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