Messages in this thread Patch in this message | | | From | David Brownell <> | Subject | Re: [patch 2.6.24-rc6-mm 8/9] gpiolib: pca9539 i2c gpio expander support | Date | Sat, 5 Jan 2008 11:40:55 -0800 |
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From: eric miao <eric.miao@marvell.com> Subject: [PATCH] gpiolib: support PCA9539 GPIO expander
This adds a new-style I2C driver with basic support for the sixteen bit PCA9539 GPIO expanders. These chips have multiple registers, push-pull output drivers, and (not supported in this patch) pin change interrupts.
Board-specific code must provide "pca9539_platform_data" with each chip's "i2c_board_info". That provides the GPIO numbers to be used by that chip, and callbacks for board-specific setup/teardown logic.
Derived from drivers/i2c/chips/pca9539.c (which has no current known users). This is faster and simpler; it uses 16-bit register access, and cache the OUTPUT and DIRECTION registers for fast access
Signed-off-by: eric miao <eric.miao@marvell.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> --- Incorporates cleanups noted by Jean Delvare.
drivers/gpio/Kconfig | 10 + drivers/gpio/Makefile | 1 drivers/gpio/pca9539.c | 271 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/i2c/pca9539.h | 18 ++ 4 files changed, 300 insertions(+)
--- at91.orig/drivers/gpio/Kconfig 2008-01-05 11:27:12.000000000 -0800 +++ at91/drivers/gpio/Kconfig 2008-01-05 11:27:12.000000000 -0800 @@ -27,6 +27,16 @@ config DEBUG_GPIO comment "I2C GPIO expanders:" +config GPIO_PCA9539 + tristate "PCA9539 16-bit I/O port" + depends on I2C + help + Say yes here to support the PCA9539 16-bit I/O port. These + parts are made by NXP and TI. + + This driver can also be built as a module. If so, the module + will be called pca9539. + config GPIO_PCF857X tristate "PCF857x, PCA857x, and PCA967x I2C GPIO expanders" depends on I2C --- at91.orig/drivers/gpio/Makefile 2008-01-05 11:27:12.000000000 -0800 +++ at91/drivers/gpio/Makefile 2008-01-05 11:27:12.000000000 -0800 @@ -1,6 +1,7 @@ # gpio support: dedicated expander chips, etc obj-$(CONFIG_GPIO_MCP23S08) += mcp23s08.o +obj-$(CONFIG_GPIO_PCA9539) += pca9539.o obj-$(CONFIG_GPIO_PCF857X) += pcf857x.o ifeq ($(CONFIG_DEBUG_GPIO),y) --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ at91/drivers/gpio/pca9539.c 2008-01-05 11:32:06.000000000 -0800 @@ -0,0 +1,271 @@ +/* + * pca9539.c - 16-bit I/O port with interrupt and reset + * + * 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/pca9539.h> + +#include <asm/gpio.h> + + +#define NR_PCA9539_GPIOS 16 + +#define PCA9539_INPUT 0 +#define PCA9539_OUTPUT 2 +#define PCA9539_INVERT 4 +#define PCA9539_DIRECTION 6 + +struct pca9539_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 pca9539_write_reg(struct pca9539_chip *chip, int reg, uint16_t val) +{ + if (i2c_smbus_write_word_data(chip->client, reg, val) < 0) + return -EIO; + else + return 0; +} + +static int pca9539_read_reg(struct pca9539_chip *chip, int reg, uint16_t *val) +{ + int ret; + + ret = i2c_smbus_read_word_data(chip->client, reg); + if (ret < 0) { + dev_err(&chip->client->dev, "failed reading register\n"); + return -EIO; + } + + *val = (uint16_t)ret; + return 0; +} + +static int pca9539_gpio_direction_input(struct gpio_chip *gc, unsigned off) +{ + struct pca9539_chip *chip; + uint16_t reg_val; + int ret; + + chip = container_of(gc, struct pca9539_chip, gpio_chip); + + reg_val = chip->reg_direction | (1u << off); + ret = pca9539_write_reg(chip, PCA9539_DIRECTION, reg_val); + if (ret) + return ret; + + chip->reg_direction = reg_val; + return 0; +} + +static int pca9539_gpio_direction_output(struct gpio_chip *gc, + unsigned off, int val) +{ + struct pca9539_chip *chip; + uint16_t