diff options
| author | James Hogan | 2013-05-24 17:21:12 +0100 |
|---|---|---|
| committer | Linus Walleij | 2013-06-16 11:56:50 +0200 |
| commit | a2df4269cad79635201587c5c5404f0b1cb0b05c (patch) | |
| tree | de7f7f4147fb891561970c30aaf054f9ba070043 | |
| parent | 73ae368cd309dae277b66444d471ac62825ee407 (diff) | |
pinconf-generic: add BIAS_BUS_HOLD pinconf
Add a new PIN_CONFIG_BIAS_BUS_HOLD pin configuration for a bus holder
pin mode (also known as bus keeper, or repeater). This is a weak latch
which drives the last value on a tristate bus. Another device on the bus
can drive the bus high or low before going tristate to change the value
driven by the pin.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
| -rw-r--r-- | drivers/pinctrl/pinconf-generic.c | 1 | ||||
| -rw-r--r-- | include/linux/pinctrl/pinconf-generic.h | 6 |
2 files changed, 7 insertions, 0 deletions
diff --git a/drivers/pinctrl/pinconf-generic.c b/drivers/pinctrl/pinconf-generic.c index 33a5392cf40c..ba465b3e85ef 100644 --- a/drivers/pinctrl/pinconf-generic.c +++ b/drivers/pinctrl/pinconf-generic.c @@ -37,6 +37,7 @@ struct pin_config_item { static struct pin_config_item conf_items[] = { PCONFDUMP(PIN_CONFIG_BIAS_DISABLE, "input bias disabled", NULL), PCONFDUMP(PIN_CONFIG_BIAS_HIGH_IMPEDANCE, "input bias high impedance", NULL), + PCONFDUMP(PIN_CONFIG_BIAS_BUS_HOLD, "input bias bus hold", NULL), PCONFDUMP(PIN_CONFIG_BIAS_PULL_UP, "input bias pull up", NULL), PCONFDUMP(PIN_CONFIG_BIAS_PULL_DOWN, "input bias pull down", NULL), PCONFDUMP(PIN_CONFIG_DRIVE_PUSH_PULL, "output drive push pull", NULL), diff --git a/include/linux/pinctrl/pinconf-generic.h b/include/linux/pinctrl/pinconf-generic.h index 6aa238096622..ac05b3cfeacc 100644 --- a/include/linux/pinctrl/pinconf-generic.h +++ b/include/linux/pinctrl/pinconf-generic.h @@ -29,6 +29,11 @@ * if for example some other pin is going to drive the signal connected * to it for a while. Pins used for input are usually always high * impedance. + * @PIN_CONFIG_BIAS_BUS_HOLD: the pin will be set to weakly latch so that it + * weakly drives the last value on a tristate bus, also known as a "bus + * holder", "bus keeper" or "repeater". This allows another device on the + * bus to change the value by driving the bus high or low and switching to + * tristate. The argument is ignored. * @PIN_CONFIG_BIAS_PULL_UP: the pin will be pulled up (usually with high * impedance to VDD). If the argument is != 0 pull-up is enabled, * if it is 0, pull-up is disabled. @@ -78,6 +83,7 @@ enum pin_config_param { PIN_CONFIG_BIAS_DISABLE, PIN_CONFIG_BIAS_HIGH_IMPEDANCE, + PIN_CONFIG_BIAS_BUS_HOLD, PIN_CONFIG_BIAS_PULL_UP, PIN_CONFIG_BIAS_PULL_DOWN, PIN_CONFIG_DRIVE_PUSH_PULL, |