/* * pca953x.c - 4/8/16 bit I/O ports * * Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com> * Copyright (C) 2007 Marvell International Ltd. * * Derived from drivers/i2c/chips/pca9539.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/i2c.h> #include <linux/i2c/pca953x.h> #include <asm/gpio.h> #define PCA953X_INPUT 0 #define PCA953X_OUTPUT 1 #define PCA953X_INVERT 2 #define PCA953X_DIRECTION 3 /* This is temporary - in 2.6.26 i2c_driver_data should replace it. */ struct pca953x_desc { char name[I2C_NAME_SIZE]; unsigned long driver_data; }; static const struct pca953x_desc pca953x_descs[] = { { "pca9534", 8, }, { "pca9535", 16, }, { "pca9536", 4, }, { "pca9537", 4, }, { "pca9538", 8, }, { "pca9539", 16, }, /* REVISIT several pca955x parts should work here too */ }; struct pca953x_chip { unsigned gpio_start; uint16_t reg_output; uint16_t reg_direction; struct i2c_client *client; struct gpio_chip gpio_chip; }; /* NOTE: we can't currently rely on fault codes to come from SMBus * calls, so we map all errors to EIO here and return zero otherwise. */ static int pca953x_write_reg(struct pca953x_chip *chip, int reg, uint16_t val) { int ret; if (chip->gpio_chip.ngpio <= 8) ret = i2c_smbus_write_byte_data(chip->client, reg, val); else ret = i2c_smbus_write_word_data(chip->client, reg << 1, val); if (ret < 0) { dev_err(&chip->client->dev, "failed writing register\n"); return -EIO; } return 0; } static int pca953x_read_reg(struct pca953x_chip *chip, int reg, uint16_t *val) { int ret; if (chip->gpio_chip.ngpio <= 8) ret = i2c_smbus_read_byte_data(chip->client, reg); else ret = i2c_smbus_read_word_data(chip->client, reg << 1); if (ret < 0) { dev_err(&chip->client->dev, "failed reading register\n"); return -EIO; } *val = (uint16_t)ret; return 0; } static int pca953x_gpio_direction_input(struct gpio_chip *gc, unsigned off) { struct pca953x_chip *chip; uint16_t reg_val; int ret; chip = container_of(gc, struct pca953x_chip, gpio_chip); reg_val = chip->reg_direction | (1u << off); ret = pca953x_write_reg(chip, PCA953X_DIRECTION, reg_val); if (ret) return ret; chip->reg_direction = reg_val; return 0; } static int pca953x_gpio_direction_output(struct gpio_chip *gc, unsigned off, int val) { struct pca953x_chip *chip; uint16_t reg_val; int ret; chip = container_of(gc, struct pca953x_chip, gpio_chip); /* set output level */ if (val) reg_val = chip->reg_output | (1u << off); else reg_val = chip->reg_output & ~(1u << off); ret = pca953x_write_reg(chip, PCA953X_OUTPUT, reg_val); if (ret) return ret; chip->reg_output = reg_val; /* then direction */ reg_val = chip->reg_direction & ~(1u << off); ret = pca953x_write_reg(chip, PCA953X_DIRECTION, reg_val); if (ret) return ret; chip->reg_direction = reg_val; return 0; } static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off) { struct pca953x_chip *chip; uint16_t reg_val; int ret; chip = container_of(gc, struct pca953x_chip, gpio_chip); ret = pca953x_read_reg(chip, PCA953X_INPUT, ®_val); if (ret < 0) { /* NOTE: diagnostic already emitted; that's all we should * do unless gpio_*_value_cansleep() calls become different * from their nonsleeping siblings (and report faults). */ return 0; } return (reg_val & (1u << off)) ? 1 : 0; } static void pca953x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val) { struct pca953x_chip *chip; uint16_t reg_val; int ret; chip = container_of(gc, struct pca953x_chip, gpio_chip); if (val) reg_val = chip->reg_output | (1u << off); else reg_val = chip->reg_output & ~(1u << off); ret = pca953x_write_reg(chip, PCA953X_OUTPUT, reg_val); if (ret) return; chip->reg_output = reg_val; } static void pca953x_setup_gpio(struct pca953x_chip *chip, int gpios) { struct gpio_chip *gc; gc = &chip->gpio_chip; gc->direction_input = pca953x_gpio_direction_input; gc->direction_output = pca953x_gpio_direction_output; gc->get = pca953x_gpio_get_value; gc->set = pca953x_gpio_set_value; gc->base = chip->gpio_start; gc->ngpio = gpios; gc->label = chip->client->name; } static int __devinit pca953x_probe(struct i2c_client *client) { struct pca953x_platform_data *pdata; struct pca953x_chip *chip; int ret, i; const struct pca953x_desc *id = NULL; pdata = client->dev.platform_data; if (pdata == NULL) return -ENODEV; /* this loop vanishes when we get i2c_device_id */ for (i = 0; i < ARRAY_SIZE(pca953x_descs); i++) if (!strcmp(pca953x_descs[i].name, client->name)) { id = pca953x_descs + i; break; } if (!id) return -ENODEV; chip = kzalloc(sizeof(struct pca953x_chip), GFP_KERNEL); if (chip == NULL) return -ENOMEM; chip->client = client; chip->gpio_start = pdata->gpio_base; /* initialize cached registers from their original values. * we can't share this chip with another i2c master. */ pca953x_setup_gpio(chip, id->driver_data); ret = pca953x_read_reg(chip, PCA953X_OUTPUT, &chip->reg_output); if (ret) goto out_failed; ret = pca953x_read_reg(chip, PCA953X_DIRECTION, &chip->reg_direction); if (ret) goto out_failed; /* set platform specific polarity inversion */ ret = pca953x_write_reg(chip, PCA953X_INVERT, pdata->invert); if (ret) goto out_failed; 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 pca953x_remove(struct i2c_client *client) { struct pca953x_platform_data *pdata = client->dev.platform_data; struct pca953x_chip *chip = i2c_get_clientdata(client); int ret = 0; 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; } kfree(chip); return 0; } static struct i2c_driver pca953x_driver = { .driver = { .name = "pca953x", }, .probe = pca953x_probe, .remove = pca953x_remove, }; static int __init pca953x_init(void) { return i2c_add_driver(&pca953x_driver); } module_init(pca953x_init); static void __exit pca953x_exit(void) { i2c_del_driver(&pca953x_driver); } module_exit(pca953x_exit); MODULE_AUTHOR("eric miao <eric.miao@marvell.com>"); MODULE_DESCRIPTION("GPIO expander driver for PCA953x"); MODULE_LICENSE("GPL");