From: "Valdis Klētnieks" <valdis.kletnieks@vt.edu>
To: Dinh Nguyen <dinguyen@kernel.org>
Cc: devicetree@vger.kernel.org, daniel.thompson@linaro.org,
tony.luck@intel.com, manivannan.sadhasivam@linaro.org,
keescook@chromium.org, robh@kernel.org, linus.walleij@linaro.org,
anton@enomsg.org, linux@armlinux.org.uk,
linux-kernel@vger.kernel.org, p.zabel@pengutronix.de,
ccross@android.com, frowand.list@gmail.com,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCHv5] drivers/amba: add reset control to amba bus probe
Date: Tue, 27 Aug 2019 15:25:24 -0400 [thread overview]
Message-ID: <30608.1566933924@turing-police> (raw)
In-Reply-To: <20190826154252.22952-1-dinguyen@kernel.org>
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On Mon, 26 Aug 2019 10:42:52 -0500, Dinh Nguyen said:
> The primecell controller on some SoCs, i.e. SoCFPGA, is held in reset by
> default. Until recently, the DMA controller was brought out of reset by the
> bootloader(i.e. U-Boot). But a recent change in U-Boot, the peripherals
> that are not used are held in reset and are left to Linux to bring them
> out of reset.
>
> Add a mechanism for getting the reset property and de-assert the primecell
> module from reset if found. This is a not a hard fail if the reset properti
> is not present in the device tree node, so the driver will continue to
> probe.
Does this DTRT for both old and new U-Boots? My naive reading of this patch
says on an old U-Boot, we end up attempting to bring it out of reset even though
they had already been brought out.
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WARNING: multiple messages have this Message-ID (diff)
From: "Valdis Klētnieks" <valdis.kletnieks@vt.edu>
To: Dinh Nguyen <dinguyen@kernel.org>
Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
robh@kernel.org, linux@armlinux.org.uk, frowand.list@gmail.com,
keescook@chromium.org, anton@enomsg.org, ccross@android.com,
tony.luck@intel.com, daniel.thompson@linaro.org,
linus.walleij@linaro.org, manivannan.sadhasivam@linaro.org,
linux-arm-kernel@lists.infradead.org, p.zabel@pengutronix.de
Subject: Re: [PATCHv5] drivers/amba: add reset control to amba bus probe
Date: Tue, 27 Aug 2019 15:25:24 -0400 [thread overview]
Message-ID: <30608.1566933924@turing-police> (raw)
In-Reply-To: <20190826154252.22952-1-dinguyen@kernel.org>
[-- Attachment #1: Type: text/plain, Size: 803 bytes --]
On Mon, 26 Aug 2019 10:42:52 -0500, Dinh Nguyen said:
> The primecell controller on some SoCs, i.e. SoCFPGA, is held in reset by
> default. Until recently, the DMA controller was brought out of reset by the
> bootloader(i.e. U-Boot). But a recent change in U-Boot, the peripherals
> that are not used are held in reset and are left to Linux to bring them
> out of reset.
>
> Add a mechanism for getting the reset property and de-assert the primecell
> module from reset if found. This is a not a hard fail if the reset properti
> is not present in the device tree node, so the driver will continue to
> probe.
Does this DTRT for both old and new U-Boots? My naive reading of this patch
says on an old U-Boot, we end up attempting to bring it out of reset even though
they had already been brought out.
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next prev parent reply other threads:[~2019-08-27 19:25 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-26 15:42 [PATCHv5] drivers/amba: add reset control to amba bus probe Dinh Nguyen
2019-08-26 15:42 ` Dinh Nguyen
2019-08-26 15:51 ` Philipp Zabel
2019-08-26 15:51 ` Philipp Zabel
2019-08-27 19:25 ` Valdis Klētnieks [this message]
2019-08-27 19:25 ` Valdis Klētnieks
2019-08-28 13:34 ` Dinh Nguyen
2019-08-28 13:34 ` Dinh Nguyen
2019-08-28 13:46 ` Valdis Klētnieks
2019-08-28 13:46 ` Valdis Klētnieks
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