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

From: [email-masked] (Kishon Vijay Abraham I)
Date: Wed, 13 May 2015 14:52:29 +0530

Hi Felipe,

On Monday 11 May 2015 11:43 PM, Hans de Goede wrote:
> 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 ?

We don't want to be adding platform specific hooks in PHY framework. While 
exporting a function from PHY to MUSB is not the best thing, it's still okay 
since it is from musb sunxi glue only no?

Thanks
Kishon