mirror of
git://git.openwrt.org/openwrt/openwrt.git
synced 2025-10-31 05:54:26 -04:00
68d9cb8214
Run tested: ath79, ipq40xx Build tested: ath79, ipq40xx Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
68 lines
2.2 KiB
Diff
68 lines
2.2 KiB
Diff
From: Russell King <rmk+kernel@armlinux.org.uk>
|
|
Bcc: linux@mail.armlinux.org.uk
|
|
Subject: [PATCH 2/7] i2c: pxa: avoid complaints with non-responsive slaves
|
|
MIME-Version: 1.0
|
|
Content-Disposition: inline
|
|
Content-Transfer-Encoding: 8bit
|
|
Content-Type: text/plain; charset="utf-8"
|
|
|
|
Running i2cdetect on a PXA I2C adapter is very noisy; it complains
|
|
whenever a slave fails to respond to the address cycle. Since it is
|
|
normal to probe for slaves in this way, we should not fill the kernel
|
|
log. This is especially true with SFP modules that take a while to
|
|
respond on the I2C bus, and probing via the I2C bus is the only way to
|
|
detect that they are ready.
|
|
|
|
Fix this by changing the internal transfer return code from I2C_RETRY
|
|
to a new NO_SLAVE code (mapped to -ENXIO, as per the I2C documentation
|
|
for this condition, but we still return -EREMOTEIO to the I2C stack to
|
|
maintain long established driver behaviour.)
|
|
|
|
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
|
|
---
|
|
drivers/i2c/busses/i2c-pxa.c | 12 ++++++++----
|
|
1 file changed, 8 insertions(+), 4 deletions(-)
|
|
|
|
--- a/drivers/i2c/busses/i2c-pxa.c
|
|
+++ b/drivers/i2c/busses/i2c-pxa.c
|
|
@@ -91,6 +91,7 @@
|
|
*/
|
|
#define DEF_TIMEOUT 32
|
|
|
|
+#define NO_SLAVE (-ENXIO)
|
|
#define BUS_ERROR (-EREMOTEIO)
|
|
#define XFER_NAKED (-ECONNREFUSED)
|
|
#define I2C_RETRY (-2000) /* an error has occurred retry transmit */
|
|
@@ -838,7 +839,7 @@ static void i2c_pxa_irq_txempty(struct p
|
|
*/
|
|
if (isr & ISR_ACKNAK) {
|
|
if (i2c->msg_ptr == 0 && i2c->msg_idx == 0)
|
|
- ret = I2C_RETRY;
|
|
+ ret = NO_SLAVE;
|
|
else
|
|
ret = XFER_NAKED;
|
|
}
|
|
@@ -1066,16 +1067,19 @@ static int i2c_pxa_internal_xfer(struct
|
|
{
|
|
int ret, i;
|
|
|
|
- for (i = i2c->adap.retries; i >= 0; i--) {
|
|
+ for (i = 0; ; ) {
|
|
ret = xfer(i2c, msgs, num);
|
|
- if (ret != I2C_RETRY)
|
|
+ if (ret != I2C_RETRY && ret != NO_SLAVE)
|
|
goto out;
|
|
+ if (++i >= i2c->adap.retries)
|
|
+ break;
|
|
|
|
if (i2c_debug)
|
|
dev_dbg(&i2c->adap.dev, "Retrying transmission\n");
|
|
udelay(100);
|
|
}
|
|
- i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
|
|
+ if (ret != NO_SLAVE)
|
|
+ i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
|
|
ret = -EREMOTEIO;
|
|
out:
|
|
i2c_pxa_set_slave(i2c, ret);
|