From: Peter Rosin <p...@axentia.se> Hi!
I have a signal connected to a gpio pin which is the output of a comparator. By changing the level of one of the inputs to the comparator, I can detect the envelope of the other input to the comparator by using a series of measurements much in the same maner a manual ADC works, but watching for changes on the comparator over a period of time instead of only the immediate output. Now, the input signal to the comparator might have a high frequency, which will cause the output from the comparator (and thus the GPIO input) to change rapidly. A common(?) idiom for this is to use the interrupt status register to catch the glitches, but then not have any interrupt tied to the pin as that could possibly generate pointless bursts of (expensive) interrupts. So, these two patches expose an interface to the PIO_ISR register of the pio controllers on the platform I'm targetting. The first patch adds some infrastructure to the gpio core and the second patch hooks up "my" pin controller. But hey, this seems like an old problem and I was surprised that I had to touch the source to do it. Which makes me wonder what I'm missing and what others needing to see short pulses on a pin but not needing/wanting interrupts are doing? Yes, there needs to be a way to select the interrupt edge w/o actually arming the interrupt, that is missing. And probably other things too, but I didn't want to do more work in case this is a dead end for some reason... Cheers, Peter Peter Rosin (2): gpio: Add isr property of gpio pins pinctrl: at91: expose the isr bit Documentation/gpio/sysfs.txt | 12 ++++++++++ drivers/gpio/gpiolib-sysfs.c | 30 ++++++++++++++++++++++++ drivers/gpio/gpiolib.c | 15 ++++++++++++ drivers/pinctrl/pinctrl-at91.c | 50 ++++++++++++++++++++++++++++++++++++---- include/linux/gpio/consumer.h | 1 + include/linux/gpio/driver.h | 2 ++ 6 files changed, 106 insertions(+), 4 deletions(-) -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/