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/module.h> 12 #include <linux/iio/iio.h> 13 #include <linux/iio/trigger.h> 14 #include <linux/interrupt.h> 15 #include <linux/regmap.h> 16 #include <linux/iio/common/st_sensors.h> 17 #include "st_sensors_core.h" 18 19 /** 20 * st_sensors_new_samples_available() - check if more samples came in 21 * @indio_dev: IIO device reference. 22 * @sdata: Sensor data. 23 * 24 * returns: 25 * false - no new samples available or read error 26 * true - new samples available 27 */ 28 static bool st_sensors_new_samples_available(struct iio_dev *indio_dev, 29 struct st_sensor_data *sdata) 30 { 31 int ret, status; 32 33 /* How would I know if I can't check it? */ 34 if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr) 35 return true; 36 37 /* No scan mask, no interrupt */ 38 if (!indio_dev->active_scan_mask) 39 return false; 40 41 ret = regmap_read(sdata->regmap, 42 sdata->sensor_settings->drdy_irq.stat_drdy.addr, 43 &status); 44 if (ret < 0) { 45 dev_err(indio_dev->dev.parent, 46 "error checking samples available\n"); 47 return false; 48 } 49 50 return !!(status & sdata->sensor_settings->drdy_irq.stat_drdy.mask); 51 } 52 53 /** 54 * st_sensors_irq_handler() - top half of the IRQ-based triggers 55 * @irq: irq number 56 * @p: private handler data 57 */ 58 static irqreturn_t st_sensors_irq_handler(int irq, void *p) 59 { 60 struct iio_trigger *trig = p; 61 struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig); 62 struct st_sensor_data *sdata = iio_priv(indio_dev); 63 64 /* Get the time stamp as close in time as possible */ 65 sdata->hw_timestamp = iio_get_time_ns(indio_dev); 66 return IRQ_WAKE_THREAD; 67 } 68 69 /** 70 * st_sensors_irq_thread() - bottom half of the IRQ-based triggers 71 * @irq: irq number 72 * @p: private handler data 73 */ 74 static irqreturn_t st_sensors_irq_thread(int irq, void *p) 75 { 76 struct iio_trigger *trig = p; 77 struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig); 78 struct st_sensor_data *sdata = iio_priv(indio_dev); 79 80 /* 81 * If this trigger is backed by a hardware interrupt and we have a 82 * status register, check if this IRQ came from us. Notice that 83 * we will process also if st_sensors_new_samples_available() 84 * returns negative: if we can't check status, then poll 85 * unconditionally. 86 */ 87 if (sdata->hw_irq_trigger && 88 st_sensors_new_samples_available(indio_dev, sdata)) { 89 iio_trigger_poll_chained(p); 90 } else { 91 dev_dbg(indio_dev->dev.parent, "spurious IRQ\n"); 92 return IRQ_NONE; 93 } 94 95 /* 96 * If we have proper level IRQs the handler will be re-entered if 97 * the line is still active, so return here and come back in through 98 * the top half if need be. 99 */ 100 if (!sdata->edge_irq) 101 return IRQ_HANDLED; 102 103 /* 104 * If we are using edge IRQs, new samples arrived while processing 105 * the IRQ and those may be missed unless we pick them here, so poll 106 * again. If the sensor delivery frequency is very high, this thread 107 * turns into a polled loop handler. 108 */ 109 while (sdata->hw_irq_trigger && 110 st_sensors_new_samples_available(indio_dev, sdata)) { 111 dev_dbg(indio_dev->dev.parent, 112 "more samples came in during polling\n"); 113 sdata->hw_timestamp = iio_get_time_ns(indio_dev); 114 iio_trigger_poll_chained(p); 115 } 116 117 return IRQ_HANDLED; 118 } 119 120 int st_sensors_allocate_trigger(struct iio_dev *indio_dev, 121 const struct iio_trigger_ops *trigger_ops) 122 { 123 struct st_sensor_data *sdata = iio_priv(indio_dev); 124 struct device *parent = indio_dev->dev.parent; 125 unsigned long irq_trig; 126 int err; 127 128 sdata->trig = devm_iio_trigger_alloc(parent, "%s-trigger", 129 indio_dev->name); 130 if (sdata->trig == NULL) { 131 dev_err(&indio_dev->dev, "failed to allocate iio trigger.