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/openbmc/qemu/hw/gpio/
H A Dpcf8574.c1 /* SPDX-License-Identifier: GPL-2.0-only */
4 * NXP PCF8574 8-port I2C GPIO expansion chip.
19 * PCF8574 and compatible chips incorporate quasi-bidirectional
20 * IO. Electrically it means that device sustain pull-up to line
23 * IO access is implemented as simple I2C single-byte read
28 * In essence, user can think of quasi-bidirectional IO as
29 * open-drain line, except presence of builtin rising edge acceleration
43 uint8_t lastrq; /* Last requested state. If changed - assert irq */
45 uint8_t output; /* Pull-up (1) or drive low (0) on bit */
53 s->lastrq = MAKE_64BIT_MASK(0, PORTS_COUNT); in pcf8574_reset()
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/openbmc/linux/Documentation/devicetree/bindings/gpio/
H A Dnxp,pcf8575.yaml1 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
3 ---
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
7 title: PCF857x-compatible I/O expanders
10 - Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
13 The PCF857x-compatible chips have "quasi-bidirectional" I/O lines that can be
14 driven high by a pull-up current source or driven low to ground. This
25 - maxim,max7328
26 - maxim,max7329
27 - nxp,pca8574
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/openbmc/u-boot/doc/device-tree-bindings/gpio/
H A Dgpio-pcf857x.txt1 * PCF857x-compatible I/O expanders
3 The PCF857x-compatible chips have "quasi-bidirectional" I/O lines that can be
4 driven high by a pull-up current source or driven low to ground. This combines
14 - compatible: should be one of the following.
15 - "maxim,max7328": For the Maxim MAX7378
16 - "maxim,max7329": For the Maxim MAX7329
17 - "nxp,pca8574": For the NXP PCA8574
18 - "nxp,pca8575": For the NXP PCA8575
19 - "nxp,pca9670": For the NXP PCA9670
20 - "nxp,pca9671": For the NXP PCA9671
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/openbmc/u-boot/drivers/gpio/
H A Dpcf8575_gpio.c1 // SPDX-License-Identifier: GPL-2.0
5 * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/
10 * Driver for TI PCF-8575 16-bit I2C gpio expander. Based on
11 * gpio-pcf857x Linux Kernel(v4.7) driver.
20 * supports PCF8575 16-bit expander by TI and NXP.
29 #include <asm-generic/gpio.h>
36 /* NOTE: these chips have strange "quasi-bidirectional" I/O pins.
45 * our software copy of the "latch" then matches the chip's all-ones
52 /* Read/Write to 16-bit I/O expander */
63 chip->chip_addr); in pcf8575_i2c_write_le16()
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/openbmc/linux/drivers/gpio/
H A Dgpio-pcf857x.c1 // SPDX-License-Identifier: GPL-2.0-or-later
59 * that pin be used as an input; it's not an open-drain model, but acts
60 * a bit like one. This is described as "quasi-bidirectional"; read the
80 /*-------------------------------------------------------------------------*/
82 /* Talk to 8-bit I/O expander */
94 /* Talk to 16-bit I/O expander */
116 /*-------------------------------------------------------------------------*/
123 mutex_lock(&gpio->lock); in pcf857x_input()
124 gpio->out |= (1 << offset); in pcf857x_input()
125 status = gpio->write(gpio->client, gpio->out); in pcf857x_input()
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H A DKconfig1 # SPDX-License-Identifier: GPL-2.0-only
47 this symbol, but new drivers should use the generic gpio-regmap
57 non-sleeping contexts. They can make bitbanged serial protocols
118 Enables support for the idio-16 library functions. The idio-16 library
120 ACCES IDIO-16 family such as the 104-IDIO-16 and the PCI-IDIO-16.
122 If built as a module its name will be gpio-idio-16.
128 tristate "GPIO driver for 74xx-ICs with MMIO access"
132 Say yes here to support GPIO functionality for 74xx-compatible ICs
149 If driver is built as a module it will be called gpio-altera.
310 tristate "Generic memory-mapped GPIO controller support (MMIO platform device)"
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