Le dimanche 14 janvier 2018 à 11:28 +0000, Jonathan Cameron a écrit : > On Sat, 13 Jan 2018 14:37:03 +0100 > Marc CAPDEVILLE <[email protected]> wrote: > > > Somme ACPI enumerated devices are known to support smbus alert protocol. > > Theses devices may be miss-enumerated with the reserved smbus ARA address. > > > > This is the case on Asus T100 tablet where cm3218 ambiant light sensor > > expose two i2c serial bus connections, with the first one being the alert > > response address. > > > > This patch make a match on known ACPI ids for which devices are smbus ARA > > capable, then skip the connection if it has the reserved 0x0c address and > > mark it with I2C_CLIENT_ALERT flag. So device is enumerated with the > > correct address. > > I wonder if we are safe to always skip 0x0c address whether or not > we know the device supports ARA. The exception may be for devices > that do support ARA but are rolling their own support the hard way...
The device is only flagged with I2C_CLIENT_ALERT if its ID is in the i2c_acpi_alert_device_ids. IF a driver want to be enumerated with the reserved Ox0c address, It just have to not put its Id in this table. But this may break with registering the smbus_alert device as the address will be marked as busy for this adapter. > I suppose it's possible there are i2c devices (not smbus where the > spec says you must not use 0x0c for normal address IIRC) that use > this address. Does anyone know of any? I think this possible, but a such device can't share the bus with a smbus alert capable device. > > > Jonathan > > > > > Signed-off-by: Marc CAPDEVILLE <[email protected]> > > --- > > drivers/i2c/i2c-core-acpi.c | 23 +++++++++++++++++++++-- > > include/linux/i2c.h | 1 + > > 2 files changed, 22 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c > > index a9126b3cda61..5a8886f14329 100644 > > --- a/drivers/i2c/i2c-core-acpi.c > > +++ b/drivers/i2c/i2c-core-acpi.c > > @@ -59,8 +59,14 @@ static int i2c_acpi_fill_info(struct acpi_resource *ares, > > void *data) > > if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) > > return 1; > > > > - if (lookup->index != -1 && lookup->n++ != lookup->index) > > - return 1; > > + if (lookup->index != -1) { > > + if (lookup->n++ != lookup->index) > > + return 1; > > + } else { > > + if (lookup->info->flags & I2C_CLIENT_ALERT && > > + sb->slave_address == 0x0c) > > + return 1; > > + } > > > > status = acpi_get_handle(lookup->device_handle, > > sb->resource_source.string_ptr, > > @@ -85,6 +91,15 @@ static const struct acpi_device_id > > i2c_acpi_ignored_device_ids[] = { > > {} > > }; > > > > +static const struct acpi_device_id i2c_acpi_alert_device_ids[] = { > > + /* > > + * Smbus alert capable device which may have the reserved ARA > > address > > + * in their serial bus resources list. > > + */ > > + { "CPLM3218", 0 }, > > + {} > > +}; > > + > > static int i2c_acpi_do_lookup(struct acpi_device *adev, > > struct i2c_acpi_lookup *lookup) > > { > > @@ -100,6 +115,10 @@ static int i2c_acpi_do_lookup(struct acpi_device *adev, > > return -ENODEV; > > > > memset(info, 0, sizeof(*info)); > > + > > + if (acpi_match_device_ids(adev, i2c_acpi_alert_device_ids) == 0) > > + info->flags |= I2C_CLIENT_ALERT; > > + > > lookup->device_handle = acpi_device_handle(adev); > > > > /* Look up for I2cSerialBus resource */ > > diff --git a/include/linux/i2c.h b/include/linux/i2c.h > > index 7592dce12923..b0d6f1333442 100644 > > --- a/include/linux/i2c.h > > +++ b/include/linux/i2c.h > > @@ -743,6 +743,7 @@ 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_ALERT 0x100 /* Client use SMBUS alert > > protocol */ > > #define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB > > protocol */ > > /* Must match I2C_M_STOP|IGNORE_NAK > > */ > > > >
