Subject: [PATCHv5 10/20] phy: add support for USB cluster on the Armada 375 SoC

From: [email-masked] (Gregory CLEMENT)
Date: Wed, 14 May 2014 16:08:48 +0200

Hi Kishon,

Given the answers I provided to your concerns. I don't see any modification
to do to this driver. Do you agree?

If not which change is mandatory from your point of view?

Thanks,

Gregory

On 13/05/2014 11:41, Gregory CLEMENT wrote:
> On 13/05/2014 10:06, Gregory CLEMENT wrote:
>> On 13/05/2014 07:53, Kishon Vijay Abraham I wrote:
>>> Hi,
>>>
>>> On Sunday 11 May 2014 11:47 PM, Thomas Petazzoni wrote:
>>>> From: Gregory CLEMENT <[email-masked]>
>>>>
>>>> The Armada 375 SoC comes with an USB2 host and device controller and
>>>> an USB3 controller. The USB cluster control register allows to manage
>>>> common features of both USB controllers.
>>>>
>>>> This commit adds a driver integrated in the generic PHY framework to
>>>> control this USB cluster feature.
>>>>
>>>> Signed-off-by: Gregory CLEMENT <[email-masked]>
>>>> Signed-off-by: Thomas Petazzoni <[email-masked]>
>>>> ---
>>>>  drivers/phy/Kconfig              |   6 ++
>>>>  drivers/phy/Makefile             |   1 +
>>>>  drivers/phy/phy-armada375-usb2.c | 157 +++++++++++++++++++++++++++++++++++++++
>>>>  3 files changed, 164 insertions(+)
>>>>  create mode 100644 drivers/phy/phy-armada375-usb2.c
>>>>
>>>> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
>>>> index 3bb05f1..e63cf9d 100644
>>>> --- a/drivers/phy/Kconfig
>>>> +++ b/drivers/phy/Kconfig
>>>> @@ -15,6 +15,12 @@ config GENERIC_PHY
>>>>  	  phy users can obtain reference to the PHY. All the users of this
>>>>  	  framework should select this config.
>>>>  
>>>> +config ARMADA375_USBCLUSTER_PHY
>>>> +	def_bool y
>>>> +	depends on MACH_ARMADA_375 || COMPILE_TEST
>>>> +	depends on OF
>>>> +	select GENERIC_PHY
>>>> +
>>>>  config PHY_EXYNOS_MIPI_VIDEO
>>>>  	tristate "S5P/EXYNOS SoC series MIPI CSI-2/DSI PHY driver"
>>>>  	depends on HAS_IOMEM
>>>> diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
>>>> index 2faf78e..47d5a86 100644
>>>> --- a/drivers/phy/Makefile
>>>> +++ b/drivers/phy/Makefile
>>>> @@ -3,6 +3,7 @@
>>>>  #
>>>>  
>>>>  obj-$(CONFIG_GENERIC_PHY)		+= phy-core.o
>>>> +obj-$(CONFIG_ARMADA375_USBCLUSTER_PHY)	+= phy-armada375-usb2.o
>>>>  obj-$(CONFIG_BCM_KONA_USB2_PHY)		+= phy-bcm-kona-usb2.o
>>>>  obj-$(CONFIG_PHY_EXYNOS_DP_VIDEO)	+= phy-exynos-dp-video.o
>>>>  obj-$(CONFIG_PHY_EXYNOS_MIPI_VIDEO)	+= phy-exynos-mipi-video.o
>>>> diff --git a/drivers/phy/phy-armada375-usb2.c b/drivers/phy/phy-armada375-usb2.c
>>>> new file mode 100644
>>>> index 0000000..a6f746d
>>>> --- /dev/null
>>>> +++ b/drivers/phy/phy-armada375-usb2.c
>>>> @@ -0,0 +1,157 @@
>>>> +/*
>>>> + * USB cluster support for Armada 375 platform.
>>>> + *
>>>> + * Copyright (C) 2014 Marvell
>>>> + *
>>>> + * Gregory CLEMENT <[email-masked]>
>>>> + *
>>>> + * This file is licensed under the terms of the GNU General Public
>>>> + * License version 2 or later. This program is licensed "as is"
>>>> + * without any warranty of any kind, whether express or implied.
>>>> + *
>>>> + * Armada 375 comes with an USB2 host and device controller and an
>>>> + * USB3 controller. The USB cluster control register allows to manage
>>>> + * common features of both USB controllers.
