Hi Rafał,

On Mon, Dec 8, 2014 at 3:27 PM, Rafał Miłecki [off-list ref] wrote:

SN54HC595 and SN74HC595 are devices based on shift registers controlled
with 5 input signals (serial-in) and providing 8 outputs (parallel-out).

They are present on some Broadcom home router boards where manufacturer
needed few extra GPIOs.

This driver simply uses specified GPIOs to control shift registers and
registers another GPIO chip. So you can call it a GPIO extender.

Due to the hardware design only output direction is supported. Reading
values is handled using tiny internal cache.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
---
 .../devicetree/bindings/gpio/gpio-sn54hc595.txt    |  35 ++++
 drivers/gpio/Kconfig                               |  11 ++
 drivers/gpio/Makefile                              |   1 +
 drivers/gpio/gpio-sn54hc595.c                      | 219 +++++++++++++++++++++

The '595 is already handled by drivers/gpio/gpio-74x164.c.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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