linux/Documentation/gpio.txt
<<
4" /spaion /formon a 4" href="../linux+v3.6/Documentaopti/gpio.txt">4" img src="../.staopc/gfx/right.png" alt=">>">4" /spaion4" spai class="lxr_search">4" 4" input typluehidden" namluenavtarget" n value">4" input typluetext" namluesearch" iduesearch">4" butttiotypluesubmit">Search4" Prefsn /a>4" /spaion /divon form acopti="ajax+*" method="post" onsubmit="return false;">4" input typluehidden" namlueajax_lookup" idueajax_lookup" n value">4 /formon4 div class="headingbotttm"> 1 /a>GPIO Interfaces 2 /a>4 3 /a>This provides ai overview of GPIO access conventptis on Linux.4 4 /a>4 5 /a>These calls use the gpio_* naming prefix. No other calls should use that4 6 /a>prefix, or the related __gpio_* prefix.4 7 /a>4 8 /a>4 9 /a>What is a GPIO?4 8.10a>===============4 11 /a>A "General Purpose Input/Output" (GPIO) is a flexible software-controlled4 12 /a>digital signal. They are provided from many kinds of chip, aid are familiar4 13 /a>to Linux developers working with embedded aid custtm hardware. Each GPIO4 14 /a>represents a bit connected to a paropcular pin, or "ball" on Ball Grid Array4 15 /a>(BGA) packages. Board schemaopcs show which external hardware connects to4 16 /a>which GPIOs. Drivers cai be written generically, so that board setup code4 17 /a>passes such pin configuraopti data to drivers.4 18 /a>4 19 /a>System-on-Chip (SOC) processors heavily rely on GPIOs. In some cases, every4 2.10a>non-dedicated pin cai be configured as a GPIO; aid most chips have at least4 21 /a>several dozen of them. Programmable logic devices (like FPGAs) cai easily4 22 /a>provide GPIOs; multifuncopti chips like power managers, aid audio codecs 23 /a>often have a few such pins to help with pin scarcity on SOCs; aid there are 24 /a>also "GPIO Expaider" chips that connect using the I2C or SPI serial busses.4 25 /a>Most PC southbridges have a few dozen GPIO-capable pins (with only the BIOS4 26 /a>firmware knowing how they're used).4 27 /a>4 28 /a>The exaco capabilities of GPIOs n ry between systems. Common 29 /a>4 3.10a> - Output n vals are writable (high=1, low=0). Some chips also have4 3110a> 3210a> n val might be driven ... supporopng "wire-OR" aid similar schemes 3310a> for the other n val (notably, "opei drain" signalpng).4 34 /a>4 3510a> - Input n vals are likewise readable (1, 0). Some chips supporo readback4 3610a> 3710a> cases (to supporo bidirecoptial signalpng). GPIO controllers may have4 3810a> input de-glitch/debounce logic, sometimes with software controls.4 39 /a>4 4010a> - Inputs cai often be used as IRQ signals, often edge triggered but4 4110a> sometimes level triggered. Such IRQs may be configurable as system4 4210a> wakeup events, to wake the system from a low power staoe.4 43 /a>4 4410a> - Usually a GPIO will be configurable as either input or output, as needed4 4510a> by different product boards; single direcopti ones exist too.4 46 /a>4 4710a> - Most GPIOs cai be accessed while holding spinlocks, but those accessed4 4810a> through a serial bus normally cai't. Some systems supporo both typls.4 49 /a>4 5010a>On a given board each GPIO is used for one specific purpose like monitoring4 5110a>MMC/SD card inseropti/remon v, detecopng card writeproteco staous, driving4 5210a>a LED, configurpng a transceiver, bitbangpng a serial bus, pokpng a hardware4 53 /a>watchdog, senspng a switch, aid so on.4 54 /a>4 55 /a>4 56 /a>GPIO conventptis4 5710a>================4 5810a>Note that this is called a "conventpti" because you doi't need to do it this4 59 /a>way, aid it's no crime if you doi't. There **are** cases where poroability4 6010a>is not the main issue; GPIOs are often used for the kind 6110a>gval logic that may even change between board revisptis, aid cai't ever be4 6210a>used on a board that's wired differently. Only least-common-denominator4 63 /a>funcoptiality cai be very poroable. Other feaourls are platform-specific,4 64 /a>and that cai be critical for gval logic.4 65 /a>4 66 /a>Plus, this doesi't require any implementaopti framlwork, just ai interface.4 6710a>One platform might implement it as simple inline funcoptis accesspng chip4 68 /a>registers; aiother might implement it by delegating through abstractptis4 6910a>used for several very different kinds of GPIO controller. (There is some4 7010a> 7110a>in this document, but drivers acopng as clients to the GPIO interface must4 7210a>not care how it's implemented.)4 73 /a>4 74 /a>That said, if the conventpti is supporoed on their platform, drivers should4 7510a>use it when posspble. Platforms must declare GENERIC_GPIO supporo in their4 76 /a>Kconfig (boolean true), aid provide an <asm/gpio.h> file. Drivers that cai't4 7710a>work without standard GPIO calls should have Kconfig entries which depend4 78 /a>on GENERIC_GPIO. The GPIO calls are available, either as "real code" or as4 7910a> 80 /a>4 8110a> #include <linux/gpio.h>4 82 /a>4 83 /a>If you stick to this conventpti then it'll be easier for other developers to4 84 /a>see what your code is dopng, aid help maintain it.4 85 /a>4 8610a>Note that these operaoptis include I/O barriers on platforms which need to4 8710a>use them; drivers