>>>> + */
>>>> +
>>>> +#include <linux/init.h>
>>>> +#include <linux/io.h>
>>>> +#include <linux/kernel.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/of_address.h>
>>>> +#include <linux/phy/phy.h>
>>>> +#include <linux/platform_device.h>
>>>> +#include <linux/slab.h>
>>>> +
>>>> +#define USB2_PHY_CONFIG_DISABLE BIT(0)
>>>> +
>>>> +/* The USB cluster allows to choose between two PHYs */
>>>> +#define NB_PHY 2
>>>> +
>>>> +enum {
>>>> +	PHY_USB2 = 0,
>>>> +	PHY_USB3 = 1,
>>>> +};
>>>> +
>>>> +struct armada375_cluster_phy {
>>>> +	struct phy *phy;
>>>> +	void __iomem *reg;
>>>> +	bool enable;
>>>> +	bool use_usb3;
>>>> +};
>>>> +
>>>> +struct armada375_cluster_phy usb_cluster_phy[NB_PHY];
>>>> +
>>>> +static int armada375_usb_phy_init(struct phy *phy)
>>>> +{
>>>> +	struct armada375_cluster_phy *cluster_phy = phy_get_drvdata(phy);
>>>> +	u32 reg;
>>>
>>> This function should be protected since both your PHYs use this ops.
>>
>> Right
> 
> Actually only one PHY can access this register. See the probe function,
> cluster_phy->enable is only set to true for one PHY.
> 
>>
>>>> +
>>>> +	if (!cluster_phy->enable)
>>>> +		return -ENODEV;
>>>> +
>>>> +	reg = readl(cluster_phy->reg);
>>>> +	if (cluster_phy->use_usb3)
>>>> +		reg |= USB2_PHY_CONFIG_DISABLE;
>>>> +	else
>>>> +		reg &= ~USB2_PHY_CONFIG_DISABLE;
>>>> +	writel(reg, cluster_phy->reg);
>>>
>>> This is confusing since both your PHYs control the same bit?
> 
> Same here at the end the bit is accessed by only one PHY.
> 
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static struct phy_ops armada375_usb_phy_ops = {
>>>> +	.init = armada375_usb_phy_init,
>>>> +	.owner		= THIS_MODULE,
>>>> +};
>>>> +
>>>> +static struct phy *armada375_usb_phy_xlate(struct device *dev,
>>>> +					struct of_phandle_args *args)
>>>> +{
>>>> +	if (WARN_ON(args->args[0] >= NB_PHY))
>>>> +		return ERR_PTR(-ENODEV);
>>>> +
>>>> +	return usb_cluster_phy[args->args[0]].phy;
>>>> +}
>>>> +
>>>> +static int armada375_usb_phy_probe(struct platform_device *pdev)
>>>> +{
>>>> +	struct device *dev = &pdev->dev;
>>>> +	struct phy *phy;
>>>> +	struct phy_provider *phy_provider;
>>>> +	void __iomem *usb_cluster_base;
>>>> +	struct device_node *xhci_node;
>>>> +	struct resource *res;
>>>> +	int i;
>>>> +
>>>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>>> +	usb_cluster_base = devm_ioremap_resource(&pdev->dev, res);
>>>> +	if (!usb_cluster_base)
>>>> +		return -ENOMEM;
>>>> +
>>>> +	for (i = 0; i < NB_PHY; i++) {
>>>
>>> For devices which have multiple PHYs, each PHY should be modelled as the
>>> sub-node of the *PHY provider* device node.
>>
>> Actually it is the opposite the same PHY is shared between the EHCI
>> and the xHCI controllers. It is more a PHY muxer than a PHY itself.
>>
>> I had to create 2 logical PHYs because once the phy_init() is called
>> by a USB driver then the .init ops is not called anymore by the next
>> call to phy_init(). One of the goal of this is to disable a port for
>> the USB controller which can't use it due to the configuration of the
>> USB cluster.
>>
>> But I can see how to make this two "pseudo" PHYs sub-node of the *PHY
>> provider* device node. It shouldn't change the internal logic of this
>> driver.
> 
