* [PATCH] i2c-powermac: Reject unsupported I2C transactions
@ 2009-09-30 20:14 Jean Delvare
2009-10-14 5:39 ` Benjamin Herrenschmidt
0 siblings, 1 reply; 2+ messages in thread
From: Jean Delvare @ 2009-09-30 20:14 UTC (permalink / raw)
To: Linux I2C, linuxppc-dev; +Cc: Paul Mackerras
The i2c-powermac driver doesn't support arbitrary multi-message I2C
transactions, only SMBus ones. Make it clear by returning an error if
a multi-message I2C transaction is attempted. This is better than only
processing the first message, because most callers won't recover from
the short transaction. Anyone wishing to issue multi-message
transactions should use the SMBus API instead of the raw I2C API.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
---
drivers/i2c/busses/i2c-powermac.c | 6 ++++++
1 file changed, 6 insertions(+)
--- linux-2.6.32-rc1.orig/drivers/i2c/busses/i2c-powermac.c 2009-06-10 05:05:27.000000000 +0200
+++ linux-2.6.32-rc1/drivers/i2c/busses/i2c-powermac.c 2009-09-30 20:29:42.000000000 +0200
@@ -146,6 +146,12 @@ static int i2c_powermac_master_xfer( str
int read;
int addrdir;
+ if (num != 1) {
+ dev_err(&adap->dev,
+ "Multi-message I2C transactions not supported\n");
+ return -EOPNOTSUPP;
+ }
+
if (msgs->flags & I2C_M_TEN)
return -EINVAL;
read = (msgs->flags & I2C_M_RD) != 0;
--
Jean Delvare
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] i2c-powermac: Reject unsupported I2C transactions
2009-09-30 20:14 [PATCH] i2c-powermac: Reject unsupported I2C transactions Jean Delvare
@ 2009-10-14 5:39 ` Benjamin Herrenschmidt
0 siblings, 0 replies; 2+ messages in thread
From: Benjamin Herrenschmidt @ 2009-10-14 5:39 UTC (permalink / raw)
To: Jean Delvare; +Cc: linuxppc-dev, Paul Mackerras, Linux I2C
On Wed, 2009-09-30 at 22:14 +0200, Jean Delvare wrote:
> The i2c-powermac driver doesn't support arbitrary multi-message I2C
> transactions, only SMBus ones. Make it clear by returning an error if
> a multi-message I2C transaction is attempted. This is better than only
> processing the first message, because most callers won't recover from
> the short transaction. Anyone wishing to issue multi-message
> transactions should use the SMBus API instead of the raw I2C API.
>
> Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> ---
> drivers/i2c/busses/i2c-powermac.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> --- linux-2.6.32-rc1.orig/drivers/i2c/busses/i2c-powermac.c 2009-06-10 05:05:27.000000000 +0200
> +++ linux-2.6.32-rc1/drivers/i2c/busses/i2c-powermac.c 2009-09-30 20:29:42.000000000 +0200
> @@ -146,6 +146,12 @@ static int i2c_powermac_master_xfer( str
> int read;
> int addrdir;
>
> + if (num != 1) {
> + dev_err(&adap->dev,
> + "Multi-message I2C transactions not supported\n");
> + return -EOPNOTSUPP;
> + }
> +
> if (msgs->flags & I2C_M_TEN)
> return -EINVAL;
> read = (msgs->flags & I2C_M_RD) != 0;
>
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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