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---
r: 172365
b: refs/heads/master
c: c7b25a9
h: refs/heads/master
i:
  172363: b56c855
v: v3
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Jean Delvare committed Dec 6, 2009
1 parent 3fbdb18 commit 80f7798
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2 changes: 1 addition & 1 deletion [refs]
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---
refs/heads/master: abe38388e50f4d89726fd0c0cceea61563c7026b
refs/heads/master: c7b25a9e96dc89954ae8d8f473f56fae62030f84
44 changes: 44 additions & 0 deletions trunk/Documentation/i2c/old-module-parameters
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I2C device driver binding control from user-space
=================================================

Up to kernel 2.6.32, many i2c drivers used helper macros provided by
<linux/i2c.h> which created standard module parameters to let the user
control how the driver would probe i2c buses and attach to devices. These
parameters were known as "probe" (to let the driver probe for an extra
address), "force" (to forcibly attach the driver to a given device) and
"ignore" (to prevent a driver from probing a given address).

With the conversion of the i2c subsystem to the standard device driver
binding model, it became clear that these per-module parameters were no
longer needed, and that a centralized implementation was possible. The new,
sysfs-based interface is described in the documentation file
"instantiating-devices", section "Method 4: Instantiate from user-space".

Below is a mapping from the old module parameters to the new interface.

Attaching a driver to an I2C device
-----------------------------------

Old method (module parameters):
# modprobe <driver> probe=1,0x2d
# modprobe <driver> force=1,0x2d
# modprobe <driver> force_<device>=1,0x2d

New method (sysfs interface):
# echo <device> 0x2d > /sys/bus/i2c/devices/i2c-1/new_device

Preventing a driver from attaching to an I2C device
---------------------------------------------------

Old method (module parameters):
# modprobe <driver> ignore=1,0x2f

New method (sysfs interface):
# echo dummy 0x2f > /sys/bus/i2c/devices/i2c-1/new_device
# modprobe <driver>

Of course, it is important to instantiate the "dummy" device before loading
the driver. The dummy device will be handled by i2c-core itself, preventing
other drivers from binding to it later on. If there is a real device at the
problematic address, and you want another driver to bind to it, then simply
pass the name of the device in question instead of "dummy".
65 changes: 1 addition & 64 deletions trunk/drivers/i2c/i2c-core.c
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Expand Up @@ -1259,40 +1259,13 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
return -ENOMEM;
temp_client->adapter = adapter;

/* Force entries are done first, and are not affected by ignore
entries */
if (address_data->forces) {
const unsigned short * const *forces = address_data->forces;
int kind;

for (kind = 0; forces[kind]; kind++) {
for (i = 0; forces[kind][i] != I2C_CLIENT_END;
i += 2) {
if (forces[kind][i] == adap_id
|| forces[kind][i] == ANY_I2C_BUS) {
dev_dbg(&adapter->dev, "found force "
"parameter for adapter %d, "
"addr 0x%02x, kind %d\n",
adap_id, forces[kind][i + 1],
kind);
temp_client->addr = forces[kind][i + 1];
err = i2c_detect_address(temp_client,
kind, driver);
if (err)
goto exit_free;
}
}
}
}

/* Stop here if the classes do not match */
if (!(adapter->class & driver->class))
goto exit_free;

/* Stop here if we can't use SMBUS_QUICK */
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_QUICK)) {
if (address_data->probe[0] == I2C_CLIENT_END
&& address_data->normal_i2c[0] == I2C_CLIENT_END)
if (address_data->normal_i2c[0] == I2C_CLIENT_END)
goto exit_free;

dev_warn(&adapter->dev, "SMBus Quick command not supported, "
Expand All @@ -1301,43 +1274,7 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
goto exit_free;
}

/* Probe entries are done second, and are not affected by ignore
entries either */
for (i = 0; address_data->probe[i] != I2C_CLIENT_END; i += 2) {
if (address_data->probe[i] == adap_id
|| address_data->probe[i] == ANY_I2C_BUS) {
dev_dbg(&adapter->dev, "found probe parameter for "
"adapter %d, addr 0x%02x\n", adap_id,
address_data->probe[i + 1]);
temp_client->addr = address_data->probe[i + 1];
err = i2c_detect_address(temp_client, -1, driver);
if (err)
goto exit_free;
}
}