\n"); 132 return -ENOMEM; 133 } 134 135 iio_trigger_set_drvdata(sdata->trig, indio_dev); 136 sdata->trig->ops = trigger_ops; 137 138 irq_trig = irqd_get_trigger_type(irq_get_irq_data(sdata->irq)); 139 /* 140 * If the IRQ is triggered on falling edge, we need to mark the 141 * interrupt as active low, if the hardware supports this. 142 */ 143 switch(irq_trig) { 144 case IRQF_TRIGGER_FALLING: 145 case IRQF_TRIGGER_LOW: 146 if (!sdata->sensor_settings->drdy_irq.addr_ihl) { 147 dev_err(&indio_dev->dev, 148 "falling/low specified for IRQ but hardware supports only rising/high: will request rising/high\n"); 149 if (irq_trig == IRQF_TRIGGER_FALLING) 150 irq_trig = IRQF_TRIGGER_RISING; 151 if (irq_trig == IRQF_TRIGGER_LOW) 152 irq_trig = IRQF_TRIGGER_HIGH; 153 } else { 154 /* Set up INT active low i.e. falling edge */ 155 err = st_sensors_write_data_with_mask(indio_dev, 156 sdata->sensor_settings->drdy_irq.addr_ihl, 157 sdata->sensor_settings->drdy_irq.mask_ihl, 1); 158 if (err < 0) 159 return err; 160 dev_info(&indio_dev->dev, 161 "interrupts on the falling edge or active low level\n"); 162 } 163 break; 164 case IRQF_TRIGGER_RISING: 165 dev_info(&indio_dev->dev, 166 "interrupts on the rising edge\n"); 167 break; 168 case IRQF_TRIGGER_HIGH: 169 dev_info(&indio_dev->dev, 170 "interrupts active high level\n"); 171 break; 172 default: 173 /* This is the most preferred mode, if possible */ 174 dev_err(&indio_dev->dev, 175 "unsupported IRQ trigger specified (%lx), enforce rising edge\n", irq_trig); 176 irq_trig = IRQF_TRIGGER_RISING; 177 } 178 179 /* Tell the interrupt handler that we're dealing with edges */ 180 if (irq_trig == IRQF_TRIGGER_FALLING || 181 irq_trig == IRQF_TRIGGER_RISING) { 182 if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr) { 183 dev_err(&indio_dev->dev, 184 "edge IRQ not supported w/o stat register.\n"); 185 return -EOPNOTSUPP; 186 } 187 sdata->edge_irq = true; 188 } else { 189 /* 190 * If we're not using edges (i.e. level interrupts) we 191 * just mask off the IRQ, handle one interrupt, then 192 * if the line is still low, we return to the 193 * interrupt handler top half again and start over. 194 */ 195 irq_trig |= IRQF_ONESHOT; 196 } 197 198 /* 199 * If the interrupt pin is Open Drain, by definition this 200 * means that the interrupt line may be shared with other 201 * peripherals. But to do this we also need to have a status 202 * register and mask to figure out if this sensor was firing 203 * the IRQ or not, so we can tell the interrupt handle that 204 * it was "our" interrupt. 205 */ 206 if (sdata->int_pin_open_drain && 207 sdata->sensor_settings->drdy_irq.stat_drdy.addr) 208 irq_trig |= IRQF_SHARED; 209 210 err = devm_request_threaded_irq(parent, 211 sdata->irq, 212 st_sensors_irq_handler, 213 st_sensors_irq_thread, 214 irq_trig, 215 sdata->trig->name, 216 sdata->trig); 217 if (err) { 218 dev_err(&indio_dev->dev, "failed to request trigger IRQ.\n"); 219 return err; 220 } 221 222 err = devm_iio_trigger_register(parent, sdata->trig); 223 if (err < 0) { 224 dev_err(&indio_dev->dev, "failed to register iio trigger.\n"); 225 return err; 226 } 227 indio_dev->trig = iio_trigger_get(sdata->trig); 228 229 return 0; 230 } 231 EXPORT_SYMBOL(st_sensors_allocate_trigger); 232 233 int st_sensors_validate_device(struct iio_trigger *trig, 234 struct iio_dev *indio_dev) 235 { 236 struct iio_dev *indio = iio_trigger_get_drvdata(trig); 237 238 if (indio != indio_dev) 239 return -EINVAL; 240 241 return 0; 242 } 243 EXPORT_SYMBOL(st_sensors_validate_device); 244 245 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>"); 246 MODULE_DESCRIPTION("STMicroelectronics ST-sensors trigger"); 247 MODULE_LICENSE("GPL v2"); 248