From: Luca Ceresoli <luca@lucaceresoli.net> To: Marc Zyngier <maz@kernel.org>, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org Cc: "Pali Rohár" <pali@kernel.org>, "Alyssa Rosenzweig" <alyssa@rosenzweig.io>, "Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>, "Bjorn Helgaas" <bhelgaas@google.com>, "Mark Kettenis" <mark.kettenis@xs4all.nl>, kernel-team@android.com Subject: Re: [PATCH v3 3/3] PCI: apple: Fix #PERST polarity Date: Tue, 23 Nov 2021 22:36:11 +0100 [thread overview] Message-ID: <453389da-b041-94b3-009e-6c6323134936@lucaceresoli.net> (raw) In-Reply-To: <20211123180636.80558-4-maz@kernel.org> Hi Mark, On 23/11/21 19:06, Marc Zyngier wrote: > Now that #PERST is properly defined as active-low in the device tree, > fix the driver to correctly drive the line indemendently of the > implied polarity. > > Fixes: 1e33888fbe44 ("PCI: apple: Add initial hardware bring-up") > Suggested-by: Pali Rohár <pali@kernel.org> > Signed-off-by: Marc Zyngier <maz@kernel.org> Thanks for quickly addressing this! Do we need a transition path for backward compatibility with old DTs already around? Something like this [0]. You said [1] the DT actually used is not even the one in the kernel, thus how do we guarantee DT and driver switch to the new polarity all at once? [0] https://lkml.org/lkml/2021/6/24/1049 [1] https://lkml.org/lkml/2021/11/23/455 > --- > drivers/pci/controller/pcie-apple.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c > index 957960a733c4..03bc56f39be5 100644 > --- a/drivers/pci/controller/pcie-apple.c > +++ b/drivers/pci/controller/pcie-apple.c > @@ -540,7 +540,7 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie, > rmw_set(PORT_APPCLK_EN, port->base + PORT_APPCLK); > > /* Engage #PERST before setting up the clock */ > > - gpiod_set_value(reset, 0); > + gpiod_set_value(reset, 1); > > ret = apple_pcie_setup_refclk(pcie, port); > if (ret < 0) > @@ -551,7 +551,7 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie, > > /* Deassert #PERST */ > rmw_set(PORT_PERST_OFF, port->base + PORT_PERST); > - gpiod_set_value(reset, 1); > + gpiod_set_value(reset, 0); Minor note: if it were me I would coalesce patches 1 and 3 together, otherwise we are insisting on a wrong implementation (patch 1) to later fix it all (this patch). -- Luca
WARNING: multiple messages have this Message-ID (diff)
From: Luca Ceresoli <luca@lucaceresoli.net> To: Marc Zyngier <maz@kernel.org>, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org Cc: "Pali Rohár" <pali@kernel.org>, "Alyssa Rosenzweig" <alyssa@rosenzweig.io>, "Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>, "Bjorn Helgaas" <bhelgaas@google.com>, "Mark Kettenis" <mark.kettenis@xs4all.nl>, kernel-team@android.com Subject: Re: [PATCH v3 3/3] PCI: apple: Fix #PERST polarity Date: Tue, 23 Nov 2021 22:36:11 +0100 [thread overview] Message-ID: <453389da-b041-94b3-009e-6c6323134936@lucaceresoli.net> (raw) In-Reply-To: <20211123180636.80558-4-maz@kernel.org> Hi Mark, On 23/11/21 19:06, Marc Zyngier wrote: > Now that #PERST is properly defined as active-low in the device tree, > fix the driver to correctly drive the line indemendently of the > implied polarity. > > Fixes: 1e33888fbe44 ("PCI: apple: Add