1# 2# GPIO infrastructure and expanders 3# 4 5config ARCH_WANT_OPTIONAL_GPIOLIB 6 bool 7 help 8 Select this config option from the architecture Kconfig, if 9 it is possible to use gpiolib on the architecture, but let the 10 user decide whether to actually build it or not. 11 Select this instead of ARCH_REQUIRE_GPIOLIB, if your architecture does 12 not depend on GPIOs being available, but rather let the user 13 decide whether he needs it or not. 14 15config ARCH_REQUIRE_GPIOLIB 16 bool 17 select GPIOLIB 18 help 19 Platforms select gpiolib if they use this infrastructure 20 for all their GPIOs, usually starting with ones integrated 21 into SOC processors. 22 Selecting this from the architecture code will cause the gpiolib 23 code to always get built in. 24 25 26 27menuconfig GPIOLIB 28 bool "GPIO Support" 29 depends on ARCH_WANT_OPTIONAL_GPIOLIB || ARCH_REQUIRE_GPIOLIB 30 select GENERIC_GPIO 31 help 32 This enables GPIO support through the generic GPIO library. 33 You only need to enable this, if you also want to enable 34 one or more of the GPIO expansion card drivers below. 35 36 If unsure, say N. 37 38if GPIOLIB 39 40config DEBUG_GPIO 41 bool "Debug GPIO calls" 42 depends on DEBUG_KERNEL 43 help 44 Say Y here to add some extra checks and diagnostics to GPIO calls. 45 The checks help ensure that GPIOs have been properly initialized 46 before they are used and that sleeping calls aren not made from 47 nonsleeping contexts. They can make bitbanged serial protocols 48 slower. The diagnostics help catch the type of setup errors 49 that are most common when setting up new platforms or boards. 50 51config GPIO_SYSFS 52 bool "/sys/class/gpio/... (sysfs interface)" 53 depends on SYSFS && EXPERIMENTAL 54 help 55 Say Y here to add a sysfs interface for GPIOs. 56 57 This is mostly useful to work around omissions in a system's 58 kernel support. Those are common in custom and semicustom 59 hardware assembled using standard kernels with a minimum of 60 custom patches. In those cases, userspace code may import 61 a given GPIO from the kernel, if no kernel driver requested it. 62 63 Kernel drivers may also request that a particular GPIO be 64 exported to userspace; this can be useful when debugging. 65 66# put expanders in the right section, in alphabetical order 67 68comment "I2C GPIO expanders:" 69 70config GPIO_MAX732X 71 tristate "MAX7319, MAX7320-7327 I2C Port Expanders" 72 depends on I2C 73 help 74 Say yes here to support the MAX7319, MAX7320-7327 series of I2C 75 Port Expanders. Each IO port on these chips has a fixed role of 76 Input (designated by 'I'), Push-Pull Output ('O'), or Open-Drain 77 Input and Output (designed by 'P'). The combinations are listed 78 below: 79 80 8 bits: max7319 (8I), max7320 (8O), max7321 (8P), 81 max7322 (4I4O), max7323 (4P4O) 82 83 16 bits: max7324 (8I8O), max7325 (8P8O), 84 max7326 (4I12O), max7327 (4P12O) 85 86 Board setup code must specify the model to use, and the start 87 number for these GPIOs. 88 89config GPIO_PCA953X 90 tristate "PCA953x, PCA955x, and MAX7310 I/O ports" 91 depends on I2C 92 help 93 Say yes here to provide access to several register-oriented 94 SMBus I/O expanders, made mostly by NXP or TI. Compatible 95 models include: 96 97 4 bits: pca9536, pca9537 98 99 8 bits: max7310, pca9534, pca9538, pca9554, pca9557 100 101 16 bits: pca9535, pca9539, pca9555 102 103 This driver can also be built as a module. If so, the module 104 will be called pca953x. 105 106config GPIO_PCF857X 107 tristate "PCF857x, PCA{85,96}7x, and MAX732[89] I2C GPIO expanders" 108 depends on I2C 109 help 110 Say yes here to provide access to most "quasi-bidirectional" I2C 111 GPIO expanders used for additional digital outputs or inputs. 112 Most of these parts are from NXP, though TI is a second source for 113 some of them. Compatible models include: 114 115 8 bits: pcf8574, pcf8574a, pca8574, pca8574a, 116 pca9670, pca9672, pca9674, pca9674a, 117 max7328, max7329 118 119 16 bits: pcf8575, pcf8575c, pca8575, 120 pca9671, pca9673, pca9675 121 122 Your board setup code will need to declare the expanders in 123 use, and assign numbers to the GPIOs they expose. Those GPIOs 124 can then be used from drivers and other kernel code, just like 125 other GPIOs, but only accessible from task contexts. 126 127 This driver provides an in-kernel interface to those GPIOs using 128 platform-neutral GPIO calls. 129 130comment "PCI GPIO expanders:" 131 132config GPIO_BT8XX 133 tristate "BT8XX GPIO abuser" 134 depends on PCI && VIDEO_BT848=n 135 help 136 The BT8xx frame grabber chip has 24 GPIO pins than can be abused 137 as a cheap PCI GPIO card. 138 139 This chip can be found on Miro, Hauppauge and STB TV-cards. 140 141 The card needs to be physically altered for using it as a 142 GPIO card. For more information on how to build a GPIO card 143 from a BT8xx TV card, see the documentation file at 144 Documentation/bt8xxgpio.txt 145 146 If unsure, say N. 147 148comment "SPI GPIO expanders:" 149 150config GPIO_MAX7301 151 tristate "Maxim MAX7301 GPIO expander" 152 depends on SPI_MASTER 153 help 154 gpio driver for Maxim MAX7301 SPI GPIO expander. 155 156config GPIO_MCP23S08 157 tristate "Microchip MCP23S08 I/O expander" 158 depends on SPI_MASTER 159 help 160 SPI driver for Microchip MCP23S08 I/O expander. This provides 161 a GPIO interface supporting inputs and outputs. 162 163endif 164