staging: comedi: fix minimum AO period for NI 625x and NI 628x

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@delmic.com>
Acked-By: Ian Abbott <abbotti@mev.co.uk>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/ni_pcimio.c b/drivers/staging/comedi/drivers/ni_pcimio.c
index aaac0b2cc9eb7172ab963aa361e8d7e828ceb751..fd1662b4175db8755b8c605ed90f08437c12ba4c 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_pcimio.c
+++ b/drivers/staging/comedi/drivers/ni_pcimio.c
@@ -963,7 +963,7 @@ static const struct ni_board_struct ni_boards[] = {
         .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,
@@ -982,7 +982,7 @@ static const struct ni_board_struct ni_boards[] = {
         .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,
@@ -1001,7 +1001,7 @@ static const struct ni_board_struct ni_boards[] = {
         .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,
@@ -1037,7 +1037,7 @@ static const struct ni_board_struct ni_boards[] = {
         .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,
@@ -1056,7 +1056,7 @@ static const struct ni_board_struct ni_boards[] = {
         .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,
@@ -1092,7 +1092,7 @@ static const struct ni_board_struct ni_boards[] = {
         .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,
@@ -1111,7 +1111,7 @@ static const struct ni_board_struct ni_boards[] = {
         .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,
@@ -1147,7 +1147,7 @@ static const struct ni_board_struct ni_boards[] = {
         .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,