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From: Kent Gibson <warthog618@gmail.com>
To: linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org,
	bgolaszewski@baylibre.com, linus.walleij@linaro.org,
	andy.shevchenko@gmail.com, arnd@arndb.de
Cc: Kent Gibson <warthog618@gmail.com>
Subject: [PATCH v10 05/20] gpiolib: make cdev a build option
Date: Mon, 28 Sep 2020 08:27:52 +0800	[thread overview]
Message-ID: <20200928002807.12146-6-warthog618@gmail.com> (raw)
In-Reply-To: <20200928002807.12146-1-warthog618@gmail.com>

Make the gpiolib-cdev module a build option.  This allows the CDEV
interface to be removed from the kernel to reduce kernel size in
applications where is it not required, and provides the parent for
other CDEV interface specific build options to follow.

Suggested-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
 drivers/gpio/Kconfig        | 17 +++++++++++++++--
 drivers/gpio/Makefile       |  2 +-
 drivers/gpio/gpiolib-cdev.h | 15 +++++++++++++++
 3 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 5cfdaf3b004d..e4debd66d71f 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -66,8 +66,21 @@ config GPIO_SYSFS
 
 	  This ABI is deprecated. If you want to use GPIO from userspace,
 	  use the character device /dev/gpiochipN with the appropriate
-	  ioctl() operations instead. The character device is always
-	  available.
+	  ioctl() operations instead.
+
+config GPIO_CDEV
+	bool
+	prompt "Character device (/dev/gpiochipN) support" if EXPERT
+	default y
+	help
+	  Say Y here to add the character device /dev/gpiochipN interface
+	  for GPIOs. The character device allows userspace to control GPIOs
+	  using ioctl() operations.
+
+	  Only say N if you are sure that the GPIO character device is not
+	  required.
+
+	  If unsure, say Y.
 
 config GPIO_GENERIC
 	depends on HAS_IOMEM # Only for IOMEM drivers
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 639275eb4e4d..6c3791a55a7b 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -6,8 +6,8 @@ ccflags-$(CONFIG_DEBUG_GPIO)	+= -DDEBUG
 obj-$(CONFIG_GPIOLIB)		+= gpiolib.o
 obj-$(CONFIG_GPIOLIB)		+= gpiolib-devres.o
 obj-$(CONFIG_GPIOLIB)		+= gpiolib-legacy.o
-obj-$(CONFIG_GPIOLIB)		+= gpiolib-cdev.o
 obj-$(CONFIG_OF_GPIO)		+= gpiolib-of.o
+obj-$(CONFIG_GPIO_CDEV)		+= gpiolib-cdev.o
 obj-$(CONFIG_GPIO_SYSFS)	+= gpiolib-sysfs.o
 obj-$(CONFIG_GPIO_ACPI)		+= gpiolib-acpi.o
 
diff --git a/drivers/gpio/gpiolib-cdev.h b/drivers/gpio/gpiolib-cdev.h
index 973578e7ad10..19a4e3d57120 100644
--- a/drivers/gpio/gpiolib-cdev.h
+++ b/drivers/gpio/gpiolib-cdev.h
@@ -5,7 +5,22 @@
 
 #include <linux/device.h>
 
+#ifdef CONFIG_GPIO_CDEV
+
 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt);
 void gpiolib_cdev_unregister(struct gpio_device *gdev);
 
+#else
+
+static inline int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
+{
+	return 0;
+}
+
+static inline void gpiolib_cdev_unregister(struct gpio_device *gdev)
+{
+}
+
+#endif /* CONFIG_GPIO_CDEV */
+
 #endif /* GPIOLIB_CDEV_H */
-- 
2.28.0


  parent reply	other threads:[~2020-09-28  0:29 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-28  0:27 [PATCH v10 00/20] gpio: cdev: add uAPI v2 Kent Gibson
2020-09-28  0:27 ` [PATCH v10 01/20] gpiolib: cdev: gpio_desc_to_lineinfo() should set info offset Kent Gibson
2020-09-28  0:27 ` [PATCH v10 02/20] gpiolib: cdev: replace strncpy() with strscpy() Kent Gibson
2020-09-28  0:27 ` [PATCH v10 03/20] gpio: uapi: define GPIO_MAX_NAME_SIZE for array sizes Kent Gibson
2020-09-28  0:27 ` [PATCH v10 04/20] gpio: uapi: define uAPI v2 Kent Gibson
2020-09-28  0:27 ` Kent Gibson [this message]
2020-09-28  0:27 ` [PATCH v10 06/20] gpiolib: add build option for CDEV v1 ABI Kent Gibson
2020-09-28  0:27 ` [PATCH v10 07/20] gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL Kent Gibson
2020-09-28  0:27 ` [PATCH v10 08/20] gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL Kent Gibson
2020-09-28  0:27 ` [PATCH v10 09/20] gpiolib: cdev: support edge detection for uAPI v2 Kent Gibson
2020-09-28  0:27 ` [PATCH v10 10/20] gpiolib: cdev: support GPIO_V2_LINE_SET_CONFIG_IOCTL Kent Gibson
2020-09-28  0:27 ` [PATCH v10 11/20] gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES_IOCTL Kent Gibson
2020-09-28  0:27 ` [PATCH v10 12/20] gpiolib: cdev: support setting debounce Kent Gibson
2020-09-28  0:28 ` [PATCH v10 13/20] gpio: uapi: document uAPI v1 as deprecated Kent Gibson
2020-09-28  0:28 ` [PATCH v10 14/20] tools: gpio: port lsgpio to v2 uAPI Kent Gibson
2020-09-28  0:28 ` [PATCH v10 15/20] tools: gpio: port gpio-watch " Kent Gibson
2020-09-28  0:28 ` [PATCH v10 16/20] tools: gpio: rename nlines to num_lines Kent Gibson
2020-09-28  0:28 ` [PATCH v10 17/20] tools: gpio: port gpio-hammer to v2 uAPI Kent Gibson
2020-09-28  0:28 ` [PATCH v10 18/20] tools: gpio: port gpio-event-mon " Kent Gibson
2020-09-28  0:28 ` [PATCH v10 19/20] tools: gpio: add multi-line monitoring to gpio-event-mon Kent Gibson
2020-09-28  0:28 ` [PATCH v10 20/20] tools: gpio: add debounce support " Kent Gibson
2020-09-29 15:13 ` [PATCH v10 00/20] gpio: cdev: add uAPI v2 Bartosz Golaszewski
2020-09-29 16:22   ` Andy Shevchenko

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