1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * STMicroelectronics sensors trigger library driver
4 *
5 * Copyright 2012-2013 STMicroelectronics Inc.
6 *
7 * Denis Ciocca <denis.ciocca@st.com>
8 */
9
10#include <linux/kernel.h>
11#include <linux/iio/iio.h>
12#include <linux/iio/trigger.h>
13#include <linux/interrupt.h>
14#include <linux/regmap.h>
15#include <linux/iio/common/st_sensors.h>
16#include "st_sensors_core.h"
17
18/**
19 * st_sensors_new_samples_available() - check if more samples came in
20 * @indio_dev: IIO device reference.
21 * @sdata: Sensor data.
22 *
23 * returns:
24 * false - no new samples available or read error
25 * true - new samples available
26 */
27static bool st_sensors_new_samples_available(struct iio_dev *indio_dev,
28 struct st_sensor_data *sdata)
29{
30 int ret, status;
31
32 /* How would I know if I can't check it? */
33 if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr)
34 return true;
35
36 /* No scan mask, no interrupt */
37 if (!indio_dev->active_scan_mask)
38 return false;
39
40 ret = regmap_read(map: sdata->regmap,
41 reg: sdata->sensor_settings->drdy_irq.stat_drdy.addr,
42 val: &status);
43 if (ret < 0) {
44 dev_err(indio_dev->dev.parent,
45 "error checking samples available\n");
46 return false;
47 }
48
49 return !!(status & sdata->sensor_settings->drdy_irq.stat_drdy.mask);
50}
51
52/**
53 * st_sensors_irq_handler() - top half of the IRQ-based triggers
54 * @irq: irq number
55 * @p: private handler data
56 */
57static irqreturn_t st_sensors_irq_handler(int irq, void *p)
58{
59 struct iio_trigger *trig = p;
60 struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
61 struct st_sensor_data *sdata = iio_priv(indio_dev);
62
63 /* Get the time stamp as close in time as possible */
64 sdata->hw_timestamp = iio_get_time_ns(indio_dev);
65 return IRQ_WAKE_THREAD;
66}
67
68/**
69 * st_sensors_irq_thread() - bottom half of the IRQ-based triggers
70 * @irq: irq number
71 * @p: private handler data
72 */
73static irqreturn_t st_sensors_irq_thread(int irq, void *p)
74{
75 struct iio_trigger *trig = p;
76 struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
77 struct st_sensor_data *sdata = iio_priv(indio_dev);
78
79 /*
80 * If this trigger is backed by a hardware interrupt and we have a
81 * status register, check if this IRQ came from us. Notice that
82 * we will process also if st_sensors_new_samples_available()
83 * returns negative: if we can't check status, then poll
84 * unconditionally.
85 */
86 if (sdata->hw_irq_trigger &&
87 st_sensors_new_samples_available(indio_dev, sdata)) {
88 iio_trigger_poll_nested(trig: p);
89 } else {
90 dev_dbg(indio_dev->dev.parent, "spurious IRQ\n");
91 return IRQ_NONE;
92 }
93
94 /*
95 * If we have proper level IRQs the handler will be re-entered if
96 * the line is still active, so return here and come back in through
97 * the top half if need be.
98 */
99 if (!sdata->edge_irq)
100 return IRQ_HANDLED;
101
102 /*
103 * If we are using edge IRQs, new samples arrived while processing
104 * the IRQ and those may be missed unless we pick them here, so poll
105 * again. If the sensor delivery frequency is very high, this thread
106 * turns into a polled loop handler.
107 */
108 while (sdata->hw_irq_trigger &&
109 st_sensors_new_samples_available(indio_dev, sdata)) {
110 dev_dbg(indio_dev->dev.parent,
111 "more samples came in during polling\n");
112 sdata->hw_timestamp = iio_get_time_ns(indio_dev);
113 iio_trigger_poll_nested(trig: p);
114 }
115
116 return IRQ_HANDLED;
117}
118
119int st_sensors_allocate_trigger(struct iio_dev *indio_dev,
120 const struct iio_trigger_ops *trigger_ops)
121{
122 struct st_sensor_data *sdata = iio_priv(indio_dev);
123 struct device *parent = indio_dev->dev.parent;
124 unsigned long irq_trig;
125 int err;
126
127 sdata->trig = devm_iio_trigger_alloc(parent, "%s-trigger",
128 indio_dev->name);
129 if (sdata->trig == NULL) {
130 dev_err(&indio_dev->dev, "failed to allocate iio trigger.\n");
131 return -ENOMEM;
132 }
133
134 iio_trigger_set_drvdata(trig: sdata->trig, data: indio_dev);
135 sdata->trig->ops = trigger_ops;
136
137 irq_trig = irqd_get_trigger_type(d: irq_get_irq_data(irq: sdata->irq));
138 /*
139 * If the IRQ is triggered on falling edge, we need to mark the
140 * interrupt as active low, if the hardware supports this.
