[PATCH] gpiolib: don't build HTE code with CONFIG_HTE disabled

[PATCH] gpiolib: don't build HTE code with CONFIG_HTE disabled

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Hardware timestamping is only used on tegra186 platforms but we include
the code and export the symbols everywhere. Shrink the binary a bit by
compiling the relevant functions conditionally.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 drivers/gpio/gpiolib.c        |  2 ++
 include/linux/gpio/consumer.h | 36 +++++++++++++++++++++--------------
 2 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index be3351583508..0f4b31f4a995 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2908,6 +2908,7 @@ int gpiod_direction_output_nonotify(struct gpio_desc *desc, int value)
 	return ret;
 }
 
+#if IS_ENABLED(CONFIG_HTE)
 /**
  * gpiod_enable_hw_timestamp_ns - Enable hardware timestamp in nanoseconds.
  *
@@ -2973,6 +2974,7 @@ int gpiod_disable_hw_timestamp_ns(struct gpio_desc *desc, unsigned long flags)
 	return ret;
 }
 EXPORT_SYMBOL_GPL(gpiod_disable_hw_timestamp_ns);
+#endif /* CONFIG_HTE */
 
 /**
  * gpiod_set_config - sets @config for a GPIO
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index db2dfbae8edb..2175f62e2178 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -110,8 +110,6 @@ int gpiod_get_direction(struct gpio_desc *desc);
 int gpiod_direction_input(struct gpio_desc *desc);
 int gpiod_direction_output(struct gpio_desc *desc, int value);
 int gpiod_direction_output_raw(struct gpio_desc *desc, int value);
-int gpiod_enable_hw_timestamp_ns(struct gpio_desc *desc, unsigned long flags);
-int gpiod_disable_hw_timestamp_ns(struct gpio_desc *desc, unsigned long flags);
 
 /* Value get/set from non-sleeping context */
 int gpiod_get_value(const struct gpio_desc *desc);
@@ -348,18 +346,6 @@ static inline int gpiod_direction_output_raw(struct gpio_desc *desc, int value)
 	WARN_ON(desc);
 	return -ENOSYS;
 }
-static inline int gpiod_enable_hw_timestamp_ns(struct gpio_desc *desc,
-					       unsigned long flags)
-{
-	WARN_ON(desc);
-	return -ENOSYS;
-}
-static inline int gpiod_disable_hw_timestamp_ns(struct gpio_desc *desc,
-						unsigned long flags)
-{
-	WARN_ON(desc);
-	return -ENOSYS;
-}
 static inline int gpiod_get_value(const struct gpio_desc *desc)
 {
 	/* GPIO can never have been requested */
@@ -560,6 +546,28 @@ struct gpio_desc *devm_fwnode_gpiod_get_index(struct device *dev,
 
 #endif /* CONFIG_GPIOLIB */
 
+#if IS_ENABLED(CONFIG_GPIOLIB) && IS_ENABLED(CONFIG_HTE)
+int gpiod_enable_hw_timestamp_ns(struct gpio_desc *desc, unsigned long flags);
+int gpiod_disable_hw_timestamp_ns(struct gpio_desc *desc, unsigned long flags);
+#else
+static inline int gpiod_enable_hw_timestamp_ns(struct gpio_desc *desc,
+					       unsigned long flags)
+{
+#if !IS_ENABLED(CONFIG_GPIOLIB)
+	WARN_ON(desc);
+#endif
+	return -ENOSYS;
+}
+static inline int gpiod_disable_hw_timestamp_ns(struct gpio_desc *desc,
+						unsigned long flags)
+{
+#if !IS_ENABLED(CONFIG_GPIOLIB)
+	WARN_ON(desc);
+#endif
+	return -ENOSYS;
+}
+#endif /* CONFIG_GPIOLIB && CONFIG_HTE */
+
 static inline
 struct gpio_desc *devm_fwnode_gpiod_get(struct device *dev,
 					struct fwnode_handle *fwnode,
-- 
2.45.2

Re: [PATCH] gpiolib: don't build HTE code with CONFIG_HTE disabled

[Linus Walleij]

Hi Bartosz,

On Thu, Feb 6, 2025 at 3:37 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> Hardware timestamping is only used on tegra186 platforms but we include
> the code and export the symbols everywhere. Shrink the binary a bit by
> compiling the relevant functions conditionally.
>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

> +static inline int gpiod_enable_hw_timestamp_ns(struct gpio_desc *desc,
> +                                              unsigned long flags)
> +{
> +#if !IS_ENABLED(CONFIG_GPIOLIB)
> +       WARN_ON(desc);
> +#endif
> +       return -ENOSYS;

I think you can just:

if (!IS_ENABLED(CONFIG_GPIOLIB))
  WARN_ON()
else
  return -ENOSYS;

here, so it's not so ifdeffy.
The compiler will eliminate the second branch.

Yours,
Linus Walleij