linux-kernel - Re: [PATCH v5 2/2] phy: rockchip-inno-usb2: add a new driver for Rockchip usb2phy

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Message-ID: <20086422.3ieDmpZrvB@diego>
Date:	Wed, 15 Jun 2016 11:04:20 +0200
From:	Heiko Stübner <heiko@...ech.de>
To:	Frank Wang <frank.wang@...k-chips.com>
Cc:	dianders@...omium.org, linux@...ck-us.net, groeck@...omium.org,
	jwerner@...omium.org, kishon@...com, robh+dt@...nel.org,
	pawel.moll@....com, mark.rutland@....com,
	ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
	linux-usb@...r.kernel.org, linux-rockchip@...ts.infradead.org,
	xzy.xu@...k-chips.com, kever.yang@...k-chips.com,
	huangtao@...k-chips.com, william.wu@...k-chips.com
Subject: Re: [PATCH v5 2/2] phy: rockchip-inno-usb2: add a new driver for Rockchip usb2phy

Hi Frank,

Am Mittwoch, 15. Juni 2016, 11:23:26 schrieb Frank Wang:
> On 2016/6/14 21:27, Heiko Stübner wrote:
> > Am Montag, 13. Juni 2016, 10:10:10 schrieb Frank Wang:
> >> The newer SoCs (rk3366, rk3399) take a different usb-phy IP block
> >> than rk3288 and before, and most of phy-related registers are also
> >> different from the past, so a new phy driver is required necessarily.
> >> 
> >> Signed-off-by: Frank Wang <frank.wang@...k-chips.com>
> >> ---
> >> 
> >> Changes in v5:
> >>   - Added 'reg' in the data block to match the different phy-blocks in
> >>   dt.
> >> 
> >> Changes in v4:
> >>   - Removed some processes related to 'vbus_host-supply'.
> >> 
> >> Changes in v3:
> >>   - Resolved the mapping defect between fixed value in driver and the
> >> 
> >> property in devicetree.
> >> 
> >>   - Optimized 480m output clock register function.
> >>   - Code cleanup.
> >> 
> >> Changes in v2:
> >>   - Changed vbus_host operation from gpio to regulator in *_probe.
> >>   - Improved the fault treatment relate to 480m clock register.
> >>   - Cleaned up some meaningless codes in *_clk480m_disable.
> >>   - made more clear the comment of *_sm_work.
> >>   
> >>   drivers/phy/Kconfig                  |    7 +
> >>   drivers/phy/Makefile                 |    1 +
> >>   drivers/phy/phy-rockchip-inno-usb2.c |  645
> >> 
> >> ++++++++++++++++++++++++++++++++++ 3 files changed, 653 insertions(+)
> >> 
> >> [...]
> >> 
> >> +
> >> +static int rockchip_usb2phy_exit(struct phy *phy)
> >> +{
> >> +	struct rockchip_usb2phy_port *rport = phy_get_drvdata(phy);
> >> +
> >> 
> > 	if (!rport->port_cfg)
> > 	
> > 		return 0;
> >> 
> >> +	if (rport->port_id == USB2PHY_PORT_HOST)
> >> +		cancel_delayed_work_sync(&rport->sm_work);
> >> +
> > 
> > you will also need to resume the port here, if it is suspended at this
> > point, as phy_power_off gets called after phy_exit and would probably
> > produce clk enable/disable mismatches otherwise.
> 
> Hmm, from my personal point of view, when canceling sm_work here, it may
> not cause the port goes to suspend, isn't it? besides, clk only prepared
> in *_usb2phy_resume(), and unprepared in *_usb2phy_suspend(), so if we
> resume port here,  the prepare_count of clk will be increased again, I
> am afraid this is not correct, and am I wrong? would you like to tell me
> more details?

usb2phy_resume gets called both initially through phy_power_on as well.
So it's on but through the first scheduled work call, might get suspended when 
nothing is connected. (clk_enable and clk_disable will run).
If nothing is connected on unload phy_power_off will get called while the 
clock actually is still disabled.

So I think it's either resuming on exit, or at least making sure to do nothing 
in that case in the phy_power_off callback of the driver.