PCA9539 - new driver

drivers/i2c/chips/Kconfig +10 -0

@@ -440,4 +440,14 @@
 	  This driver can also be built as a module.  If so, the module
 	  will be called m41t00.
 
+config SENSORS_PCA9539
+	tristate "PCA9539 16-bit digital IO"
+	depends on I2C && EXPERIMENTAL
+	help
+	  If you say yes here you get support for the PCA9539
+	  low power digital I/O with 16 bit.
+          
+	  This driver can also be built as a module.  If so, the module
+	  will be called pca9539.
+
 endmenu

diff -uEbBN linux-2.6.12-rc4-clean/drivers/i2c/chips/Makefile linux-2.6.12-rc4-pca9539/drivers/i2c/chips/Makefile

drivers/i2c/chips/Makefile +0 -0

 ifeq ($(CONFIG_I2C_DEBUG_CHIP),y)
 EXTRA_CFLAGS += -DDEBUG

diff -uEbBN linux-2.6.12-rc4-clean/drivers/i2c/chips/pca9539.c linux-2.6.12-rc4-pca9539/drivers/i2c/chips/pca9539.c

drivers/i2c/chips/pca9539.c +61 -0

@@ -0,0 +1,203 @@
+/*
+    pca9539.c - 16 port digital I/O with interrupt and reset
+    
+    Copyright (C) 2005 Ben Gardner <[email protected]>
+
+    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/i2c.h>
+#include <linux/i2c-sensor.h>
+
+/* Addresses to scan */
+static unsigned short normal_i2c[] = { 0x74, 0x75, 0x76, 0x77, I2C_CLIENT_END };
+static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
+
+/* Insmod parameters */
+SENSORS_INSMOD_1(pca9539);
+
+enum pca9539_cmd
+{
+	PCA9539_INPUT_0 = 0,
+	PCA9539_INPUT_1 = 1,
+	PCA9539_OUTPUT_0 = 2,
+	PCA9539_OUTPUT_1 = 3,
+	PCA9539_INVERT_0 = 4,
+	PCA9539_INVERT_1 = 5,
+	PCA9539_CONFIG_0 = 6,
+	PCA9539_CONFIG_1 = 7
+};
+
+struct pca9539_data {
+	struct i2c_client client;
+	struct semaphore  update_lock;
+};
+
+static int pca9539_attach_adapter(struct i2c_adapter *adapter);
+static int pca9539_detect(struct i2c_adapter *adapter, int address, int kind);
+static int pca9539_detach_client(struct i2c_client *client);
+
+
+/* This is the driver that will be inserted */
+static struct i2c_driver pca9539_driver = {
+	.owner		= THIS_MODULE,
+	.name		= "pca9539",
+	.flags		= I2C_DF_NOTIFY,
+	.attach_adapter	= pca9539_attach_adapter,
+	.detach_client	= pca9539_detach_client,
+};
+
+static void pca9539_store_reg(struct device *dev, const char *buf, 
+			      enum pca9539_cmd cmd)
+{
+	struct pca9539_data *data = i2c_get_clientdata(to_i2c_client(dev));
+	u8 val = simple_strtoul(buf, NULL, 0);
+	i2c_smbus_write_byte_data(&data->client, cmd, val);
+}

drivers/i2c/chips/pca9539.c +5 -0

+{									\
+	return pca9539_show_reg(dev, buf, enum_name);			\
+}
+
+show_data(PCA9539_INPUT_0);

drivers/i2c/chips/pca9539.c +17 -0

+{									\
+	pca9539_store_reg(dev, buf, enum_name);				\
+	return count;							\
+}
+
+store_data(PCA9539_OUTPUT_0);
+store_data(PCA9539_OUTPUT_1);
+store_data(PCA9539_INVERT_0);
+store_data(PCA9539_INVERT_1);
+store_data(PCA9539_CONFIG_0);
+store_data(PCA9539_CONFIG_1);
+
+/* Define the device attributes */
+#define my_rw_attr(name,enum_name) \
+static DEVICE_ATTR(name,S_IRUGO|S_IWUGO,show_##enum_name,store_##enum_name)
+
+#define my_ro_attr(name,enum_name) \

drivers/i2c/chips/pca9539.c +26 -0

+static int pca9539_attach_adapter(struct i2c_adapter *adapter)
+{
+	return i2c_detect(adapter, &addr_data, pca9539_detect);
+}
+
+/* This function is called by i2c_detect */
+static int pca9539_detect(struct i2c_adapter *adapter, int address, int kind)
+{
+	struct i2c_client *new_client;
+	struct pca9539_data *data;
+	int err = 0;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE
+				     | I2C_FUNC_SMBUS_WRITE_BYTE_DATA
+				     | I2C_FUNC_SMBUS_READ_BYTE_DATA))
+		goto exit;
+
+	/* OK. For now, we presume we have a valid client. We now create the
+	   client structure, even though we cannot fill it completely yet. */
+	if (!(data = kmalloc(sizeof(struct pca9539_data), GFP_KERNEL))) {
+		err = -ENOMEM;
+		goto exit;
+	}
+	memset(data, 0, sizeof(struct pca9539_data));
+	
+	new_client = &data->client;

drivers/i2c/chips/pca9539.c +6 -0

+	strlcpy(new_client->name, "pca9539", I2C_NAME_SIZE);
+
+	/* Tell the I2C layer a new client has arrived */
+	if ((err = i2c_attach_client(new_client)))
+		goto exit_kfree;
+

drivers/i2c/chips/pca9539.c +37 -0

+
+exit_kfree:
+	kfree(data);
+exit:
+	return err;
+}
+
+static int pca9539_detach_client(struct i2c_client *client)
+{
+	int err;
+
+	if ((err = i2c_detach_client(client))) {
+		dev_err(&client->dev,
+			"Client deregistration failed, client not detached.\n");
+		return err;
+	}
+
+	kfree(i2c_get_clientdata(client));
+	return 0;
+}
+
+static int __init pca9539_init(void)
+{
+	return i2c_add_driver(&pca9539_driver);
+}
+
+static void __exit pca9539_exit(void)
+{
+	i2c_del_driver(&pca9539_driver);
+}
+
+MODULE_AUTHOR("Ben Gardner <[email protected]>");
+MODULE_DESCRIPTION("PCA9539 driver");
+MODULE_LICENSE("GPL");
+
+module_init(pca9539_init);
+module_exit(pca9539_exit);

Review

Quoted 2 lines

(quoted diff) +2 -0

+	/* Detection: not sure how to do that... 
+	 * possibility: toggle the value read from invert0 and see if

Review

Quoted 2 lines

(quoted diff) +2 -0

+	 * changes polarity.
+	 */

I can try to help you with this a bit. Please can you use i2cdump to dump chip registers?

Here's the i2cdump output.
The device only supports 8 registers (0-7), so the output isn't too surprising.

AFAIK, this device isn't likely to be on any common motherboard. Perhaps detection isn't necessary?

Please fix the driver so it works with -mm- kernels and maybe also the alphabetical issue.