[PATCHv2 1/2] USB: host: ehci_atmel: Add suspend/resume support

[boris.brezillon@free-electrons.com (Boris Brezillon)]

On Sat, 17 Jan 2015 16:36:34 +0100
Sylvain Rochet <sylvain.rochet@finsecur.com> wrote:

> This patch add suspend/resume support for Atmel EHCI, mostly
> about disabling and unpreparing clocks so USB PLL is stopped
> before entering sleep state.
> 
> Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>

Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>

> ---
>  drivers/usb/host/ehci-atmel.c | 32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
> 
> diff --git a/drivers/usb/host/ehci-atmel.c b/drivers/usb/host/ehci-atmel.c
> index 56a8850..2e0043b 100644
> --- a/drivers/usb/host/ehci-atmel.c
> +++ b/drivers/usb/host/ehci-atmel.c
> @@ -37,6 +37,8 @@ static int clocked;
>  
>  static void atmel_start_clock(void)
>  {
> +	if (clocked)
> +		return;
>  	if (IS_ENABLED(CONFIG_COMMON_CLK)) {
>  		clk_set_rate(uclk, 48000000);
>  		clk_prepare_enable(uclk);
> @@ -48,6 +50,8 @@ static void atmel_start_clock(void)
>  
>  static void atmel_stop_clock(void)
>  {
> +	if (!clocked)
> +		return;
>  	clk_disable_unprepare(fclk);
>  	clk_disable_unprepare(iclk);
>  	if (IS_ENABLED(CONFIG_COMMON_CLK))
> @@ -174,6 +178,32 @@ static int ehci_atmel_drv_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +#ifdef CONFIG_PM
> +static int ehci_atmel_drv_suspend(struct platform_device *pdev, pm_message_t mesg)
> +{
> +	struct usb_hcd *hcd = platform_get_drvdata(pdev);
> +	int ret;
> +
> +	ret = ehci_suspend(hcd, false);
> +	if (ret)
> +		return ret;
> +
> +	atmel_stop_clock();
> +	return 0;
> +}
> +
> +static int ehci_atmel_drv_resume(struct platform_device *pdev)
> +{
> +	struct usb_hcd *hcd = platform_get_drvdata(pdev);
> +
> +	atmel_start_clock();
> +	return ehci_resume(hcd, false);
> +}
> +#else
> +#define ehci_atmel_drv_suspend NULL
> +#define ehci_atmel_drv_resume  NULL
> +#endif
> +
>  #ifdef CONFIG_OF
>  static const struct of_device_id atmel_ehci_dt_ids[] = {
>  	{ .compatible = "atmel,at91sam9g45-ehci" },
> @@ -187,6 +217,8 @@ static struct platform_driver ehci_atmel_driver = {
>  	.probe		= ehci_atmel_drv_probe,
>  	.remove		= ehci_atmel_drv_remove,
>  	.shutdown	= usb_hcd_platform_shutdown,
> +	.suspend	= ehci_atmel_drv_suspend,
> +	.resume		= ehci_atmel_drv_resume,
>  	.driver		= {
>  		.name	= "atmel-ehci",
>  		.of_match_table	= of_match_ptr(atmel_ehci_dt_ids),



-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com