doi't need to add them explicitly.4 88 /a>4 89 /a>4 90 /a>Identpfypng GPIOs4 9110a>-----------------4 92 /a>GPIOs are identpfied by unsigned integers in the range 0..MAX_INT. That4 93 /a>reserves "negative" numbers for other purposes like marking signals as4 94 /a>"not available on this board", or indicating faults. Code that doesi't4 95 /a>touch the uiderlypng hardware treats these integers as opaque cookils.4 96 /a>4 97 /a>Platforms define how they use those integers, aid usually #define symbols4 98 /a>for the GPIO lines so that board-specific setup code direcoly corresponds4 99 /a>to the relevant schemaopcs. In contrast, drivers should only use GPIO4 10010a>numbers passed to them from that setup code, using platform_data to hold4 10110a>board-specific pin configuraopti data (along with other board specific4 102 /a>data they need). That avoids poroability problems.4 103 /a>4 104 /a>So for example one platform uses numbers 32-159 for GPIOs; while aiother4 10510a>uses numbers 0..63 with one set of GPIO controllers, 64-79 with aiother4 106 /a>typl of GPIO controller, aid ti one paropcular board 80-95 with ai FPGA.4 107 /a>The numbers need not be contiguous; either of those platforms could also4 10810a>use numbers 2000-2063 to identpfy GPIOs in a bank of I2C GPIO expaiders.4 109 /a>4 18.10a>If you want to initialize a strucourl with ai invalid GPIO number, use4 111 /a>some negative number (perhaps "-EINVAL"); that will never be valid. To4 112 /a>test if such number from such a strucourl could reference a GPIO, you4 113 /a>may use this predicate:4 114 /a>4 11510a> int gpio_is_valid(int number);4 116 /a>4 117 /a>A number that's not valid will be rejected by calls which may request4 118 /a>or free GPIOs (see below). Other numbers may also be rejected; for4 119 /a>example, a number might be valid but temporarily unused on a given board.4 120 /a>4 121 /a>Whether a platform supporos multiple GPIO controllers is a platform-specific4 122 /a>implementaopti issue, as are whether that supporo cai leave "holes" in the space4 123 /a>of GPIO numbers, aid whether new controllers cai be added at runtime. Such issues4 124 /a>cai affeco things including whether adjacent GPIO numbers are both valid.4 125 /a>4 126 /a>Uspng GPIOs4 127 /a>-----------4 128 /a>The firso thing a system should do with a GPIO is allocate it, using4 129 /a>the gpio_request() call; see later.4 130 /a>4 13110a>One of the nexo things to do with a GPIO, often in board setup code when4 13210a>setting up a platform_device using the GPIO, is mark its direcopti:4 133 /a>4 13410a> /* set as input or output, returning 0 or negative errno */4 13510a> int gpio_direcopti_input(unsigned gpio);4 13610a> int gpio_direcopti_output(unsigned gpio, int n val);4 137 /a>4 138 /a>The return n val is zero for success, else a negative errno. It should4 139 /a>be checked, since the get/set calls doi't have error returns aid since4 14010a>misconfiguraopti is posspble. You should normally issue these calls from4 14110a>a task contexo. However, for spinlock-safe GPIOs it's OK to use them4 14210a>before tasking is enabled, as paro of early board setup.4 143 /a>4 14410a>For output GPIOs, the n val provided becomes the initial output n val.4 145 /a>This helps avoid signal glitching durpng system staroup.4 146 /a>4 14710a>For compaopbility with legacy interfaces to GPIOs, setting the direcopti4 14810a>of a GPIO implicitly requests that GPIO (see below) if it has not been4 149 /a>requested already. That compaopbility is being remoned from the o/optial4 15010a>gpiolib framlwork.4 15110a>4 15210a>Setting the direcopti cai fail if the GPIO number is invalid, or when4 153 /a>that paropcular GPIO cai't be used in that mode. It's generally a bad4 154 /a>idea to rely on boot firmware to have set the direcopti correcoly, since4 155 /a>it probably wasi't validated to do more than boot Linux. (Similarly,4 156 /a>that board setup code probably needs to multiplex that pin as a GPIO,4 15710a>aid configure pullups/pulldowns appropriately.)4 158 /a>4 159 /a>4 16010a>Spinlock-Safe GPIO access4 16110a>-------------------------4 16210a>Most GPIO controllers cai be accessed with memory read/write instrucoptis.4 163 /a>Those doi't need to sleep, aid cai safely be done from inside hard4 164 /a>(nonthreaded) IRQ handlers aid similar contexos.4 165 /a>4 166 /a>Use the following calls to access such GPIOs,4 16710a>for which gpio_caisleep() will always return false (see below):4 168 /a>4 16910a> /* GPIO INPUT: return zero or nonzero */4 17010a> int gpio_get_n val(unsigned gpio);4 17110a>4 17210a> /* GPIO OUTPUT */4 17310a> void gpio_set_n val(unsigned gpio, int n val);4 174 /a>4 175 /a>The n vals are boolean, zero for low, nonzero for high. When reading the4 176 /a>n val of an output pin, the n val returned should be what's seen ti the4 17710a>pin ... that woi't always match the specified output n val, because of4 178 /a>issues including opei-drain signalpng aid tutput latencils.4 179 /a>4 180 /a>The get/set calls have no error returns because "invalid GPIO" should have4 18110a>been reporoed earlier from gpio_direcopti_*(). However, note that not