linux-kernel - RE: [PATCH v4 2/4] phy: rcar-gen3-usb2: cleanup the role

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Date:   Tue, 10 Oct 2017 07:57:38 +0000
From:   Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
To:     Simon Horman <horms@...ge.net.au>
CC:     "kishon@...com" <kishon@...com>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-renesas-soc@...r.kernel.org" 
        <linux-renesas-soc@...r.kernel.org>
Subject: RE: [PATCH v4 2/4] phy: rcar-gen3-usb2: cleanup the
 role_{store,show}()

Hi Simon-san,

Thank you for the comments!

> From: Simon Horman, Sent: Tuesday, October 10, 2017 4:46 PM
> 
> On Tue, Oct 10, 2017 at 02:58:28PM +0900, Yoshihiro Shimoda wrote:
> > This patch cleanups the role_{store,show}() and replaces the local
> > "bool" for host/device mode selection with the "enum phy_mode" in
> > the role_store().
> >
> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
> > ---
> >  drivers/phy/renesas/phy-rcar-gen3-usb2.c | 58 ++++++++++++++++++++++----------
> >  1 file changed, 40 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/phy/renesas/phy-rcar-gen3-usb2.c b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
> > index e00e99a..7619468 100644
> > --- a/drivers/phy/renesas/phy-rcar-gen3-usb2.c
> > +++ b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
> > @@ -219,14 +219,10 @@ static bool rcar_gen3_is_host(struct rcar_gen3_chan *ch)
> >  	return !(readl(ch->base + USB2_COMMCTRL) & USB2_COMMCTRL_OTG_PERI);
> >  }
> >
> > -static ssize_t role_store(struct device *dev, struct device_attribute *attr,
> > -			  const char *buf, size_t count)
> > +static ssize_t rcar_gen3_otg_change_role(struct rcar_gen3_chan *ch,
> > +					 enum phy_mode mode)
> >  {
> > -	struct rcar_gen3_chan *ch = dev_get_drvdata(dev);
> > -	bool is_b_device, is_host, new_mode_is_host;
> > -
> > -	if (!ch->has_otg || !ch->phy->init_count)
> > -		return -EIO;
> > +	bool is_b_device, is_host;
> >
> >  	/*
> >  	 * is_b_device: true is B-Device. false is A-Device.
> > @@ -234,18 +230,13 @@ static ssize_t role_store(struct device *dev, struct device_attribute *attr,
> >  	 */
> >  	is_b_device = rcar_gen3_check_id(ch);
> >  	is_host = rcar_gen3_is_host(ch);
> > -	if (!strncmp(buf, "host", strlen("host")))
> > -		new_mode_is_host = true;
> > -	else if (!strncmp(buf, "peripheral", strlen("peripheral")))
> > -		new_mode_is_host = false;
> > -	else
> > -		return -EINVAL;
> >
> >  	/* If current and new mode is the same, this returns the error */
> > -	if (is_host == new_mode_is_host)
> > +	if ((is_host && mode == PHY_MODE_USB_HOST) ||
> > +	    (!is_host && mode == PHY_MODE_USB_DEVICE))
> 
> Maybe it is not worth the effort, but it seems that if
> rcar_gen3_is_host returned enum phy_mode then the above
> could be changed into a single comparison.

It's a nice idea! Since role_show() below should not be changed,
I will add rcar_gen3_is_phy_mode_host() and changed the above code
into a single comparison.

> >  		return -EINVAL;
> >
> > -	if (new_mode_is_host) {		/* And is_host must be false */
> > +	if (mode == PHY_MODE_USB_HOST) { /* And is_host must be false */
> >  		if (!is_b_device)	/* A-Peripheral */
> >  			rcar_gen3_init_from_a_peri_to_a_host(ch);
> >  		else			/* B-Peripheral */
> > @@ -257,6 +248,32 @@ static ssize_t role_store(struct device *dev, struct device_attribute *attr,
> >  			rcar_gen3_init_for_peri(ch);
> >  	}
> >
> > +	return 0;
> > +}
> > +
> > +static ssize_t role_store(struct device *dev, struct device_attribute *attr,
> > +			  const char *buf, size_t count)
> > +{
> > +	struct rcar_gen3_chan *ch = dev_get_drvdata(dev);
> > +	enum phy_mode mode;
> > +	ssize_t ret = -EIO;
> > +
> > +	if (!ch->phy->init_count)
> > +		return -EIO;
> > +
> > +	if (!strncmp(buf, "host", strlen("host")))
> > +		mode = PHY_MODE_USB_HOST;
> > +	else if (!strncmp(buf, "peripheral", strlen("peripheral")))
> > +		mode = PHY_MODE_USB_DEVICE;
> > +	else
> > +		return -EINVAL;
> > +
> > +	if (ch->has_otg)
> > +		ret = rcar_gen3_otg_change_role(ch, mode);
> > +
> > +	if (ret < 0)
> > +		return ret;
> > +
> >  	return count;
> >  }
> >
> > @@ -264,12 +281,17 @@ static ssize_t role_show(struct device *dev, struct device_attribute *attr,
> >  			 char *buf)
> >  {
> >  	struct rcar_gen3_chan *ch = dev_get_drvdata(dev);
> > +	bool is_host;
> >
> > -	if (!ch->has_otg || !ch->phy->init_count)
> > +	if (!ch->phy->init_count)
> > +		return -EIO;
> > +
> > +	if (ch->has_otg)
> > +		is_host = rcar_gen3_is_host(ch);
> > +	else
> >  		return -EIO;
> >
> > -	return sprintf(buf, "%s\n", rcar_gen3_is_host(ch) ? "host" :
> > -							    "peripheral");
> > +	return sprintf(buf, "%s\n", is_host ? "host" : "peripheral");
> >  }
> 
> I'm not sure why the above hunk is necessary.
> They function seems logically the same before and after.

Indeed. So, I will keep rcar_gen3_is_host() as bool and
remove the role_show() modification.

Best regards,
Yoshihiro Shimoda

> >  static DEVICE_ATTR_RW(role);
> >
> > --
> > 1.9.1
> >