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-rw-r--r--Documentation/i2c/i2c-stub18
-rw-r--r--drivers/i2c/busses/i2c-stub.c79
2 files changed, 65 insertions, 32 deletions
diff --git a/Documentation/i2c/i2c-stub b/Documentation/i2c/i2c-stub
index 9cc081e69764..89e69ad3436c 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 a54adc50d162..84df29da1ddc 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>");
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-29 02:36:45 +0000