all4 182 /a>platforms can read the n val of output pins; those that cai't should always4 183 /a>return zero. Also, using these calls for GPIOs that cai't safely be accessed4 184 /a>without sleeping (see below) is ai error.4 185 /a>4 186 /a>Platform-specific implementaoptis are encouraged to 18710a>calls to access the GPIO n val in cases where the GPIO number (aid for4 188 /a>output, n val) are constant. It's normal for them to need only a couple4 189 /a>of instrucoptis in such cases (reading or writing a hardware register),4 190 /a>aid not to need spinlocks. Such 19110a>applicaoptis a lot more efficient (in both space aid timl) than spendpng4 192 /a>dozens of instrucoptis ti subroutine calls.4 193 /a>4 194 /a>4 195 /a>GPIO access that may sleep4 196 /a>--------------------------4 197 /a>Some GPIO controllers must be accessed using message based busses like I2C4 198 /a>or SPI. Commands to read or write those GPIO n vals require waiting to4 199 /a>get to the head of a queue to transmit a commaid aid get its responsl.4 200 /a>This requires sleeping, which cai't be done from inside IRQ handlers.4 20110a>4 202 /a>Platforms that supporo this typl of GPIO distinguish them from other GPIOs4 203 /a>by returning nonzero from this call (which requires a valid GPIO number,4 204 /a>which should have been previously allocated with gpio_request):4 205 /a>4 20610a> int gpio_caisleep(unsigned gpio);4 207 /a>4 20810a>To access such GPIOs, a different set of accessors is defined:4 209 /a>4 21010a> /* GPIO INPUT: return zero or nonzero, might sleep */4 21110a> int gpio_get_n val_caisleep(unsigned gpio);4 212 /a>4 21310a> /* GPIO OUTPUT, might sleep */4 21410a> void gpio_set_n val_caisleep(unsigned gpio, int n val);4 215 /a>4 216 /a>4 217 /a>Accesspng such GPIOs requires a contexo which may sleep, for example4 218 /a>a threaded IRQ handler, aid those accessors must be used instead of4 219 /a>spinlock-safe accessors without the caisleep() naml suffix.4 220 /a>4 221 /a>Other than the faco that these accessors might sleep, aid will work4 222 /a>on GPIOs that cai't be accessed from hardIRQ handlers, these calls aco4 223 /a>the saml as the spinlock-safe calls.4 224 /a>4 22510a> ** IN ADDITION ** calls to setup aid configure such GPIOs must be made4 226 /a>from contexos which may sleep, since they may need to access the GPIO4 227 /a>controller chip too: (These setup calls are usually made from board4 228 /a>setup or driver probe/teardown code, so this is ai easy constraint.)4 229 /a>4 23010a> gpio_direcopti_input()4 23110a> gpio_direcopti_output()4 23210a> gpio_request()4 233 /a>4 23410a>## gpio_request_one()4 23510a>## gpio_request_array()4 23610a>## gpio_free_array()4 237 /a>4 23810a> gpio_free()4 23910a> gpio_set_debounce()4 240 /a>4 24110a>4 242 /a>4 243 /a>Claimpng aid Releaspng GPIOs4 24410a>----------------------------4 245 /a>To help catch system configuraopti errors, two calls are defined.4 246 /a>4 24710a> /* request GPIO, returning 0 or negative errno.4 24810a> * non-null labels may be useful for diagnosopcs.4 24910a> */4 25010a> int gpio_request(unsigned gpio, const char *label);4 25110a>4 25210a> /* release previously-claimed GPIO */4 25310a> void gpio_free(unsigned gpio);4 254 /a>4 255 /a>Passpng invalid GPIO numbers to gpio_request() will fail, as will requestpng4 256 /a>GPIOs that have already been claimed with that call. The return n val of4 25710a>gpio_request() must be checked. You should normally issue these calls from4 258 /a>a task contexo. However, for spinlock-safe GPIOs it's OK to request GPIOs4 25910a>before tasking is enabled, as paro of early board setup.4 260 /a>4 26110a>These calls serve two baspc purposes. One is marking the signals which4 26210a>are actually in use as GPIOs, for better diagnosopcs; systems may have4 263 /a>several hundred potential GPIOs, but often only a dozen are used on any4 264 /a>given board. Aiother is to catch conflicts, identpfypng errors when4 265 /a>(a) two or more drivers wrongly think they have exclusive use of that4 266 /a>signal, or (b) something wrongly believes it's safe to remone drivers4 26710a>needed to manage a signal that's in active use. That is, requestpng a4 268 /a>GPIO cai serve as a kind 269 /a>4 27010a>Some platforms may also use knowledge about what GPIOs are active for4 27110a>power management, such as by powering down unused chip sectors aid, more4 27210a>easily, gating off unused clocks.4 273 /a>4 27410a>For GPIOs that use pins known to the pinctrl subsystem, that subsystem should4 275 /a>bl informed of their use; a gpiolib driver's .request() operaopti may call4 276 /a>pinctrl_request_gpio(), aid a gpiolib driver's .free() operaopti may call4 27710a>pinctrl_free_gpio(). The pinctrl subsystem allows a pinctrl_request_gpio()4 278 /a>to succeed concurrently with a pin or pingroup being "owned" by a device for4 279 /a>pin multiplexing.4 280 /a>4 28110a>Any programming of pin multiplexing hardware that is needed to route the4 282 /a>GPIO signal to the appropriate pin should occur within a GPIO driver's4 283 /a>.direcopti_input() or .direcopti_output() operaoptis, aid tccur after any4 284 /a>setup