Re: Is a multiplexer using latches a gpio controller?

[Andy Shevchenko <andy.shevchenko@xxxxxxxxx>]

On Tue, Jul 19, 2022 at 12:58 AM Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
>
> On Mon, Jul 18, 2022 at 10:22 PM Uwe Kleine-König
> <u.kleine-koenig@xxxxxxxxxxxxxx> wrote:

...

> I would use the actual 74xx numbers for the TTL circuits in the compatible.
> I have actually merged this placeholder (without bindings nor driver):
>
>         /*
>          * 74HC4094 which is used as a rudimentary GPIO expander
>          * FIXME:
>          * - Create device tree bindings for this as GPIO expander
>          * - Write a pure DT GPIO driver using these bindings
>          * - Support cascading in the style of gpio-74x164.c (cannot
> be reused, very different)
>          */
>         gpio_74: gpio-74hc4094 {
>                 compatible = "nxp,74hc4094";
>                 cp-gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
>                 d-gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>;
>                 str-gpios = <&gpio0 2 GPIO_ACTIVE_HIGH>;
>                 /* oe-gpios is optional */
>                 gpio-controller;
>                 #gpio-cells = <2>;
>                 /* We are not cascaded */
>                 registers-number = <1>;
>                 gpio-line-names = "CONTROL_HSS0_CLK_INT",
> "CONTROL_HSS1_CLK_INT", "CONTROL_HSS0_DTR_N",
>                                 "CONTROL_HSS1_DTR_N", "CONTROL_EXT",
> "CONTROL_AUTO_RESET",
>                                 "CONTROL_PCI_RESET_N", "CONTROL_EEPROM_WC_N";
>         };
>
> What's nice with 74HC4094 is that it has a strobe (str) signal so you can send
> out all the values and then strobe them out in one go. But your construction
> makes sense too!

But 4094 is SPI and covered by 74x164 driver, while Uwe's case is
parallel drivers, which covered by
74xx driver.

-- 
With Best Regards,
Andy Shevchenko