From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kVF78-0004d8-Hf for barebox@lists.infradead.org; Wed, 21 Oct 2020 14:29:19 +0000 Date: Wed, 21 Oct 2020 16:29:15 +0200 From: Marco Felsch Message-ID: <20201021142915.2wfefcrazkq42bgv@pengutronix.de> References: <20201020111537.29328-1-u.kleine-koenig@pengutronix.de> <20201020133317.dc6yt2yt4tyk5ogm@pengutronix.de> <20201020140934.GS13710@pengutronix.de> <20201020142806.kmxoy6byavdwe5cv@pengutronix.de> <20201020145844.4id6iyuihl3hkt3x@pengutronix.de> <20201021054907.sunblqmijd4jl6zn@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201021054907.sunblqmijd4jl6zn@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH] usb: i.MX: improve regulator handling To: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Cc: barebox@lists.infradead.org On 20-10-21 07:49, Uwe Kleine-K=F6nig wrote: > On Tue, Oct 20, 2020 at 04:58:44PM +0200, Marco Felsch wrote: > > On 20-10-20 16:28, Marco Felsch wrote: > > > On 20-10-20 16:09, Sascha Hauer wrote: > > > > On Tue, Oct 20, 2020 at 03:33:17PM +0200, Marco Felsch wrote: > > > > > Hi Uwe, > > > > > = > > > > > On 20-10-20 13:15, Uwe Kleine-K=F6nig wrote: > > > > > > Instead of just ignoring errors related to regulator getting er= ror out. > > > > > > In case there is no regulator in the device tree, regulator_get= () returns > > > > > > the dummy regulator and not an error code, so the change is rig= ht for > > > > > > this situation, too. > > > > > > = > > > > > > Signed-off-by: Uwe Kleine-K=F6nig > > > > > > --- > > > > > > drivers/usb/imx/chipidea-imx.c | 7 +++++-- > > > > > > 1 file changed, 5 insertions(+), 2 deletions(-) > > > > > > = > > > > > > diff --git a/drivers/usb/imx/chipidea-imx.c b/drivers/usb/imx/c= hipidea-imx.c > > > > > > index 786beede6d89..dd0e3c1a2a58 100644 > > > > > > --- a/drivers/usb/imx/chipidea-imx.c > > > > > > +++ b/drivers/usb/imx/chipidea-imx.c > > > > > > @@ -267,8 +267,11 @@ static int imx_chipidea_probe(struct devic= e_d *dev) > > > > > > } > > > > > > = > > > > > > ci->vbus =3D regulator_get(dev, "vbus"); > > > > > > - if (IS_ERR(ci->vbus)) > > > > > > - ci->vbus =3D NULL; > > > > > > + if (IS_ERR(ci->vbus)) { > > > > > > + ret =3D ERR_PTR(ci->vbus); > > > > > > + dev_err(dev, "Cannot get vbus regulator: %s\n", strerror(-re= t)); > > > > > > + return ret; > > > > > = > > > > > Returning the error here can cause problems with exisiting boards= , e.g. > > > > > if the regulator support is missing for the specified vbus regula= tor. > > > > > This is often the case since we have very limited regulator suppo= rt for > > > > > now. > > > > = > > > > But when there is a regulator we also have to control it, right? > > > = > > > So you need to add each regulator driver or worst case you need to add > > > PMIC drivers. > = > Right, as if you don't the hardware might be off and USB won't work > without a useful error message. Adding a warining seems valid to me but returning a error is wrong since the mainline driver explicite says: "/* no vbus regulator is needed */". > > > If I remember correctly, I added the same for mci which > > > broke a lot of boards. Later you reverted those commit. Now Oleksij > > > added the regulator support for the fec driver and people are startin= g = > > > to remove the phy-supply handle from the barebox-dt's (commit 84cf5cf= a9a > > > ("ARM: dts: imx6qdl: pfla02: Remove fec phy-supply")). I'm not again > = > Looking at 84cf5cfa9a there is at least a comment missing about why this > property is deleted. Something like > = > diff --git a/arch/arm/dts/imx6qdl-phytec-pfla02.dtsi b/arch/arm/dts/imx6q= dl-phytec-pfla02.dtsi > index b83511cb011f..7a12e2a06be4 100644 > --- a/arch/arm/dts/imx6qdl-phytec-pfla02.dtsi > +++ b/arch/arm/dts/imx6qdl-phytec-pfla02.dtsi > @@ -84,6 +84,11 @@ > }; > = > &fec { > + /* > + * barebox doesn't have a driver for the PMIC providing the phy-supply > + * (dlg,da9063). So remove the phy-supply property and rely on the > + * PMIC's reset default which has this supply enabled. > + */ > /delete-property/ phy-supply; > }; > = > = > > > this patch, just wanted to show the consequences of it. > > = > > Sorry I have to correct myself, pls check the linux driver: > > = > > static int ci_get_platdata(struct device *dev, > > struct ci_hdrc_platform_data *platdata) > > { > > = > > ... > > = > > /* Get the vbus regulator */ > > platdata->reg_vbus =3D devm_regulator_get_optional(dev, "vbus"); > > if (PTR_ERR(platdata->reg_vbus) =3D=3D -EPROBE_DEFER) { > > return -EPROBE_DEFER; > > } else if (PTR_ERR(platdata->reg_vbus) =3D=3D -ENODEV) { > > /* no vbus regulator is needed */ > > platdata->reg_vbus =3D NULL; > > } else if (IS_ERR(platdata->reg_vbus)) { > > dev_err(dev, "Getting regulator error: %ld\n", > > PTR_ERR(platdata->reg_vbus)); > > return PTR_ERR(platdata->reg_vbus); > > } > = > The difference between regulator_get and regulator_get_optional is that > the former doesn't return -ENODEV but yields the dummy regulator > instead. = Nope, regulator_get returns dummy-regulators too and -ENODEV is returned in case of regulator_get_optional() too, pls. check: /* Internal regulator request function */ struct regulator *_regulator_get(struct device *dev, const char *id, enum regulator_get_type get_type) { ... } Regards, Marco > (Yes, this is the inversed semantic compared with > gpio_get_optional() and clk_get_optional().) So using > devm_regulator_get_optional and ignoring -ENODEV is kind of strange. So > I think the above can be simplified to: > = > platdata->reg_vbus =3D devm_regulator_get(dev, "vbus"); > if (IS_ERR(platdata->reg_vbus)) > return dev_err_probe(dev, PTR_ERR(platdata->reg_vbus), > "Failed to get vbus regulator\n"); > = > = > and then it is more obvious that my barebox patch does the same. > = > Am I missing something? > = > Best regards > Uwe > = > -- = > Pengutronix e.K. | Uwe Kleine-K=F6nig = | > Industrial Linux Solutions | https://www.pengutronix.de/ | > _______________________________________________ > barebox mailing list > barebox@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/barebox -- = Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox