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Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kdT88-0002jd-4G; Fri, 13 Nov 2020 07:04:20 +0000 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 1kdT7y-0002dd-M9 for linux-amlogic@lists.infradead.org; Fri, 13 Nov 2020 07:04:13 +0000 Received: from pty.hi.pengutronix.de ([2001:67c:670:100:1d::c5]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kdT7e-0002r8-3x; Fri, 13 Nov 2020 08:03:50 +0100 Received: from ukl by pty.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1kdT7Z-0004f0-FQ; Fri, 13 Nov 2020 08:03:45 +0100 Date: Fri, 13 Nov 2020 08:03:43 +0100 From: Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= To: Thierry Reding Subject: About devm_platform_ioremap_resource [Was: Re: [PATCH 01/32] pwm: sun4i: convert to devm_platform_ioremap_resource] Message-ID: <20201113070343.lhcsbyvi5baxn3lq@pengutronix.de> References: <20191229080610.7597-1-tiny.windzz@gmail.com> <20201112161346.gp5nenuagx5wmwl2@pengutronix.de> <20201112190649.GA908613@ulmo> <20201112211429.kfyqzkmmchjo6pll@pengutronix.de> MIME-Version: 1.0 In-Reply-To: <20201112211429.kfyqzkmmchjo6pll@pengutronix.de> X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-amlogic@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201113_020410_816022_EBC0B0BA X-CRM114-Status: GOOD ( 18.64 ) X-BeenThere: linux-amlogic@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: alexandre.belloni@bootlin.com, heiko@sntech.de, Yangtao Li , Linus Walleij , linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org, linux-riscv@lists.infradead.org, festevam@gmail.com, f.fainelli@gmail.com, shc_work@mail.ru, Bartosz Golaszewski , khilman@baylibre.com, wens@csie.org, jonathanh@nvidia.com, linux-rockchip@lists.infradead.org, ludovic.desroches@microchip.com, bcm-kernel-feedback-list@broadcom.com, linux-imx@nxp.com, slemieux.tyco@gmail.com, linux-pwm@vger.kernel.org, rjui@broadcom.com, s.hauer@pengutronix.de, mripard@kernel.org, vz@mleia.com, linux-mediatek@lists.infradead.org, linux-rpi-kernel@lists.infradead.org, paul.walmsley@sifive.com, matthias.bgg@gmail.com, linux-amlogic@lists.infradead.org, Lee Jones , Andy Shevchenko , linux-arm-kernel@lists.infradead.org, sbranden@broadcom.com, Greg Kroah-Hartman , nicolas.ferre@microchip.com, palmer@dabbelt.com, kernel@pengutronix.de, shawnguo@kernel.org, claudiu.beznea@microchip.com, nsaenzjulienne@suse.de Content-Type: multipart/mixed; boundary="===============2364418415735706887==" Sender: "linux-amlogic" Errors-To: linux-amlogic-bounces+linux-amlogic=archiver.kernel.org@lists.infradead.org --===============2364418415735706887== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="bfm7upvbg2x7q3rm" Content-Disposition: inline --bfm7upvbg2x7q3rm Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hello, [Added lkml and the people involved in commit 7945f929f1a7 ("drivers: provide devm_platform_ioremap_resource()") to Cc:. For the new readers: This is about patches making use of devm_platform_ioremap_resource() instead of open coding it. Full context at https://lore.kernel.org/r/20201112190649.GA908613@ulmo] On Thu, Nov 12, 2020 at 10:14:29PM +0100, Uwe Kleine-K=F6nig wrote: > On Thu, Nov 12, 2020 at 08:06:49PM +0100, Thierry Reding wrote: > > I also think that it's overly narrow is scope, so you can't actually > > "blindly" use this helper and I've seen quite a few cases where this was > > unknowingly used for cases where it shouldn't have been used and then > > broke things (because some drivers must not do the request_mem_region() > > for example). >=20 > You have a link to such an accident? I got a hint in private here: https://lore.kernel.org/r/1555670144-24220-1-= git-send-email-aisheng.dong@nxp.com devm_platform_ioremap_resource() is platform_get_resource() + devm_ioremap_resource() and here it was used to replace platform_get_resource() + devm_ioremap(). IMHO the unlucky thing in this situation is that devm_ioremap_resource() and devm_ioremap() are different by more than just how they get the area to remap. (i.e. devm_ioremap_resource() also does devm_request_mem_region().) So the problem is not the added wrapper, but unclear semantics in the functions it uses. In my eyes devm_ioremap() and devm_platform_ioremap_resource() should better be named devm_request_ioremap() and devm_platform_request_ioremap_resource() respectively. Is it worth to rename these for clearity? Best regards Uwe --=20 Pengutronix e.K. | Uwe Kleine-K=F6nig | Industrial Linux Solutions | https://www.pengutronix.de/ | --bfm7upvbg2x7q3rm Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEfnIqFpAYrP8+dKQLwfwUeK3K7AkFAl+uL8wACgkQwfwUeK3K 7AmhFQf/UMY3Z/O4ajFXsCh5aeqAW1EKy0wv+YtVLmLASYlkvBQ5OpoaFH6U7oZY a1BVjZ2I3q3pi1zMs+2dPAkylNi0VEIERvwncqHOfYN4FjdNsI85rKbxu4DNsWHJ wlaQxLwmUmDXDESpJ4RN8JqF/V/nPZfj/4V52ANK31PZ+i4fYnIlW6TU0cJwoJ9s aGSM2QwTb27uaRg5hqZqfOyIkt3wwkDJIF65H/vi64r0Gtm3c+0iKbEmlXr2XZCh APhFgQQDGFOMXdSBZeFxTtuLCzuG/RA3Fxb+7okleZUL6GrSwq7xWHJGorO136kq mo88jw2ceYf/qJA9E4atasOfbQUtlg== =gJ1m -----END PGP SIGNATURE----- --bfm7upvbg2x7q3rm-- --===============2364418415735706887== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-amlogic mailing list linux-amlogic@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-amlogic --===============2364418415735706887==--