From bc1143280f7ca878e1309a1d1c0899275ff32d27 Mon Sep 17 00:00:00 2001
From: Bert Vermeulen <bert@biot.com>
Date: Wed, 12 Jun 2013 15:45:37 +0200
Subject: [PATCH] cem-dt-885x: Hold off measurements in max/min hold mode

---
 hardware/cem-dt-885x/protocol.c | 17 ++++++++++++++---
 hardware/cem-dt-885x/protocol.h |  1 +
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/hardware/cem-dt-885x/protocol.c b/hardware/cem-dt-885x/protocol.c
index 8b09d324..b727ada9 100644
--- a/hardware/cem-dt-885x/protocol.c
+++ b/hardware/cem-dt-885x/protocol.c
@@ -117,13 +117,26 @@ static void process_mset(const struct sr_dev_inst *sdi)
 		fvalue += (devc->buf[0] & 0x0f) * 10;
 		fvalue += ((devc->buf[1] & 0xf0) >> 4);
 		fvalue += (devc->buf[1] & 0x0f) / 10.0;
+		devc->last_spl = fvalue;
+		break;
+	case TOKEN_MEAS_WAS_READOUT:
+	case TOKEN_MEAS_WAS_BARGRAPH:
+		if (devc->cur_mqflags & (SR_MQFLAG_MAX | SR_MQFLAG_MIN)) {
+			if (devc->token == TOKEN_MEAS_WAS_BARGRAPH) {
+				/* The device still sends bargraph measurements even
+				 * when in max/min hold mode. Suppress them here, unless
+				 * they're readout values. This duplicates the behavior
+				 * of the device display exactly. */
+				break;
+			}
+		}
 		memset(&analog, 0, sizeof(struct sr_datafeed_analog));
 		analog.mq = SR_MQ_SOUND_PRESSURE_LEVEL;
 		analog.mqflags = devc->cur_mqflags;
 		analog.unit = SR_UNIT_DECIBEL_SPL;
 		analog.probes = sdi->probes;
 		analog.num_samples = 1;
-		analog.data = &fvalue;
+		analog.data = &devc->last_spl;
 		packet.type = SR_DF_ANALOG;
 		packet.payload = &analog;
 		sr_session_send(devc->cb_data, &packet);
@@ -138,8 +151,6 @@ static void process_mset(const struct sr_dev_inst *sdi)
 	case TOKEN_STORE_FULL:
 	case TOKEN_RECORDING_ON:
 	case TOKEN_RECORDING_OFF:
-	case TOKEN_MEAS_WAS_READOUT:
-	case TOKEN_MEAS_WAS_BARGRAPH:
 	case TOKEN_BATTERY_OK:
 	case TOKEN_BATTERY_LOW:
 	case TOKEN_MEAS_RANGE_OK:
diff --git a/hardware/cem-dt-885x/protocol.h b/hardware/cem-dt-885x/protocol.h
index 7f296e83..f3809fc2 100644
--- a/hardware/cem-dt-885x/protocol.h
+++ b/hardware/cem-dt-885x/protocol.h
@@ -79,6 +79,7 @@ struct dev_context {
 	unsigned char token;
 	int buf_len;
 	unsigned char buf[BUF_SIZE];
+	float last_spl;
 
 };