diff mbox series

[07/21] gpiolib: provide gpio_device_get_base()

Message ID 20230905185309.131295-8-brgl@bgdev.pl (mailing list archive)
State Handled Elsewhere, archived
Headers show
Series gpio: convert users to gpio_device_find() and remove gpiochip_find() | expand

Commit Message

Bartosz Golaszewski Sept. 5, 2023, 6:52 p.m. UTC
From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Let's start adding getters for the opaque struct gpio_device. Start with
a function allowing to retrieve the base GPIO number.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 drivers/gpio/gpiolib.c      | 13 +++++++++++++
 include/linux/gpio/driver.h |  3 +++
 2 files changed, 16 insertions(+)

Comments

Linus Walleij Sept. 7, 2023, 7:17 a.m. UTC | #1
On Tue, Sep 5, 2023 at 8:53 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> Let's start adding getters for the opaque struct gpio_device. Start with
> a function allowing to retrieve the base GPIO number.
>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

I guess you have a solid usecase for drivers needing to do this
crazy thing, because I suppose you feel as much as me that
this should rather be gpiolib-internal and confined to
drivers/gpio/gpiolib.h?

If you add a valid reason for making this globally visible outside
of drivers/[gpio|pinctrl] to the commit message I guess I can live
with it because we need to think of the bigger picture:
Acked-by: Linus Walleij <linus.walleij@linaro.org>

It brings to mind the now confusing "base" inside of
struct gpio_chip. We all know it should go away, but since it
is never used during the lifetime of the gpio_chip - or SHOULD
never be used - it should rather be an argument to
[devm_]gpiochip_add_data( .... int base);...

Maybe something we should add to our TODO file.

Yours,
Linus Walleij
Bartosz Golaszewski Sept. 7, 2023, 7:57 a.m. UTC | #2
On Thu, Sep 7, 2023 at 9:17 AM Linus Walleij <linus.walleij@linaro.org> wrote:
>
> On Tue, Sep 5, 2023 at 8:53 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>
> > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> >
> > Let's start adding getters for the opaque struct gpio_device. Start with
> > a function allowing to retrieve the base GPIO number.
> >
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> I guess you have a solid usecase for drivers needing to do this
> crazy thing, because I suppose you feel as much as me that
> this should rather be gpiolib-internal and confined to
> drivers/gpio/gpiolib.h?
>
> If you add a valid reason for making this globally visible outside
> of drivers/[gpio|pinctrl] to the commit message I guess I can live
> with it because we need to think of the bigger picture:
> Acked-by: Linus Walleij <linus.walleij@linaro.org>
>
> It brings to mind the now confusing "base" inside of
> struct gpio_chip. We all know it should go away, but since it
> is never used during the lifetime of the gpio_chip - or SHOULD
> never be used - it should rather be an argument to
> [devm_]gpiochip_add_data( .... int base);...
>
> Maybe something we should add to our TODO file.
>
> Yours,
> Linus Walleij

For this series it's the HTE driver that uses it and I don't have a
good idea about how to change it. Dipen?

I would also love to make pinctrl not use the internal GPIOLIB header
so it'll be another user, unless you can figure out a way to not use
gc->base? :)

I think we're stuck with it for now.

Bart
Dipen Patel Oct. 3, 2023, 8:32 p.m. UTC | #3
On 9/7/23 12:57 AM, Bartosz Golaszewski wrote:
> On Thu, Sep 7, 2023 at 9:17 AM Linus Walleij <linus.walleij@linaro.org> wrote:
>>
>> On Tue, Sep 5, 2023 at 8:53 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>>
>>> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>>>
>>> Let's start adding getters for the opaque struct gpio_device. Start with
>>> a function allowing to retrieve the base GPIO number.
>>>
>>> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>>
>> I guess you have a solid usecase for drivers needing to do this
>> crazy thing, because I suppose you feel as much as me that
>> this should rather be gpiolib-internal and confined to
>> drivers/gpio/gpiolib.h?
>>
>> If you add a valid reason for making this globally visible outside
>> of drivers/[gpio|pinctrl] to the commit message I guess I can live
>> with it because we need to think of the bigger picture:
>> Acked-by: Linus Walleij <linus.walleij@linaro.org>
>>
>> It brings to mind the now confusing "base" inside of
>> struct gpio_chip. We all know it should go away, but since it
>> is never used during the lifetime of the gpio_chip - or SHOULD
>> never be used - it should rather be an argument to
>> [devm_]gpiochip_add_data( .... int base);...
>>
>> Maybe something we should add to our TODO file.
>>
>> Yours,
>> Linus Walleij
> 
> For this series it's the HTE driver that uses it and I don't have a
> good idea about how to change it. Dipen?

Missed responding to this, apologies. I believe we are having similar
discussion in the hte only patch. We can continue discussing there.

> 
> I would also love to make pinctrl not use the internal GPIOLIB header
> so it'll be another user, unless you can figure out a way to not use
> gc->base? :)
> 
> I think we're stuck with it for now.
> 
> Bart
diff mbox series

Patch

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 9637a79a9a60..9715bbc698e9 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -233,6 +233,19 @@  struct gpio_device *gpiod_to_device(struct gpio_desc *desc)
 }
 EXPORT_SYMBOL_GPL(gpiod_to_device);
 
+/**
+ * gpio_device_get_base() - Get the base GPIO number allocated by this device
+ * @gdev: GPIO device
+ *
+ * Returns:
+ * First GPIO number in the global GPIO numberspace for this device.
+ */
+int gpio_device_get_base(struct gpio_device *gdev)
+{
+	return gdev->base;
+}
+EXPORT_SYMBOL_GPL(gpio_device_get_base);
+
 /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
 static int gpiochip_find_base(int ngpio)
 {
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index e3747e730ed1..b68b3493b29d 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -780,6 +780,9 @@  void gpiochip_unlock_as_irq(struct gpio_chip *gc, unsigned int offset);
 struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc);
 struct gpio_device *gpiod_to_device(struct gpio_desc *desc);
 
+/* struct gpio_device getters */
+int gpio_device_get_base(struct gpio_device *gdev);
+
 #else /* CONFIG_GPIOLIB */
 
 #include <linux/err.h>