/* * 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");