Re: [PATCH 12/12] USB: chipidea: add imx usbmisc support

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Sascha & Shawn, Felipe & Alex,

What's your opinion where I put this driver? The usbmisc drivers is
SoC specific and provide callbacks to ci13xxx_imx driver at runtime.

- How to organize the driver
This patch is designed to put all per-soc driver in one file. But
I plan to put it in discrete files.

- Where to put it
  Option 1: arch/arm/mach-imx/ehci-imxXXX.c
  Option 2: drivers/usb/chipidea/imx/ , yes, we may need a folder.
  Both is fine for me.

On Fri, Jul 13, 2012 at 04:14:27PM +0200, Marc Kleine-Budde wrote:
> On 07/13/2012 04:02 PM, Richard Zhao wrote:
> > On Fri, Jul 13, 2012 at 02:25:45PM +0200, Michael Grzeschik wrote:
> >> On Thu, Jul 12, 2012 at 03:01:52PM +0800, Richard Zhao wrote:
> >>> i.MX usb controllers shares non-core registers, which may include
> >>> SoC specific controls. We take it as a usbmisc device and usbmisc
> >>> driver export functions needed by ci13xxx_imx driver.
> >>
> >> So this is SoC and not chipidea specific and should not be sorted into
> >> this subdir.
> > Yes, but it's usb specific and serve chipidea usb IP.
> 
> I don't care where this code is located.
I need maintainers' instruction here. :)
> 
> >>> For example, Sabrelite board has bad over-current design, we can
> >>> usbmisc to disable over-current detect.
> >>
> >> This driver layout is also reflected in:
> >>
> >> arch/arm/mach-imx/ehci-imx*.c
> > It sounds sensible, but I'm not quite sure. I saw drivers are moving
> > out of there, event it's SoC specific, for example, clk, pinmux. And
> > the non-core registers might not only be setup onetime on boot, but
> > be called at runtime by usb driver. For now, it's set once.
> >>
> >> You should use these existing mx*_initialize_usb_hw functions to avoid
> >> code duplication
> 
> > I can not see what duplication it can avoid.
> 
> We want to use the chipidea driver for the other imx, too. We already
> have existing code for the non-DT case in arch/arm/mach-imx/ehci-imx*.c.
> So we need to glue these functions to the DT or duplicate the code,
> which is to be avoided.
The existing code is too simple. ci13xxx_imx may call them at runtime.
> 
> >> and add your mx6_initialize_usb_hw routine for mx6 there.
> > Maybe.
> 
> Or at least next to the other imx usb-misc code (wherever that will end up).
> 
> >> This devicetree based glue code in this file can be reused to
> >> call the right mx*_initialize_usb_hw by the compatible.
> > The glue code makes it more like a normal driver. Doesn't it?
> >>
> >> We already have common flags available like i.e. MXC_EHCI_POWER_PINS_ENABLED
> >> which is currently used to disable overcurrent detection.
> > The flags may be replace with properties in DT bindings.
> 
> Yes, write some code that extracts these flags from the DT and then
> calls the existing code (for the existing imx platforms).
> 
> >>> Signed-off-by: Richard Zhao <richard.zhao@xxxxxxxxxxxxx>
> >>> ---
> >>>  .../devicetree/bindings/usb/imx-usbmisc.txt        |   15 ++
> >>>  drivers/usb/chipidea/Makefile                      |    2 +-
> >>>  drivers/usb/chipidea/ci13xxx_imx.c                 |    4 +
> >>>  drivers/usb/chipidea/imx_usbmisc.c                 |  144 ++++++++++++++++++++
> >>>  4 files changed, 164 insertions(+), 1 deletion(-)
> >>>  create mode 100644 Documentation/devicetree/bindings/usb/imx-usbmisc.txt
> >>>  create mode 100644 drivers/usb/chipidea/imx_usbmisc.c
> >>>
> >>> diff --git a/Documentation/devicetree/bindings/usb/imx-usbmisc.txt b/Documentation/devicetree/bindings/usb/imx-usbmisc.txt