141 */
142 switch(irq_trig) {
143 case IRQF_TRIGGER_FALLING:
144 case IRQF_TRIGGER_LOW:
145 if (!sdata->sensor_settings->drdy_irq.addr_ihl) {
146 dev_err(&indio_dev->dev,
147 "falling/low specified for IRQ but hardware supports only rising/high: will request rising/high\n");
148 if (irq_trig == IRQF_TRIGGER_FALLING)
149 irq_trig = IRQF_TRIGGER_RISING;
150 if (irq_trig == IRQF_TRIGGER_LOW)
151 irq_trig = IRQF_TRIGGER_HIGH;
152 } else {
153 /* Set up INT active low i.e. falling edge */
154 err = st_sensors_write_data_with_mask(indio_dev,
155 reg_addr: sdata->sensor_settings->drdy_irq.addr_ihl,
156 mask: sdata->sensor_settings->drdy_irq.mask_ihl, data: 1);
157 if (err < 0)
158 return err;
159 dev_info(&indio_dev->dev,
160 "interrupts on the falling edge or active low level\n");
161 }
162 break;
163 case IRQF_TRIGGER_RISING:
164 dev_info(&indio_dev->dev,
165 "interrupts on the rising edge\n");
166 break;
167 case IRQF_TRIGGER_HIGH:
168 dev_info(&indio_dev->dev,
169 "interrupts active high level\n");
170 break;
171 default:
172 /* This is the most preferred mode, if possible */
173 dev_err(&indio_dev->dev,
174 "unsupported IRQ trigger specified (%lx), enforce rising edge\n", irq_trig);
175 irq_trig = IRQF_TRIGGER_RISING;
176 }
177
178 /* Tell the interrupt handler that we're dealing with edges */
179 if (irq_trig == IRQF_TRIGGER_FALLING ||
180 irq_trig == IRQF_TRIGGER_RISING) {
181 if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr) {
182 dev_err(&indio_dev->dev,
183 "edge IRQ not supported w/o stat register.\n");
184 return -EOPNOTSUPP;
185 }
186 sdata->edge_irq = true;
187 } else {
188 /*
189 * If we're not using edges (i.e. level interrupts) we
190 * just mask off the IRQ, handle one interrupt, then
191 * if the line is still low, we return to the
192 * interrupt handler top half again and start over.
193 */
194 irq_trig |= IRQF_ONESHOT;
195 }
196
197 /*
198 * If the interrupt pin is Open Drain, by definition this
199 * means that the interrupt line may be shared with other
200 * peripherals. But to do this we also need to have a status
201 * register and mask to figure out if this sensor was firing
202 * the IRQ or not, so we can tell the interrupt handle that
203 * it was "our" interrupt.
204 */
205 if (sdata->int_pin_open_drain &&
206 sdata->sensor_settings->drdy_irq.stat_drdy.addr)
207 irq_trig |= IRQF_SHARED;
208
209 err = devm_request_threaded_irq(dev: parent,
210 irq: sdata->irq,
211 handler: st_sensors_irq_handler,
212 thread_fn: st_sensors_irq_thread,
213 irqflags: irq_trig,
214 devname: sdata->trig->name,
215 dev_id: sdata->trig);
216 if (err) {
217 dev_err(&indio_dev->dev, "failed to request trigger IRQ.\n");
218 return err;
219 }
220
221 err = devm_iio_trigger_register(dev: parent, trig_info: sdata->trig);
222 if (err < 0) {
223 dev_err(&indio_dev->dev, "failed to register iio trigger.\n");
224 return err;
225 }
226 indio_dev->trig = iio_trigger_get(trig: sdata->trig);
227
228 return 0;
229}
230EXPORT_SYMBOL_NS(st_sensors_allocate_trigger, IIO_ST_SENSORS);
231
232int st_sensors_validate_device(struct iio_trigger *trig,
233 struct iio_dev *indio_dev)
234{
235 struct iio_dev *indio = iio_trigger_get_drvdata(trig);
236
237 if (indio != indio_dev)
238 return -EINVAL;
239
240 return 0;
241}
242EXPORT_SYMBOL_NS(st_sensors_validate_device, IIO_ST_SENSORS);
243

source code of linux/drivers/iio/common/st_sensors/st_sensors_trigger.c