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gpio: samsung: Update documentation

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Update Samsung GPIO API documentation to reflect removal of
the s3c24xx specific gpio API. While at it, fix some typos.

The notes on conversion from s3c2410_* functions to the gpiolib
API are left here just in case there is any out of tree code that
still needs to be converted.

Signed-off-by: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
This commit is contained in:
Sylwester Nawrocki 2012-09-07 06:40:29 +09:00 committed by Kukjin Kim
parent ef97fa65ef
commit 98025c8c75
2 changed files with 28 additions and 62 deletions
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82
Documentation/arm/Samsung-S3C24XX/GPIO.txt
View file

@ -1,4 +1,4 @@
S3C2410 GPIO Control
S3C24XX GPIO Control
====================
Introduction
@ -12,7 +12,7 @@ Introduction
of the s3c2410 GPIO system, please read the Samsung provided
data-sheet/users manual to find out the complete list.
See Documentation/arm/Samsung/GPIO.txt for the core implemetation.
See Documentation/arm/Samsung/GPIO.txt for the core implementation.
GPIOLIB
@ -41,8 +41,8 @@ GPIOLIB
GPIOLIB conversion
------------------
If you need to convert your board or driver to use gpiolib from the exiting
s3c2410 api, then here are some notes on the process.
If you need to convert your board or driver to use gpiolib from the phased
out s3c2410 API, then here are some notes on the process.
1) If your board is exclusively using an GPIO, say to control peripheral
power, then it will require to claim the gpio with gpio_request() before
@ -55,7 +55,7 @@ s3c2410 api, then here are some notes on the process.
as they have the same arguments, and can either take the pin specific
values, or the more generic special-function-number arguments.
3) s3c2410_gpio_pullup() changs have the problem that whilst the
3) s3c2410_gpio_pullup() changes have the problem that whilst the
s3c2410_gpio_pullup(x, 1) can be easily translated to the
s3c_gpio_setpull(x, S3C_GPIO_PULL_NONE), the s3c2410_gpio_pullup(x, 0)
are not so easy.
@ -74,7 +74,7 @@ s3c2410 api, then here are some notes on the process.
when using gpio_get_value() on an output pin (s3c2410_gpio_getpin
would return the value the pin is supposed to be outputting).
6) s3c2410_gpio_getirq() should be directly replacable with the
6) s3c2410_gpio_getirq() should be directly replaceable with the
gpio_to_irq() call.
The s3c2410_gpio and gpio_ calls have always operated on the same gpio
@ -105,7 +105,7 @@ PIN Numbers
-----------
Each pin has an unique number associated with it in regs-gpio.h,
eg S3C2410_GPA(0) or S3C2410_GPF(1). These defines are used to tell
e.g. S3C2410_GPA(0) or S3C2410_GPF(1). These defines are used to tell
the GPIO functions which pin is to be used.
With the conversion to gpiolib, there is no longer a direct conversion
@ -120,31 +120,27 @@ 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);
void s3c_gpio_cfgpin(unsigned int pin, unsigned int function);
Eg:
e.g.:
s3c2410_gpio_cfgpin(S3C2410_GPA(0), S3C2410_GPA0_ADDR0);
s3c2410_gpio_cfgpin(S3C2410_GPE(8), S3C2410_GPE8_SDDAT1);
s3c_gpio_cfgpin(S3C2410_GPA(0), S3C_GPIO_SFN(1));
s3c_gpio_cfgpin(S3C2410_GPE(8), S3C_GPIO_SFN(2));
which would turn GPA(0) into the lowest Address line A0, and set
GPE(8) to be connected to the SDIO/MMC controller's SDDAT1 line.
The s3c_gpio_cfgpin() call is a functional replacement for this call.
Reading the current configuration
---------------------------------
The current configuration of a pin can be read by using:
The current configuration of a pin can be read by using standard
gpiolib function:
s3c2410_gpio_getcfg(unsigned int pin);
s3c_gpio_getcfg(unsigned int pin);
The return value will be from the same set of values which can be
passed to s3c2410_gpio_cfgpin().
The s3c_gpio_getcfg() call should be a functional replacement for
this call.
passed to s3c_gpio_cfgpin().
Configuring a pull-up resistor
@ -154,61 +150,33 @@ Configuring a pull-up resistor
pull-up resistors enabled. This can be configured by the following
function:
void s3c2410_gpio_pullup(unsigned int pin, unsigned int to);
void s3c_gpio_setpull(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.
The s3c_gpio_setpull() offers similar functionality, but with the
ability to encode whether the pull is up or down. Currently there
is no 'just on' state, so up or down must be selected.
Where the to value is S3C_GPIO_PULL_NONE to set the pull-up off,
and S3C_GPIO_PULL_UP to enable the specified pull-up. Any other
values are currently undefined.
Getting the state of a PIN
--------------------------
Getting and setting 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.
This call is now implemented by the relevant gpiolib calls, convert
your board or driver to use gpiolib.
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.
This call is now implemented by the relevant gpiolib calls, convert
These calls are now implemented by the relevant gpiolib calls, convert
your board or driver to use gpiolib.
Getting the IRQ number associated with a PIN
--------------------------------------------
The following function can map the given pin number to an IRQ
A standard gpiolib function can map the given pin number to an IRQ
number to pass to the IRQ system.
int s3c2410_gpio_getirq(unsigned int pin);
int gpio_to_irq(unsigned int pin);
Note, not all pins have an IRQ.
This call is now implemented by the relevant gpiolib calls, convert
your board or driver to use gpiolib.
Authour
Author
-------
Ben Dooks, 03 October 2004
Copyright 2004 Ben Dooks, Simtec Electronics

8
Documentation/arm/Samsung/GPIO.txt
View file

@ -5,14 +5,14 @@ Introduction
------------
This outlines the Samsung GPIO implementation and the architecture
specific calls provided alongisde the drivers/gpio core.
specific calls provided alongside the drivers/gpio core.
S3C24XX (Legacy)
----------------
See Documentation/arm/Samsung-S3C24XX/GPIO.txt for more information
about these devices. Their implementation is being brought into line
about these devices. Their implementation has been brought into line
with the core samsung implementation described in this document.
@ -29,7 +29,7 @@ GPIO numbering is synchronised between the Samsung and gpiolib system.
PIN configuration
-----------------
Pin configuration is specific to the Samsung architecutre, with each SoC
Pin configuration is specific to the Samsung architecture, with each SoC
registering the necessary information for the core gpio configuration
implementation to configure pins as necessary.
@ -38,5 +38,3 @@ driver or machine to change gpio configuration.
See arch/arm/plat-samsung/include/plat/gpio-cfg.h for more information
on these functions.