> >>> new file mode 100644
> >>> index 0000000..09f01ca
> >>> --- /dev/null
> >>> +++ b/Documentation/devicetree/bindings/usb/imx-usbmisc.txt
> >>> @@ -0,0 +1,15 @@
> >>> +* Freescale i.MX non-core registers
> >>> +
> >>> +Required properties:
> >>> +- compatible: Should be "fsl,imx6q-usbmisc"
> >>> +- reg: Should contain registers location and length
> >>> +
> >>> +Optional properties:
> >>> +- fsl,disable-over-current: disable over current detect
> >>> +
> >>> +Examples:
> >>> +usbmisc@02184800 {
> >>> +	compatible = "fsl,imx6q-usbmisc";
> >>> +	reg = <0x02184800 0x200>;
> >>> +	fsl,disable-over-current;
> >>> +};
> >>> diff --git a/drivers/usb/chipidea/Makefile b/drivers/usb/chipidea/Makefile
> >>> index 3f56b76..46fc31c 100644
> >>> --- a/drivers/usb/chipidea/Makefile
> >>> +++ b/drivers/usb/chipidea/Makefile
> >>> @@ -17,5 +17,5 @@ ifneq ($(CONFIG_PCI),)
> >>>  endif
> >>>  
> >>>  ifneq ($(CONFIG_OF_DEVICE),)
> >>> -	obj-$(CONFIG_USB_CHIPIDEA)	+= ci13xxx_imx.o
> >>> +	obj-$(CONFIG_USB_CHIPIDEA)	+= ci13xxx_imx.o imx_usbmisc.o
> >>>  endif
> >>> diff --git a/drivers/usb/chipidea/ci13xxx_imx.c b/drivers/usb/chipidea/ci13xxx_imx.c
> >>> index b3173d8..dd7f3a3 100644
> >>> --- a/drivers/usb/chipidea/ci13xxx_imx.c
> >>> +++ b/drivers/usb/chipidea/ci13xxx_imx.c
> >>> @@ -24,6 +24,8 @@
> >>>  
> >>>  #include "ci.h"
> >>>  
> >>> +int imx_usbmisc_init(struct device *usbdev);
> >>> +
> >>>  #define pdev_to_phy(pdev) \
> >>>  	((struct usb_phy *)platform_get_drvdata(pdev))
> >>>  #define ci_to_imx_data(ci) \
> >>> @@ -142,6 +144,8 @@ static int __devinit ci13xxx_imx_probe(struct platform_device *pdev)
> >>>  		dma_set_coherent_mask(&pdev->dev, *pdev->dev.dma_mask);
> >>>  	}
> >>>  
> >>> +	imx_usbmisc_init(&pdev->dev);
> >>> +
> >>>  	platform_set_drvdata(pdev, data);
> >>>  
> >>>  	plat_ci = ci13xxx_add_device(&pdev->dev,
> >>> diff --git a/drivers/usb/chipidea/imx_usbmisc.c b/drivers/usb/chipidea/imx_usbmisc.c
> >>> new file mode 100644
> >>> index 0000000..33a8ec0
> >>> --- /dev/null
> >>> +++ b/drivers/usb/chipidea/imx_usbmisc.c
> >>> @@ -0,0 +1,144 @@
> >>> +/*
> >>> + * Copyright 2012 Freescale Semiconductor, Inc.
> >>> + *
> >>> + * The code contained herein is licensed under the GNU General Public
> >>> + * License. You may obtain a copy of the GNU General Public License
> >>> + * Version 2 or later at the following locations:
> >>> + *
> >>> + * http://www.opensource.org/licenses/gpl-license.html
> >>> + * http://www.gnu.org/copyleft/gpl.html
> >>> + */
> >>> +
> >>> +#include <linux/module.h>
> >>> +#include <linux/of_platform.h>
> >>> +#include <linux/clk.h>
> >>> +#include <linux/err.h>
> >>> +#include <asm/io.h>
> >>> +
> >>> +struct usbmisc;
> >>> +
> >>> +struct soc_data {
> >>> +	int (*init) (struct usbmisc *usbmisc, int id);
> >>> +	void (*exit) (struct usbmisc *usbmisc, int id);
> >>> +};
> >>> +
> >>> +struct usbmisc {
> >>> +	struct soc_data *soc_data;
> >>> +	void __iomem *base;
> >>> +	struct clk *clk;
> >>> +
> >>> +	int dis_oc:1;
> >>> +};
> >>> +
> >>> +/* Since we only have one usbmisc device at runtime, we global variables */
> >>> +static struct usbmisc *usbmisc;
> >>
> >> Global variable?
> > Yes. we only have one usbmisc.
> >>
> >>> +
> >>> +static int imx6q_usbmisc_init(struct usbmisc *usbmisc, int id)
> >>
> >> What is initialized here? How about "preconfigure"?
> >> Even better is to reuse mx*_initialize_usb_hw here.
> > It's used to call by ci13xxx_imx driver.
> >>
> >>> +{
> >>> +	u32 reg;
> >>> +
> >>> +	if (usbmisc->dis_oc) {
> >>> +		reg = readl_relaxed(usbmisc->base + id * 4);
> >>> +		writel_relaxed(reg | (1 << 7), usbmisc->base + id * 4);
