From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EF4267E9 for ; Tue, 26 Nov 2024 09:29:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732613392; cv=none; b=C9BNll8+xm/qrYRsEqSmCV4zovFHqYrQ5O6Hbajfd2wJ0cnx15PVQo4JaqEsCOHYpTn8hL90hmorNcPLSYfdfz/K+HVUiFAFjAg2lH54Za+nPWM8DUw3vosnZk61KmNimRNlyPCkWjgFclsPCxJjZn5hv+fiVA5fd8eNB0s6hu8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732613392; c=relaxed/simple; bh=+TV9OkllNR5xS/4pW/hZcS8f9O/25pyCeKXiGLdXnfo=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=mBvhBFz1sJMEk7Cd6xRuWkvUe8mbE+EjKu2OodQCT85xsUhNkf4Vzb+kk9v47oqmIKOITVnTMgscwxqo/dFnllIVqRrcn+lTgl4OORcygWdlbxPl+lA+4nNa0pDf5DsB6CY1HMe6vscpZajdnqpW6CgZmse+Q2SXZztUNeRIjeE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1tFrsv-0007BB-JZ; Tue, 26 Nov 2024 10:29:29 +0100 Received: from lupine.office.stw.pengutronix.de ([2a0a:edc0:0:900:1d::4e] helo=lupine) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1tFrst-000E0I-18; Tue, 26 Nov 2024 10:29:28 +0100 Received: from pza by lupine with local (Exim 4.96) (envelope-from ) id 1tFrsu-0001mR-09; Tue, 26 Nov 2024 10:29:28 +0100 Message-ID: <74d4fc4c6f08fde2d6759633cb2280ecb18cbd91.camel@pengutronix.de> Subject: Re: [PATCH 2/2] drm/imagination: add reset control support From: Philipp Zabel To: Parthiban Nallathambi , Frank Binns , Matt Coster , David Airlie , Simona Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Rob Herring , Krzysztof Kozlowski , Conor Dooley Cc: dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Date: Tue, 26 Nov 2024 10:29:27 +0100 In-Reply-To: <20241125-pvr-reset-v1-2-b437b8052948@linumiz.com> References: <20241125-pvr-reset-v1-0-b437b8052948@linumiz.com> <20241125-pvr-reset-v1-2-b437b8052948@linumiz.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.46.4-2 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: p.zabel@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: devicetree@vger.kernel.org On Mo, 2024-11-25 at 22:07 +0530, Parthiban Nallathambi wrote: > On some platforms like Allwinner A133 with GE8300 includes > reset control from reset control unit. Add reset control > optionally from the devicetree. >=20 > Signed-off-by: Parthiban Nallathambi > --- > drivers/gpu/drm/imagination/pvr_device.h | 8 ++++++++ > drivers/gpu/drm/imagination/pvr_drv.c | 5 +++++ > drivers/gpu/drm/imagination/pvr_power.c | 16 +++++++++++++++- > 3 files changed, 28 insertions(+), 1 deletion(-) >=20 > diff --git a/drivers/gpu/drm/imagination/pvr_device.h b/drivers/gpu/drm/i= magination/pvr_device.h > index 6d0dfacb677b..21ec7dd64415 100644 > --- a/drivers/gpu/drm/imagination/pvr_device.h > +++ b/drivers/gpu/drm/imagination/pvr_device.h > @@ -23,6 +23,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -131,6 +132,13 @@ struct pvr_device { > */ > struct clk *mem_clk; > =20 > + /** > + * @reset: Optional reset control > + * > + * This may be used on some platforms to reset the GPU module/IP. > + */ > + struct reset_control *reset; > + > /** @irq: IRQ number. */ > int irq; > =20 > diff --git a/drivers/gpu/drm/imagination/pvr_drv.c b/drivers/gpu/drm/imag= ination/pvr_drv.c > index fb17196e05f4..d9b918410ea9 100644 > --- a/drivers/gpu/drm/imagination/pvr_drv.c > +++ b/drivers/gpu/drm/imagination/pvr_drv.c > @@ -36,6 +36,7 @@ > #include > #include > #include > +#include > #include > =20 > /** > @@ -1427,6 +1428,10 @@ pvr_probe(struct platform_device *plat_dev) > pm_runtime_use_autosuspend(&plat_dev->dev); > pvr_watchdog_init(pvr_dev); > =20 > + pvr_dev->reset =3D devm_reset_control_get_optional_exclusive(&plat_dev-= >dev, "ahb"); > + if (PTR_ERR(pvr_dev->reset) =3D=3D -EPROBE_DEFER) > + return PTR_ERR(pvr_dev->reset); pvr_dev->reset =3D devm_reset_control_get_optional_exclusive(&plat_dev->de= v, "ahb"); if (IS_ERR(pvr_dev->reset)) return PTR_ERR(pvr_dev->reset); Please don't ignore errors. devm_reset_control_get_optional_exclusive() returns NULL if the "ahb" reset control isn't specified in the device tree, and the reset_control_assert/deassert() functions accept that as a non-existing reset, see [1]. [1] https://docs.kernel.org/driver-api/reset.html#optional-resets > + > err =3D pvr_device_init(pvr_dev); > if (err) > goto err_watchdog_fini; > diff --git a/drivers/gpu/drm/imagination/pvr_power.c b/drivers/gpu/drm/im= agination/pvr_power.c > index ba7816fd28ec..a24ed85f36c7 100644 > --- a/drivers/gpu/drm/imagination/pvr_power.c > +++ b/drivers/gpu/drm/imagination/pvr_power.c > @@ -15,6 +15,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -252,6 +253,9 @@ pvr_power_device_suspend(struct device *dev) > clk_disable_unprepare(pvr_dev->sys_clk); > clk_disable_unprepare(pvr_dev->core_clk); > =20 > + if (!IS_ERR(pvr_dev->reset)) > + reset_control_assert(pvr_dev->reset); reset_control_assert(pvr_dev->reset); This just returns 0 if pvr_dev->reset =3D=3D NULL. > + > err_drm_dev_exit: > drm_dev_exit(idx); > =20 > @@ -270,9 +274,15 @@ pvr_power_device_resume(struct device *dev) > if (!drm_dev_enter(drm_dev, &idx)) > return -EIO; > =20 > + if (!IS_ERR(pvr_dev->reset)) { > + err =3D reset_control_reset(pvr_dev->reset); > + if (err) > + goto err_drm_dev_exit; > + } err =3D reset_control_reset(pvr_dev->reset); if (err) goto err_drm_dev_exit; > + > err =3D clk_prepare_enable(pvr_dev->core_clk); > if (err) > - goto err_drm_dev_exit; > + goto err_reset_exit; > =20 > err =3D clk_prepare_enable(pvr_dev->sys_clk); > if (err) > @@ -301,6 +311,10 @@ pvr_power_device_resume(struct device *dev) > err_core_clk_disable: > clk_disable_unprepare(pvr_dev->core_clk); > =20 > +err_reset_exit: > + if (!IS_ERR(pvr_dev->reset)) > + reset_control_assert(pvr_dev->reset); err_reset_exit: reset_control_assert(pvr_dev->reset); > + > err_drm_dev_exit: > drm_dev_exit(idx); > =20 >=20 regards Philipp