/**************************************************************************** * drivers/analog/adc.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /**************************************************************************** * Private Function Prototypes ****************************************************************************/ static int adc_open(FAR struct file *filep); static int adc_close(FAR struct file *filep); static ssize_t adc_read(FAR struct file *fielp, FAR char *buffer, size_t buflen); static int adc_ioctl(FAR struct file *filep, int cmd, unsigned long arg); static int adc_reset(FAR struct adc_dev_s *dev); static int adc_receive(FAR struct adc_dev_s *dev, uint8_t ch, int32_t data); static void adc_notify(FAR struct adc_dev_s *dev); static int adc_poll(FAR struct file *filep, struct pollfd *fds, bool setup); static int adc_reset_fifo(FAR struct adc_dev_s *dev); static int adc_samples_on_read(FAR struct adc_dev_s *dev); /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_adc_fops = { adc_open, /* open */ adc_close, /* close */ adc_read, /* read */ NULL, /* write */ NULL, /* seek */ adc_ioctl, /* ioctl */ NULL, /* mmap */ NULL, /* truncate */ adc_poll /* poll */ }; static const struct adc_callback_s g_adc_callback = { adc_receive, /* au_receive */ adc_reset /* au_reset */ }; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: adc_open * * Description: * This function is called whenever the ADC device is opened. * ****************************************************************************/ static int adc_open(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR struct adc_dev_s *dev = inode->i_private; uint8_t tmp; int ret; /* If the port is the middle of closing, wait until the close is * finished. */ ret = nxmutex_lock(&dev->ad_closelock); if (ret >= 0) { /* Increment the count of references to the device. If this is the * first time that the driver has been opened for this device, then * initialize the device. */ tmp = dev->ad_ocount + 1; if (tmp == 0) { /* More than 255 opens; uint8_t overflows to zero */ ret = -EMFILE; } else { /* Check if this is the first time that the driver has been * opened. */ if (tmp == 1) { /* Yes.. perform one time hardware initialization. */ irqstate_t flags = enter_critical_section(); ret = dev->ad_ops->ao_setup(dev); if (ret == OK) { /* Mark the FIFOs empty */ dev->ad_recv.af_head = 0; dev->ad_recv.af_tail = 0; /* Clear overrun indicator */ dev->ad_isovr = false; /* Finally, Enable the ADC RX interrupt */ dev->ad_ops->ao_rxint(dev, true); } leave_critical_section(flags); } /* Save the new open count on success */ dev->ad_ocount = tmp; } nxmutex_unlock(&dev->ad_closelock); } return ret; } /**************************************************************************** * Name: adc_close * * Description: * This routine is called when the ADC device is closed. * It waits for the last remaining data to be sent. * ****************************************************************************/ static int adc_close(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR struct adc_dev_s *dev = inode->i_private; irqstate_t flags; int ret; ret = nxmutex_lock(&dev->ad_closelock); if (ret >= 0) { /* Decrement the references to the driver. If the reference count will * decrement to 0, then uninitialize the driver. */ if (dev->ad_ocount > 1) { dev->ad_ocount--; nxmutex_unlock(&dev->ad_closelock); } else { /* There are no more references to the port */ dev->ad_ocount = 0; /* Free the IRQ and disable the ADC device */ flags = enter_critical_section(); /* Disable interrupts */ dev->ad_ops->ao_shutdown(dev); /* Disable the ADC */ leave_critical_section(flags); nxmutex_unlock(&dev->ad_closelock); } } return ret; } /**************************************************************************** * Name: adc_read ****************************************************************************/ static ssize_t adc_read(FAR struct file *filep, FAR char *buffer, size_t buflen) { FAR struct inode *inode = filep->f_inode; FAR struct adc_dev_s *dev = inode->i_private; size_t nread; irqstate_t flags; int ret = 0; int msglen; ainfo("buflen: %d\n", (int)buflen); /* Determine the size of the messages to return. * * REVISIT: What if buflen is 8 does that mean 4 messages of size 2? Or * 2 messages of size 4? What if buflen is 12. Does that mean 3 at size * 4? Or 4 at size 3? The form of the return data should probably really * be specified via IOCTL. */ if (buflen % 5 == 0) { msglen = 5; } else if (buflen % 4 == 0) { msglen = 4; } else if (buflen % 3 == 0) { msglen = 3; } else if (buflen % 2 == 0) { msglen = 2; } else if (buflen == 1) { msglen = 1; } else { msglen = 5; } if (buflen >= msglen) { /* Interrupts must be disabled while accessing the ad_recv FIFO */ flags = enter_critical_section(); while (dev->ad_recv.af_head == dev->ad_recv.af_tail) { /* Check if there was an overrun, if set we need to return EIO */ if (dev->ad_isovr) { dev->ad_isovr = false; ret = -EIO; goto return_with_irqdisabled; } /* The receive FIFO is empty -- was non-blocking mode selected? */ if (filep->f_oflags & O_NONBLOCK) { ret = -EAGAIN; goto return_with_irqdisabled; } /* Wait for a message to be received */ dev->ad_nrxwaiters++; ret = nxsem_wait(&dev->ad_recv.af_sem); dev->ad_nrxwaiters--; if (ret < 0) { goto return_with_irqdisabled; } } /* The ad_recv FIFO is not empty. Copy all buffered data that will fit * in the user buffer. */ nread = 0; do { FAR struct adc_msg_s *msg = &dev->ad_recv.af_buffer[dev->ad_recv.af_head]; /* Will the next message in the FIFO fit into the user buffer? */ if (nread + msglen > buflen) { /* No.. break out of the loop now with nread equal to the * actual number of bytes transferred. */ break; } /* Feed ADC data to entropy pool */ add_sensor_randomness(msg->am_data); /* Copy the message to the user buffer */ if (msglen == 1) { /* Only one channel, return MS 8-bits of the sample. */ buffer[nread] = msg->am_data >> 24; } else if (msglen == 2) { /* Only one channel, return only the MS 16-bits of the sample. */ int16_t data16 = msg->am_data >> 16; memcpy(&buffer[nread], &data16, 2); } else if (msglen == 3) { int16_t data16; /* Return the channel and the MS 16-bits of the sample. */ buffer[nread] = msg->am_channel; data16 = msg->am_data >> 16; memcpy(&buffer[nread + 1], &data16, 2); } else if (msglen == 4) { int32_t data24; #ifdef CONFIG_ENDIAN_BIG /* In the big endian case, we simply copy the MS three bytes * which are indices: 0-2. */ data24 = msg->am_data; #else /* In the little endian case, indices 0-2 correspond to the * the three LS bytes. */ data24 = msg->am_data >> 8; #endif /* Return the channel and the most significant 24-bits */ buffer[nread] = msg->am_channel; memcpy(&buffer[nread + 1], &data24, 3); } else { /* Return the channel and all four bytes of the sample */ buffer[nread] = msg->am_channel; memcpy(&buffer[nread + 1], &msg->am_data, 4); } nread += msglen; /* Increment the head of the circular message buffer */ if (++dev->ad_recv.af_head >= CONFIG_ADC_FIFOSIZE) { dev->ad_recv.af_head = 0; } } while (dev->ad_recv.af_head != dev->ad_recv.af_tail); /* All of the messages have been transferred. Return the number of * bytes that were read. */ ret = nread; return_with_irqdisabled: leave_critical_section(flags); } ainfo("Returning: %d\n", ret); return ret; } /**************************************************************************** * Name: adc_ioctl ****************************************************************************/ static int adc_ioctl(FAR struct file *filep, int cmd, unsigned long arg) { FAR struct inode *inode = filep->f_inode; FAR struct adc_dev_s *dev = inode->i_private; int ret; switch (cmd) { case ANIOC_RESET_FIFO: { ret = adc_reset_fifo(dev); } break; case ANIOC_SAMPLES_ON_READ: { ret = adc_samples_on_read(dev); } break; default: { /* Those IOCTLs might be used in arch specific section */ ret = dev->ad_ops->ao_ioctl(dev, cmd, arg); } break; } return ret; } /**************************************************************************** * Name: adc_reset ****************************************************************************/ static int adc_reset(FAR struct adc_dev_s *dev) { /* Set overrun flag to give read a chance to recover */ dev->ad_isovr = true; /* No need to notify here. The adc_receive callback will be called next. * If an ADC overrun occurs then there must be at least one conversion. */ return OK; } /**************************************************************************** * Name: adc_receive ****************************************************************************/ static int adc_receive(FAR struct adc_dev_s *dev, uint8_t ch, int32_t data) { FAR struct adc_fifo_s *fifo = &dev->ad_recv; int nexttail; int errcode = -ENOMEM; /* Check if adding this new message would over-run the drivers ability to * enqueue read data. */ nexttail = fifo->af_tail + 1; if (nexttail >= CONFIG_ADC_FIFOSIZE) { nexttail = 0; } /* Refuse the new