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: NMaxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: NFlorian Fainelli <florian@openwrt.org>
Acked-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: NFlorian Fainelli <florian@openwrt.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: NFlorian Fainelli <florian@openwrt.org>
Acked-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: NFlorian Fainelli <florian@openwrt.org>
Acked-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: NLinus 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: NPaul 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: NH Hartley Sweeten <hartleys@visionengravers.com>
Signed-off-by: NLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NGrant 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: NGrant Likely <grant.likely@secretlab.ca>

Remove the #define GEN_74X164_GPIO_COUNT since it's only used in
one place and it's meaning is obvious.  Also remove the #define
GEN_74X164_DRIVER_NAME and use spi->modalias to set the gpio chip's
label and the string "74x164" for the driver name.

Reorder the code slightly to remove the need to prototype
gen_74x164_set_value.
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

The function gen_74x164_remove and mc33880_remove are used only wrapped
by __devexit_p so define it using __devexit.
Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

Add support for generic 74x164 serial-in/parallel-out 8-bits shift
register.  This driver can be used as a GPIO output expander.

[akpm@linux-foundation.org: remove unused local `refresh']
Signed-off-by: NMiguel Gaio <miguel.gaio@efixo.com>
Signed-off-by: NJuhos Gabor <juhosg@openwrt.org>
Signed-off-by: NFlorian Fainelli <florian@openwrt.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>