Messages in this thread | | | From | Venu Byravarasu <> | Date | Wed, 20 Mar 2013 18:13:07 +0530 | Subject | RE: [PATCH 7/7] usb: phy: registering tegra USB PHY as platform driver |
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> -----Original Message----- > From: Stephen Warren [mailto:swarren@wwwdotorg.org] > Sent: Wednesday, March 20, 2013 1:51 AM > To: Venu Byravarasu > Cc: gregkh@linuxfoundation.org; stern@rowland.harvard.edu; > balbi@ti.com; linux-usb@vger.kernel.org; linux-kernel@vger.kernel.org; > linux-tegra@vger.kernel.org; devicetree-discuss@lists.ozlabs.org > Subject: Re: [PATCH 7/7] usb: phy: registering tegra USB PHY as platform > driver > > On 03/18/2013 06:29 AM, Venu Byravarasu wrote: > > Registered tegra USB PHY as a separate platform driver. > > > > diff --git a/drivers/usb/phy/tegra_usb_phy.c > b/drivers/usb/phy/tegra_usb_phy.c > > > static void tegra_usb_phy_close(struct usb_phy *x) > > { > > if (phy->is_ulpi_phy) > > clk_put(phy->clk); > > phy->clk is obtained using devm_clk_get(). This typically means you > never need to clk_put() it, and if for some reason you really have to, > you should use devm_clk_put() instead of plain clk_put().
Agree, will remove clk_put.
> > > @@ -774,23 +667,53 @@ struct tegra_usb_phy > *tegra_usb_phy_open(struct device *dev, int instance, > > > + err = gpio_request(phy->reset_gpio, "ulpi_phy_reset_b"); > > I think you can use devm_gpio_request() here to simplify the error-handling.
Sure, will do.
> > I wonder why in the ULPI case, all the code is inline here, whereas in > the UTMI case, this simply calls a function. Wouldn't it be more > consistent to have the following code here: > > if (phy->is_ulpi_phy) > err = ulpi_open(); > else > err = utmip_open(); > if (err) > goto fail;
Sure, will take care of this in next patch.
> > > +static int tegra_usb_phy_probe(struct platform_device *pdev) > > Hmmm. Note that in order to make deferred probe work correctly, all the > gpio_request(), clk_get(), etc. calls that acquire resources from other > drivers must happen here in probe() and not in tegra_usb_phy_open().
In present code tegra_usb_phy_open() is indirectly called via usb_phy_init() from ehci-tegra.c. Between obtaining PHY handle (and hence getting into deferred probe, when it is not available) and calling usb_phy_init, no other USB registers were accessed. Hence I was doing this way.
Do you still think it would be better to move gpio and clk APIs to probe?
> > > + err = of_property_match_string(np, "dr_mode", "otg"); > > + if (err < 0) { > > + err = of_property_match_string(np, "dr_mode", "gadget"); > > Again, use "peripheral", not "gadget".
Will do.
> > > +struct usb_phy *tegra_usb_get_phy(struct device_node *dn) > > +{ > > + struct device *dev; > > + struct tegra_usb_phy *tegra_phy; > > + > > + dev = driver_find_device(&tegra_usb_phy_driver.driver, NULL, dn, > > + tegra_usb_phy_match); > > + if (!dev) > > + return ERR_PTR(-EPROBE_DEFER); > > + > > + tegra_phy = dev_get_drvdata(dev); > > + > > + return &tegra_phy->u_phy; > > +} > > I think you need a module_get() somewhere in there, and also need to add > a tegra_usb_put_phy() function too, so you can call module_put() from it.
Am not clear on why to add module_get here. Can you plz provide more details?
Thanks Stephen, for the review.
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