1 /* 2 * STMicroelectronics sensors buffer library driver 3 * 4 * Copyright 2012-2013 STMicroelectronics Inc. 5 * 6 * Denis Ciocca <denis.ciocca@st.com> 7 * 8 * Licensed under the GPL-2. 9 */ 10 11 #include <linux/kernel.h> 12 #include <linux/module.h> 13 #include <linux/slab.h> 14 #include <linux/iio/iio.h> 15 #include <linux/iio/trigger.h> 16 #include <linux/interrupt.h> 17 #include <linux/iio/buffer.h> 18 #include <linux/iio/trigger_consumer.h> 19 #include <linux/iio/triggered_buffer.h> 20 #include <linux/irqreturn.h> 21 22 #include <linux/iio/common/st_sensors.h> 23 24 25 static int st_sensors_get_buffer_element(struct iio_dev *indio_dev, u8 *buf) 26 { 27 int i; 28 struct st_sensor_data *sdata = iio_priv(indio_dev); 29 unsigned int num_data_channels = sdata->num_data_channels; 30 31 for_each_set_bit(i, indio_dev->active_scan_mask, num_data_channels) { 32 const struct iio_chan_spec *channel = &indio_dev->channels[i]; 33 unsigned int bytes_to_read = 34 DIV_ROUND_UP(channel->scan_type.realbits + 35 channel->scan_type.shift, 8); 36 unsigned int storage_bytes = 37 channel->scan_type.storagebits >> 3; 38 39 buf = PTR_ALIGN(buf, storage_bytes); 40 if (sdata->tf->read_multiple_byte(&sdata->tb, sdata->dev, 41 channel->address, 42 bytes_to_read, buf, 43 sdata->multiread_bit) < 44 bytes_to_read) 45 return -EIO; 46 47 /* Advance the buffer pointer */ 48 buf += storage_bytes; 49 } 50 51 return 0; 52 } 53 54 irqreturn_t st_sensors_trigger_handler(int irq, void *p) 55 { 56 int len; 57 struct iio_poll_func *pf = p; 58 struct iio_dev *indio_dev = pf->indio_dev; 59 struct st_sensor_data *sdata = iio_priv(indio_dev); 60 s64 timestamp; 61 62 /* 63 * If we do timetamping here, do it before reading the values, because 64 * once we've read the values, new interrupts can occur (when using 65 * the hardware trigger) and the hw_timestamp may get updated. 66 * By storing it in a local variable first, we are safe. 67 */ 68 if (iio_trigger_using_own(indio_dev)) 69 timestamp = sdata->hw_timestamp; 70 else 71 timestamp = iio_get_time_ns(indio_dev); 72 73 len = st_sensors_get_buffer_element(indio_dev, sdata->buffer_data); 74 if (len < 0) 75 goto st_sensors_get_buffer_element_error; 76 77 iio_push_to_buffers_with_timestamp(indio_dev, sdata->buffer_data, 78 timestamp); 79 80 st_sensors_get_buffer_element_error: 81 iio_trigger_notify_done(indio_dev->trig); 82 83 return IRQ_HANDLED; 84 } 85 EXPORT_SYMBOL(st_sensors_trigger_handler); 86 87 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>"); 88 MODULE_DESCRIPTION("STMicroelectronics ST-sensors buffer"); 89 MODULE_LICENSE("GPL v2"); 90