linux-kernel - Re: [PATCH 1/1] USB: PHY: JZ4770: Fix uninitialized value written to HW register

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Message-ID: <87bliwi5kx.fsf@kernel.org>
Date:   Thu, 27 Aug 2020 16:25:18 +0300
From:   Felipe Balbi <balbi@...nel.org>
To:     Paul Cercueil <paul@...pouillou.net>
Cc:     周琰杰 <zhouyanjie@...yeetech.com>,
        周正 <sernia.zhou@...mail.com>,
        漆鹏振 <aric.pzqi@...enic.com>, od@...c.me,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] USB: PHY: JZ4770: Fix uninitialized value written
 to HW register


Hi,

Paul Cercueil <paul@...pouillou.net> writes:
>>>  @@ -172,7 +172,8 @@ static int ingenic_usb_phy_init(struct usb_phy 
>>> *phy)
>>>   		return err;
>>>   	}
>>> 
>>>  -	priv->soc_info->usb_phy_init(phy);
>>>  +	reg = priv->soc_info->usb_phy_init(phy);
>>>  +	writel(reg, priv->base + REG_USBPCR_OFFSET);
>> 
>> not fixing any bug.
>> 
>> Looking at the code, the bug follows after this line. It would suffice
>> to read REG_USBPCR_OFFSET in order to initialize reg. This bug fix 
>> could
>> have been a one liner.
>
> There's no need to re-read a register when you have the value readily 
> available. It just needs to be returned from the usb_phy_init 
> callbacks. But yes, it's not a one-liner.

there's a difference between making a bug fix and reworking the behavior
of the driver ;-)

>>>  @@ -195,19 +196,15 @@ static void ingenic_usb_phy_remove(void *phy)
>>>   	usb_remove_phy(phy);
>>>   }
>>> 
>>>  -static void jz4770_usb_phy_init(struct usb_phy *phy)
>>>  +static u32 jz4770_usb_phy_init(struct usb_phy *phy)
>> 
>> not a bug fix
>> 
>>>   {
>>>  -	struct jz4770_phy *priv = phy_to_jz4770_phy(phy);
>>>  -	u32 reg;
>>>  -
>>>  -	reg = USBPCR_AVLD_REG | USBPCR_COMMONONN | USBPCR_IDPULLUP_ALWAYS 
>>> |
>>>  +	return USBPCR_AVLD_REG | USBPCR_COMMONONN | 
>>> USBPCR_IDPULLUP_ALWAYS |
>>>   		USBPCR_COMPDISTUNE_DFT | USBPCR_OTGTUNE_DFT | 
>>> USBPCR_SQRXTUNE_DFT |
>>>   		USBPCR_TXFSLSTUNE_DFT | USBPCR_TXRISETUNE_DFT | 
>>> USBPCR_TXVREFTUNE_DFT |
>>>   		USBPCR_POR;
>>>  -	writel(reg, priv->base + REG_USBPCR_OFFSET);
>> 
>> not a bug fix
>> 
>>>   }
>>> 
>>>  -static void jz4780_usb_phy_init(struct usb_phy *phy)
>>>  +static u32 jz4780_usb_phy_init(struct usb_phy *phy)
>> 
>> not a bug fix
>> 
>>>  @@ -216,11 +213,10 @@ static void jz4780_usb_phy_init(struct 
>>> usb_phy *phy)
>>>   		USBPCR1_WORD_IF_16BIT;
>>>   	writel(reg, priv->base + REG_USBPCR1_OFFSET);
>>> 
>>>  -	reg = USBPCR_TXPREEMPHTUNE | USBPCR_COMMONONN | USBPCR_POR;
>>>  -	writel(reg, priv->base + REG_USBPCR_OFFSET);
>>>  +	return USBPCR_TXPREEMPHTUNE | USBPCR_COMMONONN | USBPCR_POR;
>> 
>> not a bug fix
>> 
>>>   }
>>> 
>>>  -static void x1000_usb_phy_init(struct usb_phy *phy)
>>>  +static u32 x1000_usb_phy_init(struct usb_phy *phy)
>> 
>> not a bug fix
>> 
>>>   {
>>>   	struct jz4770_phy *priv = phy_to_jz4770_phy(phy);
>>>   	u32 reg;
>>>  @@ -228,13 +224,12 @@ static void x1000_usb_phy_init(struct usb_phy 
>>> *phy)
>>>   	reg = readl(priv->base + REG_USBPCR1_OFFSET) | 
>>> USBPCR1_WORD_IF_16BIT;
>>>   	writel(reg, priv->base + REG_USBPCR1_OFFSET);
>>> 
>>>  -	reg = USBPCR_SQRXTUNE_DCR_20PCT | USBPCR_TXPREEMPHTUNE |
>>>  +	return USBPCR_SQRXTUNE_DCR_20PCT | USBPCR_TXPREEMPHTUNE |
>>>   		USBPCR_TXHSXVTUNE_DCR_15MV | USBPCR_TXVREFTUNE_INC_25PPT |
>>>   		USBPCR_COMMONONN | USBPCR_POR;
>>>  -	writel(reg, priv->base + REG_USBPCR_OFFSET);
>> 
>> not a bug fix
>> 
>>>   }
>>> 
>>>  -static void x1830_usb_phy_init(struct usb_phy *phy)
>>>  +static u32 x1830_usb_phy_init(struct usb_phy *phy)
>> 
>> not a bug fix
>> 
>>>   {
>>>   	struct jz4770_phy *priv = phy_to_jz4770_phy(phy);
>>>   	u32 reg;
>>>  @@ -246,9 +241,8 @@ static void x1830_usb_phy_init(struct usb_phy 
>>> *phy)
>>>   		USBPCR1_DMPD | USBPCR1_DPPD;
>>>   	writel(reg, priv->base + REG_USBPCR1_OFFSET);
>>> 
>>>  -	reg = USBPCR_IDPULLUP_OTG | USBPCR_VBUSVLDEXT 
>>> |	USBPCR_TXPREEMPHTUNE |
>>>  +	return USBPCR_IDPULLUP_OTG | USBPCR_VBUSVLDEXT | 
>>> USBPCR_TXPREEMPHTUNE |
>>>   		USBPCR_COMMONONN | USBPCR_POR;
>>>  -	writel(reg, priv->base + REG_USBPCR_OFFSET);
>> 
>> not a bug fix
>
> Well, if you don't like my bug fix, next time wait for my Reviewed-by.

why so angry? Take a break every once in a while. Besides, someone else
already sent the oneliner before you ;-)

In any case, why should I wait for your Reviewed-by? Get maintainer
doesn't list you as the maintainer for it. Do you want to update
MAINTAINERS by any chance?

-- 
balbi

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