linux-kernel - Re: [PATCH 4/8] ARM: mvebu: Add USB3 UTMI support

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Message-ID: <53511865.701@free-electrons.com>
Date:	Fri, 18 Apr 2014 14:19:49 +0200
From:	Gregory CLEMENT <gregory.clement@...e-electrons.com>
To:	Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
CC:	Mathias Nyman <mathias.nyman@...el.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	Jason Cooper <jason@...edaemon.net>,
	Andrew Lunn <andrew@...n.ch>,
	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
	Ezequiel Garcia <ezequiel.garcia@...e-electrons.com>,
	linux-arm-kernel@...ts.infradead.org,
	Lior Amsalem <alior@...vell.com>,
	Tawfik Bayouk <tawfik@...vell.com>,
	Nadav Haklai <nadavh@...vell.com>,
	Grant Likely <grant.likely@...aro.org>,
	Rob Herring <robh+dt@...nel.org>, devicetree@...r.kernel.org
Subject: Re: [PATCH 4/8] ARM: mvebu: Add USB3 UTMI support

Hi Sebastian,

On 18/04/2014 13:19, Sebastian Hesselbarth wrote:
> On 04/18/2014 12:22 PM, Gregory CLEMENT wrote:
>> The usb3-utmi registers allow to configure the internal USB PHY of the
>> Armada 380/385 SoCs. A small initialization is needed to be able to use
>> the USB3 ports.
>>
>> Signed-off-by: Gregory CLEMENT <gregory.clement@...e-electrons.com>
>> ---
>>  arch/arm/mach-mvebu/Makefile   |  2 +-
>>  arch/arm/mach-mvebu/usb-utmi.c | 64 ++++++++++++++++++++++++++++++++++++++++++
> 
> Gregory,
> 
> there is the generic PHY framework, that could possibly be used to
> avoid adding more code to arch/arm/mach-mvebu.

Given the very low information I have about UTMI I was a bit reluctant to
write a driver. This is, for me, more a platform specific initialization than
something which can be used for a driver. However I will have a look on it.

> 
>>  2 files changed, 65 insertions(+), 1 deletion(-)
>>  create mode 100644 arch/arm/mach-mvebu/usb-utmi.c
>>
>> diff --git a/arch/arm/mach-mvebu/Makefile b/arch/arm/mach-mvebu/Makefile
>> index a63e43b6b451..2d98a3eeecf6 100644
>> --- a/arch/arm/mach-mvebu/Makefile
>> +++ b/arch/arm/mach-mvebu/Makefile
>> @@ -4,7 +4,7 @@ ccflags-$(CONFIG_ARCH_MULTIPLATFORM) := -I$(srctree)/$(src)/include \
>>  AFLAGS_coherency_ll.o		:= -Wa,-march=armv7-a
>>  
>>  obj-y				 += system-controller.o mvebu-soc-id.o
>> -obj-$(CONFIG_MACH_MVEBU_V7)      += board-v7.o
>> +obj-$(CONFIG_MACH_MVEBU_V7)      += board-v7.o  usb-utmi.o
>>  obj-$(CONFIG_MACH_DOVE)		 += dove.o
>>  obj-$(CONFIG_ARCH_MVEBU)	 += coherency.o coherency_ll.o pmsu.o
>>  obj-$(CONFIG_SMP)                += platsmp.o headsmp.o
>> diff --git a/arch/arm/mach-mvebu/usb-utmi.c b/arch/arm/mach-mvebu/usb-utmi.c
>> new file mode 100644
>> index 000000000000..e91e86f85eb4
>> --- /dev/null
>> +++ b/arch/arm/mach-mvebu/usb-utmi.c
>> @@ -0,0 +1,64 @@
>> +/*
>> + * USB UTMI support for Armada 38x platform.
>> + *
>> + * Copyright (C) 2014 Marvell
>> + *
>> + * Gregory CLEMENT <gregory.clement@...e-electrons.com>
>> + *
>> + * This file is licensed under the terms of the GNU General Public
>> + * License version 2.  This program is licensed "as is" without any
>> + * warranty of any kind, whether express or implied.
>> + *
>> + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/init.h>
>> +#include <linux/of_address.h>
>> +#include <linux/io.h>
>> +#include <linux/slab.h>
> 
> nit: sort alphabetically

Right

> 
>> +#define USB_UTMI_PHY_CTRL_STATUS(i)	(0x20+i*4)
>> +#define		USB_UTMI_TX_BITSTUFF_EN BIT(1)
>> +#define		USB_UTMI_PU_PHY		BIT(5)
>> +#define		USB_UTMI_VBUS_ON_PHY	BIT(6)
> 
> nit: two TABs in front of the defines above.

Right

> 
>> +static struct of_device_id of_usb_utmi_table[] = {
>> +	{ .compatible = "marvell,armada-380-usb-utmi", },
>> +	{ /* end of list */ },
>> +};
>> +
>> +static int __init mvebu_usb_utmi_init(void)
>> +{
>> +	struct device_node *np;
>> +
>> +	np = of_find_matching_node(NULL, of_usb_utmi_table);
>> +	if (np) {
>> +		void __iomem *usb_utmi_base, *utmi_base;
>> +
>> +		usb_utmi_base = of_iomap(np, 0);
>> +		BUG_ON(!usb_utmi_base);
>> +
>> +		utmi_base = of_iomap(np, 1);
>> +		BUG_ON(!utmi_base);
>> +
>> +		writel(USB_UTMI_TX_BITSTUFF_EN |
>> +			   USB_UTMI_PU_PHY |
>> +			   USB_UTMI_VBUS_ON_PHY,
>> +			   usb_utmi_base + USB_UTMI_PHY_CTRL_STATUS(0));
>> +
>> +		/*
>> +		 * Magic init... the registers and their value are not
>> +		 * documented
>> +		 */
>> +		writel(0x40605205, utmi_base);
>> +		writel(0x409, utmi_base + 4);
>> +		writel(0x1be7f6f, utmi_base + 0xc);
> 
> nit: decimal/hexadecimal offsets, also IMHO filling the values

OK

> written with leading zeros improves readability of "magic init"
> alot :)

Well it still remains magic! But I will do it.

Thanks,

Gregory


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