Re: [PATCHv5 07/20] usb: host: xhci-plat: add clock support

[Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org>]

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On Sun, May 11, 2014 at 08:17:55PM +0200, Thomas Petazzoni wrote:
> From: Gregory CLEMENT <gregory.clement-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
> 
> Some platforms (such as the Armada 38x ones) can gate the clock of
> their USB controller. This patch adds the support for one clock in
> xhci-plat, by enabling it during probe and disabling it on remove.
> 
> To achieve this, it adds a 'struct clk *' member in xhci_hcd. While
> only used for now in xhci-plat, it might be used by other drivers in
> the future. Moreover, the xhci_hcd structure already holds other
> members such as msix_count and msix_entries, which are MSI-X specific,
> and therefore only used by xhci-pci.
> 
> Signed-off-by: Gregory CLEMENT <gregory.clement-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>

FWIW

Acked-by: Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org>

> ---
>  drivers/usb/host/xhci-plat.c | 24 +++++++++++++++++++++++-
>  drivers/usb/host/xhci.h      |  2 ++
>  2 files changed, 25 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
> index f5351af..8108e58 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>
> @@ -91,6 +92,7 @@ static int xhci_plat_probe(struct platform_device *pdev)
>  	struct xhci_hcd		*xhci;
>  	struct resource         *res;
>  	struct usb_hcd		*hcd;
> +	struct clk              *clk;
>  	int			ret;
>  	int			irq;
>  
> @@ -137,14 +139,27 @@ static int xhci_plat_probe(struct platform_device *pdev)
>  		goto release_mem_region;
>  	}
>  
> +	/*
> +	 * Not all platforms have a clk so it is not an error if the
> +	 * clock does not exists.
> +	 */
> +	clk = devm_clk_get(&pdev->dev, NULL);
> +	if (!IS_ERR(clk)) {
> +		ret = clk_prepare_enable(clk);
> +		if (ret)
> +			goto unmap_registers;
> +	}
> +
>  	ret = usb_add_hcd(hcd, irq, IRQF_SHARED);
>  	if (ret)
> -		goto unmap_registers;
> +		goto disable_clk;
> +
>  	device_wakeup_enable(hcd->self.controller);
>  
>  	/* USB 2.0 roothub is stored in the platform_device now. */
>  	hcd = platform_get_drvdata(pdev);
>  	xhci = hcd_to_xhci(hcd);
> +	xhci->clk = clk;
>  	xhci->shared_hcd = usb_create_shared_hcd(driver, &pdev->dev,
>  			dev_name(&pdev->dev), hcd);
>  	if (!xhci->shared_hcd) {
> @@ -173,6 +188,10 @@ put_usb3_hcd:
>  dealloc_usb2_hcd:
>  	usb_remove_hcd(hcd);
>  
> +disable_clk:
> +	if (!IS_ERR(clk))
> +		clk_disable_unprepare(clk);
> +
>  unmap_registers:
>  	iounmap(hcd->regs);
>  
> @@ -189,11 +208,14 @@ static int xhci_plat_remove(struct platform_device *dev)
>  {
>  	struct usb_hcd	*hcd = platform_get_drvdata(dev);
>  	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
> +	struct clk *clk = xhci->clk;
>  
>  	usb_remove_hcd(xhci->shared_hcd);
>  	usb_put_hcd(xhci->shared_hcd);
>  
>  	usb_remove_hcd(hcd);
> +	if (!IS_ERR(clk))
> +		clk_disable_unprepare(clk);
>  	iounmap(hcd->regs);
>  	release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
>  	usb_put_hcd(hcd);
> diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
> index d280e92..003dc09 100644
> --- a/drivers/usb/host/xhci.h
> +++ b/drivers/usb/host/xhci.h
> @@ -1478,6 +1478,8 @@ struct xhci_hcd {
>  	/* msi-x vectors */
>  	int		msix_count;
>  	struct msix_entry	*msix_entries;
> +	/* optional clock */
> +	struct clk		*clk;
>  	/* data structures */
>  	struct xhci_device_context_array *dcbaa;
>  	struct xhci_ring	*cmd_ring;
> -- 
> 1.9.2
> 

-- 
balbi

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