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i2c: ocores: generate stop condition after timeout in polling mode 

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: 69c8c0c0ef ("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>
This commit is contained in:
Gregor Herburger 2023-04-13 11:37:37 +02:00 committed by Wolfram Sang
parent aa874cdfec
commit f8160d3b35
1 changed files with 19 additions and 16 deletions
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35
drivers/i2c/busses/i2c-ocores.c
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@ -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;