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i2c-stub: Allow user to disable some commands 

Add a module parameter to override the functionality bitfield. This
lets the user disable some commands. This can be used to force a chip
driver to take different code paths.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
This commit is contained in:
Jean Delvare 2009-12-06 17:06:29 +01:00
parent 4710317891
commit 38f41f282f
2 changed files with 12 additions and 2 deletions
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6
Documentation/i2c/i2c-stub
View File

@ -33,6 +33,12 @@ PARAMETERS:
int chip_addr[10]:
The SMBus addresses to emulate chips at.
unsigned long functionality:
Functionality override, to disable some commands. See I2C_FUNC_*
constants in <linux/i2c.h> for the suitable values. For example,
value 0x1f0000 would only enable the quick, byte and byte data
commands.
CAVEATS:
If your target driver polls some byte or word waiting for it to change, the

8
drivers/i2c/busses/i2c-stub.c
View File

@ -35,6 +35,10 @@ module_param_array(chip_addr, ushort, NULL, S_IRUGO);
MODULE_PARM_DESC(chip_addr,
"Chip addresses (up to 10, between 0x03 and 0x77)");
static unsigned long functionality = ~0UL;
module_param(functionality, ulong, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(functionality, "Override functionality bitfield");
struct stub_chip {
u8 pointer;
u16 words[256]; /* Byte operations use the LSB as per SMBus
@ -152,9 +156,9 @@ static s32 stub_xfer(struct i2c_adapter * adap, u16 addr, unsigned short flags,
static u32 stub_func(struct i2c_adapter *adapter)
{
return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
return (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
I2C_FUNC_SMBUS_I2C_BLOCK;
I2C_FUNC_SMBUS_I2C_BLOCK) & functionality;
}
static const struct i2c_algorithm smbus_algorithm = {