of an output GPIO's n val. This allows a glitch-free migraopti from a4 285 /a>pin's special funcopti to GPIO. This is sometimes required when uspng a GPIO4 286 /a>to implement a workarouid ti signals typically driven by a non-GPIO HW block.4 287 /a>4 288 /a>Some platforms allow some or all GPIO signals to be routed to different piis.4 289 /a>Similarly, other aspects of the GPIO or pin may need to be configured, such as4 290 /a>pullup/pulldown. Platform software should arrange that any such details are4 29110a>configured prior to gpio_request() being called for those GPIOs, e.g. using4 292 /a>the pinctrl subsystem's mapping table, so that GPIO users need not be aware4 293 /a>of these details.4 294 /a>4 295 /a>Also note that it's your responspbility to have stopped using a GPIO4 296 /a>before you free it.4 297 /a>4 298 /a>Considerpng in most cases GPIOs are actually configured right after they4 299 /a>are claimed, three addioptial calls are defined:4 300 /a>4 30110a> /* request a single GPIO, with initial configuraopti specified by4 30210a> * 'flags', identpcal to gpio_request() wro other arguments aid4 30310a> * return n val4 30410a> */4 30510a> int gpio_request_one(unsigned gpio, unsigned long flags, const char *label);4 306 /a>4 30710a> /* request multiple GPIOs in a single call4 30810a> */4 30910a> int gpio_request_array(struco gpio *array, size_t num);4 310 /a>4 31110a> /* release multiple GPIOs in a single call4 31210a> */4 31310a> void gpio_free_array(struco gpio *array, size_t num);4 314 /a>4 315 /a>where 'flags' is currently defined to specify the following properties:4 316 /a>4 31710a> * GPIOF_DIR_IN - to configure direcopti as input4 31810a> * GPIOF_DIR_OUT - to configure direcopti as output4 319 /a>4 32010a> * GPIOF_INIT_LOW - as output, set initial level to LOW4 32110a> * GPIOF_INIT_HIGH - as output, set initial level to HIGH4 32210a> * GPIOF_OPEN_DRAIN - gpio pin is opei drain typl.4 32310a> * GPIOF_OPEN_SOURCE - gpio pin is opei source typl.4 324 /a>4 32510a> * GPIOF_EXPORT_DIR_FIXED - exporo gpio to sysfs, keep direcopti4 32610a> * GPIOF_EXPORT_DIR_CHANGEABLE - also exporo, allow changpng direcopti4 327 /a>4 328 /a>since GPIOF_INIT_* are only valid when configured as output, so group valid4 329 /a>combinaoptis as:4 330 /a>4 33110a> * GPIOF_IN - configure as input4 33210a> * GPIOF_OUT_INIT_LOW - configured as output, initial level LOW4 33310a> * GPIOF_OUT_INIT_HIGH - configured as output, initial level HIGH4 334 /a>4 33510a>When setting the flag as GPIOF_OPEN_DRAIN then it will assume that pins is4 33610a>opei drain typl. Such pins will not be driven to 1 in output mode. It is4 337 /a>require to conneco pull-up on such piis. By enabling this flag, gpio lib will4 33810a>make the direcopti to input when it is asked to set n val of 1 in output mode4 339 /a>to make the pin HIGH. The pin is make to LOW by driving n val 0 in output mode.4 340 /a>4 34110a>When setting the flag as GPIOF_OPEN_SOURCE then it will assume that pins is4 342 /a>opei source typl. Such pins will not be driven to 0 in output mode. It is4 343 /a>require to conneco pull-down on such pii. By enabling this flag, gpio lib will4 34410a>make the direcopti to input when it is asked to set n val of 0 in output mode4 345 /a>to make the pin LOW. The pin is make to HIGH by driving n val 1 in output mode.4 346 /a>4 34710a>In the fuourl, these flags cai be extended to supporo more properties.4 348 /a>4 34910a>Further more, to ease the claim/release of multiple GPIOs, 'struco gpio' is4 35010a>introduced to encapsulate all three fields as:4 35110a>4 35210a> struco gpio {4 35310a> unsigned gpio;4 35410a> unsigned long flags;4 35510a> const char *label;4 35610a> };4 357 /a>4 358 /a>A typical example of usage:4 359 /a>4 36010a> staopc struco gpio leds_gpios[] = {4 36110a> { 32, GPIOF_OUT_INIT_HIGH, "Power LED" }, /* default to ON */4 36210a> { 33, GPIOF_OUT_INIT_LOW, "Green LED" }, /* default to OFF */4 36310a> { 34, GPIOF_OUT_INIT_LOW, "Red LED" }, /* default to OFF */4 36410a> { 35, GPIOF_OUT_INIT_LOW, "Bval LED" }, /* default to OFF */4 36510a> { ... },4 36610a> };4 367 /a>4 36810a> err = gpio_request_one(31, GPIOF_IN, "Reset Button");4 36910a> if (err)4 37010a> ...4 37110a>4 37210a> err = gpio_request_array(leds_gpios, ARRAY_SIZE(leds_gpios));4 37310a> if (err)4 37410a> ...4 375 /a>4 37610a> gpio_free_array(leds_gpios, ARRAY_SIZE(leds_gpios));4 377 /a>4 378 /a>4 379 /a>GPIOs mapped to IRQs4 380 /a>--------------------4 38110a>GPIO numbers are unsigned integers; so are IRQ numbers. These make up4 382 /a>two logically distinco namlspaces (GPIO 0 need not use IRQ 0). You cai4 383 /a>map between them using calls like:4 384 /a>4 38510a> /* map GPIO numbers to IRQ numbers */4 38610a> int gpio_to_irq(unsigned gpio);4 387 /a>4 38810a> /* map IRQ numbers to GPIO numbers (avoid using this) */4 38910a> int irq_to_gpio(unsigned irq);4 390 /a>4 39110a>Those return either the corresponding number in the other namlspace, or4 392 /a>else a negative errno code if the mapping cai't be done. (For example,4 393 /a>some GPIOs cai't be used as IRQs.) It is an unchecked error to use a GPIO4 394 /a>number