| Message ID | 1440780258-23652-1-git-send-email-bjorn.andersson@sonymobile.com |
|---|---|
| State | New |
| Headers | show |
On Fri 28 Aug 09:44 PDT 2015, Bjorn Andersson wrote: > It's possible to have gpio chips hanging off unreliable remote buses > where the get() operation will fail to acquire a readout of the current > gpio state. Propagate these errors to the consumer so that they can > act on, retry or ignore these failing reads, instead of treating them as > the line being held high. > > Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com> > --- > drivers/gpio/gpiolib.c | 21 ++++++++++++++------- > 1 file changed, 14 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c > index 3b5e516298e0..dc17dbf8c234 100644 > --- a/drivers/gpio/gpiolib.c > +++ b/drivers/gpio/gpiolib.c > @@ -1173,15 +1173,16 @@ EXPORT_SYMBOL_GPL(gpiod_is_active_low); > * that the GPIO was actually requested. > */ > > -static bool _gpiod_get_raw_value(const struct gpio_desc *desc) > +static int _gpiod_get_raw_value(const struct gpio_desc *desc) > { > struct gpio_chip *chip; > - bool value; > int offset; > + int value; > > chip = desc->chip; > offset = gpio_chip_hwgpio(desc); > - value = chip->get ? chip->get(chip, offset) : false; > + value = chip->get ? chip->get(chip, offset) : -EIO; Linus, Alexandre, please feel free to apply this with -ENOTSUPP in accordance to Alexandre's comment in [1], if you prefer that. I picked -EIO as that's what's used in most other places when the get() op is missing. Maybe we should follow up with separate patch to make that consistent? [1] https://lkml.org/lkml/2015/8/31/8 > + value = value < 0 ? value : !!value; > trace_gpio_value(desc_to_gpio(desc), 1, value); > return value; > } Regards, Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Sep 1, 2015 at 2:16 PM, Bjorn Andersson <bjorn.andersson@sonymobile.com> wrote: > On Fri 28 Aug 09:44 PDT 2015, Bjorn Andersson wrote: > >> It's possible to have gpio chips hanging off unreliable remote buses >> where the get() operation will fail to acquire a readout of the current >> gpio state. Propagate these errors to the consumer so that they can >> act on, retry or ignore these failing reads, instead of treating them as >> the line being held high. >> >> Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com> >> --- >> drivers/gpio/gpiolib.c | 21 ++++++++++++++------- >> 1 file changed, 14 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c >> index 3b5e516298e0..dc17dbf8c234 100644 >> --- a/drivers/gpio/gpiolib.c >> +++ b/drivers/gpio/gpiolib.c >> @@ -1173,15 +1173,16 @@ EXPORT_SYMBOL_GPL(gpiod_is_active_low); >> * that the GPIO was actually requested. >> */ >> >> -static bool _gpiod_get_raw_value(const struct gpio_desc *desc) >> +static int _gpiod_get_raw_value(const struct gpio_desc *desc) >> { >> struct gpio_chip *chip; >> - bool value; >> int offset; >> + int value; >> >> chip = desc->chip; >> offset = gpio_chip_hwgpio(desc); >> - value = chip->get ? chip->get(chip, offset) : false; >> + value = chip->get ? chip->get(chip, offset) : -EIO; > > Linus, Alexandre, please feel free to apply this with -ENOTSUPP in > accordance to Alexandre's comment in [1], if you prefer that. I picked > -EIO as that's what's used in most other places when the get() op is > missing. > > Maybe we should follow up with separate patch to make that consistent? I will let Linus decide which value is the more appropriate, the patch looks solid to me! Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Thanks! -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Aug 28, 2015 at 6:44 PM, Bjorn Andersson <bjorn.andersson@sonymobile.com> wrote: > It's possible to have gpio chips hanging off unreliable remote buses > where the get() operation will fail to acquire a readout of the current > gpio state. Propagate these errors to the consumer so that they can > act on, retry or ignore these failing reads, instead of treating them as > the line being held high. > > Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com> This patch applied for fixes with Alex' Review-tag. Thanks for fixing this! Should I even tag it for stable? Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Sep 1, 2015 at 7:16 AM, Bjorn Andersson <bjorn.andersson@sonymobile.com> wrote: > Linus, Alexandre, please feel free to apply this with -ENOTSUPP in > accordance to Alexandre's comment in [1], if you prefer that. I picked > -EIO as that's what's used in most other places when the get() op is > missing. I applied as-is for fixes. > Maybe we should follow up with separate patch to make that consistent? A patch doing this would be appropriate for devel as it makes deeper semantic changes. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 3b5e516298e0..dc17dbf8c234 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1173,15 +1173,16 @@ EXPORT_SYMBOL_GPL(gpiod_is_active_low); * that the GPIO was actually requested. */ -static bool _gpiod_get_raw_value(const struct gpio_desc *desc) +static int _gpiod_get_raw_value(const struct gpio_desc *desc) { struct gpio_chip *chip; - bool value; int offset; + int value; chip = desc->chip; offset = gpio_chip_hwgpio(desc); - value = chip->get ? chip->get(chip, offset) : false; + value = chip->get ? chip->get(chip, offset) : -EIO; + value = value < 0 ? value : !!value; trace_gpio_value(desc_to_gpio(desc), 1, value); return value; } @@ -1191,7 +1192,7 @@ static bool _gpiod_get_raw_value(const struct gpio_desc *desc) * @desc: gpio whose value will be returned * * Return the GPIO's raw value, i.e. the value of the physical line disregarding - * its ACTIVE_LOW status. + * its ACTIVE_LOW status, or negative errno on failure. * * This function should be called from contexts where we cannot sleep, and will * complain if the GPIO chip functions potentially sleep. @@ -1211,7 +1212,7 @@ EXPORT_SYMBOL_GPL(gpiod_get_raw_value); * @desc: gpio whose value will be returned * * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into - * account. + * account, or negative errno on failure. * * This function should be called from contexts where we cannot sleep, and will * complain if the GPIO chip functions potentially sleep. @@ -1225,6 +1226,9 @@ int gpiod_get_value(const struct gpio_desc *desc) WARN_ON(desc->chip->can_sleep); value = _gpiod_get_raw_value(desc); + if (value < 0) + return value; + if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) value = !value; @@ -1547,7 +1551,7 @@ EXPORT_SYMBOL_GPL(gpiochip_unlock_as_irq); * @desc: gpio whose value will be returned * * Return the GPIO's raw value, i.e. the value of the physical line disregarding - * its ACTIVE_LOW status. + * its ACTIVE_LOW status, or negative errno on failure. * * This function is to be called from contexts that can sleep. */ @@ -1565,7 +1569,7 @@ EXPORT_SYMBOL_GPL(gpiod_get_raw_value_cansleep); * @desc: gpio whose value will be returned * * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into - * account. + * account, or negative errno on failure. * * This function is to be called from contexts that can sleep. */ @@ -1578,6 +1582,9 @@ int gpiod_get_value_cansleep(const struct gpio_desc *desc) return 0; value = _gpiod_get_raw_value(desc); + if (value < 0) + return value; + if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) value = !value;
It's possible to have gpio chips hanging off unreliable remote buses where the get() operation will fail to acquire a readout of the current gpio state. Propagate these errors to the consumer so that they can act on, retry or ignore these failing reads, instead of treating them as the line being held high. Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com> --- drivers/gpio/gpiolib.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-)