Re: [PATCH 2.6.24-rc4-mm 1/2] gpiolib: basic support for 16-bit PCA9539 GPIO expander[

["eric miao" <eric.y.miao@gmail.com>]

I'd like to create another thread in LKML for the updated version, sorry.

On Dec 15, 2007 11:56 AM, eric miao <eric.y.miao@gmail.com> wrote:
> OK,
>
> Here's the updated version, which
> 1. modify the author info but still preserve Ben's credit in the source head
> 2. Alphabetic order in Kconfig/Makefile
> 3. typo fix and corrected Philips to NXP/TI
> 4. use dev_err instead of printk
> 5. move module_{init,exit} next to the routines
> 6. preserve initial output/direction register settings
>
> Also I'd like to fire another patch to obsolete drivers/i2c/chips/pca9539.c
> as everyone agreed.
>
> From 5ebe07bbbb236b99587296cbf603a965d284ceaf Mon Sep 17 00:00:00 2001
> From: eric miao <eric.miao@marvell.com>
> Date: Mon, 10 Dec 2007 17:19:12 +0800
> Subject: [PATCH] gpiolib: basic support for 16-bit PCA9539 GPIO expander
>
> 1. use 16-bit register access to simplify the logic, cache OUTPUT
>    and DIRECTION registers for fast access
>
> 2. platform code is required to setup
>    a) the numbering of GPIO for PCA9539 (base and number)
>    c) pass "pca9539_platform_data" within "i2c_board_info"
>
> Derived from drivers/i2c/chips/pca9539.c (which has no current known
> users).
>
> Signed-off-by: eric miao <eric.miao@marvell.com>
> ---
>  drivers/gpio/Kconfig        |   10 ++
>  drivers/gpio/Makefile       |    1 +
>  drivers/gpio/pca9539.c      |  247 +++++++++++++++++++++++++++++++++++++++++++
>  include/linux/i2c/pca9539.h |   18 +++
>  4 files changed, 276 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/gpio/pca9539.c
>  create mode 100644 include/linux/i2c/pca9539.h
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index dd9e697..4b54f60 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -9,6 +9,16 @@ menu "GPIO Expanders"
>
>  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
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index 575bb57..d14fc1e 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -1,4 +1,5 @@
>  # gpio support: dedicated expander chips, etc
>
>  obj-$(CONFIG_GPIO_MCP23S08)    += mcp23s08.o
> +obj-$(CONFIG_GPIO_PCA9539)     += pca9539.o
>  obj-$(CONFIG_GPIO_PCF857X)     += pcf857x.o
> diff --git a/drivers/gpio/pca9539.c b/drivers/gpio/pca9539.c
> new file mode 100644
> index 0000000..955d891
> --- /dev/null
> +++ b/drivers/gpio/pca9539.c
> @@ -0,0 +1,247 @@
> +/*
> + *  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 (which has no current known
> + *  users).
> + *
> + *  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;
> +};
> +
> +static int pca9539_write_reg(struct pca9539_chip *chip, int reg, uint16_t val)
> +{
> +       return i2c_smbus_write_word_data(chip->client, reg, val);
> +}
> +
> +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 ret;
> +       }
> +
> +       *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, &reg_val);
> +       if (ret < 0)
> +               return ret;
> +
> +       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 */
> +       pca9539_read_reg(chip, PCA9539_OUTPUT, &chip->reg_output);
> +       pca9539_read_reg(chip, PCA9539_DIRECTION, &chip->reg_direction);
>
> +
> +       /* set platform specific polarity inversion */
> +       pca9539_write_reg(chip, PCA9539_INVERT, pdata->invert);
> +
> +       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_dbg(&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_dbg(&client->dev, "teardown failed, %d\n", ret);
> +       }
> +
> +       ret = gpiochip_remove(&chip->gpio_chip);
> +       if (ret) {
> +               dev_err(&client->dev, "failed remove gpio_chip\n");
> +               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");
> diff --git a/include/linux/i2c/pca9539.h b/include/linux/i2c/pca9539.h
> new file mode 100644
> index 0000000..611d84a
> --- /dev/null
> +++ b/include/linux/i2c/pca9539.h
> @@ -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);
> +};
> --
> 1.5.2.5.GIT
>
> --
> Cheers
> - eric
>



-- 
Cheers
- eric