Re: [PATCH v3 05/20] usb: host: xhci-plat: Add clocks support

[Jason Cooper <jason@lakedaemon.net>]

On Tue, May 06, 2014 at 02:14:00AM +0200, Gregory CLEMENT wrote:
> Some platform (such as the Armada 38x ones) can gate the clock of
> their USB controller. This patch add the support for the clock, by
> enabling them during probe and disabling them on remove.
> 
> As not all platforms have clock support then enabling and disabling
> the clocks have been placed in separate functions. Then if the clocks
> are not supported we still can use the same calls, and there is no

... ?

thx,

Jason.

> 
> Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
> ---
>  drivers/usb/host/xhci-plat.c | 57 +++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 54 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
> index f5351af4b2c5..bb37b941c8ec 100644
> --- a/drivers/usb/host/xhci-plat.c
> +++ b/drivers/usb/host/xhci-plat.c
> @@ -11,6 +11,7 @@
>   * version 2 as published by the Free Software Foundation.
>   */
>  
> +#include <linux/clk.h>
>  #include <linux/dma-mapping.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
> @@ -19,6 +20,10 @@
>  
>  #include "xhci.h"
>  
> +struct xhci_plat_priv {
> +	struct clk *clk;
> +};
> +
>  static void xhci_plat_quirks(struct device *dev, struct xhci_hcd *xhci)
>  {
>  	/*
> @@ -38,7 +43,8 @@ static int xhci_plat_setup(struct usb_hcd *hcd)
>  static const struct hc_driver xhci_plat_xhci_driver = {
>  	.description =		"xhci-hcd",
>  	.product_desc =		"xHCI Host Controller",
> -	.hcd_priv_size =	sizeof(struct xhci_hcd *),
> +	.hcd_priv_size =	sizeof(struct xhci_hcd *) +
> +				sizeof(struct xhci_plat_priv),
>  
>  	/*
>  	 * generic hardware linkage
> @@ -85,6 +91,40 @@ static const struct hc_driver xhci_plat_xhci_driver = {
>  	.bus_resume =		xhci_bus_resume,
>  };
>  
> +static int xhci_plat_enable_clk(struct platform_device *pdev)
> +{
> +	struct usb_hcd *hcd = platform_get_drvdata(pdev);
> +	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
> +	struct xhci_plat_priv *priv = (struct xhci_plat_priv *) xhci->priv;
> +
> +	priv->clk = devm_clk_get(&pdev->dev, NULL);
> +
> +	/*
> +	 * Not all platforms have a clk so it is not an error if the
> +	 * clock does not exists.
> +	 */
> +	if (IS_ERR(priv->clk))
> +		return 0;
> +
> +	return clk_prepare_enable(priv->clk);
> +}
> +
> +static void xhci_plat_disable_clk(struct platform_device *pdev)
> +{
> +	struct usb_hcd *hcd = platform_get_drvdata(pdev);
> +	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
> +	struct xhci_plat_priv *priv = (struct xhci_plat_priv *) xhci->priv;
> +
> +	/*
> +	 * Not all platforms have a clk so it is not an error if the
> +	 * clock does not exists.
> +	 */
> +	if (IS_ERR(priv->clk))
> +		return;
> +
> +	clk_disable_unprepare(priv->clk);
> +}
> +
>  static int xhci_plat_probe(struct platform_device *pdev)
>  {
>  	const struct hc_driver	*driver;
> @@ -118,7 +158,7 @@ static int xhci_plat_probe(struct platform_device *pdev)
>  
>  	hcd = usb_create_hcd(driver, &pdev->dev, dev_name(&pdev->dev));
>  	if (!hcd)
> -		return -ENOMEM;
> +		ret = -ENOMEM;
>  
>  	hcd->rsrc_start = res->start;
>  	hcd->rsrc_len = resource_size(res);
> @@ -140,6 +180,13 @@ static int xhci_plat_probe(struct platform_device *pdev)
>  	ret = usb_add_hcd(hcd, irq, IRQF_SHARED);
>  	if (ret)
>  		goto unmap_registers;
> +
> +	ret = xhci_plat_enable_clk(pdev);
> +	if (ret) {
> +		dev_dbg(&pdev->dev, "error enabling clocks\n");
> +		goto dealloc_usb2_hcd;
> +	}
> +
>  	device_wakeup_enable(hcd->self.controller);
>  
>  	/* USB 2.0 roothub is stored in the platform_device now. */
> @@ -149,7 +196,7 @@ static int xhci_plat_probe(struct platform_device *pdev)
>  			dev_name(&pdev->dev), hcd);
>  	if (!xhci->shared_hcd) {
>  		ret = -ENOMEM;
> -		goto dealloc_usb2_hcd;
> +		goto disable_clk;
>  	}
>  
>  	/*
> @@ -170,6 +217,9 @@ static int xhci_plat_probe(struct platform_device *pdev)
>  put_usb3_hcd:
>  	usb_put_hcd(xhci->shared_hcd);
>  
> +disable_clk:
> +	xhci_plat_disable_clk(pdev);
> +
>  dealloc_usb2_hcd:
>  	usb_remove_hcd(hcd);
>  
> @@ -193,6 +243,7 @@ static int xhci_plat_remove(struct platform_device *dev)
>  	usb_remove_hcd(xhci->shared_hcd);
>  	usb_put_hcd(xhci->shared_hcd);
>  
> +	xhci_plat_disable_clk(dev);
>  	usb_remove_hcd(hcd);
>  	iounmap(hcd->regs);
>  	release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
> -- 
> 1.8.1.2
>