Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 | // SPDX-License-Identifier: GPL-2.0-only /* * STMicroelectronics sensors trigger library driver * * Copyright 2012-2013 STMicroelectronics Inc. * * Denis Ciocca <denis.ciocca@st.com> */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/iio/iio.h> #include <linux/iio/trigger.h> #include <linux/interrupt.h> #include <linux/regmap.h> #include <linux/iio/common/st_sensors.h> #include "st_sensors_core.h" /** * st_sensors_new_samples_available() - check if more samples came in * @indio_dev: IIO device reference. * @sdata: Sensor data. * * returns: * false - no new samples available or read error * true - new samples available */ static bool st_sensors_new_samples_available(struct iio_dev *indio_dev, struct st_sensor_data *sdata) { int ret, status; /* How would I know if I can't check it? */ if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr) return true; /* No scan mask, no interrupt */ if (!indio_dev->active_scan_mask) return false; ret = regmap_read(sdata->regmap, sdata->sensor_settings->drdy_irq.stat_drdy.addr, &status); if (ret < 0) { dev_err(sdata->dev, "error checking samples available\n"); return false; } return !!(status & sdata->sensor_settings->drdy_irq.stat_drdy.mask); } /** * st_sensors_irq_handler() - top half of the IRQ-based triggers * @irq: irq number * @p: private handler data */ static irqreturn_t st_sensors_irq_handler(int irq, void *p) { struct iio_trigger *trig = p; struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig); struct st_sensor_data *sdata = iio_priv(indio_dev); /* Get the time stamp as close in time as possible */ sdata->hw_timestamp = iio_get_time_ns(indio_dev); return IRQ_WAKE_THREAD; } /** * st_sensors_irq_thread() - bottom half of the IRQ-based triggers * @irq: irq number * @p: private handler data */ static irqreturn_t st_sensors_irq_thread(int irq, void *p) { struct iio_trigger *trig = p; struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig); struct st_sensor_data *sdata = iio_priv(indio_dev); /* * If this trigger is backed by a hardware interrupt and we have a * status register, check if this IRQ came from us. Notice that * we will process also if st_sensors_new_samples_available() * returns negative: if we can't check status, then poll * unconditionally. */ if (sdata->hw_irq_trigger && st_sensors_new_samples_available(indio_dev, sdata)) { iio_trigger_poll_chained(p); } else { dev_dbg(sdata->dev, "spurious IRQ\n"); return IRQ_NONE; } /* * If we have proper level IRQs the handler will be re-entered if * the line is still active, so return here and come back in through * the top half if need be. */ if (!sdata->edge_irq) return IRQ_HANDLED; /* * If we are using edge IRQs, new samples arrived while processing * the IRQ and those may be missed unless we pick them here, so poll * again. If the sensor delivery frequency is very high, this thread * turns into a polled loop handler. */ while (sdata->hw_irq_trigger && st_sensors_new_samples_available(indio_dev, sdata)) { dev_dbg(sdata->dev, "more samples came in during polling\n"); sdata->hw_timestamp = iio_get_time_ns(indio_dev); iio_trigger_poll_chained(p); } return IRQ_HANDLED; } int st_sensors_allocate_trigger(struct iio_dev *indio_dev, const struct iio_trigger_ops *trigger_ops) { struct st_sensor_data *sdata = iio_priv(indio_dev); unsigned long irq_trig; int err; sdata->trig = iio_trigger_alloc("%s-trigger", indio_dev->name); if (sdata->trig == NULL) { dev_err(&indio_dev->dev, "failed to allocate iio trigger.