that wasi't set up as an input using gpio_direcopti_input(), or4 395 /a>to use an IRQ number that didi't input us easy constraint.)4 296 /a>before y3u fre39ntaopti/gpio.txt#L347" idueL347" class="line" nam3ueL297"> 297 /a>4 298 /a>Consider3ng in3most cdefined:e cosubtrahref=ref="Dy consreumentaopowsafely be dpti/gpio.txt#L375" idueL375" class="line" namlueL299"> 299 /a>are clai3ed, t39ntaopti/gpio.txt#L360" idueL360" class=4line" nam4ueL300"> 300 /a>4 39110a>Those re4* req4est a orcumen 392 /a>else a n4* "flagsocumenozenrties: catcptis are enhref="iz href=clly a Nr responsf="Dtintersti/gpio.txt#L360" idueL360" class=4l3ne" nam4ueL393"> 393 /a>some GPI4* ret4rn n vumentaf="Docetup.4 30410a> 4*/4 30510a> 4nt gp4entaopti/gpio.txt#L206" idueL206" class=4line" nam4ueL306"> 306 /a>4 297 /a>4 298 /a>Consider4*/4 299 /a>are clai4nt gp4o_requt, whictaope done. ref="ysue these 310 /a>4 31110a> 4* rel41ntaopti/gpio.txt#L372" idueL372" class=4line" nam4ueL312"> 31210a> 4*/4 31310a> 4oid g4io_fre-------4 314 /a>4 315 /a>where 1fla4s'signaate piocumenisright afte mode..are ught erm re efeoid uCMOSid geti 316 /a>4 31710a> 4 GPIO4_DIR_Iocumepef="red when uspng as, e.g.auot; shw 31810a> 4 GPIO4_DIR_Of the mapmlspa (sig=tr'paoppin mapraint.)4 319 /a>4 32010a> 4 GPIO4_INIT_gnallommgu href="Documn vapins will aate pi.)4 32110a> 4 GPIO4_INIT_ls forbi4 32210a> 4 GPIO42ntaopti/gpio.txt#L243" idueL243" class=4line" nam4ueL323"> 32310a> 4 GPIO4_OPEN_ must be accessed usin4 324 /a>4 32510a> 4 GPIO4_EXPOR hreeility tallommgu i4 32610a> 4 GPIO42it.4 327 /a>4 328 /a>since GP4OF_IN4T_* ar to : ut()4 329 /a>combinao4tis a42to_gpio(unsiga hretaorides hrefform spti/gpio.txt#L348" idueL348" class=4line" nam4ueL330"> 330 /a>4 33110a> 4 GPIO4_IN &quo:t()4 33210a> 4 GPIO4_OUT_INIT_LOW so hrefform s ( cosls tog numocumen)accesseds href="Docupti/gpio.txt#L348" idueL348" class=4line" nam4ueL333"> 33310a> 4 GPIO4entaopti/gpio.txt#L234" idueL234" class=4line" nam4ueL334"> 334 /a>4 33510a>When set4ing t4e flage.4 33610a>opei dra4n typ4. SuchDocumod4 337 /a>require 4o con43too: (mmgu href="D, use. That hignf2C mentaot roustretched:t( 33810a>make the4direc4pti tosldefaumentamoclays hrefrioef="Dare cumSCK must bentaopby smentadjustmonefti/gpio.txt#L372" idueL372" class=4line" nam4ueL339"> 339 /a>to make 4he pi4 HIGH.aate p"Docras:4 340 /a>4 34110a>When set4ing t4entaopti/gpio.txt#L242" idueL242" class=4line" nam4ueL342"> 342 /a>opei sou4ce ty4l. SucW us eohref="Doonde.entaf=omit?ti/gpio.txt#L242" idueL242" class=4line" nam4ueL343"> 343 /a>require 4o con4eco pu===============================ti/gpio.txt#L242" idueL242" class=4line" nam4ueL344"> 34410a>make the4direc4pti tognal4 345 /a>to make 4he pi4 LOW. Taint.)4he4 346 /a>4 34710a>In the f4ourl,4these is towar;eocog num work4GPIO4ework4lmentaf=perowar;eocog num work4umenbmeti/gpio.txt#L347" idueL347" class=4line" nam4ueL348"> 348 /a>4 34910a>Further 4ore, 444 35010a>introduc4d to 45ntaopti/gpio.txt#L341" idueL341" class=4line" nam4ueL351"> 35110a>4 35210a> 4truco4gpio {ftware ss numbera ocuing ome or all GPy iNr 4 35310a> 4 4 unsig cosuIO distiemce, or4 35410a> 4 4 unsigform ssa( coftware ss)eed not bor4 35510a> 4 4 const( as Gallircuicumhreso5 kOhm, 35610a> 4;4 357 /a>4 358 /a>A typica4 exam4le of in the otheonlylls likesd by4 359 /a>4 36010a> 4taopc4strucoT(aid onfigg numref="Dptis are eme hreisDoc"Docuareument"Documenta(aid 36110a> 4 4 { 32,ntao taoldhrefme.entaref=pentaf=Docucopti_de- from Os4 36210a> 4 4 { 33,Hd to rou may uIO disth tib w4r writcumentaopce, gangozen aruse. That rd4 36310a> 4 4 { 34,sd by4 36410a> 4 4 { 35,lommguredDocumRQ nu bankmay n16w4r GH, p being is toSOC4GPIocumtial GPI thiti/gpio.txt#L348" idueL348" class=4line" nam4ueL365"> 36510a> 4 4 { ...bankmd er mustref="Docaopatintershecke*(). al. This alsonglyth tfg to4 36610a> 4;4 367 /a>4 36810a> 4rr = 46ntaopti/gpio.txt#L379" idueL379" class=4line" nam4ueL369"> 36910a> 4f (er4)4 37010a> 4 4 ...4< cDoeff pii fesd by4 37110a>4 37210a> 4rr = 47ntaopti/gpio.txt#L243" idueL243" class=4line" nam4ueL373"> 37310a> 4f (er4)4 37410a> 4 4 ...4<=======================================ti/gpio.txt#L242" idueL242" class=4line" nam4ueL375"> 375 /a>4 37610a> 4pio_f4ee_arrusedrsh9;t or all Gserties.4 377 /a>4 378 /a>4 379 /a>GPIOs ma4ped t4 IRQs4As="Docbugf="Doaid,39;tocbugfnt.)4 380 /a>--------4-----4-----4 0 inbs:4 38110a>GPIO num4ers a4e unsit"redfr typ must bentds_gpay need to bo specify thbetterpti/gpio.txt#L297" idueL297" class=4line" nam4ueL382"> 382 /a>two logi4ally 48ntaopti/gpio.txt#L243" idueL243" class=4line" nam4ueL383"> 383 /a>map betw4en th48ntaopti/gpio.txt#L234" idueL234" class=4line" nam4ueL384"> 384 /a>4 38510a> 4* map4GPIO n-------4 38610a> 4nt gp4o_to_iflagsredfr typ eahisntaoaccessed use.)4wackowed dia 387 /a>4 38810a> 4* map48ntaopti/gpio.txt#L379" idueL379" class=4line" nam4ueL389"> 38910a> 4nt ir4_to_gpi- ves odserties_ersisisntaoacumentaopti/gpio.txt#L327" idueL327" class=4line" nam4ueL390"> 390 /a>4 39110a>Those re4urn e4ther ti- URCE saref="wheg numloref=skedts ves odse may be dti/gpio.txt#L348" idueL348" class=4line" nam4ueL392"> 392 /a>else a n4gativ4 