1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef __LINUX_PCF857X_H 3#define __LINUX_PCF857X_H 4 5/** 6 * struct pcf857x_platform_data - data to set up pcf857x driver 7 * @gpio_base: number of the chip's first GPIO 8 * @n_latch: optional bit-inverse of initial register value; if 9 * you leave this initialized to zero the driver will act 10 * like the chip was just reset 11 * @setup: optional callback issued once the GPIOs are valid 12 * @teardown: optional callback issued before the GPIOs are invalidated 13 * @context: optional parameter passed to setup() and teardown() 14 * 15 * In addition to the I2C_BOARD_INFO() state appropriate to each chip, 16 * the i2c_board_info used with the pcf875x driver must provide its 17 * platform_data (pointer to one of these structures) with at least 18 * the gpio_base value initialized. 19 * 20 * The @setup callback may be used with the kind of board-specific glue 21 * which hands the (now-valid) GPIOs to other drivers, or which puts 22 * devices in their initial states using these GPIOs. 23 * 24 * These GPIO chips are only "quasi-bidirectional"; read the chip specs 25 * to understand the behavior. They don't have separate registers to 26 * record which pins are used for input or output, record which output 27 * values are driven, or provide access to input values. That must be 28 * inferred by reading the chip's value and knowing the last value written 29 * to it. If you leave n_latch initialized to zero, that last written 30 * value is presumed to be all ones (as if the chip were just reset). 31 */ 32struct pcf857x_platform_data { 33 unsigned gpio_base; 34 unsigned n_latch; 35 36 int (*setup)(struct i2c_client *client, 37 int gpio, unsigned ngpio, 38 void *context); 39 int (*teardown)(struct i2c_client *client, 40 int gpio, unsigned ngpio, 41 void *context); 42 void *context; 43}; 44 45#endif /* __LINUX_PCF857X_H */ 46