| Message ID | 20200318150059.21714-7-wsa+renesas@sang-engineering.com (mailing list archive) |
|---|---|
| State | Under Review |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
| Series | i2c: of: reserve unknown and ancillary addresses | expand |
Hi, On 18/03/20 16:00, Wolfram Sang wrote: > With i2c_new_ancillary_address, we can check if the intended driver is > requesting a reserved address. Update the function to do these checks. > If the check passes, the "reserved" device will become a regular "dummy" > device. > > Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> > --- > drivers/i2c/i2c-core-base.c | 24 ++++++++++++++++++++++-- > 1 file changed, 22 insertions(+), 2 deletions(-) > > diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c > index 84464e439df5..81fb320de28d 100644 > --- a/drivers/i2c/i2c-core-base.c > +++ b/drivers/i2c/i2c-core-base.c > @@ -974,7 +974,9 @@ struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client, > const char *name, > u16 default_addr) > { > - struct device_node *np = client->dev.of_node; > + struct device_node *reserved_np, *np = client->dev.of_node; > + struct device *reserved_dev, *adapter_dev = &client->adapter->dev; > + struct i2c_client *reserved_client = NULL; > u32 addr = default_addr; > int i; > > @@ -984,7 +986,25 @@ struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client, > of_property_read_u32_index(np, "reg", i, &addr); > } > > - dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr); > + dev_info(adapter_dev, "Address for %s : 0x%x\n", name, addr); Here if we have two identical chips on the same bus, they probably will both add an ancillary device with the same name. Then a message like: i2c i2c-0: ds90ub954-q1: Address for rxport0: 0x40 won't tell which ds90ub954-q1 device is using that address. I'd rather disambiguate using something like: dev_info(adapter_dev, "%s: Address for %s: 0x%x\n", dev_name(&client->dev), name, addr); Sure, this issue did exist before this patch, but since the line is being promoted from dbg to info (which is OK), it's probably a good idea to improve the content, perhaps in a separate patch. Except for that, I tested the patch and it's working fine.
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 84464e439df5..81fb320de28d 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -974,7 +974,9 @@ struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client, const char *name, u16 default_addr) { - struct device_node *np = client->dev.of_node; + struct device_node *reserved_np, *np = client->dev.of_node; + struct device *reserved_dev, *adapter_dev = &client->adapter->dev; + struct i2c_client *reserved_client = NULL; u32 addr = default_addr; int i; @@ -984,7 +986,25 @@ struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client, of_property_read_u32_index(np, "reg", i, &addr); } - dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr); + dev_info(adapter_dev, "Address for %s : 0x%x\n", name, addr); + + /* No need to scan muxes, siblings must sit on the same adapter */ + reserved_dev = device_find_child(adapter_dev, &addr, __i2c_check_addr_busy); + if (reserved_dev) { + reserved_np = reserved_dev->of_node; + reserved_client = i2c_verify_client(reserved_dev); + put_device(reserved_dev); + } + + if (reserved_client) { + if (reserved_np != np || + strcmp(reserved_client->name, I2C_RESERVED_DRV_NAME) != 0) + return ERR_PTR(-EBUSY); + + strlcpy(reserved_client->name, I2C_DUMMY_DRV_NAME, sizeof(client->name)); + return reserved_client; + } + return i2c_new_dummy_device(client->adapter, addr); } EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
With i2c_new_ancillary_address, we can check if the intended driver is requesting a reserved address. Update the function to do these checks. If the check passes, the "reserved" device will become a regular "dummy" device. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> --- drivers/i2c/i2c-core-base.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-)