Subject: [PATCH v9 2/4] ehci-platform: Add support for clks and phy passed through devicetree

From: [email-masked] (Roger Quadros)
Date: Tue, 11 Feb 2014 12:00:38 +0200

On 02/11/2014 11:31 AM, Hans de Goede wrote:
> Hi,
> 
> On 02/11/2014 10:12 AM, Roger Quadros wrote:
>> Hi Hans,
>>
>> On 02/07/2014 05:36 PM, Hans de Goede wrote:
>>> Currently ehci-platform is only used in combination with devicetree when used
>>> with some Via socs. By extending it to (optionally) get clks and a phy from
>>> devicetree, and enabling / disabling those on power_on / off, it can be used
>>> more generically. Specifically after this commit it can be used for the
>>> ehci controller on Allwinner sunxi SoCs.
>>>
>>> Since ehci-platform is intended to handle any generic enough non pci ehci
>>> device, add a "usb-ehci" compatibility string.
>>>
>>> There already is a usb-ehci device-tree bindings document, update this
>>> with clks and phy bindings info.
>>>
>>> Although actually quite generic so far the via,vt8500 compatibilty string
>>> had its own bindings document. Somehow we even ended up with 2 of them. Since
>>> these provide no extra information over the generic usb-ehci documentation,
>>> this patch removes them.
>>>
>>> The ehci-ppc-of.c driver also claims the usb-ehci compatibility string,
>>> even though it mostly is ibm,usb-ehci-440epx specific. ehci-platform.c is
>>> not needed on ppc platforms, so add a !PPC_OF dependency to it to avoid
>>> 2 drivers claiming the same compatibility string getting build on ppc.
>>>
>>
>> This breaks all OMAP platforms on linux-next for the exact same reason. see [1].
>>
>> ./arch/arm/boot/dts/omap4.dtsi:				compatible = "ti,ehci-omap", "usb-ehci";
>> ./arch/arm/boot/dts/omap3.dtsi:				compatible = "ti,ehci-omap", "usb-ehci";
>> ./arch/arm/boot/dts/omap5.dtsi:				compatible = "ti,ehci-omap", "usb-ehci";
> 
> That should not be the case, the driver core should try to find a driver matching
> the compatibility string from left to right, or in other words from most specific
> to least specific. This is part of the whole devicetree design.
> 
> So as long as the driver claiming "ti,ehci-omap" is available at probe time that
> one should get used and things should work fine. Now if ehci-platform is built-in
> and ehci-omap is a module, then I guess one could see the described breakage.
> 
> If the driver is built-in and things are not working, then we will need to do some
> debugging as to why the left to right matching is not working as expected.

Both ehci_platform and ehci_omap were built-in and still the ehci_platform driver got
probe preference. So it looks like the left to right compatible list priority probing
feature doesn't work.

> 
> I must admit I'm not sure what happens if both are a module, the kernel direct
> module load will likely fail due to lack of a rootfs at that point, and then
> the module will later get loaded by udev I assume, at which point there are no
> loading ordering guarantees.
> 
> The easiest solution to ensure that "ti,ehci-omap" is available at probe time
> (if enabled) seems to be to change USB_EHCI_HCD_OMAP to a boolean.

That is a limitation I don't like to have for USB_EHCI_HCD_OMAP.

cheers,
-roger

> 
> 
>>
>>
>> The other platforms that claim compatibility with "usb-ehci" are
>>
>> ARM
>> ./arch/arm/boot/dts/tegra30.dtsi:		compatible = "nvidia,tegra30-ehci", "usb-ehci";
>> ./arch/arm/boot/dts/tegra20.dtsi:		compatible = "nvidia,tegra20-ehci", "usb-ehci";
>> ./arch/arm/boot/dts/spear600.dtsi:			compatible = "st,spear600-ehci", "usb-ehci";
>>
>> ./arch/arm/boot/dts/spear3xx.dtsi:			compatible = "st,spear600-ehci", "usb-ehci";
>> ./arch/arm/boot/dts/sama5d3.dtsi:			compatible = "atmel,at91sam9g45-ehci", "usb-ehci";
>> ./arch/arm/boot/dts/at91sam9g45.dtsi:			compatible = "atmel,at91sam9g45-ehci", "usb-ehci";
>> ./arch/arm/boot/dts/spear13xx.dtsi:			compatible = "st,spear600-ehci", "usb-ehci";
>> ./arch/arm/boot/dts/at91sam9x5.dtsi:			compatible = "atmel,at91sam9g45-ehci", "usb-ehci";
>> ./arch/arm/boot/dts/tegra114.dtsi:		compatible = "nvidia,tegra30-ehci", "usb-ehci";
>>
>>
>> MIPS
>> ./arch/mips/cavium-octeon/octeon_68xx.dts:				compatible = "cavium,octeon-6335-ehci","usb-ehci";
>> ./arch/mips/cavium-octeon/octeon_3xxx.dts:				compatible = "cavium,octeon-6335-ehci","usb-ehci";
>>
>> Do we know that we don't break these platforms as well?
