMicroelectronics uvis25 sensor driver");
357MODULE_LICENSE("GPL v2");