Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755196Ab2FMWmz (ORCPT ); Wed, 13 Jun 2012 18:42:55 -0400 Received: from mail127.messagelabs.com ([216.82.250.115]:52564 "EHLO mail127.messagelabs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754968Ab2FMWmw (ORCPT ); Wed, 13 Jun 2012 18:42:52 -0400 X-Env-Sender: hartleys@visionengravers.com X-Msg-Ref: server-8.tower-127.messagelabs.com!1339627371!1174968!2 X-Originating-IP: [216.166.12.32] X-StarScan-Version: 6.5.10; banners=-,-,- X-VirusChecked: Checked From: H Hartley Sweeten To: Linux Kernel Subject: [PATCH 12/15] staging: comedi: 8255: refactor subdev_8255_insn function Date: Wed, 13 Jun 2012 15:42:45 -0700 User-Agent: KMail/1.9.9 CC: , , , MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-ID: <201206131542.46112.hartleys@visionengravers.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3065 Lines: 93 Refactor the subdev_8255_insn function to follow what the user space library is doing. 1) This function requires 'data' to contain 2 parameters. Add a sanity check for this (insn->n != 2). 2) The 'data' parameters are actually a 'mask' of the valid bits and the actual 'bits' to modify. Create local variables of these names to help with maintainability. 3) The value returned in data[1] reflects the actual state of the 8255 io pins after the update of the masked bits. Fetch this data in a local variable and then set data[1]. 4) The user space library only checks for a < 0 return to indicate an error. It appears that the 'return 2' in this function is supposed to indicate the number of data parameters used to perform the command. Return the insn->n value for this, the open coded '2' looks wrong. Signed-off-by: H Hartley Sweeten Cc: Iam Abbott Cc: Frank Mori Hess Cc: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/8255.c | 42 +++++++++++++++++++++----------- 1 files changed, 27 insertions(+), 15 deletions(-) diff --git a/drivers/staging/comedi/drivers/8255.c b/drivers/staging/comedi/drivers/8255.c index 1f4b24c..da374de 100644 --- a/drivers/staging/comedi/drivers/8255.c +++ b/drivers/staging/comedi/drivers/8255.c @@ -135,26 +135,38 @@ static int subdev_8255_insn(struct comedi_device *dev, { struct subdev_8255_private *spriv = s->private; unsigned long iobase = spriv->iobase; + unsigned int mask; + unsigned int bits; + unsigned int v; + + if (insn->n != 2) + return -EINVAL; - if (data[0]) { - s->state &= ~data[0]; - s->state |= (data[0] & data[1]); + mask = data[0]; + bits = data[1]; - if (data[0] & 0xff) - spriv->io(1, _8255_DATA, s->state & 0xff, iobase); - if (data[0] & 0xff00) - spriv->io(1, _8255_DATA + 1, - (s->state >> 8) & 0xff, iobase); - if (data[0] & 0xff0000) - spriv->io(1, _8255_DATA + 2, - (s->state >> 16) & 0xff, iobase); + if (mask) { + v = s->state; + v &= ~mask; + v |= (bits & mask); + + if (mask & 0xff) + spriv->io(1, _8255_DATA, v & 0xff, iobase); + if (mask & 0xff00) + spriv->io(1, _8255_DATA + 1, (v >> 8) & 0xff, iobase); + if (mask & 0xff0000) + spriv->io(1, _8255_DATA + 2, (v >> 16) & 0xff, iobase); + + s->state = v; } - data[1] = spriv->io(0, _8255_DATA, 0, iobase); - data[1] |= (spriv->io(0, _8255_DATA + 1, 0, iobase) << 8); - data[1] |= (spriv->io(0, _8255_DATA + 2, 0, iobase) << 16); + v = spriv->io(0, _8255_DATA, 0, iobase); + v |= (spriv->io(0, _8255_DATA + 1, 0, iobase) << 8); + v |= (spriv->io(0, _8255_DATA + 2, 0, iobase) << 16); + + data[1] = v; - return 2; + return insn->n; } static void do_config(struct comedi_device *dev, struct comedi_subdevice *s) -- 1.7.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/