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

From: [email-masked] (Gregory CLEMENT)
Date: Tue, 13 May 2014 10:06:58 +0200

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

>> +
>> +	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?
>> +
>> +	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.

>> +		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