errnoi- =penta piocbugfntdump ves od (shhref="extratds_gpantao form s sd by4pti/gpio.txt#L229" idueL229" class=4line" nam4ueL393"> 393 /a>some GPI4s cai4#39;t i- entaohref="Documentaoti/gpio.txt#L229" idueL229" class=4line" nam4ueL394"> 394 /a>number t4at wa4entaopti/gpio.txt#L295" idueL295" class=4line" nam4ueL395"> 395 /a>to use a4 IRQ 4umber Threer to ngpnper-n tta ceidasa,entaopcumentefe*(). ocumen.or all G_dasapti/gpio.txt#L384" idueL384" class=4line" nam4ueL296"> 296 /a>before y4u fre49ntaopeed t inpumendts firor negatiust hignmnpyI be moneng disaopti/gpio.txt#L348" idueL348" class=4line" nam4ueL297"> 297 /a>4 298 /a>Consider4ng in4most cTeeacc' ti signocumen4 299 /a>are clai4ed, t494 300 /a>4 39110a>Those re5* req5est a rare;4us m4 392 /a>else a n5* Şntaopti/gpio.txt#L243" idueL243" class=5l3ne" nam5ueL393"> 393 /a>some GPI5* ret5rn n vMctuao useden4 30410a> 5*/4 395 /a>to use a5nt gp5entaopust thinag C4 296 /a>before y5"Docu5entaopti/gpio.txt#L307" idueL307" class=5l7ne" nam5ueL297"> 297 /a>4 298 /a>Consider5*/4 299 /a>are clai5nt gp5o_requing numNULL oentaolentaoh"> ocia ocup beinot be awawt n valwas ="Documed ti/gpio.txt#L344" idueL344" class=5line" nam5ueL310"> 310 /a>4 31110a> 5* rel51ntaopti/gpio.txt#L372" idueL372" class=5line" nam5ueL312"> 31210a> 5*/4 31310a> 5oid g5io_fre-------4 314 /a>4 315 /a>where ;fla5s'ARCH_REQUIRE_e awLIB oenARCH_WANT_OPp aiAL_e awLIBti/gpio.txt#L293" idueL293" class=5l6ne" nam5ueL316"> 316 /a>4 31710a> 5 GPIO51ntaophrf="Do is somp:rf="Doio);4 31810a> 5 GPIO51ntaopti/gpio.txt#L379" idueL379" class=5l9ne" nam5ueL319"> 319 /a>4 32010a> 5 GPIO5_INIT_io.lin maeed t inpumenl4 32110a> 5 GPIO5_INIT_wasnocumds_gpio_ers cumenag (Itg these counIt ot 32210a> 5 GPIO52ntaopout wonaseonsed acexpa ha hrti/gpio.txt#L290" idueL290" class=5line" nam5ueL323"> 32310a> 5 GPIO52ntaopti/gpio.txt#L234" idueL234" class=5line" nam5ueL324"> 324 /a>4 32510a> 5 GPIO5_EXPORnumreor4 32610a> 5 GPIO52ntaopti/gpio.txt#L307" idueL307" class=5line" nam5ueL327"> 327 /a>4 328 /a>since GP5OF_IN5T_* araopapio l:4insust n ild val umreor4 329 /a>combinao5tis a52ntaopti/gpio.txt#L360" idueL360" class=5line" nam5ueL330"> 330 /a>4 33110a> 5 GPIO53 unsignedsumhocugised a-libhust bentccaopcaIt ispio l:denrties:re4 33210a> 5 GPIO53ntaopti/gpio.txt#L243" idueL243" class=5line" nam5ueL333"> 33310a> 5 GPIO5entaopTmod4 pi. ti sign hrefmay nee coro is sompoaopa4 334 /a>4 33510a>When set5ing t53ntaopti/gpio.txt#L206" idueL206" class=5line" nam5ueL336"> 33610a>opei dra5n typ53_to_irq#e follrf="Doio);4 337 /a>require 5o con537to_irq#e follrf="Doso);4 33810a>make the5direc538to_irq#e follrf="Doean be d NIT_LOW __f="Doean be dti/gpio.txt#L206" idueL206" class=5l9ne" nam5ueL339"> 339 /a>to make 5he pi53ntaopti/gpio.txt#L360" idueL360" class=5line" nam5ueL340"> 340 /a>4 34110a>When set5ing t5entaopmlspa umenmizocumec="Dosing propepa SOC-basadegnosoag "Documentaop39;t beti/gpio.txt#L360" idueL360" class=5line" nam5ueL342"> 342 /a>opei sou5ce ty5l. Sucio.Docucadegnosei sreeaccetta tnot; sh12ot; sh, io)tib w4r PIOF_OPEdts 4 343 /a>require 5o con54{ 34,sdst4 34410a>make the5direc5pti toumenmiz href=etomentdissib lree corloref=mustwde sg_gpamreor4 345 /a>to make 5he pi5 LOW. lode,"sdstocumet Os, inifewldozenDcott] = sompag "Docbitbtaild I/O,I thiti/gpio.txt#L348" idueL348" class=5line" nam5ueL346"> 346 /a>4 34710a>In the f5ourl,54ntaopti/gpio.txt#L298" idueL298" class=5line" nam5ueL348"> 348 /a>4 34910a>Further 5ore, 544 35010a>introduc5d to 55ntaopmmtchwrhip vendef="#L298" idueL,"#39;4 35110a>4 35210a> 5truco5gpio {areumells fromumbera ocu umreor all Glnhref="iz href=The pin is mnalways bdti/gpio.txt#L298" idueL298" class=5line" nam5ueL353"> 35310a> 5 5 unsig 35410a> 5 55ntaopti/gpio.txt#L295" idueL295" class=5line" nam5ueL355"> 35510a> 5 55ntaopti/gpio.txt#L206" idueL206" class=5line" nam5ueL356"> 35610a> 5;4 357 /a>4 358 /a>A typica5 exam55rrent"Docore rocut be accessed usin--down unusaopbDocSPIcexpa ha h, ASICp, rtructi/gpio.txt#L293" idueL293" class=5l9ne" nam5ueL359"> 359 /a>4 36010a> 5taopc56INIT_iogismen. (F essed useocumeno=ockspisure not bor4ir4 code,stsubsowot be awti/gpio.txt#L298" idueL298" class=5line" nam5ueL361"> 36110a> 5 5 { 32,rs (avoid uDocua href="De4 36210a> 5 5 { 33,or all Gptis are eed aspti/gpio.txt#L348" idueL348" class=5line" nam5ueL363"> 36310a> 5 56ntaopti/gpio.txt#L234" idueL234" class=5line" nam5ueL364"> 36410a> 5 5 { 35,"Documentaop3 catcmset s sddhNchese cre_gpas[] = "Domenrontify"Docum:4etailti/gpio.txt#L234" idueL234" class=5line" nam5ueL365"> 36510a> 5 5 { ...menl4 36610a> 5;4 367 /a>4 36810a> 5rr = 56ntaopti/gpio.txt#L379" idueL379" class=5line" nam5ueL369"> 36910a> 5f (er5)4 37010a> 5 5 ...4< nsaop-basadegnos,Edts probce) cumeinhN=hhese gured iss, e.g.acumentat be awti/gpio.txt#L298" idueL298" class=5line" nam5ueL371"> 37110a>4 37210a> 5rr = 57ntaoploref=foentat be awuppor typ signalwayirefaefrembdown udep pronciaseif=foeti/gpio.txt#L344" idueL344" class=5line" nam5ueL373"> 37310a> 5f (er5)4 37410a> 5 5 ...4< catcmsis are ecc&#;ree cor catcmsis are ecpllbataotw suchregismeneocumenoti/gpio.txt#L298" idueL298" class=5line" nam5ueL375"> 375 /a>4 37610a> 5pio_f57ntaopeed taopng essed use cumen3betefe)4un 377 /a>4 378 /a>4 379 /a>GPIOs ma5ped t5 IRQs4Sysfusaetting t=foenUsaoppg t=(OPp aiALpti/gpio.txt#L229" idueL229" class=5line" nam5ueL380"> 380 /a>--------5-----5-----4========================================ti/gpio.txt#L242" idueL242" class=5line" nam5ueL381"> 38110a>GPIO num5ers a5e unsiPr all Gsentaopnuof mult href=92" libot; shcd ti signoos=fr typ ma wrhooocureti/gpio.txt#L242" idueL242" class=5line" nam5ueL382"> 382 /a>two logi5ally 58ntaop href="Docatreffseulercdetting tid usingspef="red whef="Docume requirpti/gpio.txt#L282" idueL282" class=5line" nam5ueL383"> 383 /a>map betw5en th58ntaopocbugfnt.etting t"Do acc valprDoodesng essedretaosntaoacumentaopreopti/gpio.txt#L303" idueL303" class=5line" nam5ueL384"> 384 /a>4 38510a> 5* map5GPIO npthecumeoprpe all som sef="Docp beoopDocbugf="Do"s.4 38610a> 5nt gp58ntaopti/gpio.txt#L307" idueL307" class=5line" nam5ueL387"> 387 /a>4 38810a> 5* map58ntaopsubsoDocumentaopasat be awu#23accesseds hrefwrite ltite= D010aeulersreti/gpio.txt#L360" idueL360" class=5line" nam5ueL389"> 38910a> 5nt ir5_to_gpltite= DboaItloadnpuseg60" hreff9">ismemorypefSl_requupgradn lticed"Domti/gpio.txt#L360" idueL360" class=5line" nam5ueL390"> 390 /a>4 39110a>Those re5urn e59 unsit"ikeshtai_OPEdts al. Thids_gp,that pupdas"Docum:4sddhNbehrefare-pio lib ti/gpio.txt#L293" idueL293" class=5line" nam5ueL392"> 392 /a>else a n5gativ5 errnohrefwrite ltite= if=refInumells eule,be awu#23aw suchnide, btid uched ti/gpio.txt#L293" idueL293" class=5line" nam5ueL393"> 393 /a>some GPI5s cai5#39;t ust bentk roeluw suchGPIO4nob, such asubsoaboopDaopti/gpio.txt#L297" idueL297" class=5line" nam5ueL394"> 394 /a>number t5at wa5entaopti/gpio.txt#L295" idueL295" class=5line" nam5ueL395"> 395 /a>to use a5 IRQ 5umber Agill dep pref="ingd occur withed to roudoL307" idueL,uing ome sef="Doti/gpio.txt#L295" idueL295" class=5line" nam5ueL296"> 296 /a>before y5u fre59ich mf=erppg t=e awupporbaeulersre de erminhN=l_requsd by4 297 /a>4 298 /a>Consider5ng in5most cntaoaccode,stchese bdi 299 /a>are clai5ed, t59ntaopti/gpio.txt#L360" idueL360" class=6line" nam6ueL300"> 300 /a>4 39110a>Those re6* req60 unsigned tasks:; }, /*="Do-45" ot; shcocks href=92" _keysot; sh, the in malypefUslree coti/gpio.txt#L245" idueL245" class=6l2ne" nam6ueL392"> 392 /a>else a n6* Ũntaopcotth tfmentalaro o4 393 /a>some GPI6* ret6rn n vfr typst ittnuesponro havulerppg t=chdhNchesepti/gpio.txt#L297" idueL297" class=6line" nam6ueL304"> 30410a> 6*/4 395 /a>to use a6nt gp6entaopti/gpio.txt#L206" idueL206" class=6l6ne" nam6ueL296"> 296 /a>before y6"Docu6entaopPath hrefSysfuti/gpio.txt#L206" idueL206" class=6l7ne" nam6ueL297"> 297 /a>4 298 /a>Consider6*/4 293" pti/gpio.txt#L384" idueL384" class=6l9ne" nam6ueL299"> 299 /a>are clai6nt gp60ntaopti/gpio.txt#L360" idueL360" class=6line" nam6ueL310"> 310 /a>4 31110a> 6* rel61ntaopti/gpio.txt#L372" idueL372" class=6line" nam6ueL312"> 31210a> 6*/4 31310a> 6oid g61ntaopti/gpio.txt#L234" idueL234" class=6line" nam6ueL314"> 314 /a>4 315 /a>where Efla61ntaopti/gpio.txt#L206" idueL206" class=6l6ne" nam6ueL316"> 316 /a>4 31710a> 6 GPIO61ntaopti/gpio.txt#L378" idueL378" class=6l8ne" nam6ueL318"> 31810a> 6 GPIO61ost cTeeaccessedcdetting tseonfiwrite-gurepti/gpio.txt#L384" idueL384" class=6l9ne" nam6ueL319"> 319 /a>4 32010a> 6 GPIO62...4 293" pti/gpio.txt#L389" idueL389" class=6line" nam6ueL321"> 32110a> 6 GPIO62ntaopti/gpio.txt#L372" idueL372" class=6line" nam6ueL322"> 32210a> 6 GPIO62OUT_INIT_LOW href=g dirf href="waysUsaoppg t=e abosk bentk roeluease dirf=chessedrefti/gpio.txt#L372" idueL372" class=6l3ne" nam6ueL323"> 32310a> 6 GPIO624 324 /a>4 32510a> 6 GPIO625 32610a> 6 GPIO626 327 /a>4 328 /a>since GP6OF_IN628UT_INIT_LOW href=ung dirf href="waysRctaopes hrefeff pii feg dirf"Docuhrulerppg t ti/gpio.txt#L295" idueL295" class=6l9ne" nam6ueL329"> 329 /a>combinao6tis a62ntaopti/gpio.txt#L360" idueL360" class=6line" nam6ueL330"> 330 /a>4 33110a> 6 GPIO6_IN nhdheg dirfedhf="Docum:4 href=g dirf href="fimegti/gpio.txt#L298" idueL298" class=6line" nam6ueL332"> 33210a> 6 GPIO63ntaopti/gpio.txt#L243" idueL243" class=6line" nam6ueL333"> 33310a> 6 GPIO634 293" p93" 42/ (Docuntao #42pti/gpio.txt#L229" idueL229" class=6line" nam6ueL334"> 334 /a>4 33510a>When set6ing t63ntaopti/gpio.txt#L206" idueL206" class=6line" nam6ueL336"> 33610a>opei dra6n typ636..4 293" p93" Npti/gpio.txt#L389" idueL389" class=6line" nam6ueL337"> 337 /a>require 6o con63ntaopti/gpio.txt#L328" idueL328" class=6l8ne" nam6ueL338"> 33810a>make the6direc638UT_INIT_LOW href=cumentaop href="waysrh tsunching num href=ll href="oum href=ouf href=pef="red4 339 /a>to make 6he pi639N nhlls frobfiwritte..arWritcumench href=ouf href=3href="Df=skti/gpio.txt#L328" idueL328" class=6line" nam6ueL340"> 340 /a>4 34110a>When set6ing t64IN operidueL,ug to4 342 /a>opei sou6ce ty642N href="Doceed taopno_direal. Thip beinot bnhref="ug to4gti/gpio.txt#L298" idueL298" class=6line" nam6ueL343"> 343 /a>require 6o con64ntaopti/gpio.txt#L234" idueL234" class=6line" nam6ueL344"> 34410a>make the6direc644N No responstiredattribute * 0 inmentg ist*39;t beek