From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH 2/3] thermal: sun50i: add thermal driver for h6 Date: Fri, 17 May 2019 09:31:51 +0200 Message-ID: <20190517073151.mz6hcmzubk7iqfre@flea> References: <20190512082614.9045-1-tiny.windzz@gmail.com> <20190512082614.9045-3-tiny.windzz@gmail.com> <20190512133930.t5txssl7mou2gljt@flea> <20190512214128.qjyys3vfpwdiacib@core.my.home> <20190516150252.hf4u3bloo37chy6q@flea> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="lfvwzxrwqixjwfma" Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Frank Lee Cc: Mark Rutland , Daniel Lezcano , catalin.marinas@arm.com, will.deacon@arm.com, bjorn.andersson@linaro.org, Mauro Carvalho Chehab , paulmck@linux.ibm.com, stefan.wahren@i2se.com, Linux PM , Chen-Yu Tsai , Jagan Teki , Andy Gross , rui.zhang@intel.com, devicetree@vger.kernel.org, marc.w.gonzalez@free.fr, Eduardo Valentin , enric.balletbo@collabora.com, robh+dt@kernel.org, Jonathan.Cameron@huawei.com, Linux ARM , Greg Kroah-Hartman , Linux Kernel Mailing List , olof@lixom.n List-Id: devicetree@vger.kernel.org --lfvwzxrwqixjwfma Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, May 17, 2019 at 02:10:47AM +0800, Frank Lee wrote: > > On Sun, May 12, 2019 at 11:41:28PM +0200, Ond=C5=99ej Jirman wrote: > > > > > +static int tsens_get_temp(void *data, int *temp) > > > > > +{ > > > > > + struct tsensor *s =3D data; > > > > > + struct tsens_device *tmdev =3D s->tmdev; > > > > > + int val; > > > > > + > > > > > + regmap_read(tmdev->regmap, tmdev->chip->temp_data_base + > > > > > + 0x4 * s->id, &val); > > > > > + > > > > > + if (unlikely(val =3D=3D 0)) > > > > > + return -EBUSY; > > > > > > > > I'm not sure why a val equals to 0 would be associated with EBUSY? > > > > > > Thermal zone driver can (will) call get_temp before we got the > > > first interrupt and the thermal data. In that case val will be 0. > > > > > > Resulting in: > > > > > > (val + offset) * scale =3D (-2794) * -67 =3D 187198 > > > > > > 187=C2=B0C and immediate shutdown during boot - based on cirtical > > > temperature being reached. > > > > > > Busy here means, get_temp does not yet have data. Thermal zone > > > driver just reports any error to dmesg output. > > > > Ah, that makes sense. > > > > I guess if we're switching to an interrupt-based driver, then we can > > just use a waitqueue, or is get_temp supposed to be atomic? > > I think get_temp should not be bloacked. Why not? Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com --lfvwzxrwqixjwfma Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCXN5jZwAKCRDj7w1vZxhR xRjwAQCF+RoytL/Gdpf15Jq+KQoPxEwYs/XaBIKW6ehF38tr0QD/T1i40/vfptIH f1vUZGQCwcHvI4eTbggzXinFNG1BsAM= =UQjS -----END PGP SIGNATURE----- --lfvwzxrwqixjwfma--