>>
>> cheers,
>> -roger
>>
>> [1] - http://marc.info/?l=linux-usb&m=139204800102167&w=2
>>
>>> Signed-off-by: Hans de Goede <[email-masked]>
>>> Acked-by: Alan Stern <[email-masked]>
>>> ---
>>>  Documentation/devicetree/bindings/usb/usb-ehci.txt |  25 +++-
>>>  .../devicetree/bindings/usb/via,vt8500-ehci.txt    |  15 ---
>>>  .../devicetree/bindings/usb/vt8500-ehci.txt        |  12 --
>>>  drivers/usb/host/Kconfig                           |   1 +
>>>  drivers/usb/host/ehci-platform.c                   | 147 +++++++++++++++++----
>>>  5 files changed, 142 insertions(+), 58 deletions(-)
>>>  delete mode 100644 Documentation/devicetree/bindings/usb/via,vt8500-ehci.txt
>>>  delete mode 100644 Documentation/devicetree/bindings/usb/vt8500-ehci.txt
>>>
>>> diff --git a/Documentation/devicetree/bindings/usb/usb-ehci.txt b/Documentation/devicetree/bindings/usb/usb-ehci.txt
>>> index fa18612..2c1aeeb 100644
>>> --- a/Documentation/devicetree/bindings/usb/usb-ehci.txt
>>> +++ b/Documentation/devicetree/bindings/usb/usb-ehci.txt
>>> @@ -7,13 +7,14 @@ Required properties:
>>>      (debug-port or other) can be also specified here, but only after
>>>      definition of standard EHCI registers.
>>>    - interrupts : one EHCI interrupt should be described here.
>>> -If device registers are implemented in big endian mode, the device
>>> -node should have "big-endian-regs" property.
>>> -If controller implementation operates with big endian descriptors,
>>> -"big-endian-desc" property should be specified.
>>> -If both big endian registers and descriptors are used by the controller
>>> -implementation, "big-endian" property can be specified instead of having
>>> -both "big-endian-regs" and "big-endian-desc".
>>> +
>>> +Optional properties:
>>> + - big-endian-regs : boolean, set this for hcds with big-endian registers
>>> + - big-endian-desc : boolean, set this for hcds with big-endian descriptors
>>> + - big-endian : boolean, for hcds with big-endian-regs + big-endian-desc
>>> + - clocks : a list of phandle + clock specifier pairs
>>> + - phys : phandle + phy specifier pair
>>> + - phy-names : "usb"
>>>  
>>>  Example (Sequoia 440EPx):
>>>      ehci at e0000300 {
>>> @@ -23,3 +24,13 @@ Example (Sequoia 440EPx):
>>>  	   reg = <0 e0000300 90 0 e0000390 70>;
>>>  	   big-endian;
>>>     };
>>> +
>>> +Example (Allwinner sun4i A10 SoC):
>>> +   ehci0: usb at 01c14000 {
>>> +	   compatible = "allwinner,sun4i-a10-ehci", "usb-ehci";
>>> +	   reg = <0x01c14000 0x100>;
>>> +	   interrupts = <39>;
>>> +	   clocks = <&ahb_gates 1>;
>>> +	   phys = <&usbphy 1>;
>>> +	   phy-names = "usb";
>>> +   };
>>> diff --git a/Documentation/devicetree/bindings/usb/via,vt8500-ehci.txt b/Documentation/devicetree/bindings/usb/via,vt8500-ehci.txt
>>> deleted file mode 100644
>>> index 17b3ad1..0000000
>>> --- a/Documentation/devicetree/bindings/usb/via,vt8500-ehci.txt
>>> +++ /dev/null
>>> @@ -1,15 +0,0 @@
>>> -VIA/Wondermedia VT8500 EHCI Controller
>>> ------------------------------------------------------
>>> -
>>> -Required properties:
>>> -- compatible : "via,vt8500-ehci"
>>> -- reg : Should contain 1 register ranges(address and length)
>>> -- interrupts : ehci controller interrupt
>>> -
>>> -Example:
>>> -
>>> -	ehci at d8007900 {
>>> -		compatible = "via,vt8500-ehci";
>>> -		reg = <0xd8007900 0x200>;
>>> -		interrupts = <43>;
>>> -	};
>>> diff --git a/Documentation/devicetree/bindings/usb/vt8500-ehci.txt b/Documentation/devicetree/bindings/usb/vt8500-ehci.txt
>>> deleted file mode 100644
>>> index 5fb8fd6..0000000
>>> --- a/Documentation/devicetree/bindings/usb/vt8500-ehci.txt
>>> +++ /dev/null
>>> @@ -1,12 +0,0 @@
>>> -VIA VT8500 and Wondermedia WM8xxx SoC USB controllers.
