| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <CAMhs-H-teyG7OE2cugrGFoxothf_ZQwX_jKR+9mpfu6e_FAgmA@mail.gmail.com>
Date: Fri, 25 Jun 2021 14:40:56 +0200
From: Sergio Paracuellos <sergio.paracuellos@...il.com>
To: Bartosz Golaszewski <bgolaszewski@...libre.com>
Cc: linux-gpio <linux-gpio@...r.kernel.org>,
Matthias Brugger <matthias.bgg@...il.com>,
Linus Walleij <linus.walleij@...aro.org>,
John Thomson <git@...nthomson.fastmail.com.au>,
LKML <linux-kernel@...r.kernel.org>, NeilBrown <neil@...wn.name>,
René van Dorst <opensource@...rst.com>,
Nicholas Mc Guire <hofrat@...dl.org>
Subject: Re: [PATCH] gpio: mt7621: support gpio-line-names property
Hi Bartosz,
On Fri, Jun 25, 2021 at 1:53 PM Bartosz Golaszewski
<bgolaszewski@...libre.com> wrote:
>
> On Sat, Jun 19, 2021 at 9:35 AM Sergio Paracuellos
> <sergio.paracuellos@...il.com> wrote:
> >
> > The default handling of the gpio-line-names property by the
> > gpiolib-of implementation does not work with the multiple
> > gpiochip banks per device structure used by the gpio-mt7621
> > driver.
> >
> > This commit adds driver level support for the device tree
> > property so that GPIO lines can be assigned friendly names.
> >
> > Signed-off-by: Sergio Paracuellos <sergio.paracuellos@...il.com>
> > ---
> > Hi,
> >
> > This driver has three gpiochips with 32 gpios each. Core implmentation
> > got gpio's repeated along each gpio chip if chip.names is not assigned.
> > To avoid this behaviour driver will set this names as empty or
> > with desired friendly line names. Consider the following sample with
> > minimal entries for the first chip with this patch changes applied:
> >
> > &gpio {
> > gpio-line-names = "", "", "", "",
> > "", "", "SFP LOS", "extcon port5 PoE compat",
> > "SFP module def0", "LED blue SFP", "SFP tx disable", "",
> > "switch USB power", "mode", "", "buzzer",
> > "LED blue pwr", "switch port5 PoE out", "reset";
> > };
> >
> > gpioinfo
> > gpiochip0 - 32 lines:
> > line 0: unnamed unused output active-high
> > line 1: unnamed unused input active-high
> > line 2: unnamed unused input active-high
> > line 3: unnamed unused input active-high
> > line 4: unnamed unused input active-high
> > line 5: unnamed unused input active-high
> > line 6: "SFP LOS" "los" input active-high [used]
> > line 7: "extcon port5 PoE compat" unused input active-high
> > line 8: "SFP module def0" "mod-def0" input active-low [used]
> > line 9: "LED blue SFP" "blue:sfp" output active-high [used]
> > line 10: "SFP tx disable" "tx-disable" output active-high [used]
> > line 11: unnamed unused output active-high
> > line 12: "switch USB power" "usb_power" output active-high [used]
> > line 13: "mode" "mode" input active-high [used]
> > line 14: unnamed unused input active-high
> > line 15: "buzzer" "buzzer" output active-high [used]
> > line 16: "LED blue pwr" "blue:pwr" output active-high [used]
> > line 17: "switch port5 PoE out" "sysfs" input active-high [used]
> > line 18: "reset" "reset" input active-high [used]
> > line 19: unnamed unused input active-high
> > line 20: unnamed unused input active-high
> > line 21: unnamed unused input active-high
> > line 22: unnamed unused input active-high
> > line 23: unnamed unused input active-high
> > line 24: unnamed unused input active-high
> > line 25: unnamed unused input active-high
> > line 26: unnamed unused input active-high
> > line 27: unnamed unused input active-high
> > line 28: unnamed unused input active-high
> > line 29: unnamed unused input active-high
> > line 30: unnamed unused input active-high
> > line 31: unnamed unused input active-high
> > gpiochip1 - 32 lines:
> > line 0: unnamed unused input active-high
> > line 1: unnamed unused input active-high
> > ...
