diff options
| -rw-r--r-- | Documentation/i2c/chips/pcf8574 | 12 | ||||
| -rw-r--r-- | drivers/i2c/chips/pcf8574.c | 108 |
2 files changed, 51 insertions, 69 deletions
diff --git a/Documentation/i2c/chips/pcf8574 b/Documentation/i2c/chips/pcf8574 index 5c1ad13..235815c 100644 --- a/Documentation/i2c/chips/pcf8574 +++ b/Documentation/i2c/chips/pcf8574 @@ -4,13 +4,13 @@ Kernel driver pcf8574 Supported chips: * Philips PCF8574 Prefix: 'pcf8574' - Addresses scanned: I2C 0x20 - 0x27 + Addresses scanned: none Datasheet: Publicly available at the Philips Semiconductors website http://www.semiconductors.philips.com/pip/PCF8574P.html * Philips PCF8574A Prefix: 'pcf8574a' - Addresses scanned: I2C 0x38 - 0x3f + Addresses scanned: none Datasheet: Publicly available at the Philips Semiconductors website http://www.semiconductors.philips.com/pip/PCF8574P.html @@ -38,12 +38,10 @@ For more informations see the datasheet. Accessing PCF8574(A) via /sys interface ------------------------------------- -! Be careful ! The PCF8574(A) is plainly impossible to detect ! Stupid chip. -So every chip with address in the interval [20..27] and [38..3f] are -detected as PCF8574(A). If you have other chips in this address -range, the workaround is to load this module after the one -for your others chips. +So, you have to pass the I2C bus and address of the installed PCF857A +and PCF8574A devices explicitly to the driver at load time via the +force=... parameter. On detection (i.e. insmod, modprobe et al.), directories are being created for each detected PCF8574(A): diff --git a/drivers/i2c/chips/pcf8574.c b/drivers/i2c/chips/pcf8574.c index 1b3db2b..6ec3098 100644 --- a/drivers/i2c/chips/pcf8574.c +++ b/drivers/i2c/chips/pcf8574.c @@ -38,37 +38,19 @@ #include <linux/slab.h> #include <linux/i2c.h> -/* Addresses to scan */ -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 -}; +/* Addresses to scan: none, device can't be detected */ +static const unsigned short normal_i2c[] = { I2C_CLIENT_END }; /* Insmod parameters */ I2C_CLIENT_INSMOD_2(pcf8574, pcf8574a); /* Each client has this additional data */ struct pcf8574_data { - struct i2c_client client; - int write; /* Remember last written value */ }; -static int pcf8574_attach_adapter(struct i2c_adapter *adapter); -static int pcf8574_detect(struct i2c_adapter *adapter, int address, int kind); -static int pcf8574_detach_client(struct i2c_client *client); static void pcf8574_init_client(struct i2c_client *client); -/* This is the driver that will be inserted */ -static struct i2c_driver pcf8574_driver = { - .driver = { - .name = "pcf8574", - }, - .attach_adapter = pcf8574_attach_adapter, - .detach_client = pcf8574_detach_client, -}; - /* following are the sysfs callback functions */ static ssize_t show_read(struct device *dev, struct device_attribute *attr, char *buf) { @@ -119,41 +101,22 @@ static const struct attribute_group pcf8574_attr_group = { * Real code */ -static int pcf8574_attach_adapter(struct i2c_adapter *adapter) -{ - return i2c_probe(adapter, &addr_data, pcf8574_detect); -} - -/* This function is called by i2c_probe */ -static int pcf8574_detect(struct i2c_adapter *adapter, int address, int kind) +/* Return 0 if detection is successful, -ENODEV otherwise */ +static int pcf8574_detect(struct i2c_client *client, int kind, + struct i2c_board_info *info) { - struct i2c_client *client; - struct pcf8574_data *data; - int err = 0; - const char *client_name = ""; + struct i2c_adapter *adapter = client->adapter; + const char *client_name; if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) - 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 = kzalloc(sizeof(struct pcf8574_data), GFP_KERNEL))) { - err = -ENOMEM; - goto exit; - } - - client = &data->client; - i2c_set_clientdata(client, data); - client->addr = address; - client->adapter = adapter; - client->driver = &pcf8574_driver; + return -ENODEV; /* Now, we would do the remaining detection. But the PCF8574 is plainly impossible to detect! Stupid chip. */ /* Determine the chip type */ if (kind <= 0) { - if (address >= 0x38 && address <= 0x3f) + if (client->addr >= 0x38 && client->addr <= 0x3f) kind = pcf8574a; else kind = pcf8574; @@ -163,40 +126,43 @@ static int pcf8574_detect(struct i2c_adapter *adapter, int address, int kind) client_name = "pcf8574a"; else client_name = "pcf8574"; + strlcpy(info->type, client_name, I2C_NAME_SIZE); - /* Fill in the remaining client fields and put it into the global list */ - strlcpy(client->name, client_name, I2C_NAME_SIZE); + return 0; +} + +static int pcf8574_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct pcf8574_data *data; + int err; + + data = kzalloc(sizeof(struct pcf8574_data), GFP_KERNEL); + if (!data) { + err = -ENOMEM; + goto exit; + } + + i2c_set_clientdata(client, data); - /* Tell the I2C layer a new client has arrived */ - if ((err = i2c_attach_client(client))) - goto exit_free; - /* Initialize the PCF8574 chip */ pcf8574_init_client(client); /* Register sysfs hooks */ err = sysfs_create_group(&client->dev.kobj, &pcf8574_attr_group); if (err) - goto exit_detach; + goto exit_free; return 0; - exit_detach: - i2c_detach_client(client); exit_free: kfree(data); exit: return err; } -static int pcf8574_detach_client(struct i2c_client *client) +static int pcf8574_remove(struct i2c_client *client) { - int err; - sysfs_remove_group(&client->dev.kobj, &pcf8574_attr_group); - - if ((err = i2c_detach_client(client))) - return err; - kfree(i2c_get_clientdata(client)); return 0; } @@ -208,6 +174,24 @@ static void pcf8574_init_client(struct i2c_client *client) data->write = -EAGAIN; } +static const struct i2c_device_id pcf8574_id[] = { + { "pcf8574", 0 }, + { "pcf8574a", 0 }, + { } +}; + +static struct i2c_driver pcf8574_driver = { + .driver = { + .name = "pcf8574", + }, + .probe = pcf8574_probe, + .remove = pcf8574_remove, + .id_table = pcf8574_id, + + .detect = pcf8574_detect, + .address_data = &addr_data, +}; + static int __init pcf8574_init(void) { return i2c_add_driver(&pcf8574_driver); |