diff mbox

[3.11.y.z,extended,stable] Patch "staging: comedi: adv_pci1710: fix analog output readback value" has been added to staging queue

Message ID 1392985497-5775-1-git-send-email-luis.henriques@canonical.com
State New
Headers show

Commit Message

Luis Henriques Feb. 21, 2014, 12:24 p.m. UTC 
This is a note to let you know that I have just added a patch titled

    staging: comedi: adv_pci1710: fix analog output readback value

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

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From d7e2abc82e66c9bad51820f1c6ee0fdef386884d Mon Sep 17 00:00:00 2001
From: H Hartley Sweeten <hsweeten@visionengravers.com>
Date: Wed, 5 Feb 2014 14:59:53 -0700
Subject: staging: comedi: adv_pci1710: fix analog output readback value

commit 1e85c1ea1ff2a60659e790ef8ec76c7339445841 upstream.

The last value written to a analog output channel is cached in the
private data of this driver for readback.

Currently, the wrong value is cached in the (*insn_write) functions.
The current code stores the data[n] value for readback afer the loop
has written all the values. At this time 'n' points past the end of
the data array.

Fix the functions by using a local variable to hold the data being
written to the analog output channel. This variable is then used
after the loop is complete to store the readback value. The current
value is retrieved before the loop in case no values are actually
written..

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>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 drivers/staging/comedi/drivers/adv_pci1710.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

--
1.9.0
diff mbox

Patch

diff --git a/drivers/staging/comedi/drivers/adv_pci1710.c b/drivers/staging/comedi/drivers/adv_pci1710.c
index f847bbc..acb66a9 100644
--- a/drivers/staging/comedi/drivers/adv_pci1710.c
+++ b/drivers/staging/comedi/drivers/adv_pci1710.c
@@ -489,6 +489,7 @@  static int pci171x_insn_write_ao(struct comedi_device *dev,
 				 struct comedi_insn *insn, unsigned int *data)
 {
 	struct pci1710_private *devpriv = dev->private;
+	unsigned int val;
 	int n, chan, range, ofs;

 	chan = CR_CHAN(insn->chanspec);
@@ -504,11 +505,14 @@  static int pci171x_insn_write_ao(struct comedi_device *dev,
 		outw(devpriv->da_ranges, dev->iobase + PCI171x_DAREF);
 		ofs = PCI171x_DA1;
 	}
+	val = devpriv->ao_data[chan];

-	for (n = 0; n < insn->n; n++)
-		outw(data[n], dev->iobase + ofs);
+	for (n = 0; n < insn->n; n++) {
+		val = data[n];
+		outw(val, dev->iobase + ofs);
+	}

-	devpriv->ao_data[chan] = data[n];
+	devpriv->ao_data[chan] = val;

 	return n;

@@ -678,6 +682,7 @@  static int pci1720_insn_write_ao(struct comedi_device *dev,
 				 struct comedi_insn *insn, unsigned int *data)
 {
 	struct pci1710_private *devpriv = dev->private;
+	unsigned int val;
 	int n, rangereg, chan;

 	chan = CR_CHAN(insn->chanspec);
@@ -687,13 +692,15 @@  static int pci1720_insn_write_ao(struct comedi_device *dev,
 		outb(rangereg, dev->iobase + PCI1720_RANGE);
 		devpriv->da_ranges = rangereg;
 	}
+	val = devpriv->ao_data[chan];

 	for (n = 0; n < insn->n; n++) {
-		outw(data[n], dev->iobase + PCI1720_DA0 + (chan << 1));
+		val = data[n];
+		outw(val, dev->iobase + PCI1720_DA0 + (chan << 1));
 		outb(0, dev->iobase + PCI1720_SYNCOUT);	/*  update outputs */
 	}

-	devpriv->ao_data[chan] = data[n];
+	devpriv->ao_data[chan] = val;

 	return n;
 }