Hi Wolfram,
Thanks for your patch.
On 2018-07-23 22:26:05 +0200, Wolfram Sang wrote:
> Some adapters do not support a message length of 0. Add this as a quirk
> so drivers don't have to open code it.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
> ---
>
> Only build tested.
Was this not tested when you also tested i2c-rcar and i2c-sh_mobile
drivers? In any case I think this change make much sens.
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
>
> drivers/i2c/i2c-core-base.c | 6 ++++++
> include/linux/i2c.h | 4 ++++
> 2 files changed, 10 insertions(+)
>
> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index 02d6f27b19e4..a26b3e9cc441 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -1839,9 +1839,15 @@ static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs,
> if (msgs[i].flags & I2C_M_RD) {
> if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
> return i2c_quirk_error(adap, &msgs[i], "msg too long");
> +
> + if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
> + return i2c_quirk_error(adap, &msgs[i], "no zero length");
> } else {
> if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
> return i2c_quirk_error(adap, &msgs[i], "msg too long");
> +
> + if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
> + return i2c_quirk_error(adap, &msgs[i], "no zero length");
> }
> }
>
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index bc8d42f8544f..2a98d0886d2e 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -661,6 +661,10 @@ struct i2c_adapter_quirks {
> I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR)
> /* clock stretching is not supported */
> #define I2C_AQ_NO_CLK_STRETCH BIT(4)
> +/* message cannot have length of 0 */
> +#define I2C_AQ_NO_ZERO_LEN_READ BIT(5)
> +#define I2C_AQ_NO_ZERO_LEN_WRITE BIT(6)
> +#define I2C_AQ_NO_ZERO_LEN (I2C_AQ_NO_ZERO_LEN_READ | I2C_AQ_NO_ZERO_LEN_WRITE)
>
> /*
> * i2c_adapter is the structure used to identify a physical i2c bus along
> --
> 2.11.0
>
--
Regards,
Niklas Söderlund
