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: Wed, 13 May 2015 11:43:40 +0200

Hi,

On 13-05-15 11:22, Kishon Vijay Abraham I wrote:
> 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?

Correct this only gets used by drivers/usb/musb/sunxi.c calling
directly into drivers/phy/phy-sun4i-usb.c

Regards,

Hans