initial hardware bring-up") > Suggested-by: Pali Rohár <pali@kernel.org> > Signed-off-by: Marc Zyngier <maz@kernel.org> Thanks for quickly addressing this! Do we need a transition path for backward compatibility with old DTs already around? Something like this [0]. You said [1] the DT actually used is not even the one in the kernel, thus how do we guarantee DT and driver switch to the new polarity all at once? [0] https://lkml.org/lkml/2021/6/24/1049 [1] https://lkml.org/lkml/2021/11/23/455 > --- > drivers/pci/controller/pcie-apple.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c > index 957960a733c4..03bc56f39be5 100644 > --- a/drivers/pci/controller/pcie-apple.c > +++ b/drivers/pci/controller/pcie-apple.c > @@ -540,7 +540,7 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie, > rmw_set(PORT_APPCLK_EN, port->base + PORT_APPCLK); > > /* Engage #PERST before setting up the clock */ > > - gpiod_set_value(reset, 0); > + gpiod_set_value(reset, 1); > > ret = apple_pcie_setup_refclk(pcie, port); > if (ret < 0) > @@ -551,7 +551,7 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie, > > /* Deassert #PERST */ > rmw_set(PORT_PERST_OFF, port->base + PORT_PERST); > - gpiod_set_value(reset, 1); > + gpiod_set_value(reset, 0); Minor note: if it were me I would coalesce patches 1 and 3 together, otherwise we are insisting on a wrong implementation (patch 1) to later fix it all (this patch). -- Luca _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-11-23 21:36 UTC|newest] Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-11-23 18:06 [PATCH v3 0/3] PCI: apple: Assorted #PERST fixes Marc Zyngier 2021-11-23 18:06 ` Marc Zyngier 2021-11-23 18:06 ` [PATCH v3 1/3] PCI: apple: Follow the PCIe specifications when resetting the port Marc Zyngier 2021-11-23 18:06 ` Marc Zyngier 2021-11-24 9:22 ` Luca Ceresoli 2021-11-24 9:22 ` Luca Ceresoli 2021-11-24 12:56 ` Robin Murphy 2021-11-24 12:56 ` Robin Murphy 2021-12-07 16:22 ` Bjorn Helgaas 2021-12-07 16:22 ` Bjorn Helgaas 2021-11-23 18:06 ` [PATCH v3 2/3] arm64: dts: apple: t8103: Fix PCIe #PERST polarity Marc Zyngier 2021-11-23 18:06 ` Marc Zyngier 2021-11-23 18:16 ` Mark Kettenis 2021-11-23 18:16 ` Mark Kettenis 2021-11-24 9:17 ` Luca Ceresoli 2021-11-24 9:17 ` Luca Ceresoli 2021-12-01 14:46 ` Arnd Bergmann 2021-12-01 14:46 ` Arnd Bergmann 2021-11-23 18:06 ` [PATCH v3 3/3] PCI: apple: Fix " Marc Zyngier 2021-11-23 18:06 ` Marc Zyngier 2021-11-23 21:36 ` Luca Ceresoli [this message] 2021-11-23 21:36 ` Luca Ceresoli 2021-11-24 9:02 ` Marc Zyngier 2021-11-24 9:02 ` Marc Zyngier 2021-11-24 9:16 ` Luca Ceresoli 2021-11-24 9:16 ` Luca Ceresoli 2021-11-30 11:56 ` [PATCH v3 0/3] PCI: apple: Assorted #PERST fixes Lorenzo Pieralisi 2021-11-30 11:56 ` Lorenzo Pieralisi 2021-11-30 11:59 ` Marc Zyngier 2021-11-30 11:59 ` Marc Zyngier 2021-11-30 12:12 ` Lorenzo Pieralisi 2021-11-30 12:12 ` Lorenzo Pieralisi 2021-11-30 12:45 ` Marc Zyngier 2021-11-30 12:45 ` Marc Zyngier 2021-12-01 14:48 ` Arnd Bergmann 2021-12-01 14:48 ` Arnd Bergmann 2021-12-07 10:16 ` Lorenzo Pieralisi 2021-12-07 10:16 ` Lorenzo Pieralisi 2021-12-07 20:30 ` Bjorn Helgaas 2021-12-07 20:30 ` Bjorn Helgaas
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