| Message ID | 20141013193618.GD29810@saruman |
|---|---|
| State | New |
| Headers | show |
On Mon, Oct 13, 2014 at 02:36:18PM -0500, Felipe Balbi wrote: > On Mon, Oct 13, 2014 at 02:26:32PM -0500, Felipe Balbi wrote: > > Hi, > > > > On Mon, Oct 13, 2014 at 12:24:04PM -0700, David Cohen wrote: > > > On Mon, Oct 13, 2014 at 02:14:05PM -0500, Felipe Balbi wrote: > > > > On Mon, Oct 13, 2014 at 11:23:59AM -0700, David Cohen wrote: > > > > > Even if a gpio pin is set to output, we still need to set INPUT_EN bit > > > > > > > > here you say you're setting that bit. > > > > > > > > > to be able to read its value. Without this change, we'll always read low > > > > > level state. > > > > > > > > > > Cc: <stable@vger.kernel.org> # v3.14+ > > > > > Signed-off-by: David Cohen <david.a.cohen@linux.intel.com> > > > > > --- > > > > > > > > > > Hi, > > > > > > > > > > I'm resending same v1 patch but now copying linux stable and linux gpio. > > > > > This patch is meant for all linux stable trees >= v3.14. > > > > > > > > > > Br, David > > > > > --- > > > > > > > > > > drivers/pinctrl/pinctrl-baytrail.c | 2 +- > > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > > > diff --git a/drivers/pinctrl/pinctrl-baytrail.c b/drivers/pinctrl/pinctrl-baytrail.c > > > > > index e12e5b07f6d7..c23d8ded936d 100644 > > > > > --- a/drivers/pinctrl/pinctrl-baytrail.c > > > > > +++ b/drivers/pinctrl/pinctrl-baytrail.c > > > > > @@ -318,7 +318,7 @@ static int byt_gpio_direction_output(struct gpio_chip *chip, > > > > > "Potential Error: Setting GPIO with direct_irq_en to output"); > > > > > > > > > > reg_val = readl(reg) | BYT_DIR_MASK; > > > > > - reg_val &= ~BYT_OUTPUT_EN; > > > > > + reg_val &= ~(BYT_OUTPUT_EN | BYT_INPUT_EN); > > > > > > > > but code is clearing it. Also, you're not patching byt_gpio_get(), so > > > > you can't be 'reading its value' either. Quite frankly, this looks very > > > > fishy to me. Comments on BYT_OUTPUT_EN and BYT_INPUT_EN states that > > > > those bits are active low, meaning that clearing them enables that > > > > particular feature. > > > > > > > > How can you enable a pin to be both OUTPUT and INPUT ? Look like what > > > > you really want is: > > > > > > > > diff --git a/drivers/pinctrl/pinctrl-baytrail.c b/drivers/pinctrl/pinctrl-baytrail.c > > > > index e12e5b0..69f882d 100644 > > > > --- a/drivers/pinctrl/pinctrl-baytrail.c > > > > +++ b/drivers/pinctrl/pinctrl-baytrail.c > > > > @@ -290,6 +290,7 @@ static int byt_gpio_direction_input(struct gpio_chip *chip, unsigned offset) > > > > > > > > value = readl(reg) | BYT_DIR_MASK; > > > > value &= ~BYT_INPUT_EN; /* active low */ > > > > + value |= BYT_OUTPUT_EN; /* disable output */ > > > > writel(value, reg); > > > > > > > > spin_unlock_irqrestore(&vg->lock, flags); > > > > @@ -319,6 +320,7 @@ static int byt_gpio_direction_output(struct gpio_chip *chip, > > > > > > > > reg_val = readl(reg) | BYT_DIR_MASK; > > > > reg_val &= ~BYT_OUTPUT_EN; > > > > + value |= BYT_INPUT_EN; /* disable input */ > > > > > > > > if (value) > > > > writel(reg_val | BYT_LEVEL, reg); > > > > > > > > completely untested however. Care to further explain why clearing both > > > > bits - thus enabling both INPUT and OUTPUT - is correct ? > > > > > > Actually I really meant what I sent, but perhaps I misspoke during > > > explanation. We need to clear the bit to enable the functionality. > > > > > > !BYT_INPUT_EN allows us to read the value. !BYT_OUTPUT_EN allows us to > > > set a value. If we want to set a value (acting as output) and still be > > > able to read via sysfs, we need to set both functionality (i.e. clear > > > both bits). > > > > > > I'll resend the patch with a better comment. > > > > Alright, just make sure that exposing a pin through sysfs and making it > > output high, then later switching it to input works. It looks like > > byt_gpio_direction_input() still needs to make sure OUTPUT is set. > > I also noticed that this is missing: > > diff --git a/drivers/pinctrl/pinctrl-baytrail.c b/drivers/pinctrl/pinctrl-baytrail.c > index e12e5b0..7db5ab9 100644 > --- a/drivers/pinctrl/pinctrl-baytrail.c > +++ b/drivers/pinctrl/pinctrl-baytrail.c > @@ -614,3 +614,9 @@ static int __init byt_gpio_init(void) > } > > subsys_initcall(byt_gpio_init); > + > +static void __exit byt_gpio_exit(void) > +{ > + platform_driver_unregister(&byt_gpio_driver); > +} > +module_exit(byt_gpio_exit); > > (also untested) It sure does. Want to send a formal patch and I Ack? > > ps: is BayTrail documentation available publicly ? Check Minnowboard Max :) It's baytrail. BR, David > > -- > balbi -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Oct 13, 2014 at 9:36 PM, Felipe Balbi <balbi@ti.com> wrote: > On Mon, Oct 13, 2014 at 02:26:32PM -0500, Felipe Balbi wrote: > I also noticed that this is missing: > > diff --git a/drivers/pinctrl/pinctrl-baytrail.c b/drivers/pinctrl/pinctrl-baytrail.c > index e12e5b0..7db5ab9 100644 > --- a/drivers/pinctrl/pinctrl-baytrail.c > +++ b/drivers/pinctrl/pinctrl-baytrail.c > @@ -614,3 +614,9 @@ static int __init byt_gpio_init(void) > } > > subsys_initcall(byt_gpio_init); > + > +static void __exit byt_gpio_exit(void) > +{ > + platform_driver_unregister(&byt_gpio_driver); > +} > +module_exit(byt_gpio_exit); But the Baytrail driver is not a loadable module, it is bool: config PINCTRL_BAYTRAIL bool "Intel Baytrail GPIO pin control" depends on GPIOLIB && ACPI && X86 (...) So I guess it won't need handling for removal, as it can only be compiled-in. 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, Oct 28, 2014 at 11:15:20AM +0100, Linus Walleij wrote: > On Mon, Oct 13, 2014 at 9:36 PM, Felipe Balbi <balbi@ti.com> wrote: > > On Mon, Oct 13, 2014 at 02:26:32PM -0500, Felipe Balbi wrote: > > > I also noticed that this is missing: > > > > diff --git a/drivers/pinctrl/pinctrl-baytrail.c b/drivers/pinctrl/pinctrl-baytrail.c > > index e12e5b0..7db5ab9 100644 > > --- a/drivers/pinctrl/pinctrl-baytrail.c > > +++ b/drivers/pinctrl/pinctrl-baytrail.c > > @@ -614,3 +614,9 @@ static int __init byt_gpio_init(void) > > } > > > > subsys_initcall(byt_gpio_init); > > + > > +static void __exit byt_gpio_exit(void) > > +{ > > + platform_driver_unregister(&byt_gpio_driver); > > +} > > +module_exit(byt_gpio_exit); > > But the Baytrail driver is not a loadable module, it is bool: > > config PINCTRL_BAYTRAIL > bool "Intel Baytrail GPIO pin control" > depends on GPIOLIB && ACPI && X86 > > (...) > > So I guess it won't need handling for removal, as it can only > be compiled-in. you can still unbind it through sysfs, right ? The thing also already provides a ->remove() method anyway.
On Tue, Oct 28, 2014 at 3:42 PM, Felipe Balbi <balbi@ti.com> wrote: > On Tue, Oct 28, 2014 at 11:15:20AM +0100, Linus Walleij wrote: >> On Mon, Oct 13, 2014 at 9:36 PM, Felipe Balbi <balbi@ti.com> wrote: >> > On Mon, Oct 13, 2014 at 02:26:32PM -0500, Felipe Balbi wrote: >> >> > I also noticed that this is missing: >> > >> > diff --git a/drivers/pinctrl/pinctrl-baytrail.c b/drivers/pinctrl/pinctrl-baytrail.c >> > index e12e5b0..7db5ab9 100644 >> > --- a/drivers/pinctrl/pinctrl-baytrail.c >> > +++ b/drivers/pinctrl/pinctrl-baytrail.c >> > @@ -614,3 +614,9 @@ static int __init byt_gpio_init(void) >> > } >> > >> > subsys_initcall(byt_gpio_init); >> > + >> > +static void __exit byt_gpio_exit(void) >> > +{ >> > + platform_driver_unregister(&byt_gpio_driver); >> > +} >> > +module_exit(byt_gpio_exit); >> >> But the Baytrail driver is not a loadable module, it is bool: >> >> config PINCTRL_BAYTRAIL >> bool "Intel Baytrail GPIO pin control" >> depends on GPIOLIB && ACPI && X86 >> >> (...) >> >> So I guess it won't need handling for removal, as it can only >> be compiled-in. > > you can still unbind it through sysfs, right ? The thing also already > provides a ->remove() method anyway. Yes you're right of course... But another way to get rid of the dilemma is to set .suppress_bind_attrs = true on the .driver field of the device driver. The one can't unbind it through sysfs anymore. .driver = { .name = "foo", .suppress_bind_attrs = true, }, So one of them need to be done. I suspect this is a kind of common problem... 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/pinctrl/pinctrl-baytrail.c b/drivers/pinctrl/pinctrl-baytrail.c index e12e5b0..7db5ab9 100644 --- a/drivers/pinctrl/pinctrl-baytrail.c +++ b/drivers/pinctrl/pinctrl-baytrail.c @@ -614,3 +614,9 @@ static int __init byt_gpio_init(void) } subsys_initcall(byt_gpio_init); + +static void __exit byt_gpio_exit(void) +{ + platform_driver_unregister(&byt_gpio_driver); +} +module_exit(byt_gpio_exit);