cem-dt-885x: Support for powering off the device

[libsigrok.git] / hardware / cem-dt-885x / protocol.c

diff --git a/hardware/cem-dt-885x/protocol.c b/hardware/cem-dt-885x/protocol.c
index 3ae43a7042a51f322b115e4db1ecb76e16b34fec..5f2972f68fd3b2fe05307c1a5565f01bd0feac23 100644 (file)
--- a/hardware/cem-dt-885x/protocol.c
+++ b/hardware/cem-dt-885x/protocol.c
@@ -685,3 +685,36 @@ SR_PRIV int cem_dt_885x_meas_range_set(const struct sr_dev_inst *sdi,
 
        return ret;
 }
+
+SR_PRIV int cem_dt_885x_power_off(const struct sr_dev_inst *sdi)
+{
+       struct sr_serial_dev_inst *serial;
+       char c, cmd;
+
+       serial = sdi->conn;
+
+       /* Reopen the port in non-blocking mode, so we can properly
+        * detect when the device stops communicating. */
+       serial_close(serial);
+       if (serial_open(serial, SERIAL_RDWR | SERIAL_NONBLOCK) != SR_OK)
+               return SR_ERR;
+
+       cmd = CMD_TOGGLE_POWER_OFF;
+       while (TRUE) {
+               serial_flush(serial);
+               if (serial_write(serial, (const void *)&cmd, 1) != 1)
+                       return SR_ERR;
+               /* It never takes more than 23ms for the next token to arrive. */
+               g_usleep(25 * 1000);
+               if (serial_read(serial, &c, 1) != 1)
+                       /* Device is no longer responding. Good! */
+                       break;
+       }
+
+       /* In case the user manually turns on the device again, reset
+        * the port back to blocking. */
+       serial_close(serial);
+       serial_open(serial, SERIAL_RDWR);
+
+       return SR_OK;
+}