On Mon, 2023-02-20 at 16:17 +0000, Matthias Schiffer wrote:
> From: Gregor Herburger <gregor.herburger@xxxxxxxxxxxx>
>
> In polling mode, no stop condition is generated after a timeout. This
> causes SCL to remain low and thereby block the bus. If this happens
> during a transfer it can cause slaves to misinterpret the subsequent
> transfer and return wrong values.
>
> To solve this, pass the ETIMEDOUT error up from ocores_process_polling()
> instead of setting STATE_ERROR directly. The caller is adjusted to call
> ocores_process_timeout() on error both in polling and in IRQ mode, which
> will set STATE_ERROR and generate a stop condition.
>
> Fixes: 69c8c0c0efa8 ("i2c: ocores: add polling interface")
> Signed-off-by: Gregor Herburger <gregor.herburger@xxxxxxxxxxxx>
> Signed-off-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx>
Any chance we can get someone to have a look at this patch?
Regards,
Matthias
> ---
> drivers/i2c/busses/i2c-ocores.c | 28 +++++++++++++++-------------
> 1 file changed, 15 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c
> index a0af027db04c1..28bcda3f7040a 100644
> --- a/drivers/i2c/busses/i2c-ocores.c
> +++ b/drivers/i2c/busses/i2c-ocores.c
> @@ -342,18 +342,18 @@ static int ocores_poll_wait(struct ocores_i2c *i2c)
> * ocores_isr(), we just add our polling code around it.
> *
> * It can run in atomic context
> + *
> + * Return: 0 on success, -ETIMEDOUT on timeout
> */
> -static void ocores_process_polling(struct ocores_i2c *i2c)
> +static int ocores_process_polling(struct ocores_i2c *i2c)
> {
> while (1) {
> irqreturn_t ret;
> int err;
>
> err = ocores_poll_wait(i2c);
> - if (err) {
> - i2c->state = STATE_ERROR;
> - break; /* timeout */
> - }
> + if (err)
> + return err;
>
> ret = ocores_isr(-1, i2c);
> if (ret == IRQ_NONE)
> @@ -364,6 +364,8 @@ static void ocores_process_polling(struct ocores_i2c *i2c)
> break;
> }
> }
> +
> + return 0;
> }
>
> static int ocores_xfer_core(struct ocores_i2c *i2c,
> @@ -387,16 +389,16 @@ static int ocores_xfer_core(struct ocores_i2c *i2c,
> oc_setreg(i2c, OCI2C_DATA, i2c_8bit_addr_from_msg(i2c->msg));
> oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
>
> - if (polling) {
> - ocores_process_polling(i2c);
> - } else {
> + if (polling)
> + ret = ocores_process_polling(i2c);
> + else
> ret = wait_event_timeout(i2c->wait,
> (i2c->state == STATE_ERROR) ||
> - (i2c->state == STATE_DONE), HZ);
> - if (ret == 0) {
> - ocores_process_timeout(i2c);
> - return -ETIMEDOUT;
> - }
> + (i2c->state == STATE_DONE), HZ) ?
> + 0 : -ETIMEDOUT;
> + if (ret) {
> + ocores_process_timeout(i2c);
> + return ret;
> }
>
> return (i2c->state == STATE_DONE) ? num : -EIO;
--
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