Messages in this thread | | | Subject | Re: about pca955x led driver gpio management | From | Andrea Scian - DAVE Embedded Systems <> | Date | Tue, 17 Oct 2017 10:20:17 +0200 |
| |
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, >>
| |