forked from Minki/linux
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: Sylwester Nawrocki <sylvester.nawrocki@gmail.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
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Sylwester Nawrocki
Kukjin Kim
parent
ef97fa65ef
commit
98025c8c75
@ -1,4 +1,4 @@
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S3C2410 GPIO Control
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S3C24XX GPIO Control
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====================
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Introduction
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@ -12,7 +12,7 @@ Introduction
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of the s3c2410 GPIO system, please read the Samsung provided
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data-sheet/users manual to find out the complete list.
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See Documentation/arm/Samsung/GPIO.txt for the core implemetation.
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See Documentation/arm/Samsung/GPIO.txt for the core implementation.
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GPIOLIB
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@ -41,8 +41,8 @@ GPIOLIB
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GPIOLIB conversion
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------------------
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If you need to convert your board or driver to use gpiolib from the exiting
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s3c2410 api, then here are some notes on the process.
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If you need to convert your board or driver to use gpiolib from the phased
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out s3c2410 API, then here are some notes on the process.
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1) If your board is exclusively using an GPIO, say to control peripheral
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power, then it will require to claim the gpio with gpio_request() before
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@ -55,7 +55,7 @@ s3c2410 api, then here are some notes on the process.
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as they have the same arguments, and can either take the pin specific
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values, or the more generic special-function-number arguments.
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3) s3c2410_gpio_pullup() changs have the problem that whilst the
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3) s3c2410_gpio_pullup() changes have the problem that whilst the
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s3c2410_gpio_pullup(x, 1) can be easily translated to the
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s3c_gpio_setpull(x, S3C_GPIO_PULL_NONE), the s3c2410_gpio_pullup(x, 0)
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are not so easy.
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@ -74,7 +74,7 @@ s3c2410 api, then here are some notes on the process.
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when using gpio_get_value() on an output pin (s3c2410_gpio_getpin
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would return the value the pin is supposed to be outputting).
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6) s3c2410_gpio_getirq() should be directly replacable with the
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6) s3c2410_gpio_getirq() should be directly replaceable with the
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gpio_to_irq() call.
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The s3c2410_gpio and gpio_ calls have always operated on the same gpio
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@ -105,7 +105,7 @@ PIN Numbers
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-----------
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Each pin has an unique number associated with it in regs-gpio.h,
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eg S3C2410_GPA(0) or S3C2410_GPF(1). These defines are used to tell
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e.g. S3C2410_GPA(0) or S3C2410_GPF(1). These defines are used to tell
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the GPIO functions which pin is to be used.
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With the conversion to gpiolib, there is no longer a direct conversion
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@ -120,31 +120,27 @@ Configuring a pin
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The following function allows the configuration of a given pin to
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be changed.
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void s3c2410_gpio_cfgpin(unsigned int pin, unsigned int function);
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void s3c_gpio_cfgpin(unsigned int pin, unsigned int function);
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Eg:
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e.g.:
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s3c2410_gpio_cfgpin(S3C2410_GPA(0), S3C2410_GPA0_ADDR0);
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s3c2410_gpio_cfgpin(S3C2410_GPE(8), S3C2410_GPE8_SDDAT1);
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s3c_gpio_cfgpin(S3C2410_GPA(0), S3C_GPIO_SFN(1));
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s3c_gpio_cfgpin(S3C2410_GPE(8), S3C_GPIO_SFN(2));
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which would turn GPA(0) into the lowest Address line A0, and set
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GPE(8) to be connected to the SDIO/MMC controller's SDDAT1 line.
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The s3c_gpio_cfgpin() call is a functional replacement for this call.
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Reading the current configuration
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---------------------------------
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The current configuration of a pin can be read by using:
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The current configuration of a pin can be read by using standard
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gpiolib function:
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s3c2410_gpio_getcfg(unsigned int pin);
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s3c_gpio_getcfg(unsigned int pin);
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The return value will be from the same set of values which can be
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passed to s3c2410_gpio_cfgpin().
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The s3c_gpio_getcfg() call should be a functional replacement for
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this call.
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passed to s3c_gpio_cfgpin().
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Configuring a pull-up resistor
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@ -154,61 +150,33 @@ Configuring a pull-up resistor
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pull-up resistors enabled. This can be configured by the following
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function:
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void s3c2410_gpio_pullup(unsigned int pin, unsigned int to);
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void s3c_gpio_setpull(unsigned int pin, unsigned int to);
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Where the to value is zero to set the pull-up off, and 1 to enable
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the specified pull-up. Any other values are currently undefined.
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The s3c_gpio_setpull() offers similar functionality, but with the
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ability to encode whether the pull is up or down. Currently there
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is no 'just on' state, so up or down must be selected.
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Where the to value is S3C_GPIO_PULL_NONE to set the pull-up off,
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and S3C_GPIO_PULL_UP to enable the specified pull-up. Any other
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values are currently undefined.
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Getting the state of a PIN
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--------------------------
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Getting and setting the state of a PIN
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--------------------------------------
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The state of a pin can be read by using the function:
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unsigned int s3c2410_gpio_getpin(unsigned int pin);
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This will return either zero or non-zero. Do not count on this
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function returning 1 if the pin is set.
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This call is now implemented by the relevant gpiolib calls, convert
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your board or driver to use gpiolib.
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Setting the state of a PIN
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--------------------------
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The value an pin is outputing can be modified by using the following:
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void s3c2410_gpio_setpin(unsigned int pin, unsigned int to);
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Which sets the given pin to the value. Use 0 to write 0, and 1 to
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set the output to 1.
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This call is now implemented by the relevant gpiolib calls, convert
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These calls are now implemented by the relevant gpiolib calls, convert
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your board or driver to use gpiolib.
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Getting the IRQ number associated with a PIN
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--------------------------------------------
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The following function can map the given pin number to an IRQ
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A standard gpiolib function can map the given pin number to an IRQ
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number to pass to the IRQ system.
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int s3c2410_gpio_getirq(unsigned int pin);
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int gpio_to_irq(unsigned int pin);
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Note, not all pins have an IRQ.
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This call is now implemented by the relevant gpiolib calls, convert
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your board or driver to use gpiolib.
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Authour
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Author
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-------
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Ben Dooks, 03 October 2004
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Copyright 2004 Ben Dooks, Simtec Electronics
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@ -5,14 +5,14 @@ Introduction
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------------
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This outlines the Samsung GPIO implementation and the architecture
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specific calls provided alongisde the drivers/gpio core.
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specific calls provided alongside the drivers/gpio core.
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S3C24XX (Legacy)
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----------------
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See Documentation/arm/Samsung-S3C24XX/GPIO.txt for more information
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about these devices. Their implementation is being brought into line
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about these devices. Their implementation has been brought into line
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with the core samsung implementation described in this document.
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@ -29,7 +29,7 @@ GPIO numbering is synchronised between the Samsung and gpiolib system.
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PIN configuration
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-----------------
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Pin configuration is specific to the Samsung architecutre, with each SoC
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Pin configuration is specific to the Samsung architecture, with each SoC
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registering the necessary information for the core gpio configuration
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implementation to configure pins as necessary.
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@ -38,5 +38,3 @@ driver or machine to change gpio configuration.
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See arch/arm/plat-samsung/include/plat/gpio-cfg.h for more information
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on these functions.
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