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authorIan Abbott <abbotti@mev.co.uk>2013-02-14 16:42:15 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-02-15 10:17:55 -0800
commitf06a23c93b900c37ef14858868c00dc8f061fa22 (patch)
treef7be74dd9a9b5609fcdf45de19308d92d41ff379 /drivers/staging
parente8f311a5b6b9163f6aeba2524eaab92dc3b0fb6f (diff)
staging: comedi: vmk80xx: initialize K8055 outputs to known state
vmk8055_reset_device() is called during initialization of a Velleman K8055 (aka VM110) to send a reset command to the hardware. I don't know what this does, but I know that it doesn't reset the digital outputs as I've tried it. Since the hardware does not have any way to query the current output values and there is only the one command to update all the analog and digital outputs simultaneously (VMK8055_CMD_WRT_AD), send this command during initialization to set all the analog and digital outputs to a known state. Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging')
-rw-r--r--drivers/staging/comedi/drivers/vmk80xx.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/staging/comedi/drivers/vmk80xx.c b/drivers/staging/comedi/drivers/vmk80xx.c
index 057d840b90de..7984e036c041 100644
--- a/drivers/staging/comedi/drivers/vmk80xx.c
+++ b/drivers/staging/comedi/drivers/vmk80xx.c
@@ -436,10 +436,15 @@ exit:
static int vmk80xx_reset_device(struct vmk80xx_private *devpriv)
{
size_t size;
+ int retval;
size = le16_to_cpu(devpriv->ep_tx->wMaxPacketSize);
memset(devpriv->usb_tx_buf, 0, size);
- return vmk80xx_write_packet(devpriv, VMK8055_CMD_RST);
+ retval = vmk80xx_write_packet(devpriv, VMK8055_CMD_RST);
+ if (retval)
+ return retval;
+ /* set outputs to known state as we cannot read them */
+ return vmk80xx_write_packet(devpriv, VMK8055_CMD_WRT_AD);
}
#define DIR_IN 1