/* Normal entries are done last, unless shadowed by an ignore entry */
for (i = 0; address_data->normal_i2c[i] != I2C_CLIENT_END; i += 1) {
int j, ignore;

ignore = 0;
for (j = 0; address_data->ignore[j] != I2C_CLIENT_END;
j += 2) {
if ((address_data->ignore[j] == adap_id ||
address_data->ignore[j] == ANY_I2C_BUS)
&& address_data->ignore[j + 1]
== address_data->normal_i2c[i]) {
dev_dbg(&adapter->dev, "found ignore "
"parameter for adapter %d, "
"addr 0x%02x\n", adap_id,
address_data->ignore[j + 1]);
ignore = 1;
break;
}
}
if (ignore)
continue;

dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
"addr 0x%02x\n", adap_id,
address_data->normal_i2c[i]);
Expand Down
91 changes: 1 addition & 90 deletions trunk/include/linux/i2c.h
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Original file line number Diff line number Diff line change
Expand Up @@ -110,7 +110,7 @@ extern s32 i2c_smbus_write_i2c_block_data(struct i2c_client *client,
* @driver: Device driver model driver
* @id_table: List of I2C devices supported by this driver
* @detect: Callback for device detection
* @address_data: The I2C addresses to probe, ignore or force (for detect)
* @address_data: The I2C addresses to probe (for detect)
* @clients: List of detected clients we created (for i2c-core use only)
*
* The driver.owner field should be set to the module owner of this driver.
Expand Down Expand Up @@ -397,9 +397,6 @@ static inline void i2c_unlock_adapter(struct i2c_adapter *adapter)
*/
struct i2c_client_address_data {
const unsigned short *normal_i2c;
const unsigned short *probe;
const unsigned short *ignore;
const unsigned short * const *forces;
};

/* Internal numbers to terminate lists */
Expand Down Expand Up @@ -613,134 +610,48 @@ union i2c_smbus_data {
module_param_array(var, short, &var##_num, 0); \
MODULE_PARM_DESC(var, desc)

#define I2C_CLIENT_MODULE_PARM_FORCE(name) \
I2C_CLIENT_MODULE_PARM(force_##name, \
"List of adapter,address pairs which are " \
"unquestionably assumed to contain a `" \
# name "' chip")


#define I2C_CLIENT_INSMOD_COMMON \
I2C_CLIENT_MODULE_PARM(probe, "List of adapter,address pairs to scan " \
"additionally"); \
I2C_CLIENT_MODULE_PARM(ignore, "List of adapter,address pairs not to " \
"scan"); \
static const struct i2c_client_address_data addr_data = { \
.normal_i2c = normal_i2c, \
.probe = probe, \
.ignore = ignore, \
.forces = forces, \
}

#define I2C_CLIENT_FORCE_TEXT \
"List of adapter,address pairs to boldly assume to be present"

/* These are the ones you want to use in your own drivers. Pick the one
which matches the number of devices the driver differenciates between. */
#define I2C_CLIENT_INSMOD \
I2C_CLIENT_MODULE_PARM(force, I2C_CLIENT_FORCE_TEXT); \
static const unsigned short * const forces[] = { force, NULL }; \
I2C_CLIENT_INSMOD_COMMON

#define I2C_CLIENT_INSMOD_1(chip1) \
enum chips { any_chip, chip1 }; \
I2C_CLIENT_MODULE_PARM(force, I2C_CLIENT_FORCE_TEXT); \
I2C_CLIENT_MODULE_PARM_FORCE(chip1); \
static const unsigned short * const forces[] = { force, \
force_##chip1, NULL }; \
I2C_CLIENT_INSMOD_COMMON

#define I2C_CLIENT_INSMOD_2(chip1, chip2) \
enum chips { any_chip, chip1, chip2 }; \
I2C_CLIENT_MODULE_PARM(force, I2C_CLIENT_FORCE_TEXT); \
I2C_CLIENT_MODULE_PARM_FORCE(chip1); \
I2C_CLIENT_MODULE_PARM_FORCE(chip2); \
static const unsigned short * const forces[] = { force, \
force_##chip1, force_##chip2, NULL }; \
I2C_CLIENT_INSMOD_COMMON

#define I2C_CLIENT_INSMOD_3(chip1, chip2, chip3) \
enum chips { any_chip, chip1, chip2, chip3 }; \
I2C_CLIENT_MODULE_PARM(force, I2C_CLIENT_FORCE_TEXT); \
I2C_CLIENT_MODULE_PARM_FORCE(chip1); \
I2C_CLIENT_MODULE_PARM_FORCE(chip2); \
I2C_CLIENT_MODULE_PARM_FORCE(chip3); \
static const unsigned short * const forces[] = { force, \
force_##chip1, force_##chip2, force_##chip3, NULL }; \
I2C_CLIENT_INSMOD_COMMON

