sysclk-lwla: Work around short transfer quirk

[libsigrok.git] / src / hardware / sysclk-lwla / lwla.c

diff --git a/src/hardware/sysclk-lwla/lwla.c b/src/hardware/sysclk-lwla/lwla.c
index c884885cd918127e416fa84d84856807b2908046..6a0b5606544136ae6e2ebb0981924dcbd6844df0 100644 (file)
--- a/src/hardware/sysclk-lwla/lwla.c
+++ b/src/hardware/sysclk-lwla/lwla.c
@@ -144,33 +144,26 @@ SR_PRIV int lwla_send_command(const struct sr_usb_dev_inst *usb,
 }
 
 SR_PRIV int lwla_receive_reply(const struct sr_usb_dev_inst *usb,
-                              uint32_t *reply, int reply_len, int expect_len)
+                              void *reply, int buf_size, int *xfer_len)
 {
        int ret;
-       int xfer_len;
 
-       if (!usb || !reply || reply_len <= 0)
+       if (!usb || !reply || buf_size <= 0)
                return SR_ERR_BUG;
 
-       xfer_len = 0;
-       ret = libusb_bulk_transfer(usb->devhdl, EP_REPLY,
-                                  (unsigned char *)reply, reply_len * 4,
-                                  &xfer_len, USB_TIMEOUT_MS);
+       ret = libusb_bulk_transfer(usb->devhdl, EP_REPLY, reply, buf_size,
+                                  xfer_len, USB_TIMEOUT_MS);
        if (ret != 0) {
                sr_dbg("Failed to receive reply: %s.", libusb_error_name(ret));
                return SR_ERR;
        }
-       if (xfer_len != expect_len * 4) {
-               sr_dbg("Failed to receive reply: incorrect length %d != %d.",
-                      xfer_len, expect_len * 4);
-               return SR_ERR;
-       }
        return SR_OK;
 }
 
 SR_PRIV int lwla_read_reg(const struct sr_usb_dev_inst *usb,
                          uint16_t reg, uint32_t *value)
 {
+       int xfer_len;
        int ret;
        uint16_t command[2];
        uint32_t reply[128]; /* full EP buffer to avoid overflows */
@@ -179,16 +172,21 @@ SR_PRIV int lwla_read_reg(const struct sr_usb_dev_inst *usb,
        command[1] = LWLA_WORD(reg);
 
        ret = lwla_send_command(usb, command, ARRAY_SIZE(command));
-
        if (ret != SR_OK)
                return ret;
 
-       ret = lwla_receive_reply(usb, reply, ARRAY_SIZE(reply), 1);
+       ret = lwla_receive_reply(usb, reply, sizeof(reply), &xfer_len);
+       if (ret != SR_OK)
+               return ret;
 
-       if (ret == SR_OK)
-               *value = LWLA_TO_UINT32(reply[0]);
+       if (xfer_len != 4) {
+               sr_dbg("Invalid register read response of length %d.",
+                      xfer_len);
+               return SR_ERR;
+       }
+       *value = LWLA_TO_UINT32(reply[0]);
 
-       return ret;
+       return SR_OK;
 }
 
 SR_PRIV int lwla_write_reg(const struct sr_usb_dev_inst *usb,