Re: [PATCH 1/2] usb: dwc2: Add reset control to dwc2

[John Youn <John.Youn-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>]

On 3/28/2016 10:38 PM, dinguyen-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx@public.gmane.org wrote:
> From: Dinh Nguyen <dinguyen-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx@public.gmane.org>
> 
> Allow for platforms that have a reset controller driver in place to bring
> the USB IP out of reset.
> 
> Signed-off-by: Dinh Nguyen <dinguyen-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx@public.gmane.org>
> Cc: John Youn <johnyoun-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>
> ---
>  drivers/usb/dwc2/core.h     |    1 +
>  drivers/usb/dwc2/platform.c |   15 +++++++++++++++
>  2 files changed, 16 insertions(+)
> 
> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
> index 3c58d63..f748132 100644
> --- a/drivers/usb/dwc2/core.h
> +++ b/drivers/usb/dwc2/core.h
> @@ -837,6 +837,7 @@ struct dwc2_hsotg {
>  	void *priv;
>  	int     irq;
>  	struct clk *clk;
> +	struct reset_control *reset;
>  
>  	unsigned int queuing_high_bandwidth:1;
>  	unsigned int srp_success:1;
> diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
> index 88629be..b1fa9dd 100644
> --- a/drivers/usb/dwc2/platform.c
> +++ b/drivers/usb/dwc2/platform.c
> @@ -45,6 +45,7 @@
>  #include <linux/platform_device.h>
>  #include <linux/phy/phy.h>
>  #include <linux/platform_data/s3c-hsotg.h>
> +#include <linux/reset.h>
>  
>  #include <linux/usb/of.h>
>  
> @@ -337,6 +338,9 @@ static int dwc2_lowlevel_hw_init(struct dwc2_hsotg *hsotg)
>  {
>  	int i, ret;
>  
> +	if(hsotg->reset)
> +		reset_control_deassert(hsotg->reset);
> +
>  	/* Set default UTMI width */
>  	hsotg->phyif = GUSBCFG_PHYIF16;
>  
> @@ -434,6 +438,9 @@ static int dwc2_driver_remove(struct platform_device *dev)
>  	if (hsotg->ll_hw_enabled)
>  		dwc2_lowlevel_hw_disable(hsotg);
>  
> +	if (hsotg->reset)
> +		reset_control_assert(hsotg->reset);
> +
>  	return 0;
>  }
>  
> @@ -529,6 +536,14 @@ static int dwc2_driver_probe(struct platform_device *dev)
>  	dev_dbg(&dev->dev, "mapped PA %08lx to VA %p\n",
>  		(unsigned long)res->start, hsotg->regs);
>  
> +	hsotg->reset = devm_reset_control_get(&dev->dev, "dwc2");
> +	if (IS_ERR(hsotg->reset)) {
> +		dev_info(&dev->dev, "Could not get reset control!\n");
> +		if (PTR_ERR(hsotg->reset) == -EPROBE_DEFER)
> +			return -EPROBE_DEFER;
> +		hsotg->reset = NULL;
> +	}
> +

Hi Dinh,

Can you move into the lowlevel_hw_init()? The probe is a bit bloated
and we have these existing "lowlevel" functions where we consolidate
stuff like this. Same with the assert/deassert if possible.

Regards,
John
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