> I need to make a distinction when the PHY access by the xHCI or when
> it was access by the EHCI. If I create two new sub-node then I will
> also need to add a property to make this distinction. It seems a little
> overkill for the need.
> 
>>
>>
>>>> +		phy = devm_phy_create(dev, &armada375_usb_phy_ops, NULL);
>>>> +		if (IS_ERR(phy)) {
>>>> +			dev_err(dev, "failed to create PHY n%d\n", i);
>>>> +			return PTR_ERR(phy);
>>>> +		}
>>>> +
>>>> +		usb_cluster_phy[i].phy = phy;
>>>> +		usb_cluster_phy[i].reg = usb_cluster_base;
>>>> +		usb_cluster_phy[i].enable = false;
>>>> +		phy_set_drvdata(phy, &usb_cluster_phy[i]);
>>>> +	}
>>>> +
>>>> +	usb_cluster_phy[PHY_USB2].use_usb3 = false;
>>>> +	usb_cluster_phy[PHY_USB3].use_usb3 = true;
>>>> +
>>>> +	/*
>>>> +	 * We can't use the first usb2 unit and usb3 at the same time
>>>> +	 * to manage a USB2 device, so let's disable usb2 if usb3 is
>>>> +	 * selected. In this case the USB2 device will be managed by
>>>> +	 * the xhci controller.
>>>> +	 */
>>>> +
>>>> +	xhci_node = of_find_compatible_node(NULL, NULL,
>>>> +					"marvell,armada-375-xhci");
>>>
>>> huh.. that's too much binding between the controller and the PHY.
>>>
>>
>> That's why initially it was not part of the PHY framework.  The USB
>> cluster is really a part managing common feature between the USB
>> controllers which are part of the Armada 375 SoC.
>>
>> However the initial version was not really good, because this piece of
>> code was located in the mach- directory whereas we are trying to move
>> most of the files out of this directory now. The USB cluster is not a
>> real PHY as it is related to the PHY management this framework remains
>> the best place for it.
>>
>>>> +
>>>> +	if (xhci_node && of_device_is_available(xhci_node)) {
>>>> +		usb_cluster_phy[PHY_USB3].enable = true;
>>>> +	} else {
>>>> +		struct device_node *ehci_node;
>>>> +		ehci_node = of_find_compatible_node(NULL, NULL,
>>>> +					"marvell,orion-ehci");
>>>> +		if (ehci_node && of_device_is_available(ehci_node))
>>>> +			usb_cluster_phy[PHY_USB2].enable = true;
>>>> +		of_node_put(ehci_node);
>>>> +	}
>>>> +
>>>> +	of_node_put(xhci_node);
>>>> +
>>>> +	phy_provider = devm_of_phy_provider_register(&pdev->dev,
>>>> +						     armada375_usb_phy_xlate);
>>>> +	if (IS_ERR(phy_provider))
>>>> +		return PTR_ERR(phy_provider);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static const struct of_device_id of_usb_cluster_table[] = {
>>>> +	{ .compatible = "marvell,armada-375-usb-cluster", },
>>>> +	{ /* end of list */ },
>>>> +};
>>>> +MODULE_DEVICE_TABLE(of, of_usb_cluster_table);
>>>> +
>>>> +static struct platform_driver armada375_usb_phy_driver = {
>>>> +	.probe	= armada375_usb_phy_probe,
>>>> +	.driver = {
>>>> +		.of_match_table	= of_usb_cluster_table,
>>>> +		.name  = "armada-375-usb-cluster",
>>>> +		.owner = THIS_MODULE,
>>>> +	}
>>>> +};
>>>> +module_platform_driver(armada375_usb_phy_driver);
>>>> +
>>>> +MODULE_DESCRIPTION("Armada 375 USB cluster driver");
>>>> +MODULE_AUTHOR("Gregory CLEMENT <[email-masked]>");
>>>> +MODULE_LICENSE("GPL");
>>>
>>> GPL v2?
>>
>> No it is really GPL v2 or latter as written at the top of this file
>>
>>
>> Thanks,
>>
>> Gregory
>>
> 
> 

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com