staging: comedi: me4000: remove 'board' from me4000_ai_insn_read() (1a023870) · Commits · 戴 / test

The 'board' pointer is only used in this function to verify that the 'chan' is valid for an aref of AREF_DIFF. For differential inputs, the maximum channel is half the subdevice 'n_chan'. Use that instead and remove the 'board' variable. Also, the comedi core does not validate the aref flags. Add a check to ensure that the subdevice actually supports the AREF_DIFF mode. 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/me4000.c

+10 −4

Original line number	Diff line number	Diff line
		@@ -436,10 +436,10 @@ static void me4000_reset(struct comedi_device *dev)
		===========================================================================*/

		static int me4000_ai_insn_read(struct comedi_device *dev,
		struct comedi_subdevice *subdevice,
		struct comedi_insn insn, unsigned int data)
		struct comedi_subdevice *s,
		struct comedi_insn *insn,
		unsigned int *data)
		{
		const struct me4000_board *board = dev->board_ptr;
		int chan = CR_CHAN(insn->chanspec);
		int rang = CR_RANGE(insn->chanspec);
		int aref = CR_AREF(insn->chanspec);
		@@ -481,13 +481,19 @@ static int me4000_ai_insn_read(struct comedi_device *dev,
		break;

		case AREF_DIFF:
		if (!(s->subdev_flags && SDF_DIFF)) {
		dev_err(dev->class_dev,
		"Differential inputs are not available\n");
		return -EINVAL;
		}

		if (rang == 0 \|\| rang == 1) {
		dev_err(dev->class_dev,
		"Range must be bipolar when aref = diff\n");
		return -EINVAL;
		}

		if (chan >= board->ai_diff_nchan) {
		if (chan >= (s->n_chan / 2)) {
		dev_err(dev->class_dev,
		"Analog input is not available\n");
		return -EINVAL;

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