/*
* max732x.c - I2C Port Expander with 8/16 I/O
*
* Copyright (C) 2007 Marvell International Ltd.
* Copyright (C) 2008 Jack Ren <jack.ren@marvell.com>
* Copyright (C) 2008 Eric Miao <eric.miao@marvell.com>
*
* Derived from drivers/gpio/pca953x.c
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/gpio.h>
#include <linux/i2c.h>
#include <linux/i2c/max732x.h>
/*
* Each port of MAX732x (including MAX7319) falls into one of the
* following three types:
*
* - Push Pull Output
* - Input
* - Open Drain I/O
*
* designated by 'O', 'I' and 'P' individually according to MAXIM's
* datasheets.
*
* There are two groups of I/O ports, each group usually includes
* up to 8 I/O ports, and is accessed by a specific I2C address:
*
* - Group A : by I2C address 0b'110xxxx
* - Group B : by I2C address 0b'101xxxx
*
* where 'xxxx' is decided by the connections of pin AD2/AD0. The
* address used also affects the initial state of output signals.
*
* Within each group of ports, there are five known combinations of
* I/O ports: 4I4O, 4P4O, 8I, 8P, 8O, see the definitions below for
* the detailed organization of these ports.
*
* GPIO numbers start from 'gpio_base + 0' to 'gpio_base + 8/16',
* and GPIOs from GROUP_A are numbered before those from GROUP_B
* (if there are two groups).
*
* NOTE: MAX7328/MAX7329 are drop-in replacements for PCF8574/a, so
* they are not supported by this driver.
*/
#define PORT_NONE 0x0 /* '/' No Port */
#define PORT_OUTPUT 0x1 /* 'O' Push-Pull, Output Only */
#define PORT_INPUT 0x2 /* 'I' Input Only */
#define PORT_OPENDRAIN 0x3 /* 'P' Open-Drain, I/O */
#define IO_4I4O 0x5AA5 /* O7 O6 I5 I4 I3 I2 O1 O0 */
#define IO_4P4O 0x5FF5 /* O7 O6 P5 P4 P3 P2 O1 O0 */
#define IO_8I 0xAAAA /* I7 I6 I5 I4 I3 I2 I1 I0 */
#define IO_8P 0xFFFF /* P7 P6 P5 P4 P3 P2 P1 P0 */
#define IO_8O 0x5555 /* O7 O6 O5 O4 O3 O2 O1 O0 */
#define GROUP_A(x) ((x) & 0xffff) /* I2C Addr: 0b'110xxxx */
#define GROUP_B(x) ((x) << 16) /* I2C Addr: 0b'101xxxx */
static const struct i2c_device_id max732x_id[] = {
{ "max7319", GROUP_A(IO_8I) },
{ "max7320", GROUP_B(IO_8O) },
{ "max7321", GROUP_A(IO_8P) },
{ "max7322", GROUP_A(IO_4I4O) },
{ "max7323", GROUP_A(IO_4P4O) },
{ "max7324", GROUP_A(IO_8I) | GROUP_B(IO_8O) },
{ "max7325", GROUP_A(IO_8P) | GROUP_B(IO_8O) },
{ "max7326", GROUP_A(IO_4I4O) | GROUP_B(IO_8O) },
{ "max7327", GROUP_A(IO_4P4O) | GROUP_B(IO_8O) },
{ },
};
MODULE_DEVICE_TABLE(i2c, max732x_id);
struct max732x_chip {
struct gpio_chip gpio_chip;
struct i2c_client *client; /* "main" client */
struct i2c_client *client_dummy;
struct i2c_client *client_group_a;
struct i2c_client *client_group_b;
unsigned int mask_group_a;
unsigned int dir_input;
unsigned int dir_output;
struct mutex lock;
uint8_t reg_out[2];
};
static int max732x_write(struct max732x_chip *chip, int group_a, uint8_t val)
{
struct i2c_client *client;
int ret;
client = group_a ? chip->client_group_a : chip->client_group_b;
ret = i2c_smbus_write_byte(client, val);
if (ret < 0) {
dev_err(&client->dev, "failed writing\n");
return ret;
}
return 0;
}
static int max732x_read(struct max732x_chip *chip, int group_a, uint8_t *val)
{
struct i2c_client *client;
int ret;
client = group_a ? chip->client_group_a : chip->client_group_b;
ret = i2c_smbus_read_byte(client);
if (ret < 0) {
dev_err(&client->dev, "failed reading\n");
return ret;
}
*val = (uint8_t)ret;
return 0;
}
static inline int is_group_a(struct max732x_chip *chip, unsigned off)
{
return (1u << off) & chip->mask_group_a;
}
static int max732x_gpio_get_value(struct gpio_chip *gc, unsigned off)
{
struct max732x_chip *chip;
uint8_t reg_val;
int ret;
chip = container_of(gc, struct max732x_chip, gpio_chip);
ret = max732x_read(chip, is_group_a(chip, off), ®_val);
if (ret < 0)
return 0;
return reg_val & (1u << (off & 0x7));
}
static void max732x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
{
struct max732x_chip *chip;
uint8_t reg_out, mask = 1u << (off & 0x7);
int ret;
chip = container_of(gc, struct max732x_chip, gpio_chip);
mutex_lock(&chip->lock);
reg_out = (off > 7) ? chip->reg_out[1] : chip->reg_out[0];
reg_out = (val) ? reg_out | mask : reg_out & ~mask;
ret = max732x_write(chip, is_group_a(chip, off), reg_out);
if (ret < 0)
goto out;
/* update the shadow register then */
if (off > 7)
chip->reg_out[1] = reg_out;
else
chip->reg_out[0] = reg_out;
out:
mutex_unlock(&chip->lock);
}
static int max732x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
