On 10/17/2017 11:16 AM, Andrea Scian - DAVE Embedded Systems wrote:
>
>> On 10/17/2017 10:20 AM, Andrea Scian - DAVE Embedded Systems wrote:
>>>
>>> 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
>>
>> ok.
>>
>> You might want to take a look at how we mixed gpios and leds on the
>> witherspoon
>> system using pca9552 chips. we added a gpio-leds binding.
>>
>> https://github.com/openbmc/linux/blob/dev-4.10/arch/arm/boot/dts/aspeed-bmc-opp-witherspoon.dts
>
> understood: you configure all pins of PCA955x as GPIOs and the map the one
> you need as led with gpio-leds binding.
Sorry I got distracted.
> However to me this is a kind of workaround or, at least, there's nothing
> about this limitation into the devicetree binding (in fact, IMHO, the device
> tree binding example will just fail)
euh ? what do you mean. There is a real system using this device tree.
I think we would know about it if it didn't work. Please explain
> I wrote the attached patch which should fix the issue and allow a more
> generic approach. WDYT?
>
> (in case it looks good, I'll send the patch in the correct way)
Please send the patch to discuss, add Andrew Jeffery <and...@aj.id.au>
in cc:
Thanks,
C.
>
> Kind Regards,
>
> Andrea
>
>>>
>>>>> 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,
>>>>>
>>>
>>
