From: Juergen Beisert <jbe@xxxxxxxxxxxxxx> Subject: [PATCH] Add some help using the gpio commands at runtime Last time I used the gpio commands I was somehow confused about the behaviour of the 'gpio_get_value' command. So, I decided to add some doc for it. Here's the result. Signed-off-by: Juergen Beisert <jbe@xxxxxxxxxxxxxx> --- Documentation/commands.dox | 1 commands/gpio.c | 61 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 62 insertions(+) Index: barebox-2010.10.0/Documentation/commands.dox =================================================================== --- barebox-2010.10.0.orig/Documentation/commands.dox +++ barebox-2010.10.0/Documentation/commands.dox @@ -10,6 +10,7 @@ @li @subpage edit_command @li @subpage erase_command @li @subpage export_command +@li @subpage gpio_for_users @li @subpage tftp_command @li @subpage loadenv_command @li @subpage mount_command Index: barebox-2010.10.0/commands/gpio.c =================================================================== --- barebox-2010.10.0.orig/commands/gpio.c +++ barebox-2010.10.0/commands/gpio.c @@ -120,3 +120,64 @@ BAREBOX_CMD_START(gpio_direction_output) BAREBOX_CMD_HELP(cmd_gpio_direction_output_help) BAREBOX_CMD_END +/** +@page gpio_for_users Runtime GPIO handling + +@section regular_gpio General usage information + +These commands are available if the symbol @b CONFIG_GENERIC_GPIO and +@b CONFIG_CMD_GPIO are enabled in the Kconfig. + +@note All gpio related commands take a number to identify the pad. This +number is architecture dependent. There may be no intuitional correlation +between available pads and the GPIO numbers to be used in the commands. Due +to this it's also possible the numbers change between @b barebox releases. + +@section gpio_dir_out Switch a pad into an output GPIO +@verbatim +gpio_direction_output <gpio_no> <initial_value> +@endverbatim +- @b gpio_no Architecture dependent GPIO number +- @b initial_value Output value the pad should emit + +@note To avoid glitches on the pad's line, the routines will first setting up +the pad's value and after that switching the pad itself to output (if the +silicon is able to do so) + +@note If the pad is already configured into a non GPIO mode (if available) +this command may fail (silently) + +@section gpio_dir_in Switch a pad into an input GPIO +@verbatim +gpio_direction_input <gpio_no> +@endverbatim +- @b gpio_no Architecture dependent GPIO number + +@note If the pad is already configured into a non GPIO mode (if available) +this command may fail (silently) + +@section gpio_get_value Read in the value of an GPIO input pad +@verbatim +gpio_get_value <gpio_no> +@endverbatim + +Reads in the current pad's line value from the given GPIO number. It returns +the value as a shell return code. There is no visible output at stdout. You +can check the return value by using "echo $?" + +@note If the return code is not '0' or '1' it's meant as an error code. + +@note If the pad is not configured for GPIO mode this command may fail +(silently) and returns garbage + +@section gpio_set_value Set a new value to a GPIO output pad +@verbatim +gpio_set_value <gpio_no> <value> +@endverbatim +- @b gpio_no Architecture dependent GPIO number +- @b value Output value the pad should emit + +Sets a new output @b value to the pad with GPIO number @b gpio_no + +@note If the pad is not configured for GPIO mode this command may fail (silently) +*/ -- Pengutronix e.K. | Juergen Beisert | Linux Solutions for Science and Industry | Phone: +49-8766-939 228 | Vertretung Sued/Muenchen, Germany | Fax: +49-5121-206917-5555 | Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de/ | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
