[RFC PATCH 3/8] Philips PCA9536 4 bit I2C GPIO extender driver

[Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>]

This driver will be used by the mt9m001 and the mt9v022 camera drivers,
that can use a pca9536 to switch between 8 and 10 bit modes.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
---
 drivers/i2c/chips/Kconfig   |   10 +++
 drivers/i2c/chips/Makefile  |    1 +
 drivers/i2c/chips/pca9536.c |  153 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 164 insertions(+), 0 deletions(-)
 create mode 100644 drivers/i2c/chips/pca9536.c

diff --git a/drivers/i2c/chips/Kconfig b/drivers/i2c/chips/Kconfig
index 2e1c24f..6f492f1 100644
--- a/drivers/i2c/chips/Kconfig
+++ b/drivers/i2c/chips/Kconfig
@@ -65,6 +65,16 @@ config SENSORS_PCF8574
 	  These devices are hard to detect and rarely found on mainstream
 	  hardware.  If unsure, say N.
 
+config SENSORS_PCA9536
+	tristate "Philips PCA9536 4-bit I/O port"
+	depends on EXPERIMENTAL
+	help
+	  If you say yes here you get support for the Philips PCA9539
+	  4-bit I/O port.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called pca9536.
+
 config SENSORS_PCA9539
 	tristate "Philips PCA9539 16-bit I/O port"
 	depends on EXPERIMENTAL
diff --git a/drivers/i2c/chips/Makefile b/drivers/i2c/chips/Makefile
index ca924e1..e24c582 100644
--- a/drivers/i2c/chips/Makefile
+++ b/drivers/i2c/chips/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_DS1682)		+= ds1682.o
 obj-$(CONFIG_SENSORS_EEPROM)	+= eeprom.o
 obj-$(CONFIG_SENSORS_MAX6875)	+= max6875.o
 obj-$(CONFIG_SENSORS_M41T00)	+= m41t00.o
+obj-$(CONFIG_SENSORS_PCA9536)	+= pca9536.o
 obj-$(CONFIG_SENSORS_PCA9539)	+= pca9539.o
 obj-$(CONFIG_SENSORS_PCF8574)	+= pcf8574.o
 obj-$(CONFIG_SENSORS_PCF8591)	+= pcf8591.o
diff --git a/drivers/i2c/chips/pca9536.c b/drivers/i2c/chips/pca9536.c
new file mode 100644
index 0000000..08e5d8b
--- /dev/null
+++ b/drivers/i2c/chips/pca9536.c
@@ -0,0 +1,152 @@
+/*
+ * Driver for PCA9536 I/O Expander
+ *
+ * Copyright (C) 2008, Guennadi Liakhovetski <kernel@pengutronix.de>
+ *
+ * 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.
+ */
+
+#include <linux/videodev.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/hwmon-sysfs.h>
+
+#include <media/v4l2-common.h>
+#include <media/v4l2-chip-ident.h>
+
+#define PCA9536_INPUT 0
+#define PCA9536_OUTPUT 1
+#define PCA9536_INVERT 2
+#define PCA9536_DIRECTION 3
+
+/* following are the sysfs callback functions */
+static ssize_t pca9536_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 pca9536_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;
+}
+
+int pca9536_set_level(struct i2c_client *client, u8 pin, u8 level)
+{
+	s32 data;
+
+	if (pin > 3)
+		return -EINVAL;
+
+	/* Switch to output */
+	data = i2c_smbus_read_byte_data(client, PCA9536_DIRECTION);
+	if (data < 0)
+		return data;
+	data = i2c_smbus_write_byte_data(client, PCA9536_DIRECTION,
+					 data & ~(1 << pin));
+	if (data < 0)
+		return data;
+
+	/* Set level */
+	data = i2c_smbus_read_byte_data(client, PCA9536_OUTPUT);
+	if (data < 0)
+		return data;
+	if (level)
+		data |= (1 << pin);
+	else
+		data &= ~(1 << pin);
+	data = i2c_smbus_write_byte_data(client, PCA9536_OUTPUT, data);
+
+	return data;
+}
+EXPORT_SYMBOL(pca9536_set_level);
+
+/* Define the device attributes */
+
+#define PCA9536_ENTRY_RO(name, reg) \
+	static SENSOR_DEVICE_ATTR(name, S_IRUGO, pca9536_show, NULL, reg)
+
+#define PCA9536_ENTRY_RW(name, reg) \
+	static SENSOR_DEVICE_ATTR(name, S_IRUGO | S_IWUSR, pca9536_show, \
+				  pca9536_store, reg)
+
+PCA9536_ENTRY_RO(input, PCA9536_INPUT);
+PCA9536_ENTRY_RW(output, PCA9536_OUTPUT);
+PCA9536_ENTRY_RW(invert, PCA9536_INVERT);
+PCA9536_ENTRY_RW(direction, PCA9536_DIRECTION);
+
+static struct attribute *pca9536_attributes[] = {
+	&sensor_dev_attr_input.dev_attr.attr,
+	&sensor_dev_attr_output.dev_attr.attr,
+	&sensor_dev_attr_invert.dev_attr.attr,
+	&sensor_dev_attr_direction.dev_attr.attr,
+	NULL
+};
+
+static struct attribute_group pca9536_defattr_group = {
+	.attrs = pca9536_attributes,
+};
+
+static int pca9536_probe(struct i2c_client *client)
+{
+	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
+		pr_debug("%s: I2C-Adapter doesn't support I2C_FUNC_SMBUS_BYTE\n", __FUNCTION__);
+		return -EIO;
+	}
+
+	if (client->dev.platform_data)
+		/* This chip is going to be used from the kernel */
+		*(struct i2c_client **)client->dev.platform_data = client;
+
+	/* Register sysfs hooks */
+	return sysfs_create_group(&client->dev.kobj,
+				  &pca9536_defattr_group);
+}
+
+static int pca9536_remove(struct i2c_client *client)
+{
+	sysfs_remove_group(&client->dev.kobj, &pca9536_defattr_group);
+	return 0;
+}
+
+static struct i2c_driver pca9536_i2c_driver = {
+	.driver = {
+		.name = "pca9536",
+	},
+	.probe		= pca9536_probe,
+	.remove		= pca9536_remove,
+};
+
+static int __init pca9536_mod_init(void)
+{
+	return i2c_add_driver(&pca9536_i2c_driver);
+}
+
+static void __exit pca9536_mod_exit(void)
+{
+	i2c_del_driver(&pca9536_i2c_driver);
+}
+
+module_init(pca9536_mod_init);
+module_exit(pca9536_mod_exit);
+
+MODULE_DESCRIPTION("PCA9536 driver");
+MODULE_AUTHOR("Guennadi Liakhovetski <kernel@pengutronix.de>");
+MODULE_LICENSE("GPL");
-- 
1.5.3.4

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