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Message-Id: <20130115224319.246625270@linuxfoundation.org>
Date: Tue, 15 Jan 2013 14:44:06 -0800
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
alan@...rguk.ukuu.org.uk,
Ãric Piel <piel@...mic.com>,
Ian Abbott <abbotti@....co.uk>
Subject: [ 081/171] staging: comedi: fix minimum AO period for NI 625x and NI 628x
3.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Éric Piel <piel@...mic.com>
commit 34b55d8c48f4f76044d8f4d6ec3dc786cf210312 upstream.
The minimum period was set to 357 ns, while the divider for these boards is 50
ns. This prevented to output at maximum speed as ni_ao_cmdtest() would return
357 but would not accept it.
Not sure why it was set to 357 ns (this was done before the git history,
which starts 5 years ago). My guess is that it comes from reading the
specification stating a 2.8 MHz rate (~ 357 ns). The latest
specification states a 2.86 MHz rate (~ 350 ns), which makes a lot
more sense.
Tested on a pci-6251.
Signed-off-by: Éric Piel <piel@...mic.com>
Acked-By: Ian Abbott <abbotti@....co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
drivers/staging/comedi/drivers/ni_pcimio.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
--- a/drivers/staging/comedi/drivers/ni_pcimio.c
+++ b/drivers/staging/comedi/drivers/ni_pcimio.c
@@ -1023,7 +1023,7 @@ static const struct ni_board_struct ni_b
.ao_range_table = &range_ni_M_625x_ao,
.reg_type = ni_reg_625x,
.ao_unipolar = 0,
- .ao_speed = 357,
+ .ao_speed = 350,
.num_p0_dio_channels = 8,
.caldac = {caldac_none},
.has_8255 = 0,
@@ -1042,7 +1042,7 @@ static const struct ni_board_struct ni_b
.ao_range_table = &range_ni_M_625x_ao,
.reg_type = ni_reg_625x,
.ao_unipolar = 0,
- .ao_speed = 357,
+ .ao_speed = 350,
.num_p0_dio_channels = 8,
.caldac = {caldac_none},
.has_8255 = 0,
@@ -1061,7 +1061,7 @@ static const struct ni_board_struct ni_b
.ao_range_table = &range_ni_M_625x_ao,
.reg_type = ni_reg_625x,
.ao_unipolar = 0,
- .ao_speed = 357,
+ .ao_speed = 350,
.num_p0_dio_channels = 8,
.caldac = {caldac_none},
.has_8255 = 0,
@@ -1097,7 +1097,7 @@ static const struct ni_board_struct ni_b
.ao_range_table = &range_ni_M_625x_ao,
.reg_type = ni_reg_625x,
.ao_unipolar = 0,
- .ao_speed = 357,
+ .ao_speed = 350,
.num_p0_dio_channels = 32,
.caldac = {caldac_none},
.has_8255 = 0,
@@ -1116,7 +1116,7 @@ static const struct ni_board_struct ni_b
.ao_range_table = &range_ni_M_625x_ao,
.reg_type = ni_reg_625x,
.ao_unipolar = 0,
- .ao_speed = 357,
+ .ao_speed = 350,
.num_p0_dio_channels = 32,
.caldac = {caldac_none},
.has_8255 = 0,
@@ -1152,7 +1152,7 @@ static const struct ni_board_struct ni_b
.ao_range_table = &range_ni_M_628x_ao,
.reg_type = ni_reg_628x,
.ao_unipolar = 1,
- .ao_speed = 357,
+ .ao_speed = 350,
.num_p0_dio_channels = 8,
.caldac = {caldac_none},
.has_8255 = 0,
@@ -1171,7 +1171,7 @@ static const struct ni_board_struct ni_b
.ao_range_table = &range_ni_M_628x_ao,
.reg_type = ni_reg_628x,
.ao_unipolar = 1,
- .ao_speed = 357,
+ .ao_speed = 350,
.num_p0_dio_channels = 8,
.caldac = {caldac_none},
.has_8255 = 0,
@@ -1207,7 +1207,7 @@ static const struct ni_board_struct ni_b
.ao_range_table = &range_ni_M_628x_ao,
.reg_type = ni_reg_628x,
.ao_unipolar = 1,
- .ao_speed = 357,
+ .ao_speed = 350,
.num_p0_dio_channels = 32,
.caldac = {caldac_none},
.has_8255 = 0,
--
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