From 1f8212679cfef610a0601c547eb94420c02fb258 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Fri, 15 Apr 2016 07:07:22 -0600
Subject: [PATCH] NRF24L01:  Fix backward calculation of relative frequency. 
 Noted by Henry Zhang

---
 ChangeLog                   | 2 ++
 drivers/wireless/nrf24l01.c | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index 7ed20c82d2..eafb935383 100755
--- a/ChangeLog
+++ b/ChangeLog
@@ -11649,4 +11649,6 @@
 	  configurations (2015-04-14).
 	* Framebuffer driver:  Add a display number to each interface in order
 	  to support multiple display devices (2015-04-14).
+	* drivers/wireless/nrf24l01.c: Fix backward calculation of relative
+	  frequency.  Noted by Henry Zhang (2015-04-15).
 
diff --git a/drivers/wireless/nrf24l01.c b/drivers/wireless/nrf24l01.c
index ab7402d773..eb6c3f68c8 100644
--- a/drivers/wireless/nrf24l01.c
+++ b/drivers/wireless/nrf24l01.c
@@ -1590,7 +1590,7 @@ int nrf24l01_setradiofreq(FAR struct nrf24l01_dev_s *dev, uint32_t freq)
 
   CHECK_ARGS(dev && freq >= NRF24L01_MIN_FREQ && freq <= NRF24L01_MAX_FREQ);
 
-  value = NRF24L01_MIN_FREQ - freq;
+  value = freq - NRF24L01_MIN_FREQ;
   nrf24l01_lock(dev->spi);
   nrf24l01_writeregbyte(dev, NRF24L01_RF_CH, value);
   nrf24l01_unlock(dev->spi);