[i2c] [PATCH 1/4] i2c: Add detection capability to new-style drivers
Jean Delvare
khali at linux-fr.org
Fri Jun 6 15:02:06 CEST 2008
Add a mechanism to let new-style i2c drivers auto-detect devices they
would support and ask i2c-core to instantiate them. This is a
replacement for legacy drivers, much cleaner.
Signed-off-by: Jean Delvare <khali at linux-fr.org>
---
This patch depends on:
http://khali.linux-fr.org/devel/linux-2.6/jdelvare-i2c/i2c-use-class_for_each_device.patch
http://khali.linux-fr.org/devel/linux-2.6/jdelvare-i2c/i2c-simplify-i2c_del_driver.patch
Implementation note: i2c_detect and i2c_detect_address are basically
clones of i2c_probe and i2c_probe_address but operating on a callback
with a slightly different prototype. This duplicated code accounts
for a large part of the patch, but once legacy drivers are gone,
i2c_probe and i2c_probe_address will be removed, so this is no
long-term duplication.
drivers/i2c/i2c-core.c | 207 +++++++++++++++++++++++++++++++++++++++++++++---
include/linux/i2c.h | 14 +++
2 files changed, 210 insertions(+), 11 deletions(-)
--- linux-2.6.26-rc5.orig/include/linux/i2c.h 2008-06-05 21:04:35.000000000 +0200
+++ linux-2.6.26-rc5/include/linux/i2c.h 2008-06-05 21:54:49.000000000 +0200
@@ -43,6 +43,7 @@ struct i2c_adapter;
struct i2c_client;
struct i2c_driver;
union i2c_smbus_data;
+struct i2c_board_info;
/*
* The master routines are the ones normally used to transmit data to devices
@@ -99,6 +100,11 @@ extern s32 i2c_smbus_write_i2c_block_dat
*
* The driver.owner field should be set to the module owner of this driver.
* The driver.name field should be set to the name of this driver.
+ *
+ * @class: What kind of i2c device we may instantiate
+ * @detect: Callback for device detection
+ * @address_data: The I2C addresses to probe, ignore or force
+ * @clients: List of detected clients we created
*/
struct i2c_driver {
@@ -140,6 +146,12 @@ struct i2c_driver {
struct device_driver driver;
const struct i2c_device_id *id_table;
+
+ /* Device detection callback for automatic device creation */
+ int (*detect)(struct i2c_adapter *, int address, int kind,
+ struct i2c_board_info *);
+ const struct i2c_client_address_data *address_data;
+ struct list_head clients;
};
#define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
@@ -155,6 +167,7 @@ struct i2c_driver {
* @dev: Driver model device node for the slave.
* @irq: indicates the IRQ generated by this device (if any)
* @list: list of active/busy clients (DEPRECATED)
+ * @detected: member of a i2c_driver.clients list
* @released: used to synchronize client releases & detaches and references
*
* An i2c_client identifies a single device (i.e. chip) connected to an
@@ -172,6 +185,7 @@ struct i2c_client {
struct device dev; /* the device structure */
int irq; /* irq issued by device (or -1) */
struct list_head list; /* DEPRECATED */
+ struct list_head detected;
struct completion released;
};
#define to_i2c_client(d) container_of(d, struct i2c_client, dev)
--- linux-2.6.26-rc5.orig/drivers/i2c/i2c-core.c 2008-06-05 21:04:35.000000000 +0200
+++ linux-2.6.26-rc5/drivers/i2c/i2c-core.c 2008-06-06 14:04:40.000000000 +0200
@@ -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);
/* ------------------------------------------------------------------------- */
@@ -409,6 +411,10 @@ static int i2c_do_add_adapter(struct dev
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);
@@ -448,7 +454,7 @@ static int i2c_register_adapter(struct i
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);
@@ -554,14 +560,26 @@ static int i2c_do_del_adapter(struct dev
{
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);
if (res)
dev_err(&adapter->dev, "detach_adapter failed (%d) "
"for driver [%s]\n", res, driver->driver.name);
+
return res;
}
@@ -642,7 +660,10 @@ static int __attach_adapter(struct devic
struct i2c_adapter *adapter = to_i2c_adapter(dev);
struct i2c_driver *driver = data;
- driver->attach_adapter(adapter);
+ i2c_detect(adapter, driver);
+
+ if (driver->attach_adapter)
+ driver->attach_adapter(adapter);
return 0;
}
@@ -686,10 +707,10 @@ int i2c_register_driver(struct module *o
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;
@@ -700,6 +721,17 @@ static int __detach_adapter(struct devic
{
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
@@ -738,10 +770,7 @@ void i2c_del_driver(struct i2c_driver *d
{
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);
@@ -1196,6 +1225,162 @@ int i2c_probe(struct i2c_adapter *adapte
}
EXPORT_SYMBOL(i2c_probe);
+/* Separate detection function for new-style drivers */
+static int i2c_detect_address(struct i2c_adapter *adapter,
+ int addr, int kind, struct i2c_driver *driver)
+{
+ struct i2c_board_info info;
+ struct i2c_client *client;
+ 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));
+ err = driver->detect(adapter, addr, kind, &info);
+ if (err) {
+ /* -ENODEV can be returned if there is a chip at the given address
+ but it isn't supported by this chip driver. We catch it here as
+ this isn't an error. */
+ return err == -ENODEV ? 0 : err;
+ }
+
+ /* Consistency check */
+ if (info.type[0] == '\0' || info.addr != addr) {
+ dev_err(&adapter->dev, "Detection function returned "
+ "inconsistent data for 0x%x\n", addr);
+ } else {
+ /* Detection succeeded, instantiate the device */
+ dev_dbg(&adapter->dev, "Creating %s at 0x%x\n",
+ info.type, info.addr);
+ client = i2c_new_device(adapter, &info);
+ list_add_tail(&client->detected, &driver->clients);
+ }
+ return 0;
+}
+
+static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
+{
+ const struct i2c_client_address_data *address_data;
+ int i, err;
+ int adap_id = i2c_adapter_id(adapter);
+
+ if (!driver->detect)
+ return 0;
+ address_data = driver->address_data;
+
+ /* 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);
+ err = i2c_detect_address(adapter,
+ forces[kind][i + 1],
+ kind, driver);
+ if (err)
+ return err;
+ }
+ }
+ }
+ }
+
+ /* 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)
+ return 0;
+
+ dev_warn(&adapter->dev, "SMBus Quick command not supported, "
+ "can't probe for chips\n");
+ return -EOPNOTSUPP;
+ }
+
+ /* 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]);
+ err = i2c_detect_address(adapter,
+ address_data->probe[i + 1],
+ -1, driver);
+ if (err)
+ return err;
+ }
+ }
+
+ /* Stop here if the classes do not match */
+ if (!(adapter->class & driver->class))
+ return 0;
+
+ /* 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]);
+ err = i2c_detect_address(adapter, address_data->normal_i2c[i],
+ -1, driver);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
struct i2c_client *
i2c_new_probed_device(struct i2c_adapter *adap,
struct i2c_board_info *info,
--
Jean Delvare
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