#define I2C_CLIENT_INSMOD_4(chip1, chip2, chip3, chip4) \
enum chips { any_chip, chip1, chip2, chip3, chip4 }; \
I2C_CLIENT_MODULE_PARM(force, I2C_CLIENT_FORCE_TEXT); \
I2C_CLIENT_MODULE_PARM_FORCE(chip1); \
I2C_CLIENT_MODULE_PARM_FORCE(chip2); \
I2C_CLIENT_MODULE_PARM_FORCE(chip3); \
I2C_CLIENT_MODULE_PARM_FORCE(chip4); \
static const unsigned short * const forces[] = { force, \
force_##chip1, force_##chip2, force_##chip3, \
force_##chip4, NULL}; \
I2C_CLIENT_INSMOD_COMMON

#define I2C_CLIENT_INSMOD_5(chip1, chip2, chip3, chip4, chip5) \
enum chips { any_chip, chip1, chip2, chip3, chip4, chip5 }; \
I2C_CLIENT_MODULE_PARM(force, I2C_CLIENT_FORCE_TEXT); \
I2C_CLIENT_MODULE_PARM_FORCE(chip1); \
I2C_CLIENT_MODULE_PARM_FORCE(chip2); \
I2C_CLIENT_MODULE_PARM_FORCE(chip3); \
I2C_CLIENT_MODULE_PARM_FORCE(chip4); \
I2C_CLIENT_MODULE_PARM_FORCE(chip5); \
static const unsigned short * const forces[] = { force, \
force_##chip1, force_##chip2, force_##chip3, \
force_##chip4, force_##chip5, NULL }; \
I2C_CLIENT_INSMOD_COMMON

#define I2C_CLIENT_INSMOD_6(chip1, chip2, chip3, chip4, chip5, chip6) \
enum chips { any_chip, chip1, chip2, chip3, chip4, chip5, chip6 }; \
I2C_CLIENT_MODULE_PARM(force, I2C_CLIENT_FORCE_TEXT); \
I2C_CLIENT_MODULE_PARM_FORCE(chip1); \
I2C_CLIENT_MODULE_PARM_FORCE(chip2); \
I2C_CLIENT_MODULE_PARM_FORCE(chip3); \
I2C_CLIENT_MODULE_PARM_FORCE(chip4); \
I2C_CLIENT_MODULE_PARM_FORCE(chip5); \
I2C_CLIENT_MODULE_PARM_FORCE(chip6); \
static const unsigned short * const forces[] = { force, \
force_##chip1, force_##chip2, force_##chip3, \
force_##chip4, force_##chip5, force_##chip6, NULL }; \
I2C_CLIENT_INSMOD_COMMON

#define I2C_CLIENT_INSMOD_7(chip1, chip2, chip3, chip4, chip5, chip6, chip7) \
enum chips { any_chip, chip1, chip2, chip3, chip4, chip5, chip6, \
chip7 }; \
I2C_CLIENT_MODULE_PARM(force, I2C_CLIENT_FORCE_TEXT); \
I2C_CLIENT_MODULE_PARM_FORCE(chip1); \
I2C_CLIENT_MODULE_PARM_FORCE(chip2); \
I2C_CLIENT_MODULE_PARM_FORCE(chip3); \
I2C_CLIENT_MODULE_PARM_FORCE(chip4); \
I2C_CLIENT_MODULE_PARM_FORCE(chip5); \
I2C_CLIENT_MODULE_PARM_FORCE(chip6); \
I2C_CLIENT_MODULE_PARM_FORCE(chip7); \
static const unsigned short * const forces[] = { force, \
force_##chip1, force_##chip2, force_##chip3, \
force_##chip4, force_##chip5, force_##chip6, \
force_##chip7, NULL }; \
I2C_CLIENT_INSMOD_COMMON

#define I2C_CLIENT_INSMOD_8(chip1, chip2, chip3, chip4, chip5, chip6, chip7, chip8) \
enum chips { any_chip, chip1, chip2, chip3, chip4, chip5, chip6, \
chip7, chip8 }; \
I2C_CLIENT_MODULE_PARM(force, I2C_CLIENT_FORCE_TEXT); \
I2C_CLIENT_MODULE_PARM_FORCE(chip1); \
I2C_CLIENT_MODULE_PARM_FORCE(chip2); \
I2C_CLIENT_MODULE_PARM_FORCE(chip3); \
I2C_CLIENT_MODULE_PARM_FORCE(chip4); \
I2C_CLIENT_MODULE_PARM_FORCE(chip5); \
I2C_CLIENT_MODULE_PARM_FORCE(chip6); \
I2C_CLIENT_MODULE_PARM_FORCE(chip7); \
I2C_CLIENT_MODULE_PARM_FORCE(chip8); \
static const unsigned short * const forces[] = { force, \
force_##chip1, force_##chip2, force_##chip3, \
force_##chip4, force_##chip5, force_##chip6, \
force_##chip7, force_##chip8, NULL }; \
I2C_CLIENT_INSMOD_COMMON
#endif /* __KERNEL__ */
#endif /* _LINUX_I2C_H */

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