Subject: [linux-sunxi] Re: [PATCH 1/3] phy-sun4i-usb: Add a sunxi specific function for setting squelch-detect

From: [email-masked] (Hans de Goede)
Date: Mon, 11 May 2015 20:13:35 +0200

Hi,

On 11-05-15 17:55, Felipe Balbi wrote:
> Hi,
>
> On Sun, May 10, 2015 at 12:02:54PM +0200, Hans de Goede wrote:
>> Hi,
>>
>> On 08-05-15 18:06, Felipe Balbi wrote:
>>> Hi,
>>>
>>> On Sun, Mar 29, 2015 at 12:50:46PM +0200, Hans de Goede wrote:
>>>> The sunxi otg phy has a bug where it wrongly detects a high speed squelch
>>>> when reset on the root port gets de-asserted with a lo-speed device.
>>>>
>>>> The workaround for this is to disable squelch detect before de-asserting
>>>> reset, and re-enabling it after the reset de-assert is done. Add a sunxi
>>>> specific phy function to allow the sunxi-musb glue to do this.
>>>>
>>>> Signed-off-by: Hans de Goede <[email-masked]>
>>>> ---
>>>>   drivers/phy/phy-sun4i-usb.c       |  9 +++++++++
>>>>   include/linux/phy/phy-sun4i-usb.h | 26 ++++++++++++++++++++++++++
>>>>   2 files changed, 35 insertions(+)
>>>>   create mode 100644 include/linux/phy/phy-sun4i-usb.h
>>>>
>>>> diff --git a/drivers/phy/phy-sun4i-usb.c b/drivers/phy/phy-sun4i-usb.c
>>>> index 221e8ab..01eb08d 100644
>>>> --- a/drivers/phy/phy-sun4i-usb.c
>>>> +++ b/drivers/phy/phy-sun4i-usb.c
>>>> @@ -33,6 +33,7 @@
>>>>   #include <linux/of_address.h>
>>>>   #include <linux/of_gpio.h>
>>>>   #include <linux/phy/phy.h>
>>>> +#include <linux/phy/phy-sun4i-usb.h>
>>>>   #include <linux/platform_device.h>
>>>>   #include <linux/regulator/consumer.h>
>>>>   #include <linux/reset.h>
>>>> @@ -75,6 +76,7 @@
>>>>   #define PHY_OTG_FUNC_EN			0x28
>>>>   #define PHY_VBUS_DET_EN			0x29
>>>>   #define PHY_DISCON_TH_SEL		0x2a
>>>> +#define PHY_SQUELCH_DETECT		0x3c
>>>>
>>>>   #define MAX_PHYS			3
>>>>
>>>> @@ -322,6 +324,13 @@ static int sun4i_usb_phy_power_off(struct phy *_phy)
>>>>   	return 0;
>>>>   }
>>>>
>>>> +void sun4i_usb_phy_set_squelch_detect(struct phy *_phy, bool enabled)
>>>> +{
>>>> +	struct sun4i_usb_phy *phy = phy_get_drvdata(_phy);
>>>> +
>>>> +	sun4i_usb_phy_write(phy, PHY_SQUELCH_DETECT, enabled ? 0 : 2, 2);
>>>> +}
>>>> +
>>>>   static struct phy_ops sun4i_usb_phy_ops = {
>>>>   	.init		= sun4i_usb_phy_init,
>>>>   	.exit		= sun4i_usb_phy_exit,
>>>> diff --git a/include/linux/phy/phy-sun4i-usb.h b/include/linux/phy/phy-sun4i-usb.h
>>>> new file mode 100644
>>>> index 0000000..50aed92
>>>> --- /dev/null
>>>> +++ b/include/linux/phy/phy-sun4i-usb.h
>>>> @@ -0,0 +1,26 @@
>>>> +/*
>>>> + * Copyright (c) 2015 Hans de Goede <[email-masked]>
>>>> + *
>>>> + * This program is free software; you can redistribute it and/or modify
>>>> + * it under the terms of the GNU General Public License version 2 and
>>>> + * only version 2 as published by the Free Software Foundation.
>>>> + *
>>>> + * This program is distributed in the hope that it will be useful,
>>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>>>> + * GNU General Public License for more details.
>>>> + */
>>>> +
>>>> +#ifndef PHY_SUN4I_USB_H_
>>>> +#define PHY_SUN4I_USB_H_
>>>> +
>>>> +#include "phy.h"
>>>> +
>>>> +/**
>>>> + * sun4i_usb_phy_set_squelch_detect() - Enable/disable squelch detect
>>>> + * @phy: reference to a sun4i usb phy
>>>> + * @enabled: wether to enable or disable squelch detect
>>>> + */
>>>> +void sun4i_usb_phy_set_squelch_detect(struct phy *phy, bool enabled);
>>>
>>> breaks build if MUSB=y and SUN41_PHY=m
>>
>> Ah, good one. So I assume that it is ok to fix this by doing:
>>
>> --- a/drivers/usb/musb/Kconfig
>> +++ b/drivers/usb/musb/Kconfig
>> @@ -66,6 +66,7 @@ config USB_MUSB_SUNXI
>>          tristate "Allwinner (sunxi)"
>>          depends on ARCH_SUNXI
>>          depends on NOP_USB_XCEIV
>> + depends on PHY_SUN4I_USB
>
> I would prefer not exporting any function from phy to musb. Perhaps
> figure out with Kishon how "set_squelch" can be added to PHY fwk ?

Normally one would never want to mess with these phy settings, this
is just needed on sunxi because the otg phy there is quirky, so I
really do believe that having platform specific phy functions is
the most sensible solution here. As for adding the depends on, that
is needed at a functional level anyways because the musb code cannot
work with the phy code. All the platform specific phy functions do
is add a link time dependency to the already present functional
dependency.

>
>> Also I've not heard anything back from you wrt my other musb
>> sunxi preparation patches and the actual musb-sunxi patch? are
>> those all ready for merging?
>
> I'm a little iffy with all the function rewriting again because of a new
> set of limitations with a new platform.

I actually have done my best to avoid to touching the core code were possible,
e.g. I'm done the translating for the sunxi registers being at different
addresses at the musb_read* / musb_write* level so as to avoid invasive
surgery in the musb-core for this.

Also note that some of the bits of core code which I do change were using a
very non orthogonal API before my changes, and my changes are actually a
nice cleanup.

Regards,

Hans