linux-kernel - Re: [PATCH v4 01/15] PCI: imx6: Simplify clock handling by using bulk_clk

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Message-ID: <20231217170655.GC6748@thinkpad>
Date: Sun, 17 Dec 2023 22:36:55 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: Frank Li <Frank.Li@....com>
Cc: krzysztof.kozlowski@...aro.org, bhelgaas@...gle.com,
	conor+dt@...nel.org, devicetree@...r.kernel.org, festevam@...il.com,
	helgaas@...nel.org, hongxing.zhu@....com, imx@...ts.linux.dev,
	kernel@...gutronix.de, krzysztof.kozlowski+dt@...aro.org,
	kw@...ux.com, l.stach@...gutronix.de,
	linux-arm-kernel@...ts.infradead.org, linux-imx@....com,
	linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
	lpieralisi@...nel.org, robh@...nel.org, s.hauer@...gutronix.de,
	shawnguo@...nel.org
Subject: Re: [PATCH v4 01/15] PCI: imx6: Simplify clock handling by using
 bulk_clk_*() function

On Sun, Dec 17, 2023 at 12:11:56AM -0500, Frank Li wrote:
> Refactors the clock handling logic in the imx6 PCI driver by adding
> clk_names[] define in drvdata . Simplifies the code and makes it more
> maintainable, as future additions of SOC support will only require
> straightforward changes.
> 

Commit description should be in imperative mood as per
Documentation/process/submitting-patches.rst:

"Describe your changes in imperative mood, e.g. "make xyzzy do frotz"
instead of "[This patch] makes xyzzy do frotz" or "[I] changed xyzzy
to do frotz", as if you are giving orders to the codebase to change
its behaviour."

> Signed-off-by: Frank Li <Frank.Li@....com>
> ---
> 
> Notes:
>     Change from v3 to v4
>     - using clk_bulk_*() API
>     Change from v1 to v3
>     - none
> 
>  drivers/pci/controller/dwc/pci-imx6.c | 128 ++++++++------------------
>  1 file changed, 38 insertions(+), 90 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 74703362aeec7..2086214345e9a 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c

[...]

>  static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
> @@ -1305,32 +1265,19 @@ static int imx6_pcie_probe(struct platform_device *pdev)
>  		return imx6_pcie->reset_gpio;
>  	}
>  
> -	/* Fetch clocks */
> -	imx6_pcie->pcie_bus = devm_clk_get(dev, "pcie_bus");
> -	if (IS_ERR(imx6_pcie->pcie_bus))
> -		return dev_err_probe(dev, PTR_ERR(imx6_pcie->pcie_bus),
> -				     "pcie_bus clock source missing or invalid\n");
> +	while (imx6_pcie->drvdata->clk_names[imx6_pcie->clks_cnt]) {
> +		int i = imx6_pcie->clks_cnt;
>  
> -	imx6_pcie->pcie = devm_clk_get(dev, "pcie");
> -	if (IS_ERR(imx6_pcie->pcie))
> -		return dev_err_probe(dev, PTR_ERR(imx6_pcie->pcie),
> -				     "pcie clock source missing or invalid\n");
> +		imx6_pcie->clks[i].id = imx6_pcie->drvdata->clk_names[i];
> +		imx6_pcie->clks_cnt++;

You can just initialize clks_cnt in drv_data with sizeof() of clk_names.

> +	}
> +
> +	/* Fetch clocks */
> +	ret = devm_clk_bulk_get(dev, imx6_pcie->clks_cnt, imx6_pcie->clks);
> +	if (ret)
> +		return ret;
>  
>  	switch (imx6_pcie->drvdata->variant) {
> -	case IMX6SX:
> -		imx6_pcie->pcie_inbound_axi = devm_clk_get(dev,
> -							   "pcie_inbound_axi");
> -		if (IS_ERR(imx6_pcie->pcie_inbound_axi))
> -			return dev_err_probe(dev, PTR_ERR(imx6_pcie->pcie_inbound_axi),
> -					     "pcie_inbound_axi clock missing or invalid\n");
> -		break;
> -	case IMX8MQ:
> -	case IMX8MQ_EP:
> -		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");
> -		fallthrough;
>  	case IMX7D:
>  		if (dbi_base->start == IMX8MQ_PCIE2_BASE_ADDR)
>  			imx6_pcie->controller_id = 1;
> @@ -1353,10 +1300,6 @@ static int imx6_pcie_probe(struct platform_device *pdev)
>  	case IMX8MM_EP:
>  	case IMX8MP:
>  	case IMX8MP_EP:
> -		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))
> @@ -1372,14 +1315,6 @@ static int imx6_pcie_probe(struct platform_device *pdev)
>  	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");
> -	}
> -
>  
>  	/* Grab turnoff reset */
>  	imx6_pcie->turnoff_reset = devm_reset_control_get_optional_exclusive(dev, "turnoff");
> @@ -1470,6 +1405,9 @@ static void imx6_pcie_shutdown(struct platform_device *pdev)
>  	imx6_pcie_assert_core_reset(imx6_pcie);
>  }
>  
> +#define IMX6_CLKS_COMMON "pcie_bus", "pcie"
> +#define IMX6_CLKS_NO_PHYDRV IMX6_CLKS_COMMON, "pcie_phy"
> +

Just use the clock names directly instead of definitions. It makes the code more
readable.

Rest LGTM!

- Mani

-- 
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