From: Bjorn Helgaas <helgaas@kernel.org>
To: Kangjie Lu <kjlu@umn.edu>
Cc: linux-samsung-soc@vger.kernel.org,
Jingoo Han <jingoohan1@gmail.com>,
pakki001@umn.edu, linux-kernel@vger.kernel.org,
Krzysztof Kozlowski <krzk@kernel.org>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Kukjin Kim <kgene@kernel.org>,
linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] pci: dwc: add a check for resetting gpio
Date: Mon, 31 Dec 2018 14:40:48 -0600 [thread overview]
Message-ID: <20181231204048.GG159477@google.com> (raw)
In-Reply-To: <20181226022236.71682-1-kjlu@umn.edu>
Hi Kangjie,
Thanks for the patch.
On Tue, Dec 25, 2018 at 08:22:36PM -0600, Kangjie Lu wrote:
> devm_gpio_request_one() could fail. The fix checks its status and issues
> an error if it fails.
>
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> ---
> drivers/pci/controller/dwc/pci-exynos.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-exynos.c b/drivers/pci/controller/dwc/pci-exynos.c
> index cee5f2f590e2..e3a045e215d2 100644
> --- a/drivers/pci/controller/dwc/pci-exynos.c
> +++ b/drivers/pci/controller/dwc/pci-exynos.c
> @@ -226,9 +226,12 @@ static void exynos_pcie_assert_reset(struct exynos_pcie *ep)
> struct dw_pcie *pci = ep->pci;
> struct device *dev = pci->dev;
>
> - if (ep->reset_gpio >= 0)
> - devm_gpio_request_one(dev, ep->reset_gpio,
> - GPIOF_OUT_INIT_HIGH, "RESET");
> + if (ep->reset_gpio >= 0) {
> + if (devm_gpio_request_one(dev, ep->reset_gpio,
> + GPIOF_OUT_INIT_HIGH, "RESET"))
> + dev_err(dev, "Failed requesting reset gpio %d\n",
> + ep->reset_gpio);
> + }
Even before your patch, this code doesn't make sense to me.
devm_gpio_request_one() is a setup function and should be called in
the probe path. The "assert_reset" path should do something like
gpio_set_value(). See other callers, e.g.,
imx6_pcie_probe()
histb_pcie_probe()
mvebu_pcie_parse_port()
I'm skeptical that exynos_pcie_assert_reset() ever worked as intended,
so let's straighten that out before worrying about checking the return
code from devm_gpio_request_one().
The result should be two patches: (1) fix the devm_gpio_request_one()
usage, and (2) check the devm_gpio_request_one() return value.
> }
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
prev parent reply other threads:[~2018-12-31 20:40 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-26 2:22 [PATCH] pci: dwc: add a check for resetting gpio Kangjie Lu
2018-12-31 20:40 ` Bjorn Helgaas [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20181231204048.GG159477@google.com \
--to=helgaas@kernel.org \
--cc=jingoohan1@gmail.com \
--cc=kgene@kernel.org \
--cc=kjlu@umn.edu \
--cc=krzk@kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=linux-samsung-soc@vger.kernel.org \
--cc=lorenzo.pieralisi@arm.com \
--cc=pakki001@umn.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).