The shift registers have an output pin that, when enabled, propagates
the values of its internal register to the pins. If another value comes
to the register while the output pin is disabled, this new value will
makae the older shift into the next register in the chain.
This patch adds support for daisy-chaining the registers, using the
regular SPI chip select mechanism to manage the output pin, and the
registers-number dt property to set the number of chained registers.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
A pending cleanup will mean that module.h won't be implicitly
everywhere anymore. Make sure the modular drivers in gpio
are actually calling out for <module.h> explicitly in advance.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
The 74x164 GPIO driver has a static inline helper called
gpio_to_chip which clashes with the gpiolib namespace if we
try to expose the function with the same name from gpiolib,
and it's still confusing even if we don't do that. So rename
it to gpio_to_74x164_chip().
Reported-by: H Hartley Sweeten <hartleys@visionengravers.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Sort the gpio makefile and enforce the naming convention gpio-*.c for
gpio drivers.
v2: cleaned up filenames in Kconfig and comment blocks
v3: fixup use of BASIC_MMIO to GENERIC_GPIO for mxc
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
