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 <peda@xxxxxxxxxx>
> Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
> ---
> 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
>
