Message-ID: <20140924022736.GA5307@peterchendt>
Date:	Wed, 24 Sep 2014 10:27:52 +0800
From:	Peter Chen <peter.chen@...escale.com>
To:	Arnd Bergmann <arnd@...db.de>
CC:	<balbi@...com>, Antoine Tenart <antoine.tenart@...e-electrons.com>,
	<linux-arm-kernel@...ts.infradead.org>,
	<sebastian.hesselbarth@...il.com>, <p.zabel@...gutronix.de>,
	<thomas.petazzoni@...e-electrons.com>, <zmxu@...vell.com>,
	<devicetree@...r.kernel.org>, <linux-usb@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>,
	<alexandre.belloni@...e-electrons.com>, <jszhang@...vell.com>
Subject: Re: [PATCH v6 07/12] usb: chipidea: add a usb2 driver for ci13xxx

On Tue, Sep 23, 2014 at 07:37:25PM +0200, Arnd Bergmann wrote:
> On Tuesday 23 September 2014 11:55:15 Felipe Balbi wrote:
> > On Tue, Sep 23, 2014 at 06:44:40PM +0200, Arnd Bergmann wrote:
> > > On Tuesday 23 September 2014 15:36:45 Antoine Tenart wrote:
> > > > On Tue, Sep 23, 2014 at 12:39:04PM +0200, Arnd Bergmann wrote:
> > > > > On Tuesday 23 September 2014 12:28:03 Antoine Tenart wrote:
> > > > > > +       if (dev->of_node) {
> > > > > > +               ret = ci_hdrc_usb2_dt_probe(dev, ci_pdata);
> > > > > > +               if (ret)
> > > > > > +                       goto clk_err;
> > > > > > +       } else {
> > > > > > +               ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
> > > > > > +               if (ret)
> > > > > > +                       goto clk_err;
> > > > > > +       }
> > > > > > 
> > > > > 
> > > > > Why do you care about the non-DT case here? I think it would be nicer to
> > > > > open-code the ci_hdrc_usb2_dt_probe() function in here and remove
> > > > > the dma_set_mask_and_coherent(), which should not even be necessary for
> > > > > the case where you have a hardwired platform device.
> > > > > 
> > > > 
> > > > I thought we agreed to call dma_set_mask_and_coherent():
> > > > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-July/273335.html
> > > > 
> > > > I do not have a strong opinion on this as I only use the dt case for my
> > > > usage.
> > > 
> > > The question is more about who actually wants the non-DT case.
> > > 
> > > Since this is a new driver, I suspect that the answer is "nobody",
> > > as the existing board files are all for legacy platforms that we
> > > are not going to adapt for this driver.
> > 
> > wait a minute... will the legacy platforms be adapted to DT and, thus,
> > to this driver in the future ? I really don't want to keep several
> > copies of chipidea driver just because there are still some legacy
> > platforms still using them. I have said in the past and will say again,
> > everybody should move to the generic chipidea driver at the earliest
> > opportunity so we avoid duplication of work.
> > 
> 
> Sorry, my mistake. The intention that this new driver is meant to
> replace the existing ones wasn't clear to me from the changelog,
> and if I'd been involved in the discussion before, then I've forgotten
> about it.
> 
> It absolutely makes sense to migrate to a common driver, and in that
> case we should keep the platform_data handling and dma_set_mask_and_coherent()
> call in there, so we can do the two conversions (migrating from platform
> specific frontends to the generic one, and migrating from platform_data
> to DT) on independent schedules. Eventually I'd like all of the existing
> users of the platform_data path to move to DT, but that should not
> hold up the other cleanup if it takes longer.
> 
> There is however still my point that we shouldn't have an extra platform
> device that is not attached to the device node. I think the generic driver
> should just be part of the common code, without an extra framework.
> Something like the (entirely untested) patch below.
> 
> 	Arnd

Thanks, Arnd.

Antoine is adding a generic chipdea glue layer driver, which like ehci generic
platform driver: drivers/usb/host/ehci-platform.c, since other architectures
like MIPS (Someone submitted mips chipidea driver before) may not have device
tree support, I think non-dt support is also needed.

It is a good suggestion for adding DT support for core driver, Since we did
not do it at the first, it is a little embarrass at current situation.

- For the new chipidea glue drivers, it is ok we can have a child node
for core device at glue device node, and some common entries can be there
like: phy, vbus, dr_mode, etc. We need to add support for getting
these common things for both through device tree and platform data
(parent is DT support and parent is non-DT support) at core driver.

- For the existing glue drivers, since we can't change existed dts, we can
only do it from future SoC support. Then, in this kinds of glue drivers,
we need to support for both create core driver by node and by current
calling platform_device_add way.

