Messages in this thread Patch in this message | | | Subject | Re: [PATCH] I2C update for 2.6.7-rc1 | Date | Fri, 28 May 2004 15:00:43 -0700 | From | Greg KH <> |
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ChangeSet 1.1717.6.28, 2004/05/19 00:26:34-07:00, ebs@ebshome.net
[PATCH] I2C PPC4xx IIC driver: 0-length transaction temporary fix
this patch adds temporary fix for 0-length requests (e.g. SMBUS_QUICK) to PPC4xx IIC driver. This i2c controller doesn't support such transactions and this patch just restores previous driver version behavior making SMBUS_QUICK-based bus scan at least partially usable. This is temporary kludge until correct bit-banging emulation is implemented.
drivers/i2c/busses/i2c-ibm_iic.c | 10 ++++++++++ 1 files changed, 10 insertions(+)
diff -Nru a/drivers/i2c/busses/i2c-ibm_iic.c b/drivers/i2c/busses/i2c-ibm_iic.c --- a/drivers/i2c/busses/i2c-ibm_iic.c Fri May 28 14:52:12 2004 +++ b/drivers/i2c/busses/i2c-ibm_iic.c Fri May 28 14:52:12 2004 @@ -455,6 +455,16 @@ } for (i = 0; i < num; ++i){ if (unlikely(msgs[i].len <= 0)){ + if (num == 1 && !msgs[0].len){ + /* Special case for I2C_SMBUS_QUICK emulation. + * Although this logic is FAR FROM PERFECT, this + * is what previous driver version did. + * IBM IIC doesn't support 0-length transactions + * (except bit-banging through IICx_DIRECTCNTL). + */ + DBG("%d: zero-length msg kludge\n", dev->idx); + return 0; + } DBG("%d: invalid len %d in msg[%d]\n", dev->idx, msgs[i].len, i); return -EINVAL; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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