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 */
st_sensors_new_samples_available(struct iio_dev * indio_dev,struct st_sensor_data * sdata)27 static 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(sdata->regmap,
41 sdata->sensor_settings->drdy_irq.stat_drdy.addr,
42 &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 */
st_sensors_irq_handler(int irq,void * p)57 static 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 */
st_sensors_irq_thread(int irq,void * p)73 static 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(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(p);
114 }
115
116 return IRQ_HANDLED;
117 }
118
st_sensors_allocate_trigger(struct iio_dev * indio_dev,const struct iio_trigger_ops * trigger_ops)119 int 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(parent, "failed to allocate iio trigger.\n");
131 return -ENOMEM;
132 }
133
134 iio_trigger_set_drvdata(sdata->trig, indio_dev);
135 sdata->trig->ops = trigger_ops;
136
137 irq_trig = irqd_get_trigger_type(irq_get_irq_data(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(parent,
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 sdata->sensor_settings->drdy_irq.addr_ihl,
156 sdata->sensor_settings->drdy_irq.mask_ihl, 1);
157 if (err < 0)
158 return err;
159 dev_info(parent,
160 "interrupts on the falling edge or active low level\n");
161 }
162 break;
163 case IRQF_TRIGGER_RISING:
164 dev_info(parent, "interrupts on the rising edge\n");
165 break;
166 case IRQF_TRIGGER_HIGH:
167 dev_info(parent, "interrupts active high level\n");
168 break;
169 default:
170 /* This is the most preferred mode, if possible */
171 dev_err(parent,
172 "unsupported IRQ trigger specified (%lx), enforce rising edge\n", irq_trig);
173 irq_trig = IRQF_TRIGGER_RISING;
174 }
175
176 /* Tell the interrupt handler that we're dealing with edges */
177 if (irq_trig == IRQF_TRIGGER_FALLING ||
178 irq_trig == IRQF_TRIGGER_RISING) {
179 if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr) {
180 dev_err(parent,
181 "edge IRQ not supported w/o stat register.\n");
182 return -EOPNOTSUPP;
183 }
184 sdata->edge_irq = true;
185 } else {
186 /*
187 * If we're not using edges (i.e. level interrupts) we
188 * just mask off the IRQ, handle one interrupt, then
189 * if the line is still low, we return to the
190 * interrupt handler top half again and start over.
191 */
192 irq_trig |= IRQF_ONESHOT;
193 }
194
195 /*
196 * If the interrupt pin is Open Drain, by definition this
197 * means that the interrupt line may be shared with other
198 * peripherals. But to do this we also need to have a status
199 * register and mask to figure out if this sensor was firing
200 * the IRQ or not, so we can tell the interrupt handle that
201 * it was "our" interrupt.
202 */
203 if (sdata->int_pin_open_drain &&
204 sdata->sensor_settings->drdy_irq.stat_drdy.addr)
205 irq_trig |= IRQF_SHARED;
206
207 err = devm_request_threaded_irq(parent,
208 sdata->irq,
209 st_sensors_irq_handler,
210 st_sensors_irq_thread,
211 irq_trig,
212 sdata->trig->name,
213 sdata->trig);
214 if (err) {
215 dev_err(parent, "failed to request trigger IRQ.\n");
216 return err;
217 }
218
219 err = devm_iio_trigger_register(parent, sdata->trig);
220 if (err < 0) {
221 dev_err(parent, "failed to register iio trigger.\n");
222 return err;
223 }
224 indio_dev->trig = iio_trigger_get(sdata->trig);
225
226 return 0;
227 }
228 EXPORT_SYMBOL_NS(st_sensors_allocate_trigger, IIO_ST_SENSORS);
229
st_sensors_validate_device(struct iio_trigger * trig,struct iio_dev * indio_dev)230 int st_sensors_validate_device(struct iio_trigger *trig,
231 struct iio_dev *indio_dev)
232 {
233 struct iio_dev *indio = iio_trigger_get_drvdata(trig);
234
235 if (indio != indio_dev)
236 return -EINVAL;
237
238 return 0;
239 }
240 EXPORT_SYMBOL_NS(st_sensors_validate_device, IIO_ST_SENSORS);
241