On 10/17/2017 09:36 AM, Andrea Scian - DAVE Embedded Systems wrote:
> Dear all,
>
> I'm working on an iMX6 based board with a PCA9555 which is used both to drive LEDs and manage some GPIOs.
The PCA9555 chip and the PCA955[0-3] chips have different control
registers. You need a different led driver for it.
C.
> My current kernel is quite old (4.1.15) but I've found Cédric patches on mainline and backported to this old revision.
>
> I'm facing an issue with it, because it seems that it fails when it's used in a mixed (led/gpios) environment.
>
> E.g.: let's say that I have one led connected to LED0 output and one GPIO connected at LED1 output.
>
> I define it as
>
> pca9551: pca9551@60 {
> compatible = "nxp,pca9551";
> reg = <0x60>;
> #address-cells = <1>;
> #size-cells = <0>;
> #gpio-cells = <1>;
>
> led@0 {
> label = "led0";
> reg = <0>;
> linux,default-trigger = "none";
> };
> gpio@1 {
> label = "gpio1";
> reg = <1>;
> type = <2>; /* GPIO */
> };
> };
>
> At boot it's probed as
>
> root@sbc-lynx:~# dmesg | grep pca
> [ 5.315425] leds-pca955x 5-0060: leds-pca955x: Using pca9551 8-bit LED driver at slave address 0x60
> [ 5.350349] leds-pca955x 5-0060: gpios 511...511
>
> But I cannot access it:
>
> root@sbc-lynx:~# echo 511 > /sys/class/gpio/export
> -sh: echo: write error: Device or resource busy
>
> Because for pca955x_gpio_request_pin() this is at offset 0 (in fact is the first gpio registered of this gpio_chip) but it's the index 1 inside pca955x->leds[]
>
> Am I missing something? (maybe I made a mistake in my backport and/or I'm missing some patches about the GPIO subsystems).
>
> If I'm right I think I can send a patch to fix this (I'm thinking about having an array of GPIO index to map offset -> pca955x->leds[] index or just register all pins as GPIOs and then just report the busy state)
>
> WDYT?
>
> Kind Regards,
>