{
struct max732x_chip *chip;
unsigned int mask = 1u << off;
chip = container_of(gc, struct max732x_chip, gpio_chip);
if ((mask & chip->dir_input) == 0) {
dev_dbg(&chip->client->dev, "%s port %d is output only\n",
chip->client->name, off);
return -EACCES;
}
return 0;
}
static int max732x_gpio_direction_output(struct gpio_chip *gc,
unsigned off, int val)
{
struct max732x_chip *chip;
unsigned int mask = 1u << off;
chip = container_of(gc, struct max732x_chip, gpio_chip);
if ((mask & chip->dir_output) == 0) {
dev_dbg(&chip->client->dev, "%s port %d is input only\n",
chip->client->name, off);
return -EACCES;
}
max732x_gpio_set_value(gc, off, val);
return 0;
}
static int __devinit max732x_setup_gpio(struct max732x_chip *chip,
const struct i2c_device_id *id,
unsigned gpio_start)
{
struct gpio_chip *gc = &chip->gpio_chip;
uint32_t id_data = id->driver_data;
int i, port = 0;
for (i = 0; i < 16; i++, id_data >>= 2) {
unsigned int mask = 1 << port;
switch (id_data & 0x3) {
case PORT_OUTPUT:
chip->dir_output |= mask;
break;
case PORT_INPUT:
chip->dir_input |= mask;
break;
case PORT_OPENDRAIN:
chip->dir_output |= mask;
chip->dir_input |= mask;
break;
default:
continue;
}
if (i < 8)
chip->mask_group_a |= mask;
port++;
}
if (chip->dir_input)
gc->direction_input = max732x_gpio_direction_input;
if (chip->dir_output) {
gc->direction_output = max732x_gpio_direction_output;
gc->set = max732x_gpio_set_value;
}
gc->get = max732x_gpio_get_value;
gc->can_sleep = 1;
gc->base = gpio_start;
gc->ngpio = port;
gc->label = chip->client->name;
gc->owner = THIS_MODULE;
return port;
}
static int __devinit max732x_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct max732x_platform_data *pdata;
struct max732x_chip *chip;
struct i2c_client *c;
uint16_t addr_a, addr_b;
int ret, nr_port;
pdata = client->dev.platform_data;
if (pdata == NULL) {
dev_dbg(&client->dev, "no platform data\n");
return -EINVAL;
}
chip = kzalloc(sizeof(struct max732x_chip), GFP_KERNEL);
if (chip == NULL)
return -ENOMEM;
chip->client = client;
nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base);
addr_a = (client->addr & 0x0f) | 0x60;
addr_b = (client->addr & 0x0f) | 0x50;
switch (client->addr & 0x70) {
case 0x60:
chip->client_group_a = client;
if (nr_port > 7) {
c = i2c_new_dummy(client->adapter, addr_b);
chip->client_group_b = chip->client_dummy = c;
}
break;
case 0x50:
chip->client_group_b = client;
if (nr_port > 7) {
c = i2c_new_dummy(client->adapter, addr_a);
chip->client_group_a = chip->client_dummy = c;
}
break;
default:
dev_err(&client->dev, "invalid I2C address specified %02x\n",
client->addr);
ret = -EINVAL;
goto out_failed;
}
mutex_init(&chip->lock);
max732x_read(chip, is_group_a(chip, 0), &chip->reg_out[0]);
if (nr_port > 7)
max732x_read(chip, is_group_a(chip, 8), &chip->reg_out[1]);
ret = gpiochip_add(&chip->gpio_chip);
if (ret)
goto out_failed;
if (pdata->setup) {
ret = pdata->setup(client, chip->gpio_chip.base,
chip->gpio_chip.ngpio, pdata->context);
if (ret < 0)
dev_warn(&client->dev, "setup failed, %d\n", ret);
}
i2c_set_clientdata(client, chip);
return 0;
out_failed:
kfree(chip);
return ret;
}
static int __devexit max732x_remove(struct i2c_client *client)
{
struct max732x_platform_data *pdata = client->dev.platform_data;
struct max732x_chip *chip = i2c_get_clientdata(client);
int ret;
if (pdata->teardown) {
ret = pdata->teardown(client, chip->gpio_chip.base,
chip->gpio_chip.ngpio, pdata->context);
if (ret < 0) {
dev_err(&client->dev, "%s failed, %d\n",
"teardown", ret);
return ret;
}
}
ret = gpiochip_remove(&chip->gpio_chip);
if (ret) {
dev_err(&client->dev, "%s failed, %d\n",
"gpiochip_remove()", ret);
return ret;
}
/* unregister any dummy i2c_client */
if (chip->client_dummy)
i2c_unregister_device(chip->client_dummy);
kfree(chip);
return 0;
}
static struct i2c_driver max732x_driver = {
.driver = {
.name = "max732x",
.owner = THIS_MODULE,
},
.probe = max732x_probe,
.remove = __devexit_p(max732x_remove),
.id_table = max732x_id,
};
static int __init max732x_init(void)
{
return i2c_add_driver(&max732x_driver);
}
/* register after i2c postcore initcall and before
* subsys initcalls that may rely on these GPIOs
*/
subsys_initcall(max732x_init);
static void __exit max732x_exit(void)
{
i2c_del_driver(&max732x_driver);
}
module_exit(max732x_exit);
MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
MODULE_DESCRIPTION("GPIO expander driver for MAX732X");
MODULE_LICENSE("GPL");
