i2c: Add detection capability to new-style drivers
Add a mechanism to let new-style i2c drivers optionally autodetect
devices they would support on selected buses and ask i2c-core to
instantiate them. This is a replacement for legacy i2c drivers, much
cleaner.
Where drivers had to implement both a legacy i2c_driver and a
new-style i2c_driver so far, this mechanism makes it possible to get
rid of the legacy i2c_driver and implement both enumerated and
detected device support with just one (new-style) i2c_driver.
Here is a quick conversion guide for these drivers, step by step:
* Delete the legacy driver definition, registration and removal.
Delete the attach_adapter and detach_client methods of the legacy
driver.
* Change the prototype of the legacy detect function from
static int foo_detect(struct i2c_adapter *adapter, int address, int kind);
to
static int foo_detect(struct i2c_client *client, int kind,
struct i2c_board_info *info);
* Set the new-style driver detect callback to this new function, and
set its address_data to &addr_data (addr_data is generally provided
by I2C_CLIENT_INSMOD.)
* Add the appropriate class to the new-style driver. This is
typically the class the legacy attach_adapter method was checking
for. Class checking is now mandatory (done by i2c-core.) See
<linux/i2c.h> for the list of available classes.
* Remove the i2c_client allocation and freeing from the detect
function. A pre-allocated client is now handed to you by i2c-core,
and is freed automatically.
* Make the detect function fill the type field of the i2c_board_info
structure it was passed as a parameter, and return 0, on success. If
the detection fails, return -ENODEV.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 5e249d7..0a79f76 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -42,7 +42,9 @@
static DEFINE_MUTEX(core_lock);
static DEFINE_IDR(i2c_adapter_idr);
-#define is_newstyle_driver(d) ((d)->probe || (d)->remove)
+#define is_newstyle_driver(d) ((d)->probe || (d)->remove || (d)->detect)
+
+static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
/* ------------------------------------------------------------------------- */
@@ -418,6 +420,10 @@
struct i2c_driver *driver = to_i2c_driver(d);
struct i2c_adapter *adap = data;
+ /* Detect supported devices on that bus, and instantiate them */
+ i2c_detect(adap, driver);
+
+ /* Let legacy drivers scan this bus for matching devices */
if (driver->attach_adapter) {
/* We ignore the return code; if it fails, too bad */
driver->attach_adapter(adap);
@@ -457,7 +463,7 @@
if (adap->nr < __i2c_first_dynamic_bus_num)
i2c_scan_static_board_info(adap);
- /* let legacy drivers scan this bus for matching devices */
+ /* Notify drivers */
dummy = bus_for_each_drv(&i2c_bus_type, NULL, adap,
i2c_do_add_adapter);
@@ -563,8 +569,19 @@
{
struct i2c_driver *driver = to_i2c_driver(d);
struct i2c_adapter *adapter = data;
+ struct i2c_client *client, *_n;
int res;
+ /* Remove the devices we created ourselves */
+ list_for_each_entry_safe(client, _n, &driver->clients, detected) {
+ if (client->adapter == adapter) {
+ dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
+ client->name, client->addr);
+ list_del(&client->detected);
+ i2c_unregister_device(client);
+ }
+ }
+
if (!driver->detach_adapter)
return 0;
res = driver->detach_adapter(adapter);
@@ -651,7 +668,11 @@
struct i2c_adapter *adapter = to_i2c_adapter(dev);
struct i2c_driver *driver = data;
- driver->attach_adapter(adapter);
+ i2c_detect(adapter, driver);
+
+ /* Legacy drivers scan i2c busses directly */
+ if (driver->attach_adapter)
+ driver->attach_adapter(adapter);
return 0;
}
@@ -695,10 +716,9 @@
pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
- /* legacy drivers scan i2c busses directly */
- if (driver->attach_adapter)
- class_for_each_device(&i2c_adapter_class, driver,
- __attach_adapter);
+ INIT_LIST_HEAD(&driver->clients);
+ /* Walk the adapters that are already present */
