* [PATCH] i2c: rk3x: fix 0 length write transfers
@ 2014-10-01 17:40 Alexandru M Stan
2014-10-01 22:47 ` Doug Anderson
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Alexandru M Stan @ 2014-10-01 17:40 UTC (permalink / raw)
To: linux-arm-kernel
i2cdetect -q was broken (everything was a false positive, and no transfers were
actually being sent over i2c). The way it works is by sending a 0 length write
request and checking for NACK. This patch fixes the 0 length writes and actually
sends them.
Reported-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Alexandru M Stan <amstan@chromium.org>
---
drivers/i2c/busses/i2c-rk3x.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
index b41d979..f486d0e 100644
--- a/drivers/i2c/busses/i2c-rk3x.c
+++ b/drivers/i2c/busses/i2c-rk3x.c
@@ -238,7 +238,7 @@ static void rk3x_i2c_fill_transmit_buf(struct rk3x_i2c *i2c)
for (i = 0; i < 8; ++i) {
val = 0;
for (j = 0; j < 4; ++j) {
- if (i2c->processed == i2c->msg->len)
+ if ((i2c->processed == i2c->msg->len) && (cnt != 0))
break;
if (i2c->processed == 0 && cnt == 0)
--
2.1.0.rc2.206.gedb03e5
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH] i2c: rk3x: fix 0 length write transfers
2014-10-01 17:40 [PATCH] i2c: rk3x: fix 0 length write transfers Alexandru M Stan
@ 2014-10-01 22:47 ` Doug Anderson
2014-10-02 13:30 ` Max Schwarz
2014-10-03 0:27 ` Wolfram Sang
2 siblings, 0 replies; 5+ messages in thread
From: Doug Anderson @ 2014-10-01 22:47 UTC (permalink / raw)
To: linux-arm-kernel
Alex,
On Wed, Oct 1, 2014 at 10:40 AM, Alexandru M Stan <amstan@chromium.org> wrote:
> i2cdetect -q was broken (everything was a false positive, and no transfers were
> actually being sent over i2c). The way it works is by sending a 0 length write
> request and checking for NACK. This patch fixes the 0 length writes and actually
> sends them.
>
> Reported-by: Doug Anderson <dianders@chromium.org>
> Signed-off-by: Alexandru M Stan <amstan@chromium.org>
> ---
> drivers/i2c/busses/i2c-rk3x.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
> index b41d979..f486d0e 100644
> --- a/drivers/i2c/busses/i2c-rk3x.c
> +++ b/drivers/i2c/busses/i2c-rk3x.c
> @@ -238,7 +238,7 @@ static void rk3x_i2c_fill_transmit_buf(struct rk3x_i2c *i2c)
> for (i = 0; i < 8; ++i) {
> val = 0;
> for (j = 0; j < 4; ++j) {
> - if (i2c->processed == i2c->msg->len)
> + if ((i2c->processed == i2c->msg->len) && (cnt != 0))
This looks good to me. Basically we still need to write the address
of the device onto the bus even if there's no data.
Reviewed-by: Doug Anderson <dianders@chromium.org>
Tested-by: Doug Anderson <dianders@chromium.org>
-Doug
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH] i2c: rk3x: fix 0 length write transfers
2014-10-01 17:40 [PATCH] i2c: rk3x: fix 0 length write transfers Alexandru M Stan
2014-10-01 22:47 ` Doug Anderson
@ 2014-10-02 13:30 ` Max Schwarz
2014-10-03 0:27 ` Wolfram Sang
2014-10-03 0:27 ` Wolfram Sang
2 siblings, 1 reply; 5+ messages in thread
From: Max Schwarz @ 2014-10-02 13:30 UTC (permalink / raw)
To: linux-arm-kernel
Hi Alexandru,
On Wednesday 01 October 2014 at 10:40:41, Alexandru M Stan wrote:
> i2cdetect -q was broken (everything was a false positive, and no transfers
> were actually being sent over i2c). The way it works is by sending a 0
> length write request and checking for NACK. This patch fixes the 0 length
> writes and actually sends them.
>
> Reported-by: Doug Anderson <dianders@chromium.org>
> Signed-off-by: Alexandru M Stan <amstan@chromium.org>
> ---
> drivers/i2c/busses/i2c-rk3x.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
> index b41d979..f486d0e 100644
> --- a/drivers/i2c/busses/i2c-rk3x.c
> +++ b/drivers/i2c/busses/i2c-rk3x.c
> @@ -238,7 +238,7 @@ static void rk3x_i2c_fill_transmit_buf(struct rk3x_i2c
> *i2c) for (i = 0; i < 8; ++i) {
> val = 0;
> for (j = 0; j < 4; ++j) {
> - if (i2c->processed == i2c->msg->len)
> + if ((i2c->processed == i2c->msg->len) && (cnt != 0))
> break;
>
> if (i2c->processed == 0 && cnt == 0)
Yes, looks correct and makes i2cdetect work for me on Radxa Rock.
Reviewed-By: Max Schwarz <max.schwarz@online.de>
Tested-By: Max Schwarz <max.schwarz@online.de>
Cheers,
Max
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH] i2c: rk3x: fix 0 length write transfers
2014-10-01 17:40 [PATCH] i2c: rk3x: fix 0 length write transfers Alexandru M Stan
2014-10-01 22:47 ` Doug Anderson
2014-10-02 13:30 ` Max Schwarz
@ 2014-10-03 0:27 ` Wolfram Sang
2 siblings, 0 replies; 5+ messages in thread
From: Wolfram Sang @ 2014-10-03 0:27 UTC (permalink / raw)
To: linux-arm-kernel
On Wed, Oct 01, 2014 at 10:40:41AM -0700, Alexandru M Stan wrote:
> i2cdetect -q was broken (everything was a false positive, and no transfers were
> actually being sent over i2c). The way it works is by sending a 0 length write
> request and checking for NACK. This patch fixes the 0 length writes and actually
> sends them.
>
> Reported-by: Doug Anderson <dianders@chromium.org>
> Signed-off-by: Alexandru M Stan <amstan@chromium.org>
Applied to for-current, thanks!
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2014-10-01 17:40 [PATCH] i2c: rk3x: fix 0 length write transfers Alexandru M Stan
2014-10-01 22:47 ` Doug Anderson
2014-10-02 13:30 ` Max Schwarz
2014-10-03 0:27 ` Wolfram Sang
2014-10-03 0:27 ` Wolfram Sang
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