\n"); return -ENOMEM; } iio_trigger_set_drvdata(sdata->trig, indio_dev); sdata->trig->ops = trigger_ops; sdata->trig->dev.parent = sdata->dev; irq_trig = irqd_get_trigger_type(irq_get_irq_data(sdata->irq)); /* * If the IRQ is triggered on falling edge, we need to mark the * interrupt as active low, if the hardware supports this. */ switch(irq_trig) { case IRQF_TRIGGER_FALLING: case IRQF_TRIGGER_LOW: if (!sdata->sensor_settings->drdy_irq.addr_ihl) { dev_err(&indio_dev->dev, "falling/low specified for IRQ but hardware supports only rising/high: will request rising/high\n"); if (irq_trig == IRQF_TRIGGER_FALLING) irq_trig = IRQF_TRIGGER_RISING; if (irq_trig == IRQF_TRIGGER_LOW) irq_trig = IRQF_TRIGGER_HIGH; } else { /* Set up INT active low i.e. falling edge */ err = st_sensors_write_data_with_mask(indio_dev, sdata->sensor_settings->drdy_irq.addr_ihl, sdata->sensor_settings->drdy_irq.mask_ihl, 1); if (err < 0) goto iio_trigger_free; dev_info(&indio_dev->dev, "interrupts on the falling edge or active low level\n"); } break; case IRQF_TRIGGER_RISING: dev_info(&indio_dev->dev, "interrupts on the rising edge\n"); break; case IRQF_TRIGGER_HIGH: dev_info(&indio_dev->dev, "interrupts active high level\n"); break; default: /* This is the most preferred mode, if possible */ dev_err(&indio_dev->dev, "unsupported IRQ trigger specified (%lx), enforce rising edge\n", irq_trig); irq_trig = IRQF_TRIGGER_RISING; } /* Tell the interrupt handler that we're dealing with edges */ if (irq_trig == IRQF_TRIGGER_FALLING || irq_trig == IRQF_TRIGGER_RISING) { if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr) { dev_err(&indio_dev->dev, "edge IRQ not supported w/o stat register.\n"); err = -EOPNOTSUPP; goto iio_trigger_free; } sdata->edge_irq = true; } else { /* * If we're not using edges (i.e. level interrupts) we * just mask off the IRQ, handle one interrupt, then * if the line is still low, we return to the * interrupt handler top half again and start over. */ irq_trig |= IRQF_ONESHOT; } /* * If the interrupt pin is Open Drain, by definition this * means that the interrupt line may be shared with other * peripherals. But to do this we also need to have a status * register and mask to figure out if this sensor was firing * the IRQ or not, so we can tell the interrupt handle that * it was "our" interrupt. */ if (sdata->int_pin_open_drain && sdata->sensor_settings->drdy_irq.stat_drdy.addr) irq_trig |= IRQF_SHARED; err = request_threaded_irq(sdata->irq, st_sensors_irq_handler, st_sensors_irq_thread, irq_trig, sdata->trig->name, sdata->trig); if (err) { dev_err(&indio_dev->dev, "failed to request trigger IRQ.\n"); goto iio_trigger_free; } err = iio_trigger_register(sdata->trig); if (err < 0) { dev_err(&indio_dev->dev, "failed to register iio trigger.\n"); goto iio_trigger_register_error; } indio_dev->trig = iio_trigger_get(sdata->trig); return 0; iio_trigger_register_error: free_irq(sdata->irq, sdata->trig); iio_trigger_free: iio_trigger_free(sdata->trig); return err; } EXPORT_SYMBOL(st_sensors_allocate_trigger); void st_sensors_deallocate_trigger(struct iio_dev *indio_dev) { struct st_sensor_data *sdata = iio_priv(indio_dev); iio_trigger_unregister(sdata->trig); free_irq(sdata->irq, sdata->trig); iio_trigger_free(sdata->trig); } EXPORT_SYMBOL(st_sensors_deallocate_trigger); int st_sensors_validate_device(struct iio_trigger *trig, struct iio_dev *indio_dev) { struct iio_dev *indio = iio_trigger_get_drvdata(trig); if (indio != indio_dev) return -EINVAL; return 0; } EXPORT_SYMBOL(st_sensors_validate_device); MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>"); MODULE_DESCRIPTION("STMicroelectronics ST-sensors trigger"); MODULE_LICENSE("GPL v2"); |