Messages in this thread | | | Date | Sat, 10 Jan 2015 00:05:07 +0300 | From | Sergei Shtylyov <> | Subject | Re: [RFC 02/11] i2c: add quirk checks to core |
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Hello.
On 01/09/2015 11:45 PM, Wolfram Sang wrote:
>>> Let the core do the checks if HW quirks prevent a transfer. Saves code >> >from drivers and adds consistency.
>>> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> >>> --- >>> drivers/i2c/i2c-core.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++ >>> 1 file changed, 53 insertions(+) >>> >>> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c >>> index 39d25a8cb1ad..7b10a19abf5b 100644 >>> --- a/drivers/i2c/i2c-core.c >>> +++ b/drivers/i2c/i2c-core.c >>> @@ -2063,6 +2063,56 @@ module_exit(i2c_exit); >>> * ---------------------------------------------------- >>> */ >>> >>> +/* Check if val is exceeding the quirk IFF quirk is non 0 */ >>> +#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk))) >>> + >>> +static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg) >>> +{ >>> + dev_err(&adap->dev, "quirk: %s (addr 0x%04x, size %u)\n", err_msg, msg->addr, msg->len); >>> + return -EOPNOTSUPP; >>> +}
>> Always returning the same value doesn't make much sense. Are you trying >> to save space on the call sites?
> Please elaborate. I think it does. If a quirk matches, we report that we > don't support this transfer.
OK, but what's the point of having this function return *int* if it always returns the same value? AFAIU, you're trying to save the code space on the call sites of this function by not having *return* -EOPNOTSUPP there each time?
>> [...] >>> @@ -2080,6 +2130,9 @@ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) >>> unsigned long orig_jiffies; >>> int ret, try; >>> >>> + if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
>> So, you only check for non-zero result of this function? Perhaps it makes >> sense to return true/false instead?
> Could be done, but what would be the advantage? A lot of functions > return errno or 0.
It would have been OK if you were actually caring about the result, e.g. returning it from __i2c_transfer(). Since you don't, IMO it would make more sense to return true from i2c_check_for_quirks() (making it *bool*) iff it did find/apply a quirk.
WBR, Sergei
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