Subject: [PATCH v5 2/2] ehci-platform: Add support for clks and phy passed through devicetree

From: [email-masked] (Tony Prisk)
Date: Tue, 14 Jan 2014 17:12:35 +1300

On 14/01/14 11:45, 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.
>
> Signed-off-by: Hans de Goede <[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                   | 149 +++++++++++++++++----
>   5 files changed, 142 insertions(+), 60 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..fad10f3 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: ehci at 0x01c14000 {
> +	   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 7f30b71..5c4f892 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; priv->clks[clk] && clk < EHCI_MAX_CLKS; 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 clk, irq, err;
>   
>   	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;
> @@ -126,21 +211,25 @@ 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;
> -
> -	platform_set_drvdata(dev, hcd);
> +		goto err_power;
>   
>   	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;
>   }
> @@ -149,13 +238,19 @@ 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; priv->clks[clk] && clk < EHCI_MAX_CLKS; clk++)
> +		clk_put(priv->clks[clk]);
> +
> +	usb_put_hcd(hcd);
> +
>   	if (pdata == &ehci_platform_defaults)
>   		dev->dev.platform_data = NULL;
>   
> @@ -206,8 +301,10 @@ 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 },

You have removed the documentation for the via,vt8500-ehci and 
wm,prizm-ehci bindings (which in itself isn't really an issue), and left 
them in the driver (again, not an issue) - except now we have two 
bindings without any binding documentation?!?

I'm not sure where the 'wm,prizm-ehci' string came from (presumably me 
some time ago), but it isn't used and could be dropped.
All WonderMedia SoCs use the 'via,vt8500-ehci' - Doing a quick grep of 
arch/arm/boot/dts shows no usage of 'wm,prizm-ehci'.

Arguably, the dtsi files for the WonderMedia SoCs could be updated to 
include 'usb-ehci' as a second compatible string, and the 
'via,vt8500-ehci' could be dropped from the driver - but it does mean 
that old dts files won't work with the current kernel (and I think 
that's a no-no).

Regards
Tony P