Re: [PATCH v2 6/9] usb: xhci-mtk: add optional mcu and dma bus clocks

[Matthias Brugger <matthias.bgg@gmail.com>]

On 10/13/2017 10:26 AM, Chunfeng Yun wrote:
> There are mcu_bus and dma_bus clocks needed to be controlled by
> driver on some SoCs, so add them as optional ones
> 
> Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
> ---

Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>

>   drivers/usb/host/xhci-mtk.c |   79 ++++++++++++++++++++++++++++++++-----------
>   drivers/usb/host/xhci-mtk.h |    2 ++
>   2 files changed, 62 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
> index d60463c..e5caabe 100644
> --- a/drivers/usb/host/xhci-mtk.c
> +++ b/drivers/usb/host/xhci-mtk.c
> @@ -221,6 +221,44 @@ static int xhci_mtk_ssusb_config(struct xhci_hcd_mtk *mtk)
>   	return xhci_mtk_host_enable(mtk);
>   }
>   
> +/* ignore the error if the clock does not exist */
> +static struct clk *optional_clk_get(struct device *dev, const char *id)
> +{
> +	struct clk *opt_clk;
> +
> +	opt_clk = devm_clk_get(dev, id);
> +	/* ignore error number except EPROBE_DEFER */
> +	if (IS_ERR(opt_clk) && (PTR_ERR(opt_clk) != -EPROBE_DEFER))
> +		opt_clk = NULL;
> +
> +	return opt_clk;
> +}
> +
> +static int xhci_mtk_clks_get(struct xhci_hcd_mtk *mtk)
> +{
> +	struct device *dev = mtk->dev;
> +
> +	mtk->sys_clk = devm_clk_get(dev, "sys_ck");
> +	if (IS_ERR(mtk->sys_clk)) {
> +		dev_err(dev, "fail to get sys_ck\n");
> +		return PTR_ERR(mtk->sys_clk);
> +	}
> +
> +	mtk->ref_clk = optional_clk_get(dev, "ref_ck");
> +	if (IS_ERR(mtk->ref_clk))
> +		return PTR_ERR(mtk->ref_clk);
> +
> +	mtk->mcu_clk = optional_clk_get(dev, "mcu_ck");
> +	if (IS_ERR(mtk->mcu_clk))
> +		return PTR_ERR(mtk->mcu_clk);
> +
> +	mtk->dma_clk = optional_clk_get(dev, "dma_ck");
> +	if (IS_ERR(mtk->dma_clk))
> +		return PTR_ERR(mtk->dma_clk);
> +
> +	return 0;
> +}
> +
>   static int xhci_mtk_clks_enable(struct xhci_hcd_mtk *mtk)
>   {
>   	int ret;
> @@ -237,16 +275,34 @@ static int xhci_mtk_clks_enable(struct xhci_hcd_mtk *mtk)
>   		goto sys_clk_err;
>   	}
>   
> +	ret = clk_prepare_enable(mtk->mcu_clk);
> +	if (ret) {
> +		dev_err(mtk->dev, "failed to enable mcu_clk\n");
> +		goto mcu_clk_err;
> +	}
> +
> +	ret = clk_prepare_enable(mtk->dma_clk);
> +	if (ret) {
> +		dev_err(mtk->dev, "failed to enable dma_clk\n");
> +		goto dma_clk_err;
> +	}
> +
>   	return 0;
>   
> +dma_clk_err:
> +	clk_disable_unprepare(mtk->mcu_clk);
> +mcu_clk_err:
> +	clk_disable_unprepare(mtk->sys_clk);
>   sys_clk_err:
>   	clk_disable_unprepare(mtk->ref_clk);
>   ref_clk_err:
> -	return -EINVAL;
> +	return ret;
>   }
>   
>   static void xhci_mtk_clks_disable(struct xhci_hcd_mtk *mtk)
>   {
> +	clk_disable_unprepare(mtk->dma_clk);
> +	clk_disable_unprepare(mtk->mcu_clk);
>   	clk_disable_unprepare(mtk->sys_clk);
>   	clk_disable_unprepare(mtk->ref_clk);
>   }
> @@ -529,24 +585,9 @@ static int xhci_mtk_probe(struct platform_device *pdev)
>   		return PTR_ERR(mtk->vusb33);
>   	}
>   
> -	mtk->sys_clk = devm_clk_get(dev, "sys_ck");
> -	if (IS_ERR(mtk->sys_clk)) {
> -		dev_err(dev, "fail to get sys_ck\n");
> -		return PTR_ERR(mtk->sys_clk);
> -	}
> -
> -	/*
> -	 * reference clock is usually a "fixed-clock", make it optional
> -	 * for backward compatibility and ignore the error if it does
> -	 * not exist.
> -	 */
> -	mtk->ref_clk = devm_clk_get(dev, "ref_ck");
> -	if (IS_ERR(mtk->ref_clk)) {
> -		if (PTR_ERR(mtk->ref_clk) == -EPROBE_DEFER)
> -			return -EPROBE_DEFER;
> -
> -		mtk->ref_clk = NULL;
> -	}
> +	ret = xhci_mtk_clks_get(mtk);
> +	if (ret)
> +		return ret;
>   
>   	mtk->lpm_support = of_property_read_bool(node, "usb3-lpm-capable");
>   	/* optional property, ignore the error if it does not exist */
> diff --git a/drivers/usb/host/xhci-mtk.h b/drivers/usb/host/xhci-mtk.h
> index 67783a7..45ff5c6 100644
> --- a/drivers/usb/host/xhci-mtk.h
> +++ b/drivers/usb/host/xhci-mtk.h
> @@ -126,6 +126,8 @@ struct xhci_hcd_mtk {
>   	struct regulator *vbus;
>   	struct clk *sys_clk;	/* sys and mac clock */
>   	struct clk *ref_clk;
> +	struct clk *mcu_clk;
> +	struct clk *dma_clk;
>   	struct regmap *pericfg;
>   	struct phy **phys;
>   	int num_phys;
>