Peter

> 
> ---
> diff --git a/drivers/usb/chipidea/ci.h b/drivers/usb/chipidea/ci.h
> index 9563cb56d564..a2b20c1342f1 100644
> --- a/drivers/usb/chipidea/ci.h
> +++ b/drivers/usb/chipidea/ci.h
> @@ -207,6 +207,7 @@ struct ci_hdrc {
>  	bool				id_event;
>  	bool				b_sess_valid_event;
>  	bool				imx28_write_fix;
> +	struct clk			*clk;
>  };
>  
>  static inline struct ci_role_driver *ci_role(struct ci_hdrc *ci)
> diff --git a/drivers/usb/chipidea/ci_hdrc_usb2.c b/drivers/usb/chipidea/ci_hdrc_usb2.c
> index 6eae1de587f2..03ef35997dd8 100644
> --- a/drivers/usb/chipidea/ci_hdrc_usb2.c
> +++ b/drivers/usb/chipidea/ci_hdrc_usb2.c
> @@ -70,6 +70,7 @@ static int ci_hdrc_usb2_probe(struct platform_device *pdev)
>  	}
>  
>  	if (dev->of_node) {
> +		ret = ci_get_platdata(dev, platdata);
>  		ret = ci_hdrc_usb2_dt_probe(dev, ci_pdata);
>  		if (ret)
>  			goto clk_err;
> diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
> index 619d13e29995..32613751e731 100644
> --- a/drivers/usb/chipidea/core.c
> +++ b/drivers/usb/chipidea/core.c
> @@ -478,6 +478,15 @@ static int ci_get_platdata(struct device *dev,
>  	if (of_usb_get_maximum_speed(dev->of_node) == USB_SPEED_FULL)
>  		platdata->flags |= CI_HDRC_FORCE_FULLSPEED;
>  
> +	platdata->phy = of_phy_get(dev->of_node, 0);
> +	if (IS_ERR(platdata->phy)) {
> +		if (PTR_ERR(platdata->phy) == -EPROBE_DEFER)
> +			return -EPROBE_DEFER;
> +
> +		/* PHY is optional */
> +		platdata->phy = NULL;
> +	}
> +
>  	return 0;
>  }
>  
> @@ -559,6 +568,12 @@ static void ci_get_otg_capable(struct ci_hdrc *ci)
>  		dev_dbg(ci->dev, "It is OTG capable controller\n");
>  }
>  
> +static const struct ci_hdrc_platform_data ci_default_pdata = {
> +	.capoffset	= DEF_CAPOFFSET,
> +	.flags		= CI_HDRC_REQUIRE_TRANSCEIVER |
> +			  CI_HDRC_DISABLE_STREAMING,
> +};
> +
>  static int ci_hdrc_probe(struct platform_device *pdev)
>  {
>  	struct device	*dev = &pdev->dev;
> @@ -568,11 +583,6 @@ static int ci_hdrc_probe(struct platform_device *pdev)
>  	int		ret;
>  	enum usb_dr_mode dr_mode;
>  
> -	if (!dev_get_platdata(dev)) {
> -		dev_err(dev, "platform data missing\n");
> -		return -ENODEV;
> -	}
> -
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	base = devm_ioremap_resource(dev, res);
>  	if (IS_ERR(base))
> @@ -586,6 +596,32 @@ static int ci_hdrc_probe(struct platform_device *pdev)
>  
>  	ci->dev = dev;
>  	ci->platdata = dev_get_platdata(dev);
> +	if (!ci->platdata) {
> +		ci->platdata = devm_kmemdup(dev, &ci_default_pdata,
> +					    sizeof(ci_default_pdata),
> +					    GFP_KERNEL);
> +
> +		if (!ci->platdata)
> +			return -ENOMEM;
> +
> +		ret = ci_get_platdata(dev, platdata);
> +		if (ret)
> +			return ERR_PTR(ret);
> +	}
> +
> +	priv->clk = devm_clk_get(dev, NULL);
> +	if (!IS_ERR(priv->clk)) {
> +		ret = clk_prepare_enable(priv->clk);
> +		if (ret) {
> +			dev_err(dev, "failed to enable the clock: %d\n", ret);
> +			return ret;
> +		}
> +	}
> +
> +	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
> +	if (ret)
> +		return ret;
> +
>  	ci->imx28_write_fix = !!(ci->platdata->flags &
>  		CI_HDRC_IMX28_WRITE_FIX);
>  
> @@ -702,8 +738,8 @@ static int ci_hdrc_probe(struct platform_device *pdev)
>  	}
>  
>  	platform_set_drvdata(pdev, ci);
> -	ret = request_irq(ci->irq, ci_irq, IRQF_SHARED, ci->platdata->name,
> -			  ci);
> +	ret = devm_request_irq(ci->irq, ci_irq, IRQF_SHARED,
> +			       ci->platdata->name, ci);
>  	if (ret)
>  		goto stop;
>  
> @@ -711,10 +747,13 @@ static int ci_hdrc_probe(struct platform_device *pdev)
>  		ci_hdrc_otg_fsm_start(ci);
>  
>  	ret = dbg_create_files(ci);
> -	if (!ret)
> -		return 0;
> +	if (ret)
> +		goto stop;
> +
> +	pm_runtime_no_callbacks(dev);
> +	pm_runtime_enable(dev);
> +	return 0;
>  
> -	free_irq(ci->irq, ci);
>  stop:
>  	ci_role_destroy(ci);
>  deinit_phy:
> @@ -727,22 +766,32 @@ static int ci_hdrc_remove(struct platform_device *pdev)
>  {
>  	struct ci_hdrc *ci = platform_get_drvdata(pdev);
>  
> +	pm_runtime_disable(&pdev->dev);
>  	dbg_remove_files(ci);
>  	free_irq(ci->irq, ci);
>  	ci_role_destroy(ci);
>  	ci_hdrc_enter_lpm(ci, true);
>  	usb_phy_shutdown(ci->transceiver);
>  	kfree(ci->hw_bank.regmap);
> +	clk_disable_unprepare(ci->clk);
>  
>  	return 0;
>  }
>  
> +static const struct of_device_id ci_hdrc_usb2_of_match[] = {
> +	{ .compatible = "chipidea,usb2" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, ci_hdrc_usb2_of_match);
> +
> +
>  static struct platform_driver ci_hdrc_driver = {
>  	.probe	= ci_hdrc_probe,
>  	.remove	= ci_hdrc_remove,
>  	.driver	= {
>  		.name	= "ci_hdrc",
>  		.owner	= THIS_MODULE,
> +		.of_match_table	= of_match_ptr(ci_hdrc_usb2_of_match),
>  	},
>  };
>  
> 

-- 
Best Regards,
Peter Chen
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