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Date: Sun, 13 Jul 2008 19:18:06 -0700
From: David Brownell <david-b@...bell.net>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: lkml <linux-kernel@...r.kernel.org>,
Eric Miao <eric.y.miao@...il.com>,
Jean Delvare <khali@...ux-fr.org>,
Jack Ren <jack.ren@...vell.com>
Subject: [patch 2.6.26-rc-mm] gpio: max732x driver
From: Eric Miao <eric.miao@...vell.com>
This adds a driver supporting a family of I2C port expanders from
Maxim, which includes the MAX7319 and MAX7320-7327 chips.
Signed-off-by: Jack Ren <jack.ren@...vell.com>
Signed-off-by: Eric Miao <eric.miao@...vell.com>
Acked-by: Jean Delvare <khali@...ux-fr.org>
[ dbrownell@...rs.sourceforge.net: minor fixes ]
Signed-off-by: David Brownell <dbrownell@...rs.sourceforge.net>
---
We're growing quite the collection of dedicated GPIO expander drivers!
And the multi-function chip support is growing too. This applies after
the patch adding support for max7301 chips.
drivers/gpio/Kconfig | 19 ++
drivers/gpio/Makefile | 1
drivers/gpio/max732x.c | 385 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/i2c/max732x.h | 19 ++
4 files changed, 424 insertions(+)
--- a/drivers/gpio/Kconfig 2008-07-13 01:33:06.000000000 -0700
+++ b/drivers/gpio/Kconfig 2008-07-13 13:42:29.000000000 -0700
@@ -42,6 +42,25 @@ config GPIO_SYSFS
comment "I2C GPIO expanders:"
+config GPIO_MAX732X
+ tristate "MAX7319, MAX7320-7327 I2C Port Expanders"
+ depends on I2C
+ help
+ Say yes here to support the MAX7319, MAX7320-7327 series of I2C
+ Port Expanders. Each IO port on these chips has a fixed role of
+ Input (designated by 'I'), Push-Pull Output ('O'), or Open-Drain
+ Input and Output (designed by 'P'). The combinations are listed
+ below:
+
+ 8 bits: max7319 (8I), max7320 (8O), max7321 (8P),
+ max7322 (4I4O), max7323 (4P4O)
+
+ 16 bits: max7324 (8I8O), max7325 (8P8O),
+ max7326 (4I12O), max7327 (4P12O)
+
+ Board setup code must specify the model to use, and the start
+ number for these GPIOs.
+
config GPIO_PCA953X
tristate "PCA953x, PCA955x, and MAX7310 I/O ports"
depends on I2C
--- a/drivers/gpio/Makefile 2008-07-13 01:33:06.000000000 -0700
+++ b/drivers/gpio/Makefile 2008-07-13 08:57:46.000000000 -0700
@@ -5,6 +5,7 @@ ccflags-$(CONFIG_DEBUG_GPIO) += -DDEBUG
obj-$(CONFIG_HAVE_GPIO_LIB) += gpiolib.o
obj-$(CONFIG_GPIO_MAX7301) += max7301.o
+obj-$(CONFIG_GPIO_MAX732X) += max732x.o
obj-$(CONFIG_GPIO_MCP23S08) += mcp23s08.o
obj-$(CONFIG_GPIO_PCA953X) += pca953x.o
obj-$(CONFIG_GPIO_PCF857X) += pcf857x.o
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ b/drivers/gpio/max732x.c 2008-07-13 13:49:00.000000000 -0700
@@ -0,0 +1,385 @@
+/*
+ * max732x.c - I2C Port Expander with 8/16 I/O
+ *
+ * Copyright (C) 2007 Marvell International Ltd.
+ * Copyright (C) 2008 Jack Ren <jack.ren@...vell.com>
+ * Copyright (C) 2008 Eric Miao <eric.miao@...vell.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)
+ return -ENODEV;
+
+ 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);
+}
+module_init(max732x_init);
+
+static void __exit max732x_exit(void)
+{
+ i2c_del_driver(&max732x_driver);
+}
+module_exit(max732x_exit);
+
+MODULE_AUTHOR("Eric Miao <eric.miao@...vell.com>");
+MODULE_DESCRIPTION("GPIO expander driver for MAX732X");
+MODULE_LICENSE("GPL");
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ b/include/linux/i2c/max732x.h 2008-07-13 08:57:18.000000000 -0700
@@ -0,0 +1,19 @@
+#ifndef __LINUX_I2C_MAX732X_H
+#define __LINUX_I2C_MAX732X_H
+
+/* platform data for the MAX732x 8/16-bit I/O expander driver */
+
+struct max732x_platform_data {
+ /* number of the first GPIO */
+ unsigned gpio_base;
+
+ 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);
+};
+#endif /* __LINUX_I2C_MAX732X_H */
--
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