diff options
| -rw-r--r-- | Documentation/i2c/i2c-stub | 18 | ||||
| -rw-r--r-- | drivers/i2c/busses/i2c-stub.c | 79 |
2 files changed, 65 insertions, 32 deletions
diff --git a/Documentation/i2c/i2c-stub b/Documentation/i2c/i2c-stub index 9cc081e..89e69ad 100644 --- a/Documentation/i2c/i2c-stub +++ b/Documentation/i2c/i2c-stub @@ -6,13 +6,14 @@ This module is a very simple fake I2C/SMBus driver. It implements four types of SMBus commands: write quick, (r/w) byte, (r/w) byte data, and (r/w) word data. -You need to provide a chip address as a module parameter when loading -this driver, which will then only react to SMBus commands to this address. +You need to provide chip addresses as a module parameter when loading this +driver, which will then only react to SMBus commands to these addresses. No hardware is needed nor associated with this module. It will accept write -quick commands to one address; it will respond to the other commands (also -to one address) by reading from or writing to an array in memory. It will -also spam the kernel logs for every command it handles. +quick commands to the specified addresses; it will respond to the other +commands (also to the specified addresses) by reading from or writing to +arrays in memory. It will also spam the kernel logs for every command it +handles. A pointer register with auto-increment is implemented for all byte operations. This allows for continuous byte reads like those supported by @@ -26,8 +27,8 @@ The typical use-case is like this: PARAMETERS: -int chip_addr: - The SMBus address to emulate a chip at. +int chip_addr[10]: + The SMBus addresses to emulate chips at. CAVEATS: @@ -41,9 +42,6 @@ If the hardware for your driver has banked registers (e.g. Winbond sensors chips) this module will not work well - although it could be extended to support that pretty easily. -Only one chip address is supported - although this module could be -extended to support more. - If you spam it hard enough, printk can be lossy. This module really wants something like relayfs. diff --git a/drivers/i2c/busses/i2c-stub.c b/drivers/i2c/busses/i2c-stub.c index a54adc5..84df29d 100644 --- a/drivers/i2c/busses/i2c-stub.c +++ b/drivers/i2c/busses/i2c-stub.c @@ -24,24 +24,41 @@ #include <linux/init.h> #include <linux/module.h> #include <linux/kernel.h> +#include <linux/slab.h> #include <linux/errno.h> #include <linux/i2c.h> -static unsigned short chip_addr; -module_param(chip_addr, ushort, S_IRUGO); -MODULE_PARM_DESC(chip_addr, "Chip address (between 0x03 and 0x77)\n"); +#define MAX_CHIPS 10 -static u8 stub_pointer; -static u8 stub_bytes[256]; -static u16 stub_words[256]; +static unsigned short chip_addr[MAX_CHIPS]; +module_param_array(chip_addr, ushort, NULL, S_IRUGO); +MODULE_PARM_DESC(chip_addr, + "Chip addresses (up to 10, between 0x03 and 0x77)\n"); + +struct stub_chip { + u8 pointer; + u8 bytes[256]; + u16 words[256]; +}; + +static struct stub_chip *stub_chips; /* Return -1 on error. */ static s32 stub_xfer(struct i2c_adapter * adap, u16 addr, unsigned short flags, char read_write, u8 command, int size, union i2c_smbus_data * data) { s32 ret; - - if (addr != chip_addr) + int i; + struct stub_chip *chip = NULL; + + /* Search for the right chip */ + for (i = 0; i < MAX_CHIPS && chip_addr[i]; i++) { + if (addr == chip_addr[i]) { + chip = stub_chips + i; + break; + } + } + if (!chip) return -ENODEV; switch (size) { @@ -53,12 +70,12 @@ static s32 stub_xfer(struct i2c_adapter * adap, u16 addr, unsigned short flags, case I2C_SMBUS_BYTE: if (read_write == I2C_SMBUS_WRITE) { - stub_pointer = command; + chip->pointer = command; dev_dbg(&adap->dev, "smbus byte - addr 0x%02x, " "wrote 0x%02x.\n", addr, command); } else { - data->byte = stub_bytes[stub_pointer++]; + data->byte = chip->bytes[chip->pointer++]; dev_dbg(&adap->dev, "smbus byte - addr 0x%02x, " "read 0x%02x.\n", addr, data->byte); @@ -69,29 +86,29 @@ static s32 stub_xfer(struct i2c_adapter * adap, u16 addr, unsigned short flags, case I2C_SMBUS_BYTE_DATA: if (read_write == I2C_SMBUS_WRITE) { - stub_bytes[command] = data->byte; + chip->bytes[command] = data->byte; dev_dbg(&adap->dev, "smbus byte data - addr 0x%02x, " "wrote 0x%02x at 0x%02x.\n", addr, data->byte, command); } else { - data->byte = stub_bytes[command]; + data->byte = chip->bytes[command]; dev_dbg(&adap->dev, "smbus byte data - addr 0x%02x, " "read 0x%02x at 0x%02x.\n", addr, data->byte, command); } - stub_pointer = command + 1; + chip->pointer = command + 1; ret = 0; break; case I2C_SMBUS_WORD_DATA: if (read_write == I2C_SMBUS_WRITE) { - stub_words[command] = data->word; + chip->words[command] = data->word; dev_dbg(&adap->dev, "smbus word data - addr 0x%02x, " "wrote 0x%04x at 0x%02x.\n", addr, data->word, command); } else { - data->word = stub_words[command]; + data->word = chip->words[command]; dev_dbg(&adap->dev, "smbus word data - addr 0x%02x, " "read 0x%04x at 0x%02x.\n", addr, data->word, command); @@ -129,23 +146,41 @@ static struct i2c_adapter stub_adapter = { static int __init i2c_stub_init(void) { - if (!chip_addr) { + int i, ret; + + if (!chip_addr[0]) { printk(KERN_ERR "i2c-stub: Please specify a chip address\n"); return -ENODEV; } - if (chip_addr < 0x03 || chip_addr > 0x77) { - printk(KERN_ERR "i2c-stub: Invalid chip address 0x%02x\n", - chip_addr); - return -EINVAL; + + for (i = 0; i < MAX_CHIPS && chip_addr[i]; i++) { + if (chip_addr[i] < 0x03 || chip_addr[i] > 0x77) { + printk(KERN_ERR "i2c-stub: Invalid chip address " + "0x%02x\n", chip_addr[i]); + return -EINVAL; + } + + printk(KERN_INFO "i2c-stub: Virtual chip at 0x%02x\n", + chip_addr[i]); } - printk(KERN_INFO "i2c-stub: Virtual chip at 0x%02x\n", chip_addr); - return i2c_add_adapter(&stub_adapter); + /* Allocate memory for all chips at once */ + stub_chips = kzalloc(i * sizeof(struct stub_chip), GFP_KERNEL); + if (!stub_chips) { + printk(KERN_ERR "i2c-stub: Out of memory\n"); + return -ENOMEM; + } + + ret = i2c_add_adapter(&stub_adapter); + if (ret) + kfree(stub_chips); + return ret; } static void __exit i2c_stub_exit(void) { i2c_del_adapter(&stub_adapter); + kfree(stub_chips); } MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>"); |