From: Ian Abbott Date: Thu, 14 Feb 2013 16:42:15 +0000 (+0000) Subject: staging: comedi: vmk80xx: initialize K8055 outputs to known state X-Git-Tag: v3.9-rc1~127^2~38 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=f06a23c93b900c37ef14858868c00dc8f061fa22;p=profile%2Fivi%2Fkernel-x86-ivi.git 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/comedi/drivers/vmk80xx.c b/drivers/staging/comedi/drivers/vmk80xx.c index 057d840..7984e03 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