| Date | Sun, 03 Feb 2013 15:47:07 +0100 | From | Ben Hutchings <> | Subject | [ 023/128] staging: comedi: fix minimum AO period for NI 625x and NI 628x |
| |
3.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ãric Piel <piel@delmic.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: Ãric Piel <piel@delmic.com> Acked-By: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [bwh: Backported to 3.2: drop hunk for a board that's not listed] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- --- a/drivers/staging/comedi/drivers/ni_pcimio.c +++ b/drivers/staging/comedi/drivers/ni_pcimio.c @@ -1021,7 +1021,7 @@ 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, @@ -1040,7 +1040,7 @@ 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, @@ -1076,7 +1076,7 @@ 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, @@ -1095,7 +1095,7 @@ 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, @@ -1131,7 +1131,7 @@ 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, @@ -1150,7 +1150,7 @@ 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, @@ -1186,7 +1186,7 @@ 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,
-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|