From patchwork Thu Jan 24 03:26:39 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [27/74] staging: comedi: fix minimum AO period for NI 625x and NI 628x Date: Wed, 23 Jan 2013 17:26:39 -0000 From: Herton Ronaldo Krzesinski X-Patchwork-Id: 215140 Message-Id: <1358998046-613-28-git-send-email-herton.krzesinski@canonical.com> To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Greg Kroah-Hartman , =?UTF-8?q?=C3=89ric=20Piel?= 3.5.7.4 -stable review patch. If anyone has any objections, please let me know. ------------------ From: =?UTF-8?q?=C3=89ric=20Piel?= 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 Acked-By: Ian Abbott Signed-off-by: Greg Kroah-Hartman Signed-off-by: Herton Ronaldo Krzesinski --- drivers/staging/comedi/drivers/ni_pcimio.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/staging/comedi/drivers/ni_pcimio.c b/drivers/staging/comedi/drivers/ni_pcimio.c index 3974c0d..fa09fd7 100644 --- 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,