>>> -
>>> -Required properties:
>>> - - compatible: Should be "via,vt8500-ehci" or "wm,prizm-ehci".
>>> - - reg: Address range of the ehci registers. size should be 0x200
>>> - - interrupts: Should contain the ehci interrupt.
>>> -
>>> -usb: ehci at D8007100 {
>>> -	compatible = "wm,prizm-ehci", "usb-ehci";
>>> -	reg = <0xD8007100 0x200>;
>>> -	interrupts = <1>;
>>> -};
>>> diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
>>> index a9707da..e28cbe0 100644
>>> --- a/drivers/usb/host/Kconfig
>>> +++ b/drivers/usb/host/Kconfig
>>> @@ -255,6 +255,7 @@ config USB_EHCI_ATH79
>>>  
>>>  config USB_EHCI_HCD_PLATFORM
>>>  	tristate "Generic EHCI driver for a platform device"
>>> +	depends on !PPC_OF
>>>  	default n
>>>  	---help---
>>>  	  Adds an EHCI host driver for a generic platform device, which
>>> diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c
>>> index 01536cf..5ebd0b7 100644
>>> --- a/drivers/usb/host/ehci-platform.c
>>> +++ b/drivers/usb/host/ehci-platform.c
>>> @@ -3,6 +3,7 @@
>>>   *
>>>   * Copyright 2007 Steven Brown <[email-masked]>
>>>   * Copyright 2010-2012 Hauke Mehrtens <[email-masked]>
>>> + * Copyright 2014 Hans de Goede <[email-masked]>
>>>   *
>>>   * Derived from the ohci-ssb driver
>>>   * Copyright 2007 Michael Buesch <[email-masked]>
>>> @@ -18,6 +19,7 @@
>>>   *
>>>   * Licensed under the GNU/GPL. See COPYING for details.
>>>   */
>>> +#include <linux/clk.h>
>>>  #include <linux/dma-mapping.h>
>>>  #include <linux/err.h>
>>>  #include <linux/kernel.h>
>>> @@ -25,6 +27,7 @@
>>>  #include <linux/io.h>
>>>  #include <linux/module.h>
>>>  #include <linux/of.h>
>>> +#include <linux/phy/phy.h>
>>>  #include <linux/platform_device.h>
>>>  #include <linux/usb.h>
>>>  #include <linux/usb/hcd.h>
>>> @@ -33,6 +36,13 @@
>>>  #include "ehci.h"
>>>  
>>>  #define DRIVER_DESC "EHCI generic platform driver"
>>> +#define EHCI_MAX_CLKS 3
>>> +#define hcd_to_ehci_priv(h) ((struct ehci_platform_priv *)hcd_to_ehci(h)->priv)
>>> +
>>> +struct ehci_platform_priv {
>>> +	struct clk *clks[EHCI_MAX_CLKS];
>>> +	struct phy *phy;
>>> +};
>>>  
>>>  static const char hcd_name[] = "ehci-platform";
>>>  
>>> @@ -64,38 +74,90 @@ static int ehci_platform_reset(struct usb_hcd *hcd)
>>>  	return 0;
>>>  }
>>>  
>>> +static int ehci_platform_power_on(struct platform_device *dev)
>>> +{
>>> +	struct usb_hcd *hcd = platform_get_drvdata(dev);
