The 05/28/2021 07:51, Linus Walleij wrote:

On Thu, May 27, 2021 at 2:55 AM Steven Lee [off-list ref] wrote:

quoted

SGPIO bindings should be converted as yaml format.
In addition to the file conversion, a new property max-ngpios is
added in the yaml file as well.
The new property is required by the enhanced sgpio driver for
making the configuration of the max number of gpio pins more flexible.

Signed-off-by: Steven Lee <redacted>

(...)

quoted

+  max-ngpios:
+    description:
+      represents the number of actual hardware-supported GPIOs (ie,
+      slots within the clocked serial GPIO data). Since each HW GPIO is both an
+      input and an output, we provide max_ngpios * 2 lines on our gpiochip
+      device. We also use it to define the split between the inputs and
+      outputs; the inputs start at line 0, the outputs start at max_ngpios.
+    minimum: 0
+    maximum: 128

Why can this not be derived from the compatible value?

Normally there should be one compatible per hardware variant
of the block. And this should be aligned with that, should it not?

If this is not the case, maybe more detailed compatible strings
are needed, maybe double compatibles with compatible per
family and SoC?

Thanks for your suggestion.
I add max-ngpios in dt-bindings as there is ngpios defined in
dt-bindings, users can get the both max-ngpios and ngpios information
from dtsi without digging sgpio driver.

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/aspeed-g5.dtsi#n354

If adding more detailed compatibles is better, I will add them to sgpio driver
in V3 patch and remove max-ngpios from dt-bindings.

Since AST2600 has 2 sgpio controller one with 128 pins and another one with 80 pins.
For supporting max-ngpios in compatibles, 2 platform data for each
ast2600 sgpio controller as follows are necessary.

static const struct aspeed_sgpio_pdata ast2600_sgpiom1_pdata = {
        .max_ngpios = 128;
};
static const struct aspeed_sgpio_pdata ast2600_sgpiom2_pdata = {
        .max_ngpios = 80;
};

{ .compatible = "aspeed,ast2500-sgpio" , .data = &ast2400_sgpio_pdata, },
{ .compatible = "aspeed,ast2600-sgpiom1", .data = &ast2600_sgpiom1_pdata, },
{ .compatible = "aspeed,ast2600-sgpiom2", .data = &ast2600_sgpiom2_pdata, },

Thanks,
Steven

Yours,
Linus Walleij

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel