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-rw-r--r--Documentation/arm/Samsung-S3C24XX/GPIO.txt82
1 files changed, 25 insertions, 57 deletions
diff --git a/Documentation/arm/Samsung-S3C24XX/GPIO.txt b/Documentation/arm/Samsung-S3C24XX/GPIO.txt
index 816d6071669e..8b46c79679c4 100644
--- a/Documentation/arm/Samsung-S3C24XX/GPIO.txt
+++ b/Documentation/arm/Samsung-S3C24XX/GPIO.txt
@@ -1,4 +1,4 @@
1 S3C2410 GPIO Control 1 S3C24XX GPIO Control
2 ==================== 2 ====================
3 3
4Introduction 4Introduction
@@ -12,7 +12,7 @@ Introduction
12 of the s3c2410 GPIO system, please read the Samsung provided 12 of the s3c2410 GPIO system, please read the Samsung provided
13 data-sheet/users manual to find out the complete list. 13 data-sheet/users manual to find out the complete list.
14 14
15 See Documentation/arm/Samsung/GPIO.txt for the core implemetation. 15 See Documentation/arm/Samsung/GPIO.txt for the core implementation.
16 16
17 17
18GPIOLIB 18GPIOLIB
@@ -41,8 +41,8 @@ GPIOLIB
41GPIOLIB conversion 41GPIOLIB conversion
42------------------ 42------------------
43 43
44If you need to convert your board or driver to use gpiolib from the exiting 44If you need to convert your board or driver to use gpiolib from the phased
45s3c2410 api, then here are some notes on the process. 45out s3c2410 API, then here are some notes on the process.
46 46
471) If your board is exclusively using an GPIO, say to control peripheral 471) If your board is exclusively using an GPIO, say to control peripheral
48 power, then it will require to claim the gpio with gpio_request() before 48 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.
55 as they have the same arguments, and can either take the pin specific 55 as they have the same arguments, and can either take the pin specific
56 values, or the more generic special-function-number arguments. 56 values, or the more generic special-function-number arguments.
57 57
583) s3c2410_gpio_pullup() changs have the problem that whilst the 583) s3c2410_gpio_pullup() changes have the problem that whilst the
59 s3c2410_gpio_pullup(x, 1) can be easily translated to the 59 s3c2410_gpio_pullup(x, 1) can be easily translated to the
60 s3c_gpio_setpull(x, S3C_GPIO_PULL_NONE), the s3c2410_gpio_pullup(x, 0) 60 s3c_gpio_setpull(x, S3C_GPIO_PULL_NONE), the s3c2410_gpio_pullup(x, 0)
61 are not so easy. 61 are not so easy.
@@ -74,7 +74,7 @@ s3c2410 api, then here are some notes on the process.
74 when using gpio_get_value() on an output pin (s3c2410_gpio_getpin 74 when using gpio_get_value() on an output pin (s3c2410_gpio_getpin
75 would return the value the pin is supposed to be outputting). 75 would return the value the pin is supposed to be outputting).
76 76
776) s3c2410_gpio_getirq() should be directly replacable with the 776) s3c2410_gpio_getirq() should be directly replaceable with the
78 gpio_to_irq() call. 78 gpio_to_irq() call.
79 79
80The s3c2410_gpio and gpio_ calls have always operated on the same gpio 80The s3c2410_gpio and gpio_ calls have always operated on the same gpio
@@ -105,7 +105,7 @@ PIN Numbers
105----------- 105-----------
106 106
107 Each pin has an unique number associated with it in regs-gpio.h, 107 Each pin has an unique number associated with it in regs-gpio.h,
108 eg S3C2410_GPA(0) or S3C2410_GPF(1). These defines are used to tell 108 e.g. S3C2410_GPA(0) or S3C2410_GPF(1). These defines are used to tell
109 the GPIO functions which pin is to be used. 109 the GPIO functions which pin is to be used.
110 110
111 With the conversion to gpiolib, there is no longer a direct conversion 111 With the conversion to gpiolib, there is no longer a direct conversion
@@ -120,31 +120,27 @@ Configuring a pin
120 The following function allows the configuration of a given pin to 120 The following function allows the configuration of a given pin to
121 be changed. 121 be changed.
