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* [PATCH 1/2] iio: Fix sign extension table in mcp3422 driver
@ 2013-11-02 19:44 Peter Meerwald
  2013-11-02 19:44 ` [PATCH 2/2] iio: Drop scan_type from viperboard adc driver Peter Meerwald
  2013-11-02 22:09 ` [PATCH 1/2] iio: Fix sign extension table in mcp3422 driver Angelo Compagnucci
  0 siblings, 2 replies; 9+ messages in thread
From: Peter Meerwald @ 2013-11-02 19:44 UTC (permalink / raw)
  To: linux-iio; +Cc: Peter Meerwald, Angelo Compagnucci

the index argument to sign_extend32() gives the bit position (from 0)
to the sign bit

so e.g. if the measurement has 16-bit resolution, we need to pass 15;
a measurement of 0x8000 should be reported as -32768, not 32768

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Cc: Angelo Compagnucci <angelo.compagnucci@gmail.com>
---
 drivers/iio/adc/mcp3422.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/adc/mcp3422.c b/drivers/iio/adc/mcp3422.c
index 1294832..c8c1baa 100644
--- a/drivers/iio/adc/mcp3422.c
+++ b/drivers/iio/adc/mcp3422.c
@@ -88,10 +88,10 @@ static const int mcp3422_sample_rates[4] = {
 
 /* sample rates to sign extension table */
 static const int mcp3422_sign_extend[4] = {
-	[MCP3422_SRATE_240] = 12,
-	[MCP3422_SRATE_60] = 14,
-	[MCP3422_SRATE_15] = 16,
-	[MCP3422_SRATE_3] = 18 };
+	[MCP3422_SRATE_240] = 11,
+	[MCP3422_SRATE_60] = 13,
+	[MCP3422_SRATE_15] = 15,
+	[MCP3422_SRATE_3] = 17 };
 
 /* Client data (each client gets its own) */
 struct mcp3422 {
-- 
1.8.4.2


^ permalink raw reply related	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2013-11-09 12:51 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-11-02 19:44 [PATCH 1/2] iio: Fix sign extension table in mcp3422 driver Peter Meerwald
2013-11-02 19:44 ` [PATCH 2/2] iio: Drop scan_type from viperboard adc driver Peter Meerwald
2013-11-09 11:48   ` Jonathan Cameron
2013-11-09 13:52     ` Jonathan Cameron
2013-11-02 22:09 ` [PATCH 1/2] iio: Fix sign extension table in mcp3422 driver Angelo Compagnucci
2013-11-04 20:06   ` Jonathan Cameron
2013-11-05  7:57     ` Angelo Compagnucci
2013-11-05 13:28       ` Jonathan Cameron
2013-11-05 22:46         ` Jonathan Cameron

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