gpio: Add driver for SPI serializers

Add generic parallel-in/serial-out shift register GPIO driver.

This includes SPI compatible devices like SN74165 serial-out shift
registers and the SN65HVS88x series of industrial serializers that can
be read over the SPI bus and used for GPI (General Purpose Input).

Signed-off-by: Andrew F. Davis <afd@ti.com>
Tested-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index f52b25964bc6..d003abeb1756 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1048,6 +1048,12 @@ config GPIO_MC33880
           SPI driver for Freescale MC33880 high-side/low-side switch.
           This provides GPIO interface supporting inputs and outputs.
 
+config GPIO_PISOSR
+        tristate "Generic parallel-in/serial-out shift register"
+        help
+          GPIO driver for SPI compatible parallel-in/serial-out shift
+          registers. These are input only devices.
+
 endmenu
 
 menu "SPI or I2C GPIO expanders"