patch "staging: comedi: ni_6527: fix INSN_CONFIG_DIGITAL_TRIG support" added to staging-linus

This is a note to let you know that I've just added the patch titled

staging: comedi: ni_6527: fix INSN_CONFIG_DIGITAL_TRIG support

to my staging git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From f07804ec77d77f8a9dcf570a24154e17747bc82f Mon Sep 17 00:00:00 2001
From: Ian Abbott <[email protected]>
Date: Fri, 17 Jul 2020 15:52:54 +0100
Subject: staging: comedi: ni_6527: fix INSN_CONFIG_DIGITAL_TRIG support

ni6527_intr_insn_config() processes INSN_CONFIG comedi instructions for the "interrupt" subdevice. When data[0] is INSN_CONFIG_DIGITAL_TRIG it is configuring the digital trigger. When data[2] is COMEDI_DIGITAL_TRIG_ENABLE_EDGES it is configuring rising and falling edge detection for the digital trigger, using a base channel number (or shift amount) in data[3], a rising edge bitmask in data[4] and falling edge bitmask in data[5].

If the base channel number (shift amount) is greater than or equal to the number of channels (24) of the digital input subdevice, there are no changes to the rising and falling edges, so the mask of channels to be changed can be set to 0, otherwise the mask of channels to be changed, and the rising and falling edge bitmasks are shifted by the base channel number before calling ni6527_set_edge_detection() to change the appropriate registers. Unfortunately, the code is comparing the base channel (shift amount) to the interrupt subdevice's number of channels
(1) instead of the digital input subdevice's number of channels (24). Fix it by comparing to 32 because all shift amounts for an unsigned int must be less than that and everything from bit 24 upwards is ignored by ni6527_set_edge_detection() anyway.

---
 drivers/staging/comedi/drivers/ni_6527.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 4d1eccb5041d..4518c2680b7c 100644
@@ -332,7 +332,7 @@ static int ni6527_intr_insn_config(struct comedi_device *dev,
 		case COMEDI_DIGITAL_TRIG_ENABLE_EDGES:
 			/* check shift amount */
 			shift = data[3];
-			if (shift >= s->n_chan) {
+			if (shift >= 32) {
 				mask = 0;
 				rising = 0;
 				falling = 0;

2.27.0