On 2018-07-10 23:42, Wolfram Sang wrote: > For bus recovery, we either need to bail out early if we can read SDA or > we need to send STOP after every pulse. Otherwise recovery might be > misinterpreted as an unwanted write. So, require one of those SDA > handling functions to avoid this problem.
Assuming that all users fulfill the stricter requirement... Acked-by: Peter Rosin <[email protected]> > Signed-off-by: Wolfram Sang <[email protected]> > --- > drivers/i2c/i2c-core-base.c | 7 ++++++- > include/linux/i2c.h | 12 ++++++------ > 2 files changed, 12 insertions(+), 7 deletions(-) > > diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c > index 301285c54603..871a9731894f 100644 > --- a/drivers/i2c/i2c-core-base.c > +++ b/drivers/i2c/i2c-core-base.c > @@ -202,7 +202,8 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) > /* > * If we can set SDA, we will always create STOP here to ensure > * the additional pulses will do no harm. This is achieved by > - * letting SDA follow SCL half a cycle later. > + * letting SDA follow SCL half a cycle later. Check the > + * 'incomplete_write_byte' fault injector for details. > */ > ndelay(RECOVERY_NDELAY / 2); > if (bri->set_sda) > @@ -274,6 +275,10 @@ static void i2c_init_recovery(struct i2c_adapter *adap) > err_str = "no {get|set}_scl() found"; > goto err; > } > + if (!bri->set_sda && !bri->get_sda) { > + err_str = "either get_sda() or set_sda() needed"; > + goto err; > + } > } > > return; > diff --git a/include/linux/i2c.h b/include/linux/i2c.h > index 465afb092fa7..9d1818c56775 100644 > --- a/include/linux/i2c.h > +++ b/include/linux/i2c.h > @@ -581,12 +581,12 @@ struct i2c_timings { > * recovery. Populated internally for generic GPIO recovery. > * @set_scl: This sets/clears the SCL line. Mandatory for generic SCL > recovery. > * Populated internally for generic GPIO recovery. > - * @get_sda: This gets current value of SDA line. Optional for generic SCL > - * recovery. Populated internally, if sda_gpio is a valid GPIO, for > generic > - * GPIO recovery. > - * @set_sda: This sets/clears the SDA line. Optional for generic SCL > recovery. > - * Populated internally, if sda_gpio is a valid GPIO, for generic GPIO > - * recovery. > + * @get_sda: This gets current value of SDA line. This or set_sda() is > mandatory > + * for generic SCL recovery. Populated internally, if sda_gpio is a valid > + * GPIO, for generic GPIO recovery. > + * @set_sda: This sets/clears the SDA line. This or get_sda() is mandatory > for > + * generic SCL recovery. Populated internally, if sda_gpio is a valid GPIO, > + * for generic GPIO recovery. > * @prepare_recovery: This will be called before starting recovery. Platform > may > * configure padmux here for SDA/SCL line or something else they want. > * @unprepare_recovery: This will be called after completing recovery. > Platform >
