gpiolib: pca9539 i2c gpio expander support
eric miao [Tue, 5 Feb 2008 06:28:26 +0000 (22:28 -0800)]
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>
Acked-by: Jean Delvare <khali@linux-fr.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/gpio/Kconfig
drivers/gpio/Makefile
drivers/gpio/pca9539.c [new file with mode: 0644]
include/linux/i2c/pca9539.h [new file with mode: 0644]

index d924a32..74fac0f 100644 (file)
@@ -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
index a1fd877..470ecd6 100644 (file)
@@ -5,4 +5,5 @@ ccflags-$(CONFIG_DEBUG_GPIO)    += -DDEBUG
 obj-$(CONFIG_HAVE_GPIO_LIB)    += gpiolib.o
 
 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 (file)
index 0000000..3e85c92
--- /dev/null
@@ -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, &reg_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");
diff --git a/include/linux/i2c/pca9539.h b/include/linux/i2c/pca9539.h
new file mode 100644 (file)
index 0000000..611d84a
--- /dev/null
@@ -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);
+};