> > line 31: unnamed unused input active-high
> > gpiochip2 - 32 lines:
> > line 0: unnamed unused input active-high
> > line 1: unnamed unused input active-high
> > ...
> > line 31: unnamed unused input active-high
> >
> > To avoid gpiochip1 and gpiochip2 entries repeated with this
> > minimal lines definition change, we assign empty reserved
> > 'names' in driver code.
> >
> > Note that we also don't want to to prevent the driver from
> > succeeding at probe due to an error in the gpio-line-names
> > property and the ENODATA error is considered a valid result
> > to terminate any further labeling so there is no need for
> > an error message in that case. Other error results are
> > unexpected so an error message indicating the consequence
> > of the error is appropriate here.
> >
> > Thanks in advance for your time.
> >
> > Best regards,
> > Sergio Paracuellos
> >
> > drivers/gpio/gpio-mt7621.c | 41 ++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 41 insertions(+)
> >
> > diff --git a/drivers/gpio/gpio-mt7621.c b/drivers/gpio/gpio-mt7621.c
> > index 82fb20dca53a..b5f8fd8e928a 100644
> > --- a/drivers/gpio/gpio-mt7621.c
> > +++ b/drivers/gpio/gpio-mt7621.c
> > @@ -206,6 +206,45 @@ mediatek_gpio_xlate(struct gpio_chip *chip,
> > return gpio % MTK_BANK_WIDTH;
> > }
> >
> > +static void
> > +mediatek_gpio_set_names(struct device *dev, struct mtk_gc *rg)
> > +{
> > + struct device_node *np = dev->of_node;
> > + const char **names;
> > + int nstrings, base;
> > + unsigned int i;
> > +
> > + names = devm_kcalloc(dev, MTK_BANK_WIDTH, sizeof(*names),
> > + GFP_KERNEL);
> > + if (!names)
> > + return;
>
> While the ENODATA bit makes sense, not failing after an OOM in a
> driver is wrong. Please return the error code here.
Ok, I see your point. I didn't want the driver to fail in its setup
completion because of this property being failing but what you are
saying makes sense, so I will return -ENOMEM for this case and check
for it in 'mediatek_gpio_bank_probe'. Will send v2 with these changes
hopefully tomorrow.
Thanks,
Sergio Paracuellos
>
> Bartosz
>
> > +
> > + base = rg->bank * MTK_BANK_WIDTH;
> > + nstrings = of_property_count_strings(np, "gpio-line-names");
> > + if (nstrings <= base)
> > + goto assign_names;
> > +
> > + for (i = 0; i < MTK_BANK_WIDTH; i++) {
> > + const char *name;
> > + int ret;
> > +
> > + ret = of_property_read_string_index(np, "gpio-line-names",
> > + base + i, &name);
> > + if (ret) {
> > + if (ret != -ENODATA)
> > + dev_err(dev, "unable to name line %d: %d\n",
> > + base + i, ret);
> > + break;
> > + }
> > +
> > + if (*name)
> > + names[i] = name;
> > + }
> > +
> > +assign_names:
> > + rg->chip.names = names;
> > +}
> > +
> > static int
> > mediatek_gpio_bank_probe(struct device *dev,
> > struct device_node *node, int bank)
> > @@ -241,6 +280,8 @@ mediatek_gpio_bank_probe(struct device *dev,
> > if (!rg->chip.label)
> > return -ENOMEM;
> >
> > + mediatek_gpio_set_names(dev, rg);
> > +
> > rg->irq_chip.name = dev_name(dev);
> > rg->irq_chip.parent_device = dev;
> > rg->irq_chip.irq_unmask = mediatek_gpio_irq_unmask;
> > --
> > 2.25.1
> >
Powered by blists - more mailing lists