--- /dev/null
+ S3C2410 GPIO Control
+ ====================
+
+Introduction
+------------
+
+ The s3c2410 kernel provides an interface to configure and
+ manipulate the state of the GPIO pins, and find out other
+ information about them.
+
+ There are a number of conditions attached to the configuration
+ of the s3c2410 GPIO system, please read the Samsung provided
+ data-sheet/users manual to find out the complete list.
+
+
+Headers
+-------
+
+ See include/asm-arm/arch-s3c2410/regs-gpio.h for the list
+ of GPIO pins, and the configuration values for them. This
+ is included by using #include <asm/arch/regs-gpio.h>
+
+ The GPIO management functions are defined in the hardware
+ header include/asm-arm/arch-s3c2410/hardware.h which can be
+ included by #include <asm/arch/hardware.h>
+
+ A useful ammount of documentation can be found in the hardware
+ header on how the GPIO functions (and others) work.
+
+ Whilst a number of these functions do make some checks on what
+ is passed to them, for speed of use, they may not always ensure
+ that the user supplied data to them is correct.
+
+
+PIN Numbers
+-----------
+
+ Each pin has an unique number associated with it in regs-gpio.h,
+ eg S3C2410_GPA0 or S3C2410_GPF1. These defines are used to tell
+ the GPIO functions which pin is to be used.
+
+
+Configuring a pin
+-----------------
+
+ The following function allows the configuration of a given pin to
+ be changed.
+
+ void s3c2410_gpio_cfgpin(unsigned int pin, unsigned int function);
+
+ Eg:
+
+ s3c2410_gpio_cfgpin(S3C2410_GPA0, S3C2410_GPA0_ADDR0);
+ s3c2410_gpio_cfgpin(S3C2410_GPE8, S3C2410_GPE8_SDDAT1);
+
+ which would turn GPA0 into the lowest Address line A0, and set
+ GPE8 to be connected to the SDIO/MMC controller's SDDAT1 line.
+
+
+Reading the current configuration
+---------------------------------
+
+ The current configuration of a pin can be read by using:
+
+ s3c2410_gpio_getcfg(unsigned int pin);
+
+ The return value will be from the same set of values which can be
+ passed to s3c2410_gpio_cfgpin().
+
+
+Configuring a pull-up resistor
+------------------------------
+
+ A large proportion of the GPIO pins on the S3C2410 can have weak
+ pull-up resistors enabled. This can be configured by the following
+ function:
+
+ void s3c2410_gpio_pullup(unsigned int pin, unsigned int to);
+
+ Where the to value is zero to set the pull-up off, and 1 to enable
+ the specified pull-up. Any other values are currently undefined.
+
+
+Getting the state of a PIN
+--------------------------
+
+ The state of a pin can be read by using the function:
+
+ unsigned int s3c2410_gpio_getpin(unsigned int pin);
+
+ This will return either zero or non-zero. Do not count on this
+ function returning 1 if the pin is set.
+
+
+Setting the state of a PIN
+--------------------------
+
+ The value an pin is outputing can be modified by using the following:
+
+ void s3c2410_gpio_setpin(unsigned int pin, unsigned int to);
+
+ Which sets the given pin to the value. Use 0 to write 0, and 1 to
+ set the output to 1.
+
+
+Getting the IRQ number associated with a PIN
+--------------------------------------------
+
+ The following function can map the given pin number to an IRQ
+ number to pass to the IRQ system.
+
+ int s3c2410_gpio_getirq(unsigned int pin);
+
+ Note, not all pins have an IRQ.
+
+
+Authour
+-------
+
+
+Ben Dooks, 03 October 2004
+(c) 2004 Ben Dooks, Simtec Electronics
default by `make s3c2410_defconfig`. This configuration has support
for all the machines, and the commonly used features on them.
+ Certain machines may have their own default configurations as well,
+ please check the machine specific documentation.
+
Machines
--------
Handheld (IPAQ), available in several varieties
-Contributors
-------------
+NAND
+----
+
+ The current kernels do not have direct support for the NAND
+ controller, the latest linux-mtd CVS has support for this.
+ See http://www.linux-mtd.infradead.org/
+
+
+Serial
+------
+
+ The s3c2410 serial driver provides support for the internal
+ serial ports. These devices appear as /dev/ttySAC0 through 3.
+
+ To create device nodes for these, use the following commands
+
+ mknod ttySAC0 c 204 64
+ mknod ttySAC1 c 204 65
+ mknod ttySAC2 c 204 66
+
+
+GPIO
+----
+
+ The core contains support for manipulating the GPIO, see the
+ documentation in GPIO.txt in the same directory as this file.
+
+
+Clock Management
+----------------
+
+ The core provides the interface defined in the header file
+ include/asm-arm/hardware/clock.h, to allow control over the
+ various clock units
+
+
+Port Contributors
+-----------------
Ben Dooks
Vincent Sanders
Herbert Potzl
Arnaud Patard
+ Roc Wu
+
+
+Document Author
+---------------
+
+Ben Dooks, (c) 2004 Simtec Electronics
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