On Thursday 27 October 2016 01:23 PM, Roger Quadros wrote:

Keerthy,

On 27/10/16 06:42, Keerthy wrote:

quoted

On Sunday 23 October 2016 04:02 PM, Linus Walleij wrote:

quoted

On Wed, Oct 19, 2016 at 7:33 AM, Keerthy [off-list ref] wrote:

quoted

From: Lokesh Vutla <redacted>

Update GPIO driver to support Multiple GPIO IPs.

Signed-off-by: Lokesh Vutla <redacted>
Signed-off-by: Keerthy <j-keerthy@ti.com>

This commit message is not at all describing what the patch is doing.

What it does is bumping the GPIO pin offset in the Linux global
GPIO number space with 32 for each new controller.

quoted

+       static int bank_base;

        pdata = davinci_gpio_get_pdata(pdev);
        if (!pdata) {

@@ -226,7 +227,8 @@ static int davinci_gpio_probe(struct platform_device *pdev)
                chips[i].chip.direction_output = davinci_direction_out;
                chips[i].chip.set = davinci_gpio_set;

-               chips[i].chip.base = base;
+               chips[i].chip.base = bank_base;
+               bank_base += 32;

Why can you not rewrite the driver to pass -1 as base and
get a dynamic allocation of GPIO numbers instead? Then
you won't have this hairy problem.

Ok i will try that.

In case of k2g. There are 2 big GPIO modules GPIO0 and GPIO1.
GPIO0 comprises of 144 GPIOs
and GPIO1 has about 68 GPIOs. Wanted feedback from you on how this is being modeled.

I am creating a controller for every 32 GPIOs under the big module each containing a gpio_chip. Each 32 GPIOs chip has 2 banks of 16 GPIOs each.
Each 16 GPIO bank has an interrupt.

Is this modeling fine or do you think creating one chip with 144 pins and another with 68 pins is a better way?

If GPIO0 has 144 GPIOs, why don't we model it as a gpiochip with 144 GPIOs?
What is the benefit of partitioning it into gpiochips of 32 GPIOs each?

144 GPIOs where in 16 GPIOs form a bank. So about 9 banks with one 
interrupt each. So split it into gpiochips with 32 GPIOs each handling 2 
Interrupts.

Grygorii,

Any strong reason that you recollect of so as to why this modeling was 
chosen?

cheers,
-roger