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From:   Leonard Crestez <leonard.crestez@nxp.com>
To:     Peng Fan <peng.fan@nxp.com>,
        "shawnguo@kernel.org" <shawnguo@kernel.org>,
        Aisheng Dong <aisheng.dong@nxp.com>
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        "s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
        "festevam@gmail.com" <festevam@gmail.com>,
        Abel Vesa <abel.vesa@nxp.com>,
        "kernel@pengutronix.de" <kernel@pengutronix.de>,
        dl-linux-imx <linux-imx@nxp.com>,
        "linux-clk@vger.kernel.org" <linux-clk@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Alice Guo <alice.guo@nxp.com>
Subject: Re: [PATCH] clk: imx: imx8qxp-lpcg: use
 devm_platform_ioremap_resource
Thread-Topic: [PATCH] clk: imx: imx8qxp-lpcg: use
 devm_platform_ioremap_resource
Thread-Index: AQHVqoum7IH7ZRFDgESKl5wnHnxd3Q==
Date:   Wed, 4 Dec 2019 14:24:19 +0000
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On 2019-12-04 12:14 PM, Peng Fan wrote:=0A=
> From: Peng Fan <peng.fan@nxp.com>=0A=
> =0A=
> devm_platform_ioremap_resource() wraps platform_get_resource() and=0A=
> devm_ioremap_resource(), we could use this API to simplify the code.=0A=
> =0A=
> Signed-off-by: Peng Fan <peng.fan@nxp.com>=0A=
=0A=
This patch has been posted before and it breaks uart on imx8qxp-mek and =0A=
possibly other things.=0A=
=0A=
The old and new paths are not equivalent: devm_platform_ioremap_resource =
=0A=
calls devm_ioremap_resource differs from devm_ioremap by also calling =0A=
devm_request_mem_region.=0A=
=0A=
This prevents other mappings in the area; this is not an issue for most =0A=
drivers but imx8qxp-lpcg maps whole subsystems. For example:=0A=
=0A=
                 adma_lpcg: clock-controller@59000000 {=0A=
                         compatible =3D "fsl,imx8qxp-lpcg-adma";=0A=
                         reg =3D <0x59000000 0x2000000>;=0A=
                         #clock-cells =3D <1>;=0A=
                 };=0A=
=0A=
                 adma_lpuart0: serial@5a060000 {=0A=
                         reg =3D <0x5a060000 0x1000>;=0A=
			...=0A=
		};=0A=
=0A=
Previously: https://patchwork.kernel.org/patch/10908807/=0A=
=0A=
> ---=0A=
>   drivers/clk/imx/clk-imx8qxp-lpcg.c | 8 ++------=0A=
>   1 file changed, 2 insertions(+), 6 deletions(-)=0A=
> =0A=
> diff --git a/drivers/clk/imx/clk-imx8qxp-lpcg.c b/drivers/clk/imx/clk-imx=
8qxp-lpcg.c=0A=
> index c0aff7ca6374..3f2c2b068c73 100644=0A=
> --- a/drivers/clk/imx/clk-imx8qxp-lpcg.c=0A=
> +++ b/drivers/clk/imx/clk-imx8qxp-lpcg.c=0A=
> @@ -164,7 +164,6 @@ static int imx8qxp_lpcg_clk_probe(struct platform_dev=
ice *pdev)=0A=
>   	struct clk_hw_onecell_data *clk_data;=0A=
>   	const struct imx8qxp_ss_lpcg *ss_lpcg;=0A=
>   	const struct imx8qxp_lpcg_data *lpcg;=0A=
> -	struct resource *res;=0A=
>   	struct clk_hw **clks;=0A=
>   	void __iomem *base;=0A=
>   	int i;=0A=
> @@ -173,12 +172,9 @@ static int imx8qxp_lpcg_clk_probe(struct platform_de=
vice *pdev)=0A=
>   	if (!ss_lpcg)=0A=
>   		return -ENODEV;=0A=
>   =0A=
> -	res =3D platform_get_resource(pdev, IORESOURCE_MEM, 0);=0A=
> -	if (!res)=0A=
> -		return -EINVAL;=0A=
> -	base =3D devm_ioremap(dev, res->start, resource_size(res));=0A=
> +	base =3D devm_platform_ioremap_resource(pdev, 0);=0A=
>   	if (!base)=0A=
> -		return -ENOMEM;=0A=
> +		return PTR_ERR(base);=0A=
>   =0A=
>   	clk_data =3D devm_kzalloc(&pdev->dev, struct_size(clk_data, hws,=0A=
>   				ss_lpcg->num_max), GFP_KERNEL);=0A=
> =0A=
=0A=