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Commit 38f41f28 authored by Jean Delvare's avatar Jean Delvare
Browse files

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: default avatarJean Delvare <khali@linux-fr.org>
parent 47103178

Documentation/i2c/i2c-stub

+6 −0
Original line number Diff line number Diff line
@@ -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

drivers/i2c/busses/i2c-stub.c

+6 −2
Original line number Diff line number Diff line
@@ -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 = {