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Revert "i2c: Replace list-based mechanism for handling userspace-created clients"

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This reverts commit 3cfe39b3a8. Mux
handling is not sufficiently implemented. It needs more time.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
This commit is contained in:
Wolfram Sang 2025-02-05 14:21:36 +01:00
parent 2014c95afe
commit c4d3dfd8cc
2 changed files with 46 additions and 24 deletions
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63
drivers/i2c/i2c-core-base.c
View file

@ -1300,12 +1300,14 @@ new_device_store(struct device *dev, struct device_attribute *attr,
info.flags |= I2C_CLIENT_SLAVE;
}
info.flags |= I2C_CLIENT_USER;
client = i2c_new_client_device(adap, &info);
if (IS_ERR(client))
return PTR_ERR(client);
/* Keep track of the added device */
mutex_lock(&adap->userspace_clients_lock);
list_add_tail(&client->detected, &adap->userspace_clients);
mutex_unlock(&adap->userspace_clients_lock);
dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
info.type, info.addr);
@ -1313,15 +1315,6 @@ new_device_store(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR_WO(new_device);
static int __i2c_find_user_addr(struct device *dev, const void *addrp)
{
struct i2c_client *client = i2c_verify_client(dev);
unsigned short addr = *(unsigned short *)addrp;
return client && client->flags & I2C_CLIENT_USER &&
i2c_encode_flags_to_addr(client) == addr;
}
/*
* And of course let the users delete the devices they instantiated, if
* they got it wrong. This interface can only be used to delete devices
@ -1336,7 +1329,7 @@ delete_device_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct i2c_adapter *adap = to_i2c_adapter(dev);
struct device *child_dev;
struct i2c_client *client, *next;
unsigned short addr;
char end;
int res;
@ -1352,19 +1345,28 @@ delete_device_store(struct device *dev, struct device_attribute *attr,
return -EINVAL;
}
mutex_lock(&core_lock);
/* Make sure the device was added through sysfs */
child_dev = device_find_child(&adap->dev, &addr, __i2c_find_user_addr);
if (child_dev) {
i2c_unregister_device(i2c_verify_client(child_dev));
put_device(child_dev);
} else {
dev_err(dev, "Can't find userspace-created device at %#x\n", addr);
count = -ENOENT;
}
mutex_unlock(&core_lock);
res = -ENOENT;
mutex_lock_nested(&adap->userspace_clients_lock,
i2c_adapter_depth(adap));
list_for_each_entry_safe(client, next, &adap->userspace_clients,
detected) {
if (i2c_encode_flags_to_addr(client) == addr) {
dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
"delete_device", client->name, client->addr);
return count;
list_del(&client->detected);
i2c_unregister_device(client);
res = count;
break;
}
}
mutex_unlock(&adap->userspace_clients_lock);
if (res < 0)
dev_err(dev, "%s: Can't find device in list\n",
"delete_device");
return res;
}
static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
delete_device_store);
@ -1535,6 +1537,8 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
adap->locked_flags = 0;
rt_mutex_init(&adap->bus_lock);
rt_mutex_init(&adap->mux_lock);
mutex_init(&adap->userspace_clients_lock);
INIT_LIST_HEAD(&adap->userspace_clients);
/* Set default timeout to 1 second if not already set */
if (adap->timeout == 0)
@ -1726,6 +1730,7 @@ static int __unregister_dummy(struct device *dev, void *dummy)
void i2c_del_adapter(struct i2c_adapter *adap)
{
struct i2c_adapter *found;
struct i2c_client *client, *next;
/* First make sure that this adapter was ever added */
mutex_lock(&core_lock);
@ -1738,6 +1743,18 @@ void i2c_del_adapter(struct i2c_adapter *adap)
i2c_acpi_remove_space_handler(adap);
/* Remove devices instantiated from sysfs */
mutex_lock_nested(&adap->userspace_clients_lock,
i2c_adapter_depth(adap));
list_for_each_entry_safe(client, next, &adap->userspace_clients,
detected) {
dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
client->addr);
list_del(&client->detected);
i2c_unregister_device(client);
}
mutex_unlock(&adap->userspace_clients_lock);
/* Detach any active clients. This can't fail, thus we do not
* check the returned value. This is a two-pass process, because
* we can't remove the dummy devices during the first pass: they

7
include/linux/i2c.h
View file

@ -313,6 +313,8 @@ struct i2c_driver {
* @dev: Driver model device node for the slave.
* @init_irq: IRQ that was set at initialization
* @irq: indicates the IRQ generated by this device (if any)
* @detected: member of an i2c_driver.clients list or i2c-core's
* userspace_devices list
* @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter
* calls it to pass on slave events to the slave driver.
* @devres_group_id: id of the devres group that will be created for resources
@ -333,7 +335,6 @@ struct i2c_client {
#define I2C_CLIENT_HOST_NOTIFY 0x40 /* We want to use I2C host notify */
#define I2C_CLIENT_WAKE 0x80 /* for board_info; true iff can wake */
#define I2C_CLIENT_AUTO 0x100 /* client was auto-detected */
#define I2C_CLIENT_USER 0x200 /* client was userspace-created */
#define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */
/* Must match I2C_M_STOP|IGNORE_NAK */
@ -345,6 +346,7 @@ struct i2c_client {
struct device dev; /* the device structure */
int init_irq; /* irq set at initialization */
int irq; /* irq issued by device */
struct list_head detected;
#if IS_ENABLED(CONFIG_I2C_SLAVE)
i2c_slave_cb_t slave_cb; /* callback for slave mode */
#endif
@ -751,6 +753,9 @@ struct i2c_adapter {
char name[48];
struct completion dev_released;
struct mutex userspace_clients_lock;
struct list_head userspace_clients;
struct i2c_bus_recovery_info *bus_recovery_info;
const struct i2c_adapter_quirks *quirks;