sysclk-lwla: Skip unused registers in status poll

[libsigrok.git] / src / hardware / sysclk-lwla / lwla1034.c

diff --git a/src/hardware/sysclk-lwla/lwla1034.c b/src/hardware/sysclk-lwla/lwla1034.c
index baf3d1e94b2621733cc99395c08a62dea51283b8..fdb54e620742d061a26fbf2f625585044f85157c 100644 (file)
--- a/src/hardware/sysclk-lwla/lwla1034.c
+++ b/src/hardware/sysclk-lwla/lwla1034.c
@@ -56,9 +56,17 @@
  */
 #define READ_CHUNK_LEN36       (28 * 8)
 
-/* Bit mask for the RLE repeat-count-follows flag. */
+/* Bit mask for the RLE repeat-count-follows flag.
+ */
 #define RLE_FLAG_LEN_FOLLOWS   (UINT64_C(1) << 35)
 
+/* Start index and count for bulk long register reads.
+ * The first five long registers do not return useful values when read,
+ * so skip over them to reduce the transfer size of status poll responses.
+ */
+#define READ_LREGS_START       LREG_MEM_FILL
+#define READ_LREGS_COUNT       (LREG_STATUS + 1 - READ_LREGS_START)
+
 /** LWLA1034 register addresses.
  */
 enum reg_addr {
@@ -185,8 +193,8 @@ static inline uint64_t bulk_long_get(const struct acquisition_state *acq,
 {
        uint64_t low, high;
 
-       low  = LWLA_TO_UINT32(acq->xfer_buf_in[2 * idx]);
-       high = LWLA_TO_UINT32(acq->xfer_buf_in[2 * idx + 1]);
+       low  = LWLA_TO_UINT32(acq->xfer_buf_in[2 * (idx - READ_LREGS_START)]);
+       high = LWLA_TO_UINT32(acq->xfer_buf_in[2 * (idx - READ_LREGS_START) + 1]);
 
        return (high << 32) | low;
 }
@@ -423,8 +431,8 @@ static int prepare_request(const struct sr_dev_inst *sdi)
                break;
        case STATE_STATUS_REQUEST:
                acq->xfer_buf_out[0] = LWLA_WORD(CMD_READ_LREGS);
-               acq->xfer_buf_out[1] = LWLA_WORD(0);
-               acq->xfer_buf_out[2] = LWLA_WORD(LREG_STATUS + 1);
+               acq->xfer_buf_out[1] = LWLA_WORD(READ_LREGS_START);
+               acq->xfer_buf_out[2] = LWLA_WORD(READ_LREGS_COUNT);
                acq->xfer_out->length = 3 * sizeof(acq->xfer_buf_out[0]);
                break;
        case STATE_LENGTH_REQUEST:
@@ -463,9 +471,9 @@ static int handle_response(const struct sr_dev_inst *sdi)
 
        switch (devc->state) {
        case STATE_STATUS_REQUEST:
-               if (acq->xfer_in->actual_length != (LREG_STATUS + 1) * 8) {
+               if (acq->xfer_in->actual_length != READ_LREGS_COUNT * 8) {
                        sr_err("Received size %d doesn't match expected size %d.",
-                              acq->xfer_in->actual_length, (LREG_STATUS + 1) * 8);
+                              acq->xfer_in->actual_length, READ_LREGS_COUNT * 8);
                        return SR_ERR;
                }
                acq->mem_addr_fill = bulk_long_get(acq, LREG_MEM_FILL) & 0xFFFFFFFF;