reg_val; + int ret; + + chip = container_of(gc, struct pca9539_chip, gpio_chip); + + /* set output level */ + if (val) + reg_val = chip->reg_output | (1u << off); + else + reg_val = chip->reg_output & ~(1u << off); + + ret = pca9539_write_reg(chip, PCA9539_OUTPUT, reg_val); + if (ret) + return ret; + + chip->reg_output = reg_val; + + /* then direction */ + reg_val = chip->reg_direction & ~(1u << off); + ret = pca9539_write_reg(chip, PCA9539_DIRECTION, reg_val); + if (ret) + return ret; + + chip->reg_direction = reg_val; + return 0; +} + +static int pca9539_gpio_get_value(struct gpio_chip *gc, unsigned off) +{ + struct pca9539_chip *chip; + uint16_t reg_val; + int ret; + + chip = container_of(gc, struct pca9539_chip, gpio_chip); + + ret = pca9539_read_reg(chip, PCA9539_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 pca9539_gpio_set_value(struct gpio_chip *gc, unsigned off, int val) +{ + struct pca9539_chip *chip; + uint16_t reg_val; + int ret; + + chip = container_of(gc, struct pca9539_chip, gpio_chip); + + if (val) + reg_val = chip->reg_output | (1u << off); + else + reg_val = chip->reg_output & ~(1u << off); + + ret = pca9539_write_reg(chip, PCA9539_OUTPUT, reg_val); + if (ret) + return; + + chip->reg_output = reg_val; +} + +static int pca9539_init_gpio(struct pca9539_chip *chip) +{ + struct gpio_chip *gc; + + gc = &chip->gpio_chip; + + gc->direction_input = pca9539_gpio_direction_input; + gc->direction_output = pca9539_gpio_direction_output; + gc->get = pca9539_gpio_get_value; + gc->set = pca9539_gpio_set_value; + + gc->base = chip->gpio_start; + gc->ngpio = NR_PCA9539_GPIOS; + gc->label = "pca9539"; + + return gpiochip_add(gc); +} + +static int __devinit pca9539_probe(struct i2c_client *client) +{ + struct pca9539_platform_data *pdata; + struct pca9539_chip *chip; + int ret; + + pdata = client->dev.platform_data; + if (pdata == NULL) + return -ENODEV; + + chip = kzalloc(sizeof(struct pca9539_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. + */ + ret = pca9539_read_reg(chip, PCA9539_OUTPUT, &chip->reg_output); + if (ret) + goto out_failed; + + ret = pca9539_read_reg(chip, PCA9539_DIRECTION, &chip->reg_direction); + if (ret) + goto out_failed; + + /* set platform specific polarity inversion */ + ret = pca9539_write_reg(chip, PCA9539_INVERT, pdata->invert); + if (ret) + goto out_failed; + + ret = pca9539_init_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 pca9539_remove(struct i2c_client *client) +{ + struct pca9539_platform_data *pdata = client->dev.platform_data; + struct pca9539_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 pca9539_driver = { + .driver = { + .name = "pca9539", + }, + .probe = pca9539_probe, + .remove = pca9539_remove, +}; + +static int __init pca9539_init(void) +{ + return i2c_add_driver(&pca9539_driver); +} +module_init(pca9539_init); + +static void __exit pca9539_exit(void) +{ + i2c_del_driver(&pca9539_driver); +} +module_exit(pca9539_exit); + +MODULE_AUTHOR("eric miao <eric.miao@marvell.com>"); +MODULE_DESCRIPTION("GPIO expander driver for PCA9539"); +MODULE_LICENSE("GPL"); --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ at91/include/linux/i2c/pca9539.h 2008-01-05 11:27:12.000000000 -0800 @@ -0,0 +1,18 @@ +/* platform data for the PCA9539 16-bit I/O expander driver */ + +struct pca9539_platform_data { + /* number of the first GPIO */ + unsigned gpio_base; + + /* initial polarity inversion setting */ + uint16_t invert; + + void *context; /* param to setup/teardown */ + + int (*setup)(struct i2c_client *client, + unsigned gpio, unsigned ngpio, + void *context); + int (*teardown)(struct i2c_client *client, + unsigned gpio, unsigned ngpio, + void *context); +};
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