data if the FIFO is full */ if (nexttail != fifo->af_head) { /* Add the new, decoded ADC sample at the tail of the FIFO */ fifo->af_buffer[fifo->af_tail].am_channel = ch; fifo->af_buffer[fifo->af_tail].am_data = data; /* Increment the tail of the circular buffer */ fifo->af_tail = nexttail; adc_notify(dev); errcode = OK; } return errcode; } /**************************************************************************** * Name: adc_notify ****************************************************************************/ static void adc_notify(FAR struct adc_dev_s *dev) { FAR struct adc_fifo_s *fifo = &dev->ad_recv; /* If there are threads waiting on poll() for data to become available, * then wake them up now. */ poll_notify(dev->fds, CONFIG_ADC_NPOLLWAITERS, POLLIN); /* If there are threads waiting for read data, then signal one of them * that the read data is available. */ if (dev->ad_nrxwaiters > 0) { nxsem_post(&fifo->af_sem); } } /**************************************************************************** * Name: adc_poll ****************************************************************************/ static int adc_poll(FAR struct file *filep, struct pollfd *fds, bool setup) { FAR struct inode *inode = filep->f_inode; FAR struct adc_dev_s *dev = inode->i_private; irqstate_t flags; int ret = 0; int i; /* Interrupts must be disabled while accessing the list of poll structures * and ad_recv FIFO. */ flags = enter_critical_section(); if (setup) { /* Ignore waits that do not include POLLIN */ if ((fds->events & POLLIN) == 0) { ret = -EDEADLK; goto return_with_irqdisabled; } /* This is a request to set up the poll. Find an available * slot for the poll structure reference */ for (i = 0; i < CONFIG_ADC_NPOLLWAITERS; i++) { /* Find an available slot */ if (!dev->fds[i]) { /* Bind the poll structure and this slot */ dev->fds[i] = fds; fds->priv = &dev->fds[i]; break; } } if (i >= CONFIG_ADC_NPOLLWAITERS) { fds->priv = NULL; ret = -EBUSY; goto return_with_irqdisabled; } /* Should we immediately notify on any of the requested events? */ if (dev->ad_recv.af_head != dev->ad_recv.af_tail) { poll_notify(&fds, 1, POLLIN); } } else if (fds->priv) { /* This is a request to tear down the poll. */ struct pollfd **slot = (struct pollfd **)fds->priv; /* Remove all memory of the poll setup */ *slot = NULL; fds->priv = NULL; } return_with_irqdisabled: leave_critical_section(flags); return ret; } /**************************************************************************** * Name: adc_reset_fifo ****************************************************************************/ static int adc_reset_fifo(FAR struct adc_dev_s *dev) { irqstate_t flags; FAR struct adc_fifo_s *fifo = &dev->ad_recv; /* Interrupts must be disabled while accessing the ad_recv FIFO */ flags = enter_critical_section(); fifo->af_head = fifo->af_tail; leave_critical_section(flags); return OK; } /**************************************************************************** * Name: adc_samples_on_read ****************************************************************************/ static int adc_samples_on_read(FAR struct adc_dev_s *dev) { irqstate_t flags; FAR struct adc_fifo_s *fifo = &dev->ad_recv; int16_t ret; /* Interrupts must be disabled while accessing the ad_recv FIFO */ flags = enter_critical_section(); ret = fifo->af_tail - fifo->af_head; leave_critical_section(flags); if (ret < 0) { /* Increment return value by the size of FIFO */ ret += CONFIG_ADC_FIFOSIZE; } return ret; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: adc_register ****************************************************************************/ int adc_register(FAR const char *path, FAR struct adc_dev_s *dev) { int ret; DEBUGASSERT(path != NULL && dev != NULL); /* Bind the upper-half callbacks to the lower half ADC driver */ DEBUGASSERT(dev->ad_ops != NULL && dev->ad_ops->ao_bind != NULL); ret = dev->ad_ops->ao_bind(dev, &g_adc_callback); if (ret < 0) { aerr("ERROR: Failed to bind callbacks: %d\n", ret); return ret; } /* Initialize the ADC device structure */ dev->ad_ocount = 0; /* Initialize semaphores & mutex */ nxsem_init(&dev->ad_recv.af_sem, 0, 0); nxmutex_init(&dev->ad_closelock); /* Reset the ADC hardware */ DEBUGASSERT(dev->ad_ops->ao_reset != NULL); dev->ad_ops->ao_reset(dev); /* Register the ADC character driver */ ret = register_driver(path, &g_adc_fops, 0444, dev); if (ret < 0) { nxsem_destroy(&dev->ad_recv.af_sem); nxmutex_destroy(&dev->ad_closelock); } return ret; }