gpio: add driver for MAX7300 I2C GPIO extender

Add the MAX7300-I2C variant of the MAX7301-SPI version.  Both chips share
the same core logic, so the generic part of the in-kernel SPI-driver is
refactored into a generic part.  The I2C and SPI specific funtions are
then wrapped into seperate drivers picking up the generic part.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Juergen Beisert <j.beisert@pengutronix.de>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

6 files changed, 404 insertions, 260 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 1f1d88ae68d6..f3549b8779d8 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -65,6 +65,9 @@ config GPIO_SYSFS
 
 # put expanders in the right section, in alphabetical order
 
+config GPIO_MAX730X
+        tristate
+
 comment "Memory mapped GPIO expanders:"
 
 config GPIO_PL061
@@ -87,6 +90,13 @@ config GPIO_VR41XX
 
 comment "I2C GPIO expanders:"
 
+config GPIO_MAX7300
+        tristate "Maxim MAX7300 GPIO expander"
+        depends on I2C
+        select GPIO_MAX730X
+        help
+          GPIO driver for Maxim MAX7301 I2C-based GPIO expander.
+
 config GPIO_MAX732X
         tristate "MAX7319, MAX7320-7327 I2C Port Expanders"
         depends on I2C
@@ -226,8 +236,9 @@ comment "SPI GPIO expanders:"
 config GPIO_MAX7301
         tristate "Maxim MAX7301 GPIO expander"
         depends on SPI_MASTER
+        select GPIO_MAX730X
         help
-          gpio driver for Maxim MAX7301 SPI GPIO expander.
+          GPIO driver for Maxim MAX7301 SPI-based GPIO expander.
 
 config GPIO_MCP23S08
         tristate "Microchip MCP23S08 I/O expander"
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 48687238edb1..508a1b202cdb 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -7,6 +7,8 @@ obj-$(CONFIG_GPIOLIB)		+= gpiolib.o
 obj-$(CONFIG_GPIO_ADP5520)      += adp5520-gpio.o
 obj-$(CONFIG_GPIO_ADP5588)      += adp5588-gpio.o
 obj-$(CONFIG_GPIO_LANGWELL)     += langwell_gpio.o
+obj-$(CONFIG_GPIO_MAX730X)      += max730x.o
+obj-$(CONFIG_GPIO_MAX7300)      += max7300.o
 obj-$(CONFIG_GPIO_MAX7301)      += max7301.o
 obj-$(CONFIG_GPIO_MAX732X)      += max732x.o
 obj-$(CONFIG_GPIO_MC33880)      += mc33880.o
diff --git a/drivers/gpio/max7300.c b/drivers/gpio/max7300.c
new file mode 100644
index 000000000000..9d74eef1157a
--- /dev/null
+++ b/drivers/gpio/max7300.c
@@ -0,0 +1,94 @@
+/*
+ * drivers/gpio/max7300.c
+ *
+ * Copyright (C) 2009 Wolfram Sang, Pengutronix
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Check max730x.c for further details.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/mutex.h>
+#include <linux/i2c.h>
+#include <linux/spi/max7301.h>
+
+static int max7300_i2c_write(struct device *dev, unsigned int reg,
+                                unsigned int val)
+{
+        struct i2c_client *client = to_i2c_client(dev);
+
+        return i2c_smbus_write_byte_data(client, reg, val);
+}
+
+static int max7300_i2c_read(struct device *dev, unsigned int reg)
+{
+        struct i2c_client *client = to_i2c_client(dev);
+
+        return i2c_smbus_read_byte_data(client, reg);
+}
+
+static int __devinit max7300_probe(struct i2c_client *client,
+                         const struct i2c_device_id *id)
+{
+        struct max7301 *ts;
+        int ret;
+
+        if (!i2c_check_functionality(client->adapter,
+                        I2C_FUNC_SMBUS_BYTE_DATA))
+                return -EIO;
+
+        ts = kzalloc(sizeof(struct max7301), GFP_KERNEL);
+        if (!ts)
+                return -ENOMEM;
+
+        ts->read = max7300_i2c_read;
+        ts->write = max7300_i2c_write;
+        ts->dev = &client->dev;
+
+        ret = __max730x_probe(ts);
+        if (ret)
+                kfree(ts);
+        return ret;
+}
+
+static int __devexit max7300_remove(struct i2c_client *client)
+{
+        return __max730x_remove(&client->dev);
+}
+
+static const struct i2c_device_id max7300_id[] = {
+        { "max7300", 0 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, max7300_id);
+
+static struct i2c_driver max7300_driver = {
+        .driver = {
+                .name = "max7300",
+                .owner = THIS_MODULE,
+        },
+        .probe = max7300_probe,
+        .remove = __devexit_p(max7300_remove),
+        .id_table = max7300_id,
+};
+
+static int __init max7300_init(void)
+{
+        return i2c_add_driver(&max7300_driver);
+}
+subsys_initcall(max7300_init);
+
+static void __exit max7300_exit(void)
+{
+        i2c_del_driver(&max7300_driver);
+}
+module_exit(max7300_exit);
+
+MODULE_AUTHOR("Wolfram Sang");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("MAX7300 GPIO-Expander");
diff --git a/drivers/gpio/max7301.c b/drivers/gpio/max7301.c
index 480956f1ca50..965d9b1ea13e 100644
--- a/drivers/gpio/max7301.c
+++ b/drivers/gpio/max7301.c
@@ -1,98 +1,41 @@
-/**
+/*
  * drivers/gpio/max7301.c
  *
  * Copyright (C) 2006 Juergen Beisert, Pengutronix
  * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
+ * Copyright (C) 2009 Wolfram Sang, Pengutronix
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
- * The Maxim's MAX7301 device is an SPI driven GPIO expander. There are
- * 28 GPIOs. 8 of them can trigger an interrupt. See datasheet for more
- * details
- * Note:
- * - DIN must be stable at the rising edge of clock.
- * - when writing:
- *   - always clock in 16 clocks at once
- *   - at DIN: D15 first, D0 last
- *   - D0..D7 = databyte, D8..D14 = commandbyte
- *   - D15 = low -> write command
- * - when reading
- *   - always clock in 16 clocks at once
- *   - at DIN: D15 first, D0 last
- *   - D0..D7 = dummy, D8..D14 = register address
- *   - D15 = high -> read command
- *   - raise CS and assert it again
- *   - always clock in 16 clocks at once
- *   - at DOUT: D15 first, D0 last
- *   - D0..D7 contains the data from the first cycle
- *
+ * Check max730x.c for further details.