From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mib.mailinblack.com ([137.74.84.110]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1knlAW-0006P1-Fx for barebox@lists.infradead.org; Fri, 11 Dec 2020 16:21:21 +0000 Received: from localhost (localhost [127.0.0.1]) by mib.mailinblack.com (Postfix) with ESMTP id BB5181A42CD for ; Fri, 11 Dec 2020 16:21:16 +0000 (UTC) Date: Fri, 11 Dec 2020 17:21:10 +0100 From: Jules Maselbas Message-ID: <20201211162110.th725gs3ddrcyp5s@tellis.lin.mbt.kalray.eu> References: <20201210103104.3816-1-jmaselbas@kalray.eu> <20201211153608.GB3977@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201211153608.GB3977@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH v2 1/4] usb: dwc2: Add support for optional usb phy To: Sascha Hauer Cc: barebox@lists.infradead.org Hi Sascha, On Fri, Dec 11, 2020 at 04:36:08PM +0100, Sascha Hauer wrote: > On Thu, Dec 10, 2020 at 11:31:01AM +0100, Jules Maselbas wrote: > > Signed-off-by: Jules Maselbas > > --- > > drivers/usb/dwc2/core.h | 2 ++ > > drivers/usb/dwc2/dwc2.c | 24 ++++++++++++++++++++++++ > > drivers/usb/dwc2/dwc2.h | 1 + > > 3 files changed, 27 insertions(+) > > > > diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h > > index 090ca15fe..b9845b552 100644 > > --- a/drivers/usb/dwc2/core.h > > +++ b/drivers/usb/dwc2/core.h > > @@ -466,6 +466,8 @@ struct dwc2 { > > struct dwc2_hw_params hw_params; > > struct dwc2_core_params params; > > > > + struct phy *phy; /* optional */ > > + > > #ifdef CONFIG_USB_DWC2_HOST > > struct usb_host host; > > u8 in_data_toggle[MAX_DEVICE][MAX_ENDPOINT]; > > diff --git a/drivers/usb/dwc2/dwc2.c b/drivers/usb/dwc2/dwc2.c > > index 282e6754b..9ab3b5b53 100644 > > --- a/drivers/usb/dwc2/dwc2.c > > +++ b/drivers/usb/dwc2/dwc2.c > > @@ -50,6 +50,20 @@ static int dwc2_probe(struct device_d *dev) > > dwc2->regs = IOMEM(iores->start); > > dwc2->dev = dev; > > > > + dwc2->phy = phy_optional_get(dev, "usb2-phy"); > > + if (IS_ERR(dwc2->phy)) { > > + ret = PTR_ERR(dwc2->phy); > > + return ret; > > + } > > + > > + if (dwc2->phy) { > > + ret = phy_power_on(dwc2->phy); > > + if (ret == 0) > > + ret = phy_init(dwc2->phy); > > + if (ret) > > + goto error; > > + } > > Just like with clocks a NULL pointer is handled like a dummy phy, you > can drop the if (dwc2->phy) tests here. Alright, I'll remove theses ifs. > > Shouldn't phy_init() called before phy_power_on()? At least that's the > order I find in the Kernel in several places. Indeed, from what I've seen it is mostly phy_power_on and then phy_init. However in the dwc2 driver in Linux's kernel, it is done the other way around, see the function __dwc2_lowlevel_hw_enable in dwc2/platform.c [1] I don't fully understand the phy api. My assumption was that phy_power_on is used to power the phy interface, and that phy_init does initialisation of the phy device such as toggling the reset pin as done by usb-nop-xceiv. That's why I thought it was correct to first power on the phy and then do initilisation. But I may have missunderstand both functions. Any insight is more than welcome as I am new to this. [1] https://elixir.bootlin.com/linux/latest/source/drivers/usb/dwc2/platform.c#L145 > > dwc2_gadget_uninit(dwc2); > > + > > + if (dwc2->phy) { > > + ret = phy_exit(dwc2->phy); > > + if (ret == 0) > > + phy_power_off(dwc2->phy); > > + } > > Likewise phy_power_off() before phy_exit(). --- Jules _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox