Il 17/10/2017 10:18, Cédric Le Goater ha scritto:
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.
My typo sorry, as you can see in the device tree below, I'm using pca9551
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,
