static int ni_ai_insn_read()

in drivers/ni_mio_common.c [1821:1924]

• 93 lines of code
• 18 McCabe index (conditional complexity)

static int ni_ai_insn_read(struct comedi_device *dev,
			   struct comedi_subdevice *s,
			   struct comedi_insn *insn,
			   unsigned int *data)
{
	struct ni_private *devpriv = dev->private;
	unsigned int mask = s->maxdata;
	int i, n;
	unsigned int signbits;
	unsigned int d;

	ni_load_channelgain_list(dev, s, 1, &insn->chanspec);

	ni_clear_ai_fifo(dev);

	signbits = devpriv->ai_offset[0];
	if (devpriv->is_611x) {
		for (n = 0; n < num_adc_stages_611x; n++) {
			ni_stc_writew(dev, NISTC_AI_CMD1_CONVERT_PULSE,
				      NISTC_AI_CMD1_REG);
			udelay(1);
		}
		for (n = 0; n < insn->n; n++) {
			ni_stc_writew(dev, NISTC_AI_CMD1_CONVERT_PULSE,
				      NISTC_AI_CMD1_REG);
			/* The 611x has screwy 32-bit FIFOs. */
			d = 0;
			for (i = 0; i < NI_TIMEOUT; i++) {
				if (ni_readb(dev, NI_E_STATUS_REG) & 0x80) {
					d = ni_readl(dev,
						     NI611X_AI_FIFO_DATA_REG);
					d >>= 16;
					d &= 0xffff;
					break;
				}
				if (!(ni_stc_readw(dev, NISTC_AI_STATUS1_REG) &
				      NISTC_AI_STATUS1_FIFO_E)) {
					d = ni_readl(dev,
						     NI611X_AI_FIFO_DATA_REG);
					d &= 0xffff;
					break;
				}
			}
			if (i == NI_TIMEOUT) {
				dev_err(dev->class_dev, "timeout\n");
				return -ETIME;
			}
			d += signbits;
			data[n] = d & 0xffff;
		}
	} else if (devpriv->is_6143) {
		for (n = 0; n < insn->n; n++) {
			ni_stc_writew(dev, NISTC_AI_CMD1_CONVERT_PULSE,
				      NISTC_AI_CMD1_REG);

			/*
			 * The 6143 has 32-bit FIFOs. You need to strobe a
			 * bit to move a single 16bit stranded sample into
			 * the FIFO.
			 */
			d = 0;
			for (i = 0; i < NI_TIMEOUT; i++) {
				if (ni_readl(dev, NI6143_AI_FIFO_STATUS_REG) &
				    0x01) {
					/* Get stranded sample into FIFO */
					ni_writel(dev, 0x01,
						  NI6143_AI_FIFO_CTRL_REG);
					d = ni_readl(dev,
						     NI6143_AI_FIFO_DATA_REG);
					break;
				}
			}
			if (i == NI_TIMEOUT) {
				dev_err(dev->class_dev, "timeout\n");
				return -ETIME;
			}
			data[n] = (((d >> 16) & 0xFFFF) + signbits) & 0xFFFF;
		}
	} else {
		for (n = 0; n < insn->n; n++) {
			ni_stc_writew(dev, NISTC_AI_CMD1_CONVERT_PULSE,
				      NISTC_AI_CMD1_REG);
			for (i = 0; i < NI_TIMEOUT; i++) {
				if (!(ni_stc_readw(dev, NISTC_AI_STATUS1_REG) &
				      NISTC_AI_STATUS1_FIFO_E))
					break;
			}
			if (i == NI_TIMEOUT) {
				dev_err(dev->class_dev, "timeout\n");
				return -ETIME;
			}
			if (devpriv->is_m_series) {
				d = ni_readl(dev, NI_M_AI_FIFO_DATA_REG);
				d &= mask;
				data[n] = d;
			} else {
				d = ni_readw(dev, NI_E_AI_FIFO_DATA_REG);
				d += signbits;
				data[n] = d & 0xffff;
			}
		}
	}
	return insn->n;
}