staging: comedi: me_daq: allow differential analog inputs (8a844a91) · Commits · 戴 / test

The ai (*insn_read) allows differential analog inputs but the subdevice initialization is missing the SDF_DIFF subdev_flag to allow the user to select this mode. Fix the subdevice init. According to the manual, differential operation only works with the first 8 channels and bipolar ranges. Add a check to the (*insn_read) to ensure this. Signed-off-by:

H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by:

Ian Abbott <abbotti@mev.co.uk> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/me_daq.c

+10 −1

Original line number	Diff line number	Diff line
		@@ -246,6 +246,15 @@ static int me_ai_insn_read(struct comedi_device *dev,
		unsigned short val;
		int ret;

		/*
		* For differential operation, there are only 8 input channels
		* and only bipolar ranges are available.
		*/
		if (aref & AREF_DIFF) {
		if (chan > 7 \|\| comedi_range_is_unipolar(s, range))
		return -EINVAL;
		}

		/* stop any running conversion */
		devpriv->ctrl1 &= ~ME_CTRL1_ADC_MODE_MASK;
		writew(devpriv->ctrl1, dev->mmio + ME_CTRL1_REG);
		@@ -472,7 +481,7 @@ static int me_auto_attach(struct comedi_device *dev,

		s = &dev->subdevices[0];
		s->type = COMEDI_SUBD_AI;
		s->subdev_flags = SDF_READABLE \| SDF_COMMON;
		s->subdev_flags = SDF_READABLE \| SDF_COMMON \| SDF_DIFF;
		s->n_chan = 16;
		s->maxdata = 0x0fff;
		s->len_chanlist = 16;

Admin message