> >>
> >> #define IMX6_OTG_CTRL_USBMISC        1 << 7
> > yes.
> >>
> >>> +	}
> >>> +
> >>> +	return 0;
> >>> +}
> >>> +
> >>> +static struct soc_data imx6q_data = {
> >>> +	.init = imx6q_usbmisc_init,
> >>> +};
> >>> +
> >>> +
> >>> +static const struct of_device_id imx_usbmisc_dt_ids[] = {
> >>> +	{ .compatible = "fsl,imx6q-usbmisc", .data = &imx6q_data },
> >>
> >>         something like this:
> >> 	{ .compatible = "fsl,imx6q-usbmisc", .data = &mx6_initialize_usb_hw },
> > It's designed not only used when initialization.
> >>
> >>> +	{ /* sentinel */ }
> >>> +};
> >>> +
> >>> +static int __devinit imx_usbmisc_probe(struct platform_device *pdev)
> >>> +{
> >>> +	struct resource	*res;
> >>> +	struct usbmisc *data;
> >>> +	const struct of_device_id *of_id =
> >>> +			of_match_device(imx_usbmisc_dt_ids, &pdev->dev);
> >>> +
> >>> +	int ret;
> >>> +
> >>> +	if (usbmisc)
> >>> +		return -EBUSY;
> >>> +
> >>> +	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> >>> +	if (!data)
> >>> +		return -ENOMEM;
> >>> +
> >>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >>> +	data->base = devm_request_and_ioremap(&pdev->dev, res);
> >>> +	if (!data->base)
> >>> +		return -EADDRNOTAVAIL;
> >>> +
> >>> +	data->clk = devm_clk_get(&pdev->dev, NULL);
> >>> +	if (IS_ERR(data->clk)) {
> >>> +		dev_err(&pdev->dev,
> >>> +			"failed to get clock, err=%ld\n", PTR_ERR(data->clk));
> >>> +		return PTR_ERR(data->clk);
> >>> +	}
> >>> +
> >>> +	ret = clk_prepare_enable(data->clk);
> >>> +	if (!ret) {
> >>
> >> Better:
> >>         if (ret)
> >>                 return ret;
> > To me, it does not make much difference.
> 
> Not the the compiler, but IMHO the common pattern in the kernel is:
> 
> ret = sensible_init();
> if (ret)
> 	return ret;
> 
> do_work();
> 
> >>
> >>> +		if (of_find_property(pdev->dev.of_node,
> >>> +			"fsl,disable-over-current", NULL))
> >>> +			data->dis_oc = 1;
> >>> +		data->soc_data = of_id->data;
> >>> +		usbmisc = data;
> >>> +	}
> >>> +
> >>         if (of_find_property(pdev->dev.of_node,
> >>         ...
> >>
> >>> +	return ret;
> >>> +}
> >>> +
> >>> +static int __devexit imx_usbmisc_remove(struct platform_device *pdev)
> >>> +{
> >>> +	clk_disable_unprepare(usbmisc->clk);
> >>> +	return 0;
> >>> +}
> >>> +
> >>> +static struct platform_driver imx_usbmisc_driver = {
> >>> +	.probe = imx_usbmisc_probe,
> >>> +	.remove = __devexit_p(imx_usbmisc_remove),
> >>> +	.driver = {
> >>> +		.name = "imx_usbmisc",
> >>> +		.owner = THIS_MODULE,
> >>> +		.of_match_table = imx_usbmisc_dt_ids,
> >>> +	 },
> >>> +};
> >>> +
> >>> +int imx_usbmisc_init(struct device *usbdev)
> >>> +{
> >>> +	struct device_node *np = usbdev->of_node;
> >>> +	int ret;
> >>> +
> >>> +	if (!usbmisc)
> >>> +		return 0;
> >>> +
> >>> +	ret = of_alias_get_id(np, "usb");
> >>> +	if (ret < 0) {
> >>> +		dev_err(usbdev, "failed to get alias id, errno %d\n", ret);
> >>> +		return ret;
> >>> +	}
> >>> +
> >>> +	return usbmisc->soc_data->init(usbmisc, ret);
> >>> +}
> >>> +EXPORT_SYMBOL_GPL(imx_usbmisc_init);
> >>
> >> EXPORT_SYMBOL is only needed because it is
> >> compliled as an extra kernel module.
> > ci13xxx_imx may be module.
> 
> Why make the usb_misc an independent module, why not just link it into
> the ci13xxx_imx.ko
Yes

Thanks
Richard
> 
> Marc
> -- 
> Pengutronix e.K.                  | Marc Kleine-Budde           |
> Industrial Linux Solutions        | Phone: +49-231-2826-924     |
> Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
> Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |
> 



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