Hi Eric,
On Thu, Mar 31, 2016 at 01:41:04PM -0700, Eric Nelson wrote:
Hi Peng,
On 03/28/2016 09:57 PM, Peng Fan wrote:
Hi Eric,
On Fri, Mar 25, 2016 at 01:12:11PM -0700, Eric Nelson wrote:
Device tree parsing of GPIO nodes is currently ignoring flags.
Add support for GPIO_ACTIVE_LOW by checking for the presence of the flag and setting the desc->flags field to the driver model constant GPIOD_ACTIVE_LOW.
You may need to try this: https://patchwork.ozlabs.org/patch/597363/
Thanks for pointing this out.
This patch also works, but it has me confused.
How/why is parsing the ACTIVE_LOW flag specific to MXC?
This is a general-purpose flag in the kernel, not something machine- specific.
It also appears that there are a bunch of other copies of this same bit of code in the various mach_xlate() routines:
desc->flags = args->args[1] & GPIO_ACTIVE_LOW ? GPIOD_ACTIVE_LOW : 0;
If it's done in gpio-uclass, this isn't needed and xlate can be removed from mxc-gpio and quite a few other architectures.
Please advise,
I saw you have posted a patch set to convert other gpio drivers. But actually the translation of gpio property should be done by each gpio driver. Alought we have gpio-cells=<2> for most gpio drivers, but if there is one case that gpio-cells=<3>, and it have different meaning for each cell from other most drivers?
So I suggest we follow the linux way,
434 if (!chip->of_xlate) { 435 chip->of_gpio_n_cells = 2; 436 chip->of_xlate = of_gpio_simple_xlate; 437 }
If gpio drivers does not provide xlate function, then use a simple xlate function. If gpio drivers have their own xlate function, then use their own way. Also I do no think delete the xlate implementation is not a good idea.
Simon may give more comments on this.
Regards, Peng.
Eric