RE: [PATCH 1/3] PCI: imx: encapsulate the clock enable into one standalone function

[Richard Zhu]

> -----Original Message-----
> From: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> Sent: Wednesday, September 8, 2021 4:48 PM
> To: Richard Zhu <hongxing.zhu@xxxxxxx>; bhelgaas@xxxxxxxxxx;
> lorenzo.pieralisi@xxxxxxx
> Cc: linux-pci@xxxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> kernel@xxxxxxxxxxxxxx
> Subject: Re: [PATCH 1/3] PCI: imx: encapsulate the clock enable into one
> standalone function
> 
> Am Mittwoch, dem 08.09.2021 um 14:59 +0800 schrieb Richard Zhu:
> > No function changes, just encapsulate the i.MX PCIe clocks enable
> > operations into one standalone function
> >
> > Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> > ---
> >  drivers/pci/controller/dwc/pci-imx6.c | 82
> > +++++++++++++++++----------
> >  1 file changed, 51 insertions(+), 31 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > b/drivers/pci/controller/dwc/pci-imx6.c
> > index 80fc98acf097..0264432e4c4a 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -143,6 +143,8 @@ struct imx6_pcie {
> >  #define PHY_RX_OVRD_IN_LO_RX_DATA_EN		BIT(5)
> >  #define PHY_RX_OVRD_IN_LO_RX_PLL_EN		BIT(3)
> >
> > +static int imx6_pcie_clk_enable(struct imx6_pcie *imx6_pcie);
> > +
> I don't think this is strictly needed. Can you just move the placement of the
> new imx6_pcie_clk_enable function in the file, such that we can avoid the
> forward declaration?
> 
[Richard Zhu] Thanks for your quickly review.
Okay, would move the placement to avoid he forward declaration.

> >  static int pcie_phy_poll_ack(struct imx6_pcie *imx6_pcie, bool
> > exp_val)  {
> >  	struct dw_pcie *pci = imx6_pcie->pci; @@ -498,33 +500,12 @@ static
> > void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
> >  		}
> >  	}
> >
> > -	ret = clk_prepare_enable(imx6_pcie->pcie_phy);
> > -	if (ret) {
> > -		dev_err(dev, "unable to enable pcie_phy clock\n");
> > -		goto err_pcie_phy;
> > -	}
> > -
> > -	ret = clk_prepare_enable(imx6_pcie->pcie_bus);
> > +	ret = imx6_pcie_clk_enable(imx6_pcie);
> >  	if (ret) {
> > -		dev_err(dev, "unable to enable pcie_bus clock\n");
> > -		goto err_pcie_bus;
> > +		dev_err(dev, "unable to enable pcie clocks\n");
> > +		goto err_clks;
> >  	}
> >
> > -	ret = clk_prepare_enable(imx6_pcie->pcie);
> > -	if (ret) {
> > -		dev_err(dev, "unable to enable pcie clock\n");
> > -		goto err_pcie;
> > -	}
> > -
> > -	ret = imx6_pcie_enable_ref_clk(imx6_pcie);
> > -	if (ret) {
> > -		dev_err(dev, "unable to enable pcie ref clock\n");
> > -		goto err_ref_clk;
> > -	}
> > -
> > -	/* allow the clocks to stabilize */
> > -	usleep_range(200, 500);
> > -
> >  	/* Some boards don't have PCIe reset GPIO. */
> >  	if (gpio_is_valid(imx6_pcie->reset_gpio)) {
> >  		gpio_set_value_cansleep(imx6_pcie->reset_gpio,
> > @@ -578,13 +559,7 @@ static void imx6_pcie_deassert_core_reset(struct
> > imx6_pcie *imx6_pcie)
> >
> >  	return;
> >
> > -err_ref_clk:
> > -	clk_disable_unprepare(imx6_pcie->pcie);
> > -err_pcie:
> > -	clk_disable_unprepare(imx6_pcie->pcie_bus);
> > -err_pcie_bus:
> > -	clk_disable_unprepare(imx6_pcie->pcie_phy);
> > -err_pcie_phy:
> > +err_clks:
> >  	if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
> >  		ret = regulator_disable(imx6_pcie->vpcie);
> >  		if (ret)
> > @@ -914,6 +889,51 @@ static void imx6_pcie_pm_turnoff(struct
> imx6_pcie *imx6_pcie)
> >  	usleep_range(1000, 10000);
> >  }
> >
> > +static int imx6_pcie_clk_enable(struct imx6_pcie *imx6_pcie) {
> > +	struct dw_pcie *pci = imx6_pcie->pci;
> > +	struct device *dev = pci->dev;
> > +	int ret;
> > +
> > +	ret = clk_prepare_enable(imx6_pcie->pcie_phy);
> > +	if (ret) {
> > +		dev_err(dev, "unable to enable pcie_phy clock\n");
> > +		return ret;
> > +	}
> > +
> > +	ret = clk_prepare_enable(imx6_pcie->pcie_bus);
> > +	if (ret) {
> > +		dev_err(dev, "unable to enable pcie_bus clock\n");
> > +		goto err_pcie_bus;
> > +	}
> > +
> > +	ret = clk_prepare_enable(imx6_pcie->pcie);
> > +	if (ret) {
> > +		dev_err(dev, "unable to enable pcie clock\n");
> > +		goto err_pcie;
> > +	}
> > +
> > +	ret = imx6_pcie_enable_ref_clk(imx6_pcie);
> > +	if (ret) {
> > +		dev_err(dev, "unable to enable pcie ref clock\n");
> > +		goto err_ref_clk;
> > +	}
> > +
> > +	/* allow the clocks to stabilize */
> > +	usleep_range(200, 500);
> > +	return 0;
> > +
> > +err_ref_clk:
> > +	clk_disable_unprepare(imx6_pcie->pcie);
> > +err_pcie:
> > +	clk_disable_unprepare(imx6_pcie->pcie_bus);
> > +err_pcie_bus:
> > +	clk_disable_unprepare(imx6_pcie->pcie_phy);
> > +
> > +	return ret;
> > +
> Superfluous newline.
[Richard Zhu]Got that. Blank line would be removed later.
Thanks.

> 
> Regards,
> Lucas
> 
> > +}
> > +
> >  static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_pcie)  {
> >  	clk_disable_unprepare(imx6_pcie->pcie);
>