linux-kernel - Re: [PATCH] USB: ehci-atmel: add usb

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Date:	Fri, 18 Oct 2013 21:30:58 +0200
From:	boris brezillon <b.brezillon@...rkiz.com>
To:	Nicolas Ferre <nicolas.ferre@...el.com>
CC:	Boris BREZILLON <b.brezillon@...rkiz.com>,
	Alan Stern <stern@...land.harvard.edu>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] USB: ehci-atmel: add usb_clk for transition to CCF

Hello Nicolas,

This patch should fix the bug you were seeing with USB device 
enumaration after moving to CCF.
Tell me if this solves the issue (it worked for me).

Best Regards,

Boris

On 18/10/2013 21:26, Boris BREZILLON wrote:
> The AT91 PMC (Power Management Controller) provides a USB clock used by
> the different USB controllers (ehci, ohci and udc).
> The atmel-ehci driver must configure the usb clock rate to 48Mhz in order
> to get a fully functionnal USB host controller.
> This configuration was formely done in mach-at91/clock.c, but will be
> bypassed when moving to common clk framework.
>
> This patch adds support for usb clock retrieval and configuration only if
> CCF is enabled (CONFIG_COMMON_CLK).
>
> Signed-off-by: Boris BREZILLON <b.brezillon@...rkiz.com>
> ---
>   drivers/usb/host/ehci-atmel.c |   16 +++++++++++++++-
>   1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/host/ehci-atmel.c b/drivers/usb/host/ehci-atmel.c
> index 3b645ff..f417526 100644
> --- a/drivers/usb/host/ehci-atmel.c
> +++ b/drivers/usb/host/ehci-atmel.c
> @@ -30,13 +30,17 @@ static const char hcd_name[] = "ehci-atmel";
>   static struct hc_driver __read_mostly ehci_atmel_hc_driver;
>   
>   /* interface and function clocks */
> -static struct clk *iclk, *fclk;
> +static struct clk *iclk, *fclk, *uclk;
>   static int clocked;
>   
>   /*-------------------------------------------------------------------------*/
>   
>   static void atmel_start_clock(void)
>   {
> +	if (IS_ENABLED(CONFIG_COMMON_CLK)) {
> +		clk_set_rate(uclk, 48000000);
> +		clk_prepare_enable(uclk);
> +	}
>   	clk_prepare_enable(iclk);
>   	clk_prepare_enable(fclk);
>   	clocked = 1;
> @@ -46,6 +50,8 @@ static void atmel_stop_clock(void)
>   {
>   	clk_disable_unprepare(fclk);
>   	clk_disable_unprepare(iclk);
> +	if (IS_ENABLED(CONFIG_COMMON_CLK))
> +		clk_disable_unprepare(uclk);
>   	clocked = 0;
>   }
>   
> @@ -130,6 +136,14 @@ static int ehci_atmel_drv_probe(struct platform_device *pdev)
>   		retval = -ENOENT;
>   		goto fail_request_resource;
>   	}
> +	if (IS_ENABLED(CONFIG_COMMON_CLK)) {
> +		uclk = devm_clk_get(&pdev->dev, "usb_clk");
> +		if (IS_ERR(uclk)) {
> +			dev_err(&pdev->dev, "failed to get uclk\n");
> +			retval = PTR_ERR(uclk);
> +			goto fail_request_resource;
> +		}
> +	}
>   
>   	ehci = hcd_to_ehci(hcd);
>   	/* registers start at offset 0x0 */

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