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SubjectRe: [RFCv1 6/8] phy: amlogic: meson8b-usb2: Use phy reset callback function
Hi Anand,

On Sun, Jun 27, 2021 at 10:07 PM Anand Moon <> wrote:
> Sorry for the delay.
> We could switch the reset logic to
> *devm_reset_control_get_optional_exclusive* as below
> to fix the reset line, since both the dwc2 c90c0000.usb and c9040000.usb
> will have their own context to reset control register, it means the
> reset line is not share
> between two USB PHY nodes.
This is something I don't understand.
As discussed in our previous mails reset_control_reset in case of the
USB PHY driver (which uses the RESET_USB_OTG reset line for *both*
PHYs) is equivalent to the following code in the vendor kernel:
aml_cbus_update_bits(0x1102, 0x1<<2, 0x1<<2)

We have two PHYs but only one reset line. So in my own words I
describe the reset line as being shared.

> - priv->reset = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
> + priv->reset = devm_reset_control_get_optional_exclusive(&pdev->dev,
> + "reset");
Have you boot-tested this?
Without any .dts changes this will return NULL because there's no
reset-names = "reset"; in the .dts(i).
If you replace "reset" with NULL then I assume that the second PHY
will fail to obtain the reset line because it's shared between two
devices but we're trying to obtain it exclusively for both (PHYs).

Best regards,

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