ADP5588 GPIO

The standalone gpio-adp5588 driver was removed from the kernel. ADP5588 GPIO support is now provided by drivers/input/keyboard/adp5588-keys.c (CONFIG_KEYBOARD_ADP5588). For GPIO-only operation, use compatible = "adi,adp5588" (or "adi,adp5587"), gpio-controller and #gpio-cells = <2>, and omit keypad,num-rows and keypad,num-columns.

Supported Devices

• ADP5587

• ADP5588

Evaluation Boards

• ADP5588-EVALZ

• ADP5587CB-EVALZ

• ADP5587CP-EVALZ

Description

Configuration

Source Code

Status

Source	Mainlined?
git	Yes

Files

Function	File
driver	drivers/gpio/gpio-adp5588.c
include	include/linux/i2c/adp5588.h

Hardware configuration

There is no dedicated Blackfin STAMP evaluation board for the ADP5588. During test and driver development we used the ADP5588 Demo Mother/Daughter Board.

It can be easily wired to the Blackfin STAMP TWI/I2C header.

BF537-STAMP (P10) TWI/I2C header		ADP5588 Daughter Board
PIN	Function	PIN/Function
2	(+3.3V)	VCC
5	SCL	SCL
6	SDA	SDA
10	PORTG0	INTB
20	GND	GND

Tip

On the ADP5588 Demo Mother Board replace R30 (10kOhm PULL-UP resistor on /INTB strobe) with a 1-3kOhm resistor. The 10kOhm resistor is too weak - Blackfin might see an additional falling edge interrupt on the rising edge of /INTB.

Adding Linux driver support

Kernel configuration

Configure kernel with make menuconfig (alternatively use make xconfig or make qconfig)

Device Drivers  --->
[*] GPIO Support  --->

    --- GPIO Support
    [ ]   Debug GPIO calls
    [*]   /sys/class/gpio/... (sysfs interface)
          *** Memory mapped GPIO expanders: ***
    < >   IT8761E GPIO support
          *** I2C GPIO expanders: ***
    < >   Maxim MAX7300 GPIO expander
    < >   MAX7319, MAX7320-7327 I2C Port Expanders
    < >   PCA953x, PCA955x, TCA64xx, and MAX7310 I/O ports
    < >   PCF857x, PCA{85,96}7x, and MAX732[89] I2C GPIO expanders
    [ ]   Semtech SX150x I2C GPIO expander
    < >   GPIO Support for ADP5520 PMIC
    <*>   ADP5588 I2C GPIO expander
    [*]     Interrupt controller support for ADP5588

Devicetree configuration

For GPIO-only operation, declare the device with gpio-controller and #gpio-cells = <2> and without keypad,num-rows/keypad,num-columns:

#include <dt-bindings/gpio/gpio.h>

&i2c0 {
    #address-cells = <1>;
    #size-cells = <0>;

    gpio@34 {
        compatible = "adi,adp5588";
        reg = <0x34>;
        #gpio-cells = <2>;
        gpio-controller;
    };
};

Driver testing

When the adp5588-keys driver probes, the ADP5588 GPIOs are registered as a gpiochip. The examples below use the sysfs GPIO interface (CONFIG_GPIO_SYSFS); GPIO numbers depend on the system.

For more information see also here: GPIO Sysfs Interface for Userspace

root:/> echo 67 > /sys/class/gpio/export

root:/> echo low > /sys/class/gpio/gpio67/direction
root:/> echo high > /sys/class/gpio/gpio67/direction

root:/> echo in > /sys/class/gpio/gpio67/direction
root:/> cat /sys/class/gpio/gpio67/value
1
root:/> cat /sys/class/gpio/gpio67/value
0
root:/

More Information