[PATCH] I2C: add new pca9539 driver (69dd204b) · Commits · e / devices / android_kernel_sony_msm8994

Documentation/i2c/chips/pca9539

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		Kernel driver pca9539
		=====================

		Supported chips:
		* Philips PCA9539
		Prefix: 'pca9539'
		Addresses scanned: 0x74 - 0x77
		Datasheet:
		http://www.semiconductors.philips.com/acrobat/datasheets/PCA9539_2.pdf

		Author: Ben Gardner <bgardner@wabtec.com>


		Description
		-----------

		The Philips PCA9539 is a 16 bit low power I/O device.
		All 16 lines can be individually configured as an input or output.
		The input sense can also be inverted.
		The 16 lines are split between two bytes.


		Sysfs entries
		-------------

		Each is a byte that maps to the 8 I/O bits.
		A '0' suffix is for bits 0-7, while '1' is for bits 8-15.

		input[01] - read the current value
		output[01] - sets the output value
		direction[01] - direction of each bit: 1=input, 0=output
		invert[01] - toggle the input bit sense

		input reads the actual state of the line and is always available.
		The direction defaults to input for all channels.


		General Remarks
		---------------

		Note that each output, direction, and invert entry controls 8 lines.
		You should use the read, modify, write sequence.
		For example. to set output bit 0 of 1.
		val=$(cat output0)
		val=$(( $val \| 1 ))
		echo $val > output0

drivers/i2c/chips/Kconfig

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		@@ -440,6 +440,16 @@ config SENSORS_PCF8574
		This driver can also be built as a module. If so, the module
		will be called pcf8574.

		config SENSORS_PCA9539
		tristate "Philips PCA9539 16-bit I/O port"
		depends on I2C && EXPERIMENTAL
		help
		If you say yes here you get support for the Philips PCA9539
		16-bit I/O port.

		This driver can also be built as a module. If so, the module
		will be called pca9539.

		config SENSORS_PCF8591
		tristate "Philips PCF8591"
		depends on I2C && EXPERIMENTAL

drivers/i2c/chips/Makefile

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		@@ -35,6 +35,7 @@ obj-$(CONFIG_SENSORS_MAX1619) += max1619.o
		obj-$(CONFIG_SENSORS_MAX6875) += max6875.o
		obj-$(CONFIG_SENSORS_M41T00) += m41t00.o
		obj-$(CONFIG_SENSORS_PC87360) += pc87360.o
		obj-$(CONFIG_SENSORS_PCA9539) += pca9539.o
		obj-$(CONFIG_SENSORS_PCF8574) += pcf8574.o
		obj-$(CONFIG_SENSORS_PCF8591) += pcf8591.o
		obj-$(CONFIG_SENSORS_RTC8564) += rtc8564.o

drivers/i2c/chips/pca9539.c

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		/*
		pca9539.c - 16-bit I/O port with interrupt and reset

		Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>

		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/hwmon-sysfs.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_DIRECTION_0 = 6,
		PCA9539_DIRECTION_1 = 7,
		};

		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,
		};

		struct pca9539_data {
		struct i2c_client client;
		};

		/* following are the sysfs callback functions */
		static ssize_t pca9539_show(struct device dev, struct device_attribute attr,
		char *buf)
		{
		struct sensor_device_attribute *psa = to_sensor_dev_attr(attr);
		struct i2c_client *client = to_i2c_client(dev);
		return sprintf(buf, "%d\n", i2c_smbus_read_byte_data(client,
		psa->index));
		}

		static ssize_t pca9539_store(struct device dev, struct device_attribute attr,
		const char *buf, size_t count)
		{
		struct sensor_device_attribute *psa = to_sensor_dev_attr(attr);
		struct i2c_client *client = to_i2c_client(dev);
		unsigned long val = simple_strtoul(buf, NULL, 0);
		if (val > 0xff)
		return -EINVAL;
		i2c_smbus_write_byte_data(client, psa->index, val);
		return count;
		}

		/* Define the device attributes */

		#define PCA9539_ENTRY_RO(name, cmd_idx) \
		static SENSOR_DEVICE_ATTR(name, S_IRUGO, pca9539_show, NULL, cmd_idx)

		#define PCA9539_ENTRY_RW(name, cmd_idx) \
		static SENSOR_DEVICE_ATTR(name, S_IRUGO \| S_IWUSR, pca9539_show, \
		pca9539_store, cmd_idx)

		PCA9539_ENTRY_RO(input0, PCA9539_INPUT_0);
		PCA9539_ENTRY_RO(input1, PCA9539_INPUT_1);
		PCA9539_ENTRY_RW(output0, PCA9539_OUTPUT_0);
		PCA9539_ENTRY_RW(output1, PCA9539_OUTPUT_1);
		PCA9539_ENTRY_RW(invert0, PCA9539_INVERT_0);
		PCA9539_ENTRY_RW(invert1, PCA9539_INVERT_1);
		PCA9539_ENTRY_RW(direction0, PCA9539_DIRECTION_0);
		PCA9539_ENTRY_RW(direction1, PCA9539_DIRECTION_1);

		static struct attribute *pca9539_attributes[] = {
		&sensor_dev_attr_input0.dev_attr.attr,
		&sensor_dev_attr_input1.dev_attr.attr,
		&sensor_dev_attr_output0.dev_attr.attr,
		&sensor_dev_attr_output1.dev_attr.attr,
		&sensor_dev_attr_invert0.dev_attr.attr,
		&sensor_dev_attr_invert1.dev_attr.attr,
		&sensor_dev_attr_direction0.dev_attr.attr,
		&sensor_dev_attr_direction1.dev_attr.attr,
		NULL
		};

		static struct attribute_group pca9539_defattr_group = {
		.attrs = pca9539_attributes,
		};

		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_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;
		i2c_set_clientdata(new_client, data);
		new_client->addr = address;
		new_client->adapter = adapter;
		new_client->driver = &pca9539_driver;
		new_client->flags = 0;

		/* Detection: the pca9539 only has 8 registers (0-7).
		A read of 7 should succeed, but a read of 8 should fail. */
		if ((i2c_smbus_read_byte_data(new_client, 7) < 0) \|\|
		(i2c_smbus_read_byte_data(new_client, 8) >= 0))
		goto exit_kfree;

		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;

		/* Register sysfs hooks (don't care about failure) */
		sysfs_create_group(&new_client->dev.kobj, &pca9539_defattr_group);

		return 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.\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 <bgardner@wabtec.com>");
		MODULE_DESCRIPTION("PCA9539 driver");
		MODULE_LICENSE("GPL");

		module_init(pca9539_init);
		module_exit(pca9539_exit);