From: Bert Vermeulen <redacted>
Date: Thu, 17 Sep 2015 21:31:04 +0000 (+0200)
Subject: scpi/usbtmc: Support RL1 feature.
X-Git-Tag: libsigrok-0.4.0~277
X-Git-Url: https://sigrok.org/gitweb/?p=libsigrok.git;a=commitdiff_plain;h=baed0211a1ecada69c5ab53cf979e2e543a0ceaa

scpi/usbtmc: Support RL1 feature.

This automatically locks out local controls when a USBTMC device is
opened, and returns local control on close.
---

diff --git a/src/scpi/scpi_usbtmc_libusb.c b/src/scpi/scpi_usbtmc_libusb.c
index 36ff316b..a6eb922b 100644
--- a/src/scpi/scpi_usbtmc_libusb.c
+++ b/src/scpi/scpi_usbtmc_libusb.c
@@ -70,6 +70,9 @@ enum {
 	LOCAL_LOCKOUT               = 162,
 };
 
+/* USBTMC status codes */
+#define USBTMC_STATUS_SUCCESS      0x01
+
 /* USBTMC capabilities */
 #define USBTMC_INT_CAP_LISTEN_ONLY 0x01
 #define USBTMC_INT_CAP_TALK_ONLY   0x02
@@ -185,7 +188,7 @@ static int scpi_usbtmc_libusb_open(void *priv)
 	const struct libusb_interface_descriptor *intfdes;
 	const struct libusb_endpoint_descriptor *ep;
 	int confidx, intfidx, epidx, config = 0;
-	uint8_t capabilities[24];
+	uint8_t capabilities[24], status;
 	int ret, found = 0;
 
 	if (usb->devhdl)
@@ -313,6 +316,32 @@ static int scpi_usbtmc_libusb_open(void *priv)
 	       uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1        ? "RL1"  : "RL0",
 	       uscpi->usb488_dev_cap & USB488_DEV_CAP_DT1        ? "DT1"  : "DT0");
 
+	if (uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1) {
+		sr_dbg("Locking out local control.");
+		ret = libusb_control_transfer(usb->devhdl,
+				LIBUSB_ENDPOINT_IN         |
+				LIBUSB_REQUEST_TYPE_CLASS  |
+				LIBUSB_RECIPIENT_INTERFACE,
+				REN_CONTROL, 1,
+				uscpi->interface,
+				&status, 1,
+				TRANSFER_TIMEOUT);
+		if (ret < 0 || status != USBTMC_STATUS_SUCCESS) {
+			sr_dbg("Failed to enter REN state.");
+			return SR_OK;
+		}
+		ret = libusb_control_transfer(usb->devhdl,
+				LIBUSB_ENDPOINT_IN         |
+				LIBUSB_REQUEST_TYPE_CLASS  |
+				LIBUSB_RECIPIENT_INTERFACE,
+				LOCAL_LOCKOUT, 1,
+				uscpi->interface,
+				&status, 1,
+				TRANSFER_TIMEOUT);
+		if (ret < 0 || status != USBTMC_STATUS_SUCCESS)
+			sr_dbg("Failed to enter local lockout state.");
+	}
+
 	return SR_OK;
 }
 
@@ -527,6 +556,7 @@ static int scpi_usbtmc_libusb_close(void *priv)
 	int ret;
 	struct scpi_usbtmc_libusb *uscpi = priv;
 	struct sr_usb_dev_inst *usb = uscpi->usb;
+	uint8_t status;
 
 	if (!usb->devhdl)
 		return SR_ERR;
@@ -543,6 +573,20 @@ static int scpi_usbtmc_libusb_close(void *priv)
 		       uscpi->interrupt_ep, libusb_error_name(ret));
 	}
 
+	if (uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1) {
+		sr_dbg("Returning local control.");
+		ret = libusb_control_transfer(usb->devhdl,
+				LIBUSB_ENDPOINT_IN         |
+				LIBUSB_REQUEST_TYPE_CLASS  |
+				LIBUSB_RECIPIENT_INTERFACE,
+				GO_TO_LOCAL, 1,
+				uscpi->interface,
+				&status, 1,
+				TRANSFER_TIMEOUT);
+		if (ret < 0 || status != USBTMC_STATUS_SUCCESS)
+			sr_dbg("Failed to clear local lockout state.");
+	}
+
 	if ((ret = libusb_release_interface(usb->devhdl, uscpi->interface)) < 0)
 		sr_err("Failed to release interface: %s.",
 		       libusb_error_name(ret));