Re: [PATCH v7 8/8] PCI: imx: Add the imx8mm pcie support

Krzysztof Wilczyński
2021-12-16T16:51:56Z

Hi Richard,

Apologies for a very late review! Especially since Lorenzo already took
patches as per:

https://lore.kernel.org/linux-pci/163965080404.20006.5241609551643501749.b4-ty@arm.com/

However, perhaps it's not too late.

[...]
> @@ -446,6 +452,13 @@ static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
> break;
> case IMX7D:
> break;
> + case IMX8MM:
> + ret = clk_prepare_enable(imx6_pcie->pcie_aux);
> + if (ret) {
> + dev_err(dev, "unable to enable pcie_aux clock\n");
> + break;
> + }
> + break;

You can drop the inner break, it wouldn't do much here, unless this was
intended to be a return?

> @@ -538,6 +559,10 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
> case IMX8MQ:
> reset_control_deassert(imx6_pcie->pciephy_reset);
> break;
> + case IMX8MM:
> + if (phy_init(imx6_pcie->phy) != 0)
> + dev_err(dev, "Waiting for PHY ready timeout!\n");
> + break;

If the above, you can keep the same style as used throughout the file
already, so it would just simply be:

if (phy_init(imx6_pcie->phy))

Also, a nitpick: to be consistent with other such messages here, the error
message would be all lower-case letters.

[...]
> @@ -614,6 +639,8 @@ static void imx6_pcie_configure_type(struct imx6_pcie *imx6_pcie)
> static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
> {
> switch (imx6_pcie->drvdata->variant) {
> + case IMX8MM:
> + break;
> case IMX8MQ:

Would it warrant a comment that adds a note there to this single bare
break? Perhaps this version is not support, lack this particular
functionality, etc.

[...]
> @@ -1089,10 +1122,39 @@ static int imx6_pcie_probe(struct platform_device *pdev)
> dev_err(dev, "Failed to get PCIE APPS reset control\n");
> return PTR_ERR(imx6_pcie->apps_reset);
> }
> + break;
> + case IMX8MM:
> + imx6_pcie->pcie_aux = devm_clk_get(dev, "pcie_aux");
> + if (IS_ERR(imx6_pcie->pcie_aux))
> + return dev_err_probe(dev, PTR_ERR(imx6_pcie->pcie_aux),
> + "pcie_aux clock source missing or invalid\n");
> + imx6_pcie->apps_reset = devm_reset_control_get_exclusive(dev,
> + "apps");
> + if (IS_ERR(imx6_pcie->apps_reset)) {
> + dev_err(dev, "Failed to get PCIE APPS reset control\n");
> + return PTR_ERR(imx6_pcie->apps_reset);
> + }
> +
> + imx6_pcie->phy = devm_phy_get(dev, "pcie-phy");
> + if (IS_ERR(imx6_pcie->phy)) {
> + if (PTR_ERR(imx6_pcie->phy) == -EPROBE_DEFER)
> + return -EPROBE_DEFER;
> + dev_err(dev, "Failed to get PCIE PHY\n");
> + return PTR_ERR(imx6_pcie->phy);
> + }

A question about handling of the -EPROBE_DEFER above: why not to use the
dev_err_probe() helper similarly to the code above and below? Would there
be something different preventing the use of dev_err_probe() here too?

> break;
> default:
> break;
> }
> + /* Don't fetch the pcie_phy clock, if it has abstract PHY driver */
> + if (imx6_pcie->phy == NULL) {
> + imx6_pcie->pcie_phy = devm_clk_get(dev, "pcie_phy");
> + if (IS_ERR(imx6_pcie->pcie_phy))
> + return dev_err_probe(dev, PTR_ERR(imx6_pcie->pcie_phy),
> + "pcie_phy clock source missing or invalid\n");
> + }

Thank you for another amazing patch!

Krzysztof