From: michael@amarulasolutions•com (Michael Trimarchi)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 3/8] i2c: omap: fix error checking
Date: Thu, 25 Oct 2012 12:33:18 +0200 [thread overview]
Message-ID: <5089156E.7020701@amarulasolutions.com> (raw)
In-Reply-To: <20121025101010.GC21217@arwen.pp.htv.fi>
Hi
On 10/25/2012 12:10 PM, Felipe Balbi wrote:
> Hi,
>
> On Wed, Oct 24, 2012 at 04:41:11PM +0200, Michael Trimarchi wrote:
>> Hi
>>
>> On 10/22/2012 11:46 AM, Felipe Balbi wrote:
>>> It's impossible to have Arbitration Lost,
>>> Read Overflow, and Tranmist Underflow all
>>> asserted at the same time.
>>>
>>> Those error conditions are mutually exclusive
>>> so what the code should be doing, instead, is
>>> check each error flag separataly.
>>>
>>> Signed-off-by: Felipe Balbi <balbi@ti•com>
>>> ---
>>> drivers/i2c/busses/i2c-omap.c | 6 +++---
>>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
>>> index bea0277..e0eab38 100644
>>> --- a/drivers/i2c/busses/i2c-omap.c
>>> +++ b/drivers/i2c/busses/i2c-omap.c
>>> @@ -587,9 +587,9 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
>>> goto err_i2c_init;
>>> }
>>>
>>> - /* We have an error */
>>> - if (dev->cmd_err & (OMAP_I2C_STAT_AL | OMAP_I2C_STAT_ROVR |
>>> - OMAP_I2C_STAT_XUDF)) {
>>> + if ((dev->cmd_err & OMAP_I2C_STAT_AL)
>>> + || (dev->cmd_err & OMAP_I2C_STAT_ROVR)
>>> + || (dev->cmd_err & OMAP_I2C_STAT_XUDF)) {
>>
>> Sorry, what is the difference? I didn't understand the optimisation
>> and why now is more clear. Can you just add a comment?
>
> semantically they're not the same, right ? We want to check if each of
> those bits are set, not if all of them are set together.
>
> my 2 cents.
You are doing the same thing, but of course is better with just one *if* as before . A general rule is: when you have logic expression you can use undefined states to simplify the logic.
Michael
next prev parent reply other threads:[~2012-10-25 10:33 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-22 9:46 [PATCH 0/8] I2C patches for v3.8 merge window Felipe Balbi
2012-10-22 9:46 ` [PATCH 1/8] i2c: omap: no need to access platform_device Felipe Balbi
2012-10-22 9:46 ` [PATCH 2/8] i2c: omap: reorder exit path of omap_i2c_xfer_msg() Felipe Balbi
2012-10-25 11:40 ` Shubhrajyoti Datta
2012-10-25 12:01 ` Felipe Balbi
2012-10-22 9:46 ` [PATCH 3/8] i2c: omap: fix error checking Felipe Balbi
2012-10-24 14:41 ` Michael Trimarchi
2012-10-25 10:10 ` Felipe Balbi
2012-10-25 10:33 ` Michael Trimarchi [this message]
2012-10-25 10:48 ` Felipe Balbi
2012-10-22 9:46 ` [PATCH 4/8] i2c: omap: also complete() when stat becomes zero Felipe Balbi
2012-10-22 9:46 ` [PATCH 5/8] i2c: omap: introduce and use OMAP_I2C_IP_VERSION_3 Felipe Balbi
2012-10-22 12:27 ` Benoit Cousson
2012-10-22 12:28 ` Felipe Balbi
2012-10-22 13:05 ` Benoit Cousson
2012-10-22 13:09 ` Felipe Balbi
2012-10-22 13:18 ` [PATCH v2 5/8] i2c: omap: in case of VERSION_2 read IRQSTATUS_RAW but write to IRQSTATUS Felipe Balbi
2012-10-22 9:46 ` [PATCH 6/8] i2c: omap: wait for transfer completion before sending STP bit Felipe Balbi
2012-10-22 9:46 ` [PATCH 7/8] i2c: add 'transferred' field to struct i2c_msg Felipe Balbi
2012-10-25 12:57 ` Jean Delvare
2012-10-25 13:14 ` Russell King - ARM Linux
2012-10-25 13:42 ` Jean Delvare
2012-10-25 13:46 ` Russell King - ARM Linux
2012-10-25 13:56 ` Jean Delvare
2012-10-25 14:18 ` Russell King - ARM Linux
2012-10-27 14:32 ` Jean Delvare
2012-10-27 16:40 ` Al Viro
2012-10-27 17:02 ` Al Viro
2012-10-27 17:10 ` Al Viro
2012-10-27 19:03 ` Jean Delvare
2012-10-27 17:25 ` Russell King - ARM Linux
2012-10-22 9:46 ` [PATCH 8/8] i2c: omap: implement handling for 'transferred' bytes Felipe Balbi
2012-10-22 13:30 ` [PATCH 0/8] I2C patches for v3.8 merge window Felipe Balbi
2012-10-22 14:06 ` Shubhrajyoti Datta
2012-10-22 14:06 ` Felipe Balbi
2012-10-22 15:02 ` Shubhrajyoti
2012-11-14 16:58 ` Wolfram Sang
2012-10-25 12:25 ` [PATCH v2 0/7] " Felipe Balbi
2012-10-25 12:25 ` [PATCH v2 1/7] i2c: omap: no need to access platform_device Felipe Balbi
2012-10-25 12:41 ` Santosh Shilimkar
2012-10-25 12:25 ` [PATCH v2 2/7] i2c: omap: reorder exit path of omap_i2c_xfer_msg() Felipe Balbi
2012-10-25 12:42 ` Santosh Shilimkar
2012-10-25 12:40 ` Felipe Balbi
2012-10-25 12:53 ` Lothar Waßmann
2012-10-25 12:25 ` [PATCH v2 3/7] i2c: omap: also complete() when stat becomes zero Felipe Balbi
2012-10-25 12:43 ` Santosh Shilimkar
2012-10-25 12:39 ` Felipe Balbi
2012-10-25 12:25 ` [PATCH v2 4/7] i2c: omap: in case of VERSION_2 read IRQSTATUS_RAW but write to IRQSTATUS Felipe Balbi
2012-10-25 12:53 ` Santosh Shilimkar
2012-10-25 12:52 ` Felipe Balbi
2012-10-25 13:06 ` Santosh Shilimkar
2012-10-25 12:25 ` [PATCH v2 5/7] i2c: omap: wait for transfer completion before sending STP bit Felipe Balbi
2012-10-25 12:32 ` Felipe Balbi
2012-10-25 12:34 ` [PATCH v3 " Felipe Balbi
2012-10-25 13:01 ` [PATCH v2 " Santosh Shilimkar
2012-10-25 14:15 ` Felipe Balbi
2012-10-25 12:25 ` [PATCH v2 6/7] i2c: add 'transferred' field to struct i2c_msg Felipe Balbi
2012-10-25 12:25 ` [PATCH v2 7/7] i2c: omap: implement handling for 'transferred' bytes Felipe Balbi
2012-10-27 18:55 ` Paul Walmsley
2012-11-05 8:10 ` [PATCH v2 0/7] I2C patches for v3.8 merge window Felipe Balbi
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