+ class_for_each_device(&i2c_adapter_class, driver, __attach_adapter);
mutex_unlock(&core_lock);
return 0;
@@ -709,6 +729,17 @@
{
struct i2c_adapter *adapter = to_i2c_adapter(dev);
struct i2c_driver *driver = data;
+ struct i2c_client *client, *_n;
+
+ list_for_each_entry_safe(client, _n, &driver->clients, detected) {
+ dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
+ client->name, client->addr);
+ list_del(&client->detected);
+ i2c_unregister_device(client);
+ }
+
+ if (is_newstyle_driver(driver))
+ return 0;
/* Have a look at each adapter, if clients of this driver are still
* attached. If so, detach them to be able to kill the driver
@@ -747,10 +778,7 @@
{
mutex_lock(&core_lock);
- /* legacy driver? */
- if (!is_newstyle_driver(driver))
- class_for_each_device(&i2c_adapter_class, driver,
- __detach_adapter);
+ class_for_each_device(&i2c_adapter_class, driver, __detach_adapter);
driver_unregister(&driver->driver);
pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
@@ -1205,6 +1233,179 @@
}
EXPORT_SYMBOL(i2c_probe);
+/* Separate detection function for new-style drivers */
+static int i2c_detect_address(struct i2c_client *temp_client, int kind,
+ struct i2c_driver *driver)
+{
+ struct i2c_board_info info;
+ struct i2c_adapter *adapter = temp_client->adapter;
+ int addr = temp_client->addr;
+ int err;
+
+ /* Make sure the address is valid */
+ if (addr < 0x03 || addr > 0x77) {
+ dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
+ addr);
+ return -EINVAL;
+ }
+
+ /* Skip if already in use */
+ if (i2c_check_addr(adapter, addr))
+ return 0;
+
+ /* Make sure there is something at this address, unless forced */
+ if (kind < 0) {
+ if (i2c_smbus_xfer(adapter, addr, 0, 0, 0,
+ I2C_SMBUS_QUICK, NULL) < 0)
+ return 0;
+
+ /* prevent 24RF08 corruption */
+ if ((addr & ~0x0f) == 0x50)
+ i2c_smbus_xfer(adapter, addr, 0, 0, 0,
+ I2C_SMBUS_QUICK, NULL);
+ }
+
+ /* Finally call the custom detection function */
+ memset(&info, 0, sizeof(struct i2c_board_info));
+ info.addr = addr;
+ err = driver->detect(temp_client, kind, &info);
+ if (err) {
+ /* -ENODEV is returned if the detection fails. We catch it
+ here as this isn't an error. */
+ return err == -ENODEV ? 0 : err;
+ }
+
+ /* Consistency check */
+ if (info.type[0] == '\0') {
+ dev_err(&adapter->dev, "%s detection function provided "
+ "no name for 0x%x\n", driver->driver.name,
+ addr);
+ } else {
+ struct i2c_client *client;
+
+ /* Detection succeeded, instantiate the device */
+ dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
+ info.type, info.addr);
+ client = i2c_new_device(adapter, &info);
+ if (client)
+ list_add_tail(&client->detected, &driver->clients);
+ else
+ dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
+ info.type, info.addr);
+ }
+ return 0;
+}
+
+static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
+{
+ const struct i2c_client_address_data *address_data;
+ struct i2c_client *temp_client;
+ int i, err = 0;
+ int adap_id = i2c_adapter_id(adapter);
+
+ address_data = driver->address_data;
+ if (!driver->detect || !address_data)
+ return 0;
+
+ /* Set up a temporary client to help detect callback */
+ temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
+ if (!temp_client)
+ 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 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)
+ goto exit_free;
+
+ dev_warn(&adapter->dev, "SMBus Quick command not supported, "
+ "can't probe for chips\n");
+ err = -EOPNOTSUPP;
+ goto exit_free;
+ }
+
+ /* Stop here if the classes do not match */
+ if (!(adapter->class & driver->class))
+ 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]);
+ temp_client->addr = address_data->normal_i2c[i];
+ err = i2c_detect_address(temp_client, -1, driver);
+ if (err)
+ goto exit_free;
+ }
+
+ exit_free:
+ kfree(temp_client);
+ return err;
+}
+
struct i2c_client *
i2c_new_probed_device(struct i2c_adapter *adap,
struct i2c_board_info *info,