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Date: Thu, 10 Mar 2022 15:09:37 -0800
From: Brian Norris <briannorris@...omium.org>
To: Linus Walleij <linus.walleij@...aro.org>,
Bartosz Golaszewski <brgl@...ev.pl>
Cc: linux-gpio@...r.kernel.org, Jianqun Xu <jay.xu@...k-chips.com>,
linux-kernel@...r.kernel.org,
Brian Norris <briannorris@...omium.org>
Subject: [PATCH] gpio: Drop CONFIG_DEBUG_GPIO
CONFIG_DEBUG_GPIO has existed since the introduction of gpiolib, but its
Kconfig description and motivation seem to have been off-base for quite
some time.
Description: it says nothing about enabling extra printk()s. But -DDEBUG
does just that; it turns on every dev_dbg()/pr_debug() that would
otherwise be silent.
Purpose: might_sleep() and WARN_ON() should have very low overhead, and
anyway, there's a separate CONFIG_DEBUG_ATOMIC_SLEEP for the
might_sleep() overhead.
Additionally, the conflated purpose (extra debug checks, and extra
printing) makes for a mixed bag for users. In particular, some drivers
can be extra-spammy with -DDEBUG -- e.g., with the Rockchip GPIO driver
getting moved out of drivers/pinctrl/ in commit 936ee2675eee
("gpio/rockchip: add driver for rockchip gpio"), now some dev_dbg()
calls are enabled in its IRQ handler.
Altogether, it seems like CONFIG_DEBUG_GPIO isn't serving any good
purpose and should just be removed. It can be supplanted by dynamic
debug (which post-dates gpiolib) and atomic-debug facilities.
Signed-off-by: Brian Norris <briannorris@...omium.org>
---
drivers/gpio/Kconfig | 11 -----------
drivers/gpio/Makefile | 2 --
drivers/gpio/gpiolib.c | 30 +++++++++---------------------
3 files changed, 9 insertions(+), 34 deletions(-)
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index ad99b96f6d79..ef91cc3066f5 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -47,17 +47,6 @@ config GPIOLIB_IRQCHIP
select IRQ_DOMAIN
bool
-config DEBUG_GPIO
- bool "Debug GPIO calls"
- depends on DEBUG_KERNEL
- help
- Say Y here to add some extra checks and diagnostics to GPIO calls.
- These checks help ensure that GPIOs have been properly initialized
- before they are used, and that sleeping calls are not made from
- non-sleeping contexts. They can make bitbanged serial protocols
- slower. The diagnostics help catch the type of setup errors
- that are most common when setting up new platforms or boards.
-
config GPIO_SYSFS
bool "/sys/class/gpio/... (sysfs interface)" if EXPERT
depends on SYSFS
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 30141fec12be..f3ddac590ffe 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -1,8 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
# generic gpio support: platform drivers, dedicated expander chips, etc
-ccflags-$(CONFIG_DEBUG_GPIO) += -DDEBUG
-
obj-$(CONFIG_GPIOLIB) += gpiolib.o
obj-$(CONFIG_GPIOLIB) += gpiolib-devres.o
obj-$(CONFIG_GPIOLIB) += gpiolib-legacy.o
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 56975a6d7c9e..1e1a193987fd 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -40,18 +40,6 @@
*/
-/* When debugging, extend minimal trust to callers and platform code.
- * Also emit diagnostic messages that may help initial bringup, when
- * board setup or driver bugs are most common.
- *
- * Otherwise, minimize overhead in what may be bitbanging codepaths.
- */
-#ifdef DEBUG
-#define extra_checks 1
-#else
-#define extra_checks 0
-#endif
-
/* Device and char device-related information */
static DEFINE_IDA(gpio_ida);
static dev_t gpio_devt;
@@ -2046,7 +2034,7 @@ void gpiod_free(struct gpio_desc *desc)
module_put(desc->gdev->owner);
put_device(&desc->gdev->dev);
} else {
- WARN_ON(extra_checks);
+ WARN_ON(1);
}
}
@@ -3338,7 +3326,7 @@ EXPORT_SYMBOL_GPL(gpiochip_line_is_persistent);
*/
int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
{
- might_sleep_if(extra_checks);
+ might_sleep();
VALIDATE_DESC(desc);
return gpiod_get_raw_value_commit(desc);
}
@@ -3357,7 +3345,7 @@ int gpiod_get_value_cansleep(const struct gpio_desc *desc)
{
int value;
- might_sleep_if(extra_checks);
+ might_sleep();
VALIDATE_DESC(desc);
value = gpiod_get_raw_value_commit(desc);
if (value < 0)
@@ -3388,7 +3376,7 @@ int gpiod_get_raw_array_value_cansleep(unsigned int array_size,
struct gpio_array *array_info,
unsigned long *value_bitmap)
{
- might_sleep_if(extra_checks);
+ might_sleep();
if (!desc_array)
return -EINVAL;
return gpiod_get_array_value_complex(true, true, array_size,
@@ -3414,7 +3402,7 @@ int gpiod_get_array_value_cansleep(unsigned int array_size,
struct gpio_array *array_info,
unsigned long *value_bitmap)
{
- might_sleep_if(extra_checks);
+ might_sleep();
if (!desc_array)
return -EINVAL;
return gpiod_get_array_value_complex(false, true, array_size,
@@ -3435,7 +3423,7 @@ EXPORT_SYMBOL_GPL(gpiod_get_array_value_cansleep);
*/
void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value)
{
- might_sleep_if(extra_checks);
+ might_sleep();
VALIDATE_DESC_VOID(desc);
gpiod_set_raw_value_commit(desc, value);
}
@@ -3453,7 +3441,7 @@ EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep);
*/
void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
{
- might_sleep_if(extra_checks);
+ might_sleep();
VALIDATE_DESC_VOID(desc);
gpiod_set_value_nocheck(desc, value);
}
@@ -3476,7 +3464,7 @@ int gpiod_set_raw_array_value_cansleep(unsigned int array_size,
struct gpio_array *array_info,
unsigned long *value_bitmap)
{
- might_sleep_if(extra_checks);
+ might_sleep();
if (!desc_array)
return -EINVAL;
return gpiod_set_array_value_complex(true, true, array_size, desc_array,
@@ -3518,7 +3506,7 @@ int gpiod_set_array_value_cansleep(unsigned int array_size,
struct gpio_array *array_info,
unsigned long *value_bitmap)
{
- might_sleep_if(extra_checks);
+ might_sleep();
if (!desc_array)
return -EINVAL;
return gpiod_set_array_value_complex(false, true, array_size,
--
2.35.1.723.g4982287a31-goog
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