From: Gregor Herburger gregor.herburger@tq-group.com
[ Upstream commit f8160d3b35fc94491bb0cb974dbda310ef96c0e2 ]
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@tq-group.com Signed-off-by: Matthias Schiffer matthias.schiffer@ew.tq-group.com Acked-by: Peter Korsgaard peter@korsgaard.com Reviewed-by: Andrew Lunn andrew@lunn.ch Reviewed-by: Federico Vaga federico.vaga@cern.ch Signed-off-by: Wolfram Sang wsa@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/i2c/busses/i2c-ocores.c | 35 ++++++++++++++++++--------------- 1 file changed, 19 insertions(+), 16 deletions(-)
diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c index a0af027db04c1..2e575856c5cd5 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; + irqreturn_t ret; + int err = 0;
+ while (1) { err = ocores_poll_wait(i2c); - if (err) { - i2c->state = STATE_ERROR; + if (err) break; /* timeout */ - }
ret = ocores_isr(-1, i2c); if (ret == IRQ_NONE) @@ -364,13 +364,15 @@ static void ocores_process_polling(struct ocores_i2c *i2c) break; } } + + return err; }
static int ocores_xfer_core(struct ocores_i2c *i2c, struct i2c_msg *msgs, int num, bool polling) { - int ret; + int ret = 0; u8 ctrl;
ctrl = oc_getreg(i2c, OCI2C_CONTROL); @@ -388,15 +390,16 @@ static int ocores_xfer_core(struct ocores_i2c *i2c, oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
if (polling) { - ocores_process_polling(i2c); + 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; - } + if (wait_event_timeout(i2c->wait, + (i2c->state == STATE_ERROR) || + (i2c->state == STATE_DONE), HZ) == 0) + ret = -ETIMEDOUT; + } + if (ret) { + ocores_process_timeout(i2c); + return ret; }
return (i2c->state == STATE_DONE) ? num : -EIO;