#include <linux/i2c.h>
/* Addresses to scan */
-static unsigned short normal_i2c[] = { 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
- 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
- I2C_CLIENT_END };
+static const unsigned short normal_i2c[] = {
+ 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
+ 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
+ I2C_CLIENT_END
+};
/* Insmod parameters */
I2C_CLIENT_INSMOD_2(pcf8574, pcf8574a);
-/* Initial values */
-#define PCF8574_INIT 255 /* All outputs on (input mode) */
-
/* Each client has this additional data */
struct pcf8574_data {
struct i2c_client client;
- u8 write; /* Remember last written value */
+ int write; /* Remember last written value */
};
static int pcf8574_attach_adapter(struct i2c_adapter *adapter);
.driver = {
.name = "pcf8574",
},
- .id = I2C_DRIVERID_PCF8574,
.attach_adapter = pcf8574_attach_adapter,
.detach_client = pcf8574_detach_client,
};
static ssize_t show_write(struct device *dev, struct device_attribute *attr, char *buf)
{
struct pcf8574_data *data = i2c_get_clientdata(to_i2c_client(dev));
- return sprintf(buf, "%u\n", data->write);
+
+ if (data->write < 0)
+ return data->write;
+
+ return sprintf(buf, "%d\n", data->write);
}
static ssize_t set_write(struct device *dev, struct device_attribute *attr, const char *buf,
static DEVICE_ATTR(write, S_IWUSR | S_IRUGO, show_write, set_write);
+static struct attribute *pcf8574_attributes[] = {
+ &dev_attr_read.attr,
+ &dev_attr_write.attr,
+ NULL
+};
+
+static const struct attribute_group pcf8574_attr_group = {
+ .attrs = pcf8574_attributes,
+};
+
/*
* Real code
*/
pcf8574_init_client(new_client);
/* Register sysfs hooks */
- device_create_file(&new_client->dev, &dev_attr_read);
- device_create_file(&new_client->dev, &dev_attr_write);
+ err = sysfs_create_group(&new_client->dev.kobj, &pcf8574_attr_group);
+ if (err)
+ goto exit_detach;
return 0;
-/* OK, this is not exactly good programming practice, usually. But it is
- very code-efficient in this case. */
-
+ exit_detach:
+ i2c_detach_client(new_client);
exit_free:
kfree(data);
exit:
{
int err;
+ sysfs_remove_group(&client->dev.kobj, &pcf8574_attr_group);
+
if ((err = i2c_detach_client(client)))
return err;
static void pcf8574_init_client(struct i2c_client *client)
{
struct pcf8574_data *data = i2c_get_clientdata(client);
- data->write = PCF8574_INIT;
- i2c_smbus_write_byte(client, data->write);
+ data->write = -EAGAIN;
}
static int __init pcf8574_init(void)