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Commit 98025c8c authored by Sylwester Nawrocki's avatar Sylwester Nawrocki Committed by Kukjin Kim
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gpio: samsung: Update documentation 



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: default avatarSylwester Nawrocki <sylvester.nawrocki@gmail.com>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarKukjin Kim <kgene.kim@samsung.com>
parent ef97fa65

Documentation/arm/Samsung-S3C24XX/GPIO.txt

+25 −57
Original line number Original line Diff line number Diff line 
			S3C2410 GPIO Control

			S3C24XX GPIO Control

			====================

			====================





Introduction

Introduction
@@ -12,7 +12,7 @@ Introduction 
  of the s3c2410 GPIO system, please read the Samsung provided

  of the s3c2410 GPIO system, please read the Samsung provided

  data-sheet/users manual to find out the complete list.

  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

GPIOLIB
@@ -41,8 +41,8 @@ GPIOLIB 
GPIOLIB conversion

GPIOLIB conversion

------------------

------------------





If you need to convert your board or driver to use gpiolib from the exiting

If you need to convert your board or driver to use gpiolib from the phased

s3c2410 api, then here are some notes on the process.

out s3c2410 API, then here are some notes on the process.





1) If your board is exclusively using an GPIO, say to control peripheral

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

   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

   as they have the same arguments, and can either take the pin specific

   values, or the more generic special-function-number arguments.

   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

   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)

   s3c_gpio_setpull(x, S3C_GPIO_PULL_NONE), the s3c2410_gpio_pullup(x, 0)

   are not so easy.

   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

   when using gpio_get_value() on an output pin (s3c2410_gpio_getpin

   would return the value the pin is supposed to be outputting).

   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.

   gpio_to_irq() call.





The s3c2410_gpio and gpio_ calls have always operated on the same gpio

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,

  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.

  the GPIO functions which pin is to be used.





  With the conversion to gpiolib, there is no longer a direct conversion

  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

  The following function allows the configuration of a given pin to

  be changed.

  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);

     s3c_gpio_cfgpin(S3C2410_GPA(0), S3C_GPIO_SFN(1));

     s3c2410_gpio_cfgpin(S3C2410_GPE(8), S3C2410_GPE8_SDDAT1);

     s3c_gpio_cfgpin(S3C2410_GPE(8), S3C_GPIO_SFN(2));





   which would turn GPA(0) into the lowest Address line A0, and set

   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.

   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

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

  The return value will be from the same set of values which can be

  passed to s3c2410_gpio_cfgpin().

  passed to s3c_gpio_cfgpin().



  The s3c_gpio_getcfg() call should be a functional replacement for

  this call.









Configuring a pull-up resistor

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

  pull-up resistors enabled. This can be configured by the following

  function:

  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.





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

  Where the to value is S3C_GPIO_PULL_NONE to set the pull-up off,

  function returning 1 if the pin is set.

  and S3C_GPIO_PULL_UP to enable the specified pull-up. Any other

  values are currently undefined.





  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);

Getting and setting the state of a PIN

--------------------------------------





  Which sets the given pin to the value. Use 0 to write 0, and 1 to

  These calls are now implemented by the relevant gpiolib calls, convert

  set the output to 1.



  This call is now implemented by the relevant gpiolib calls, convert

  your board or driver to use gpiolib.

  your board or driver to use gpiolib.









Getting the IRQ number associated with a PIN

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.

  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.

  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

Ben Dooks, 03 October 2004

Copyright 2004 Ben Dooks, Simtec Electronics
 
Copyright 2004 Ben Dooks, Simtec Electronics

Documentation/arm/Samsung/GPIO.txt

+3 −5
Original line number Original line Diff line number Diff line
@@ -5,14 +5,14 @@ Introduction 
------------

------------





This outlines the Samsung GPIO implementation and the architecture

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)

S3C24XX (Legacy)

----------------

----------------





See Documentation/arm/Samsung-S3C24XX/GPIO.txt for more information

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.

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

-----------------

-----------------





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

registering the necessary information for the core gpio configuration

implementation to configure pins as necessary.

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

See arch/arm/plat-samsung/include/plat/gpio-cfg.h for more information

on these functions.
 
on these functions.