Hi Wolfram,
On 2017-11-10 12:52:10 +0100, Wolfram Sang wrote:
> We initiate STOP (or REP_START) on the second last WAIT interrupt
> currently. This works fine but is not according to the datasheet which
> says to do it on the last WAIT interrupt. This also simplifies the code
> quite a lot, so let's do it.
I like this change and I checked the flow diagrams in chapter '56.4
Operation' of the Gen2 datasheet rev 2.0 and chapter '58.3 Operation' of
the Gen3 datasheet rev 0.80, and it makes sens for both.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
For Gen2 and Gen3:
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
> ---
>
> Jacopo: another one to test, pretty please.
>
> drivers/i2c/busses/i2c-sh_mobile.c | 29 ++++++-----------------------
> 1 file changed, 6 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
> index 40a66d466c3c49..c904be631db302 100644
> --- a/drivers/i2c/busses/i2c-sh_mobile.c
> +++ b/drivers/i2c/busses/i2c-sh_mobile.c
> @@ -40,21 +40,21 @@
> /* BUS: S A8 ACK P(*) */
> /* IRQ: DTE WAIT */
> /* ICIC: */
> -/* ICCR: 0x94 0x90 */
> +/* ICCR: 0x94 0x90 */
> /* ICDR: A8 */
> /* */
> /* 1 byte transmit */
> /* BUS: S A8 ACK D8(1) ACK P(*) */
> /* IRQ: DTE WAIT WAIT */
> /* ICIC: -DTE */
> -/* ICCR: 0x94 0x90 */
> +/* ICCR: 0x94 0x90 */
> /* ICDR: A8 D8(1) */
> /* */
> /* 2 byte transmit */
> /* BUS: S A8 ACK D8(1) ACK D8(2) ACK P(*) */
> /* IRQ: DTE WAIT WAIT WAIT */
> /* ICIC: -DTE */
> -/* ICCR: 0x94 0x90 */
> +/* ICCR: 0x94 0x90 */
> /* ICDR: A8 D8(1) D8(2) */
> /* */
> /* 3 bytes or more, +---------+ gets repeated */
> @@ -113,7 +113,6 @@ enum sh_mobile_i2c_op {
> OP_TX_FIRST,
> OP_TX,
> OP_TX_STOP,
> - OP_TX_STOP_DATA,
> OP_TX_TO_RX,
> OP_RX,
> OP_RX_STOP,
> @@ -319,10 +318,7 @@ static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
> case OP_TX: /* write data */
> iic_wr(pd, ICDR, data);
> break;
> - case OP_TX_STOP_DATA: /* write data and issue a stop afterwards */
> - iic_wr(pd, ICDR, data);
> - /* fallthrough */
> - case OP_TX_STOP: /* issue a stop */
> + case OP_TX_STOP: /* issue a stop (or rep_start) */
> iic_wr(pd, ICCR, pd->send_stop ? ICCR_ICE | ICCR_TRS
> : ICCR_ICE | ICCR_TRS | ICCR_BBSY);
> break;
> @@ -356,11 +352,6 @@ static bool sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd)
> return pd->pos == -1;
> }
>
> -static bool sh_mobile_i2c_is_last_byte(struct sh_mobile_i2c_data *pd)
> -{
> - return pd->pos == pd->msg->len - 1;
> -}
> -
> static void sh_mobile_i2c_get_data(struct sh_mobile_i2c_data *pd,
> unsigned char *buf)
> {
> @@ -378,20 +369,12 @@ static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
> unsigned char data;
>
> if (pd->pos == pd->msg->len) {
> - /* Send stop if we haven't yet (DMA case) */
> - if (pd->send_stop && pd->stop_after_dma)
> - i2c_op(pd, OP_TX_STOP, 0);
> + i2c_op(pd, OP_TX_STOP, 0);
> return 1;
> }
>
> sh_mobile_i2c_get_data(pd, &data);
> -
> - if (sh_mobile_i2c_is_last_byte(pd))
> - i2c_op(pd, OP_TX_STOP_DATA, data);
> - else if (sh_mobile_i2c_is_first_byte(pd))
> - i2c_op(pd, OP_TX_FIRST, data);
> - else
> - i2c_op(pd, OP_TX, data);
> + i2c_op(pd, sh_mobile_i2c_is_first_byte(pd) ? OP_TX_FIRST : OP_TX, data);
>
> pd->pos++;
> return 0;
> --
> 2.11.0
>
--
Regards,
Niklas Söderlund