>>> +	struct ehci_platform_priv *priv = hcd_to_ehci_priv(hcd);
>>> +	int clk, ret;
>>> +
>>> +	for (clk = 0; clk < EHCI_MAX_CLKS && priv->clks[clk]; clk++) {
>>> +		ret = clk_prepare_enable(priv->clks[clk]);
>>> +		if (ret)
>>> +			goto err_disable_clks;
>>> +	}
>>> +
>>> +	if (priv->phy) {
>>> +		ret = phy_init(priv->phy);
>>> +		if (ret)
>>> +			goto err_disable_clks;
>>> +
>>> +		ret = phy_power_on(priv->phy);
>>> +		if (ret)
>>> +			goto err_exit_phy;
>>> +	}
>>> +
>>> +	return 0;
>>> +
>>> +err_exit_phy:
>>> +	phy_exit(priv->phy);
>>> +err_disable_clks:
>>> +	while (--clk >= 0)
>>> +		clk_disable_unprepare(priv->clks[clk]);
>>> +
>>> +	return ret;
>>> +}
>>> +
>>> +static void ehci_platform_power_off(struct platform_device *dev)
>>> +{
>>> +	struct usb_hcd *hcd = platform_get_drvdata(dev);
>>> +	struct ehci_platform_priv *priv = hcd_to_ehci_priv(hcd);
>>> +	int clk;
>>> +
>>> +	if (priv->phy) {
>>> +		phy_power_off(priv->phy);
>>> +		phy_exit(priv->phy);
>>> +	}
>>> +
>>> +	for (clk = EHCI_MAX_CLKS - 1; clk >= 0; clk--)
>>> +		if (priv->clks[clk])
>>> +			clk_disable_unprepare(priv->clks[clk]);
>>> +}
>>> +
>>>  static struct hc_driver __read_mostly ehci_platform_hc_driver;
>>>  
>>>  static const struct ehci_driver_overrides platform_overrides __initconst = {
>>> -	.reset =	ehci_platform_reset,
>>> +	.reset =		ehci_platform_reset,
>>> +	.extra_priv_size =	sizeof(struct ehci_platform_priv),
>>>  };
>>>  
>>> -static struct usb_ehci_pdata ehci_platform_defaults;
>>> +static struct usb_ehci_pdata ehci_platform_defaults = {
>>> +	.power_on =		ehci_platform_power_on,
>>> +	.power_suspend =	ehci_platform_power_off,
>>> +	.power_off =		ehci_platform_power_off,
>>> +};
>>>  
>>>  static int ehci_platform_probe(struct platform_device *dev)
>>>  {
>>>  	struct usb_hcd *hcd;
>>>  	struct resource *res_mem;
>>> -	struct usb_ehci_pdata *pdata;
>>> -	int irq;
>>> -	int err;
>>> +	struct usb_ehci_pdata *pdata = dev_get_platdata(&dev->dev);
>>> +	struct ehci_platform_priv *priv;
>>> +	int err, irq, clk = 0;
>>>  
>>>  	if (usb_disabled())
>>>  		return -ENODEV;
>>>  
>>>  	/*
>>> -	 * use reasonable defaults so platforms don't have to provide these.
>>> -	 * with DT probing on ARM, none of these are set.
>>> +	 * Use reasonable defaults so platforms don't have to provide these
>>> +	 * with DT probing on ARM.