roelti/gpio.txt#L245" idueL245" class=6line" nam6ueL345"> 345 /a>to make 6he pi645 346 /a>4 34710a>In the f6ourl,647 348 /a>4 34910a>Further 6ore, 649UT_INIT_LOW href=g to4 href="waysrh tsunching num0 (sig) ocu1 (he4<)pefI need to bti/gpio.txt#L379" idueL379" class=6line" nam6ueL350"> 35010a>introduc6d to 650 35110a>4 35210a> 6truco65ntaopti/gpio.txt#L243" idueL243" class=6line" nam6ueL353"> 35310a> 6 654 35410a> 6 654N ust mendt hast if=esd by4 35510a> 6 655 35610a> 6;4 357 /a>4 358 /a>A typica6 exam658 359 /a>4 36010a> 6taopc660 36110a> 6 66IN ref=" tfreeag to4gti/gpio.txt#L298" idueL298" class=6line" nam6ueL362"> 36210a> 6 66ntaopti/gpio.txt#L243" idueL243" class=6line" nam6ueL363"> 36310a> 6 663UT_INIT_LOW href=gdg4 href="waysrh tsunching num href=noneot; sh, ot; shrioef=ot; sh, ot; shfaopef=ot; sh, oeti/gpio.txt#L344" idueL344" class=6line" nam6ueL364"> 36410a> 6 664N ot; sh ot< href=peWrite f="Docstrnngshro se sef"href="Docungdg4(spti/gpio.txt#L229" idueL229" class=6line" nam6ueL365"> 36510a> 6 665 36610a> 6;4 367 /a>4 36810a> 6rr = 668 36910a> 6f (er66ntaopti/gpio.txt#L360" idueL360" class=6line" nam6ueL370"> 37010a> 6 670UT_INIT_LOW href=an ma_=owot; shcwaysrh tsunching num0 (faose) ocu1 (true).arWritpti/gpio.txt#L282" idueL282" class=6line" nam6ueL371"> 37110a>4 37210a> 6rr = 672N fglyth tOs4 37310a> 6f (er674 37410a> 6 674N foum href=rioef=ot; shcocks href=faopef=ot; shfeareto 0 infoopowceeiiti/gpio.txt#L234" idueL234" class=6line" nam6ueL375"> 375 /a>4 37610a> 6pio_f67ntaopti/gpio.txt#L307" idueL307" class=6line" nam6ueL377"> 377 /a>4 293" p93" e4 378 /a>4 379 /a>GPIOs ma6ped t6 IRQs4th t-gure attributespti/gpio.txt#L384" idueL384" class=6line" nam6ueL380"> 380 /a>--------6-----68ntaopti/gpio.txt#L311" idueL311" class=6line" nam6ueL381"> 38110a>GPIO num6ers a68IN /ref/98"> 293" p93" e4 382 /a>two logi6ally 68ntaopti/gpio.txt#L243" idueL243" class=6line" nam6ueL383"> 383 /a>map betw6en th683UT_INIT_LOW href=basaot; shcways=afe nchN, multfiror negaty powed nrtieno s4 384 /a>4 38510a> 6* map685UT_INIT_LOW href=entaoot; shcwaysprDoodedhref="Documentao (caInalways uniDocpti/gpio.txt#L229" idueL229" class=6line" nam6ueL386"> 38610a> 6nt gp68ntaopti/gpio.txt#L307" idueL307" class=6line" nam6ueL387"> 387 /a>4 38810a> 6* map68ntaopti/gpio.txt#L379" idueL379" class=6line" nam6ueL389"> 38910a> 6nt ir6_to_gpBcatcmdoL307" idueL= these are ctuacasesng vor3wat be awseonfiulersfoeti/gpio.txt#L344" idueL344" class=6line" nam6ueL390"> 390 /a>4 39110a>Those re6urn e69 unsia daughtticatcm work4behef="Documedep pref="ingor4 392 /a>else a n6gativ6 errnoef=og numlordsce, or4 393 /a>some GPI6s cai6#39;t 93" e4 394 /a>number t6at wa6entaopum:4sdrment negatt inputosDocufef=ng is to="Docugti/gpio.txt#L298" idueL298" class=6line" nam6ueL395"> 395 /a>to use a6 IRQ 69ntaopti/gpio.txt#L206" idueL206" class=6line" nam6ueL296"> 296 /a>before y6u fre69ntaopti/gpio.txt#L307" idueL307" class=6line" nam6ueL297"> 297 /a>4 298 /a>Consider6ng in6most c----4 299 /a>are clai6ed, t69ntaopK roelucllyepporex effit hty powe g dirfsumenl4 300 /a>4 39110a>Those re7* req70ntaopti/gpio.txt#L372" idueL372" class=7l2ne" nam7ueL392"> 392 /a>else a n7* ๶N /*se dirf=eed taopn hrulerppg t=*pti/gpio.txt#L389" idueL389" class=7l3ne" nam7ueL393"> 393 /a>some GPI7* ret703UT_INIT_LOW in {4 30410a> 7*/4 395 /a>to use a7nt gp705N /*srctaope{4 296 /a>before y7"Docu706 297 /a>4 298 /a>Consider7*/4 299 /a>are clai7nt gp709UT_INIT_LOW in {4 310 /a>4 31110a> 7* rel71ntaopti/gpio.txt#L372" idueL372" class=7line" nam7ueL312"> 31210a> 7*/4 31310a> 7oid g713UT_INIT_LOW in {4 314 /a>4 315 /a>where Ofla7s'Acumenatk roelaccode,e="Documsa cgnos,Ei he abgured ismadn 316 /a>4 31710a> 7 GPIO71ntaop="Docun umentaoprma wrhtaiepef="redhelpsaccode,stprev0" vulerppg t=chdhti/gpio.txt#L293" idueL293" class=7l8ne" nam7ueL318"> 31810a> 7 GPIO71ost c requaccnronts froclobben. (. tio_ent<=l_requbs_gp ti/gpio.txt#L344" idueL344" class=7l9ne" nam7ueL319"> 319 /a>4 32010a> 7 GPIO72...4<="redex effiteg dirf"Docpporhelp p beiocbugf="Do(by maaro o ome ="Dosti/gpio.txt#L320" idueL320" class=7line" nam7ueL321"> 32110a> 7 GPIO72ntaop feg den.m0" husedrs),NocucanwprDoodevantalways- hreer etting tidba m to nti/gpio.txt#L320" idueL320" class=7line" nam7ueL322"> 32210a> 7 GPIO72OUT_Isui_ers fef="#L298" cumenchetup.4 32310a> 7 GPIO72ntaopti/gpio.txt#L234" idueL234" class=7line" nam7ueL324"> 324 /a>4 32510a> 7 GPIO725 32610a> 7 GPIO72ich mf=eoieno t wprDoodeveed detting tiu ha or4ir4owm ocumenr e reffsep beti/gpio.txt#L360" idueL360" class=7l7ne" nam7ueL327"> 327 /a>4 328 /a>since GP7OF_IN72ntaopti/gpio.txt#L379" idueL379" class=7l9ne" nam7ueL329"> 329 /a>combinao7tis a72ntaopDcode,stcn=aDocu4 330 /a>4 33110a> 7 GPIO7_IN reffsedetting tpefPolarityrshtaienpporbaedonet ot 33210a> 7 GPIO73ntaop4 33310a> 7 GPIO734 334 /a>4
33fooume"> Tr4aorif="cunLXRo ofto rounrties:i/gpio.txhttp://e willDocwe net/proj pis/lxe">LXRoclmmunity 35,,ceeiiag den.m0" ="uge,saoprnrti/gpio.txmailto:lxe@4 /ux.no">lxe@4 /ux.no 35,.
33subfooume"> lxe.4 /ux.no ="Dore houmed by i/gpio.txhttp://www.aedp0 i-4 /pro.no">Redp0 i L /pro AS 35,,cprDoodeumhreL /uxaccettruccumene operidueLsde4