[i.MX6Q]configuration for PCIE_WAKE pin

[heecheol_jung]

Dear NXP

When using imx6Q as an RC, does the use of "power-on-gpio" depend on the setting of the PCIE_WAKE pin?

If I add a pull-up resistor in PCIE_WAKE line, I do not need to use power-on-gpio,

and If there is no resistor, is it necessary to trigger the internal PCIE PHY via power-on-gpio?

Thanks & regards

heecheol.jung

[igorpadykov]

Hi heecheol

could you say where did you find PCIe "power-on-gpio" in nxp linux

linux-imx - i.MX Linux kernel 

and linux documentation
https://www.nxp.com/support/developer-resources/run-time-software/i.mx-developer-resources/i.mx-6ser...

In general PCIE_WAKE is not used, for waking functionality gpio may be used:

Best regards
igor
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[heecheol_jung]

Dear Igor

Thanks for reply

In the items below there is no 'wake-up-gpio' and there is 'power-on-gpio',

is the name changed as the kernel version is up?

[ kernel 4.9.11 ]

in drivers/pci/host/pci-imx6.c (imx6_pcie_probe method)

[ kernel 4.14.78 ]

in drivers/pci/dwc/pci-imx6.c (imx_pcie_probe method)

Thanks & regards

heecheol.jung

[igorpadykov]

Hi heecheol

thanks, as decribes code it is used for enable power

 imx_pcie->power_on_gpio = of_get_named_gpio(node, "power-on-gpio", 0); if (gpio_is_valid(imx_pcie->power_on_gpio)) {  ret = devm_gpio_request_one(&pdev->dev,         imx_pcie->power_on_gpio,         GPIOF_OUT_INIT_LOW,         "PCIe power enable");

Best regards
igor

[heecheol_jung]

Dear Igor

Thanks for reply

if so, is power-on-gpio and wake-up-gpio a completely different pin?

and please let me know about pull-up resistor.

Is there a problem without a pull-up resistor in the PCIE_wake line? (ex> float?)

Thanks & regards

heecheol.jung

[igorpadykov · Accepted solution]

Hi heecheol

yes it is different pin and has not relation to wake-up-gpio or PCIE_WAKE,

description can be found on

meta-freescale-3rdparty/0023-ARM-i.MX6-dts-pcie-power-on-gpio-to-a-fixed-regulato.patch at master · ... 

Best regards
igor