122 122
123 void s3c2410_gpio_cfgpin(unsigned int pin, unsigned int function); 123 void s3c_gpio_cfgpin(unsigned int pin, unsigned int function);
124 124
125 Eg: 125 e.g.:
126 126
127 s3c2410_gpio_cfgpin(S3C2410_GPA(0), S3C2410_GPA0_ADDR0); 127 s3c_gpio_cfgpin(S3C2410_GPA(0), S3C_GPIO_SFN(1));
128 s3c2410_gpio_cfgpin(S3C2410_GPE(8), S3C2410_GPE8_SDDAT1); 128 s3c_gpio_cfgpin(S3C2410_GPE(8), S3C_GPIO_SFN(2));
129 129
130 which would turn GPA(0) into the lowest Address line A0, and set 130 which would turn GPA(0) into the lowest Address line A0, and set
131 GPE(8) to be connected to the SDIO/MMC controller's SDDAT1 line. 131 GPE(8) to be connected to the SDIO/MMC controller's SDDAT1 line.
132 132
133 The s3c_gpio_cfgpin() call is a functional replacement for this call.
134
135 133
136Reading the current configuration 134Reading the current configuration
137--------------------------------- 135---------------------------------
138 136
139 The current configuration of a pin can be read by using: 137 The current configuration of a pin can be read by using standard
138 gpiolib function:
140 139
141 s3c2410_gpio_getcfg(unsigned int pin); 140 s3c_gpio_getcfg(unsigned int pin);
142 141
143 The return value will be from the same set of values which can be 142 The return value will be from the same set of values which can be
144 passed to s3c2410_gpio_cfgpin(). 143 passed to s3c_gpio_cfgpin().
145
146 The s3c_gpio_getcfg() call should be a functional replacement for
147 this call.
148 144
149 145
150Configuring a pull-up resistor 146Configuring a pull-up resistor
@@ -154,61 +150,33 @@ Configuring a pull-up resistor
154 pull-up resistors enabled. This can be configured by the following 150 pull-up resistors enabled. This can be configured by the following
155 function: 151 function:
156 152
157 void s3c2410_gpio_pullup(unsigned int pin, unsigned int to); 153 void s3c_gpio_setpull(unsigned int pin, unsigned int to);
158
159 Where the to value is zero to set the pull-up off, and 1 to enable
160 the specified pull-up. Any other values are currently undefined.
161
162 The s3c_gpio_setpull() offers similar functionality, but with the
163 ability to encode whether the pull is up or down. Currently there
164 is no 'just on' state, so up or down must be selected.
165
166
167Getting the state of a PIN
168--------------------------
169
170 The state of a pin can be read by using the function:
171
172 unsigned int s3c2410_gpio_getpin(unsigned int pin);
173 154
174 This will return either zero or non-zero. Do not count on this 155 Where the to value is S3C_GPIO_PULL_NONE to set the pull-up off,
175 function returning 1 if the pin is set. 156 and S3C_GPIO_PULL_UP to enable the specified pull-up. Any other
157 values are currently undefined.
176 158
177 This call is now implemented by the relevant gpiolib calls, convert
178 your board or driver to use gpiolib.
179
180
181Setting the state of a PIN
182--------------------------
183
184 The value an pin is outputing can be modified by using the following:
185 159
186 void s3c2410_gpio_setpin(unsigned int pin, unsigned int to); 160Getting and setting the state of a PIN
161--------------------------------------
187 162
188 Which sets the given pin to the value. Use 0 to write 0, and 1 to 163 These calls are now implemented by the relevant gpiolib calls, convert
189 set the output to 1.
190
191 This call is now implemented by the relevant gpiolib calls, convert
192 your board or driver to use gpiolib. 164 your board or driver to use gpiolib.
193 165
194 166
195Getting the IRQ number associated with a PIN 167Getting the IRQ number associated with a PIN
196-------------------------------------------- 168--------------------------------------------
197 169
198 The following function can map the given pin number to an IRQ 170 A standard gpiolib function can map the given pin number to an IRQ
199 number to pass to the IRQ system. 171 number to pass to the IRQ system.
200 172
201 int s3c2410_gpio_getirq(unsigned int pin); 173 int gpio_to_irq(unsigned int pin);
202 174
203 Note, not all pins have an IRQ. 175 Note, not all pins have an IRQ.
204 176
205 This call is now implemented by the relevant gpiolib calls, convert
206 your board or driver to use gpiolib.
207
208 177
209Authour 178Author
210------- 179-------
211 180
212
213Ben Dooks, 03 October 2004 181Ben Dooks, 03 October 2004
214Copyright 2004 Ben Dooks, Simtec Electronics 182Copyright 2004 Ben Dooks, Simtec Electronics