linux-kernel - Re: [PATCH] usb: gadget: at91_udc: add usb_clk for transition to common clk framework

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Date:	Mon, 12 Aug 2013 15:52:01 +0200
From:	Nicolas Ferre <nicolas.ferre@...el.com>
To:	Boris BREZILLON <b.brezillon@...rkiz.com>,
	Felipe Balbi <balbi@...com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
CC:	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	"Ludovic Desroches" <ludovic.desroches@...el.com>,
	<linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] usb: gadget: at91_udc: add usb_clk for transition to
 common clk framework

On 01/08/2013 08:18, Boris BREZILLON :
> The AT91 PMC (Power Management Controller) provides an USB clock used by
> USB Full Speed host (ohci) and USB Full Speed device (udc).
> The usb drivers (ohci and udc) must configure this clock to 48Mhz.
> This configuration was formely done in mach-at91/clock.c, but this
> implementation will be removed when moving to common clk framework.
>
> This patch adds support for usb clock retrieval and configuration, and is
> backward compatible with the current at91 clk implementation (if usb clk
> is not found, it does not configure/enable it).
>
> Signed-off-by: Boris BREZILLON <b.brezillon@...rkiz.com>

Acked-by: Nicolas Ferre <nicolas.ferre@...el.com>

> ---
>   drivers/usb/gadget/at91_udc.c |   17 ++++++++++++++++-
>   drivers/usb/gadget/at91_udc.h |    2 +-
>   2 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/gadget/at91_udc.c b/drivers/usb/gadget/at91_udc.c
> index fce8e4e..ae06585 100644
> --- a/drivers/usb/gadget/at91_udc.c
> +++ b/drivers/usb/gadget/at91_udc.c
> @@ -870,6 +870,11 @@ static void clk_on(struct at91_udc *udc)
>   	if (udc->clocked)
>   		return;
>   	udc->clocked = 1;
> +
> +	if (!IS_ERR(udc->uclk)) {
> +		clk_set_rate(udc->uclk, 48000000);
> +		clk_prepare_enable(udc->uclk);
> +	}
>   	clk_prepare_enable(udc->iclk);
>   	clk_prepare_enable(udc->fclk);
>   }
> @@ -882,6 +887,8 @@ static void clk_off(struct at91_udc *udc)
>   	udc->gadget.speed = USB_SPEED_UNKNOWN;
>   	clk_disable_unprepare(udc->fclk);
>   	clk_disable_unprepare(udc->iclk);
> +	if (!IS_ERR(udc->uclk))
> +		clk_disable_unprepare(udc->uclk);
>   }
>
>   /*
> @@ -1774,10 +1781,10 @@ static int at91udc_probe(struct platform_device *pdev)
>   	/* get interface and function clocks */
>   	udc->iclk = clk_get(dev, "udc_clk");
>   	udc->fclk = clk_get(dev, "udpck");
> +	udc->uclk = clk_get(dev, "usb_clk");
>   	if (IS_ERR(udc->iclk) || IS_ERR(udc->fclk)) {
>   		DBG("clocks missing\n");
>   		retval = -ENODEV;
> -		/* NOTE: we "know" here that refcounts on these are NOPs */
>   		goto fail1;
>   	}
>
> @@ -1851,6 +1858,12 @@ fail3:
>   fail2:
>   	free_irq(udc->udp_irq, udc);
>   fail1:
> +	if (!IS_ERR(udc->uclk))
> +		clk_put(udc->uclk);
> +	if (!IS_ERR(udc->fclk))
> +		clk_put(udc->fclk);
> +	if (!IS_ERR(udc->iclk))
> +		clk_put(udc->iclk);
>   	iounmap(udc->udp_baseaddr);
>   fail0a:
>   	if (cpu_is_at91rm9200())
> @@ -1894,6 +1907,8 @@ static int __exit at91udc_remove(struct platform_device *pdev)
>
>   	clk_put(udc->iclk);
>   	clk_put(udc->fclk);
> +	if (!IS_ERR(udc->uclk))
> +		clk_put(udc->uclk);
>
>   	return 0;
>   }
> diff --git a/drivers/usb/gadget/at91_udc.h b/drivers/usb/gadget/at91_udc.h
> index e647d1c..0175246 100644
> --- a/drivers/usb/gadget/at91_udc.h
> +++ b/drivers/usb/gadget/at91_udc.h
> @@ -126,7 +126,7 @@ struct at91_udc {
>   	unsigned			active_suspend:1;
>   	u8				addr;
>   	struct at91_udc_data		board;
> -	struct clk			*iclk, *fclk;
> +	struct clk			*iclk, *fclk, *uclk;
>   	struct platform_device		*pdev;
>   	struct proc_dir_entry		*pde;
>   	void __iomem			*udp_baseaddr;
>


-- 
Nicolas Ferre
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