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

From: [email-masked] (Hans de Goede)
Date: Tue, 11 Feb 2014 10:31:50 +0100

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.

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.

Regards,

Hans

> 
> 
> 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 },
>>
>