>>>  	 */
>>> -	if (!dev_get_platdata(&dev->dev))
>>> -		dev->dev.platform_data = &ehci_platform_defaults;
>>> +	if (!pdata)
>>> +		pdata = &ehci_platform_defaults;
>>>  
>>>  	err = dma_coerce_mask_and_coherent(&dev->dev, DMA_BIT_MASK(32));
>>>  	if (err)
>>>  		return err;
>>>  
>>> -	pdata = dev_get_platdata(&dev->dev);
>>> -
>>>  	irq = platform_get_irq(dev, 0);
>>>  	if (irq < 0) {
>>>  		dev_err(&dev->dev, "no irq provided");
>>> @@ -107,17 +169,40 @@ static int ehci_platform_probe(struct platform_device *dev)
>>>  		return -ENXIO;
>>>  	}
>>>  
>>> +	hcd = usb_create_hcd(&ehci_platform_hc_driver, &dev->dev,
>>> +			     dev_name(&dev->dev));
>>> +	if (!hcd)
>>> +		return -ENOMEM;
>>> +
>>> +	platform_set_drvdata(dev, hcd);
>>> +	dev->dev.platform_data = pdata;
>>> +	priv = hcd_to_ehci_priv(hcd);
>>> +
>>> +	if (pdata == &ehci_platform_defaults && dev->dev.of_node) {
>>> +		priv->phy = devm_phy_get(&dev->dev, "usb");
>>> +		if (IS_ERR(priv->phy)) {
>>> +			err = PTR_ERR(priv->phy);
>>> +			if (err == -EPROBE_DEFER)
>>> +				goto err_put_hcd;
>>> +			priv->phy = NULL;
>>> +		}
>>> +
>>> +		for (clk = 0; clk < EHCI_MAX_CLKS; clk++) {
>>> +			priv->clks[clk] = of_clk_get(dev->dev.of_node, clk);
>>> +			if (IS_ERR(priv->clks[clk])) {
>>> +				err = PTR_ERR(priv->clks[clk]);
>>> +				if (err == -EPROBE_DEFER)
>>> +					goto err_put_clks;
>>> +				priv->clks[clk] = NULL;
>>> +				break;
>>> +			}
>>> +		}
>>> +	}
>>> +
>>>  	if (pdata->power_on) {
>>>  		err = pdata->power_on(dev);
>>>  		if (err < 0)
>>> -			return err;
>>> -	}
>>> -
>>> -	hcd = usb_create_hcd(&ehci_platform_hc_driver, &dev->dev,
>>> -			     dev_name(&dev->dev));
>>> -	if (!hcd) {
>>> -		err = -ENOMEM;
>>> -		goto err_power;
>>> +			goto err_put_clks;
>>>  	}
>>>  
>>>  	hcd->rsrc_start = res_mem->start;
>>> @@ -126,22 +211,28 @@ static int ehci_platform_probe(struct platform_device *dev)
>>>  	hcd->regs = devm_ioremap_resource(&dev->dev, res_mem);
>>>  	if (IS_ERR(hcd->regs)) {
>>>  		err = PTR_ERR(hcd->regs);
>>> -		goto err_put_hcd;
>>> +		goto err_power;
>>>  	}
>>>  	err = usb_add_hcd(hcd, irq, IRQF_SHARED);
>>>  	if (err)
>>> -		goto err_put_hcd;
>>> +		goto err_power;
>>>  
>>>  	device_wakeup_enable(hcd->self.controller);
>>>  	platform_set_drvdata(dev, hcd);
>>>  
>>>  	return err;
>>>  
>>> -err_put_hcd:
>>> -	usb_put_hcd(hcd);
>>>  err_power:
>>>  	if (pdata->power_off)
>>>  		pdata->power_off(dev);
>>> +err_put_clks:
>>> +	while (--clk >= 0)
>>> +		clk_put(priv->clks[clk]);
>>> +err_put_hcd:
>>> +	if (pdata == &ehci_platform_defaults)
>>> +		dev->dev.platform_data = NULL;
>>> +
>>> +	usb_put_hcd(hcd);
>>>  
>>>  	return err;
>>>  }
>>> @@ -150,13 +241,19 @@ static int ehci_platform_remove(struct platform_device *dev)
>>>  {
>>>  	struct usb_hcd *hcd = platform_get_drvdata(dev);
>>>  	struct usb_ehci_pdata *pdata = dev_get_platdata(&dev->dev);
>>> +	struct ehci_platform_priv *priv = hcd_to_ehci_priv(hcd);
>>> +	int clk;
>>>  
>>>  	usb_remove_hcd(hcd);
>>> -	usb_put_hcd(hcd);
>>>  
>>>  	if (pdata->power_off)
>>>  		pdata->power_off(dev);
>>>  
>>> +	for (clk = 0; clk < EHCI_MAX_CLKS && priv->clks[clk]; clk++)
>>> +		clk_put(priv->clks[clk]);
>>> +
>>> +	usb_put_hcd(hcd);
>>> +
>>>  	if (pdata == &ehci_platform_defaults)
>>>  		dev->dev.platform_data = NULL;
>>>  
>>> @@ -207,8 +304,10 @@ static int ehci_platform_resume(struct device *dev)
>>>  static const struct of_device_id vt8500_ehci_ids[] = {
>>>  	{ .compatible = "via,vt8500-ehci", },
>>>  	{ .compatible = "wm,prizm-ehci", },
>>> +	{ .compatible = "usb-ehci", },
>>>  	{}
>>>  };
>>> +MODULE_DEVICE_TABLE(of, vt8500_ehci_ids);
>>>  
>>>  static const struct platform_device_id ehci_platform_table[] = {
>>>  	{ "ehci-platform", 0 },
>>>
>>