Normally i2c_new_device will check that a client at the same address does
not already exists.
On systems with ACPI instantiated i2c-clients, normally there is 1 fw_node
per i2c-device and that fw-node contains 1 I2cSerialBus resource for that 1
i2c-device.
But in some rare cases the manufacturer has decided to describe multiple
i2c-devices in a single ACPI fwnode with multiple I2cSerialBus resources.
After an earlier attempt to fix this in the i2c-core which resulted in a
lot of extra code to support this corner-case it was decided to go for a
different approach. The next patch in this series introduces a new special
i2c-multi-instantiate driver which can be build as a module and which will
bind to the i2c-client which gets instantiated by the core for the first
I2cSerialBus resource in the fwnode.
This driver will instantiate a new i2c-client per I2cSerialBus resource,
using the driver_data from the acpi_device_id it is binding to to tell it
which chip-type (and optional irq-resource) to use when instantiating.
Since it binds to the core instantiated i2c-client and claims the
acpi_device_id of the fwnode, it also needs to instantiate a new i2c-client
for the first I2cSerialBus resource uses the chip-id for the real driver,
so that that can bind to the i2c-device described by the first I2cSerialBus
resource, this requires the new I2C_CLIENT_IGNORE_BUSY flag.
Note this means that we will be instantiating 2 i2c_client-s for the first
I2cSerialBus resource, this is not pretty, but since the multi-instantiate
driver does exactly 0 i2c-transfers this is not a problem.
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
drivers/i2c/i2c-core-base.c | 11 +++++++----
include/linux/i2c.h | 3 +++
2 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index a17f46a95f73..77d70b611bc5 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -721,7 +721,7 @@ i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
if (info->archdata)
client->dev.archdata = *info->archdata;
- client->flags = info->flags;
+ client->flags = info->flags & ~I2C_CLIENT_IGNORE_BUSY;
client->addr = info->addr;
client->irq = info->irq;
@@ -739,9 +739,12 @@ i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
}
/* Check for address business */
- status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
- if (status)
- goto out_err;
+ if (!(info->flags & I2C_CLIENT_IGNORE_BUSY)) {
+ status = i2c_check_addr_busy(adap,
+ i2c_encode_flags_to_addr(client));
+ if (status)
+ goto out_err;
+ }
client->dev.parent = &client->adapter->dev;
client->dev.bus = &i2c_bus_type;
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 44ad14e016b5..3ad73cf1b187 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -775,6 +775,9 @@ i2c_unlock_adapter(struct i2c_adapter *adapter)
#define I2C_CLIENT_SLAVE 0x20 /* we are the slave */
#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_IGNORE_BUSY 0x100 /* For board_info; skip busy check */
+ /* Do NOT use, reserved for use by */
+ /* drv/i2c/i2c-multi-instantiate.c */
#define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */
/* Must match I2C_M_STOP|IGNORE_NAK */
--
2.17.0
