[PATCH] i2c: stm32f7_i2c: save some ms in stm32_i2c_choose_solution

[Richard GENOUD]

Le 05/12/2025 à 17:49, Patrice CHOTARD a écrit :
> 
> 
> On 12/5/25 14:36, Richard Genoud wrote:
>> In stm32_i2c_choose_solution, the double loop continues even after a
>> solution is found.
>>
>> Breaking out of this double loop once a solution is found permits to
>> gain some precious ms.
>>
>> This saves about 13ms in U-Boot.
>>
>> Signed-off-by: Richard Genoud <richard.genoud at bootlin.com>
>> ---
>>   drivers/i2c/stm32f7_i2c.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/i2c/stm32f7_i2c.c b/drivers/i2c/stm32f7_i2c.c
>> index 3f51b1dd1db4..cb5e2c0e31e5 100644
>> --- a/drivers/i2c/stm32f7_i2c.c
>> +++ b/drivers/i2c/stm32f7_i2c.c
>> @@ -651,11 +651,13 @@ static int stm32_i2c_choose_solution(u32 i2cclk,
>>   						v->sclh = h;
>>   						sol_found = true;
>>   						memcpy(s, v, sizeof(*s));
>> +						goto end_loop;
>>   					}
>>   				}
>>   			}
>>   		}
>>   	}
>> +end_loop:
>>   
>>   	if (!sol_found) {
>>   		log_err("no solution at all\n");
>>
>> base-commit: c5e6d2ab7eba68cbfb600cdc131c0c375ced2ec9
> 
> 
> Hi Richard
> 
> If i have well understood the algorithm, the original implementation selects the *best* solution
> whereas with your patch, the algorithm selects the *first* solution.
> 
> Patrice

Hum, indeed. The solution with the lesser error is selected.
I'll have to study this algorithm a little bit more to see it we can 
take some shortcut.

Thanks!

Regards,
Richard