Subject: [PATCH v2] usb: gadget: at91_udc: move prepare clk into process context

From: [email-masked] (Ronald Wahl)
Date: Thu, 07 Aug 2014 17:23:58 +0200

Hi,

actually this should have been patch v3 and not v2. Anyway, the major 
difference is that I moved setting the clock rate into process context 
as well as it may also sleep.

- ron

On 07.08.2014 17:11, Ronald Wahl wrote:
> Commit 7628083227b6bc4a7e33d7c381d7a4e558424b6b added clock preparation in
> interrupt context. This is not allowed as it might sleep. Move clock
> preparation and setting clock rate into process context (at91udc_probe).
>
> Signed-off-by: Ronald Wahl <[email-masked]>
> ---
>   drivers/usb/gadget/udc/at91_udc.c | 44 ++++++++++++++++++++++++++++-----------
>   1 file changed, 32 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/usb/gadget/udc/at91_udc.c b/drivers/usb/gadget/udc/at91_udc.c
> index cfd18bc..0d685d0 100644
> --- a/drivers/usb/gadget/udc/at91_udc.c
> +++ b/drivers/usb/gadget/udc/at91_udc.c
> @@ -870,12 +870,10 @@ static void clk_on(struct at91_udc *udc)
>   		return;
>   	udc->clocked = 1;
>
> -	if (IS_ENABLED(CONFIG_COMMON_CLK)) {
> -		clk_set_rate(udc->uclk, 48000000);
> -		clk_prepare_enable(udc->uclk);
> -	}
> -	clk_prepare_enable(udc->iclk);
> -	clk_prepare_enable(udc->fclk);
> +	if (IS_ENABLED(CONFIG_COMMON_CLK))
> +		clk_enable(udc->uclk);
> +	clk_enable(udc->iclk);
> +	clk_enable(udc->fclk);
>   }
>
>   static void clk_off(struct at91_udc *udc)
> @@ -884,10 +882,10 @@ static void clk_off(struct at91_udc *udc)
>   		return;
>   	udc->clocked = 0;
>   	udc->gadget.speed = USB_SPEED_UNKNOWN;
> -	clk_disable_unprepare(udc->fclk);
> -	clk_disable_unprepare(udc->iclk);
> +	clk_disable(udc->fclk);
> +	clk_disable(udc->iclk);
>   	if (IS_ENABLED(CONFIG_COMMON_CLK))
> -		clk_disable_unprepare(udc->uclk);
> +		clk_disable(udc->uclk);
>   }
>
>   /*
> @@ -1780,14 +1778,24 @@ static int at91udc_probe(struct platform_device *pdev)
>   	}
>
>   	/* don't do anything until we have both gadget driver and VBUS */
> +	if (IS_ENABLED(CONFIG_COMMON_CLK)) {
> +		clk_set_rate(udc->uclk, 48000000);
> +		retval = clk_prepare(udc->uclk);
> +		if (retval)
> +			goto fail1;
> +	}
> +	retval = clk_prepare(udc->fclk);
> +	if (retval)
> +		goto fail1a;
> +
>   	retval = clk_prepare_enable(udc->iclk);
>   	if (retval)
> -		goto fail1;
> +		goto fail1b;
>   	at91_udp_write(udc, AT91_UDP_TXVC, AT91_UDP_TXVC_TXVDIS);
>   	at91_udp_write(udc, AT91_UDP_IDR, 0xffffffff);
>   	/* Clear all pending interrupts - UDP may be used by bootloader. */
>   	at91_udp_write(udc, AT91_UDP_ICR, 0xffffffff);
> -	clk_disable_unprepare(udc->iclk);
> +	clk_disable(udc->iclk);
>
>   	/* request UDC and maybe VBUS irqs */
>   	udc->udp_irq = platform_get_irq(pdev, 0);
> @@ -1795,7 +1803,7 @@ static int at91udc_probe(struct platform_device *pdev)
>   			0, driver_name, udc);
>   	if (retval < 0) {
>   		DBG("request irq %d failed\n", udc->udp_irq);
> -		goto fail1;
> +		goto fail1c;
>   	}
>   	if (gpio_is_valid(udc->board.vbus_pin)) {
>   		retval = gpio_request(udc->board.vbus_pin, "udc_vbus");
> @@ -1848,6 +1856,13 @@ fail3:
>   		gpio_free(udc->board.vbus_pin);
>   fail2:
>   	free_irq(udc->udp_irq, udc);
> +fail1c:
> +	clk_unprepare(udc->iclk);
> +fail1b:
> +	clk_unprepare(udc->fclk);
> +fail1a:
> +	if (IS_ENABLED(CONFIG_COMMON_CLK))
> +		clk_unprepare(udc->uclk);
>   fail1:
>   	if (IS_ENABLED(CONFIG_COMMON_CLK) && !IS_ERR(udc->uclk))
>   		clk_put(udc->uclk);
> @@ -1896,6 +1911,11 @@ static int __exit at91udc_remove(struct platform_device *pdev)
>   	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>   	release_mem_region(res->start, resource_size(res));
>
> +	if (IS_ENABLED(CONFIG_COMMON_CLK))
> +		clk_unprepare(udc->uclk);
> +	clk_unprepare(udc->fclk);
> +	clk_unprepare(udc->iclk);
> +
>   	clk_put(udc->iclk);
>   	clk_put(udc->fclk);
>   	if (IS_ENABLED(CONFIG_COMMON_CLK))
>