From 38f41f282f1f88b4038f019de51cb95984e569d5 Mon Sep 17 00:00:00 2001
From: Jean Delvare <khali@linux-fr.org>
Date: Sun, 6 Dec 2009 17:06:29 +0100
Subject: [PATCH] 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>
---
Documentation/i2c/i2c-stub | 6 ++++++
drivers/i2c/busses/i2c-stub.c | 8 ++++++--
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 = {
--
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