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authorJean Delvare <khali@linux-fr.org>2009-12-06 19:06:29 +0300
committerJean Delvare <khali@linux-fr.org>2009-12-06 19:06:29 +0300
commit38f41f282f1f88b4038f019de51cb95984e569d5 (patch)
treed885feffa6639bfb8824c4e7a68135ceed436fe4
parent4710317891e4824ce1510a6b5066abbd3e917750 (diff)
downloadlinux-38f41f282f1f88b4038f019de51cb95984e569d5.tar.xz
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>
-rw-r--r--Documentation/i2c/i2c-stub6
-rw-r--r--drivers/i2c/busses/i2c-stub.c8
2 files changed, 12 insertions, 2 deletions
diff --git a/Documentation/i2c/i2c-stub b/Documentation/i2c/i2c-stub
index d9c383b30925..326d1ee81e0e 100644
--- a/Documentation/i2c/i2c-stub
+++ b/Documentation/i2c/i2c-stub
@@ -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
diff --git a/drivers/i2c/busses/i2c-stub.c b/drivers/i2c/busses/i2c-stub.c
index 52ebeda1a64b..0c770eabe85e 100644
--- a/drivers/i2c/busses/i2c-stub.c
+++ b/drivers/i2c/busses/i2c-stub.c
@@ -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 = {