On 02/09/15 15:04, Ondrej Zary wrote:
> On Wednesday 02 September 2015, Tomi Valkeinen wrote:
>> On 24/08/15 22:37, Ondrej Zary wrote:
>>> i2c-algo-bit allows I2C adapters without SCL read capability to work but
>>> fb_ddc_read fails to work on them.
>>>
>>> Fix fb_ddc_read to work with I2C adapters not capable of reading SCL.
>>>
>>> Signed-off-by: Ondrej Zary <linux@xxxxxxxxxxxxxxxxxxxx>
>>> Acked-by: Krzysztof Helt <krzysztof.h1@xxxxx>
>>> ---
>>> drivers/video/fbdev/core/fb_ddc.c | 8 +++++---
>>> 1 file changed, 5 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/video/fbdev/core/fb_ddc.c
>>> b/drivers/video/fbdev/core/fb_ddc.c index 94322cc..22c694a 100644
>>> --- a/drivers/video/fbdev/core/fb_ddc.c
>>> +++ b/drivers/video/fbdev/core/fb_ddc.c
>>> @@ -69,10 +69,11 @@ unsigned char *fb_ddc_read(struct i2c_adapter
>>> *adapter) algo_data->setscl(algo_data->data, 1);
>>> for (j = 0; j < 5; j++) {
>>> msleep(10);
>>> - if (algo_data->getscl(algo_data->data))
>>> + if (algo_data->getscl &&
>>> + algo_data->getscl(algo_data->data))
>>> break;
>>> }
>>> - if (j == 5)
>>> + if (algo_data->getscl && j == 5)
>>> continue;
>>>
>>> algo_data->setsda(algo_data->data, 0);
>>> @@ -91,7 +92,8 @@ unsigned char *fb_ddc_read(struct i2c_adapter *adapter)
>>> algo_data->setscl(algo_data->data, 1);
>>> for (j = 0; j < 10; j++) {
>>> msleep(10);
>>> - if (algo_data->getscl(algo_data->data))
>>> + if (algo_data->getscl &&
>>> + algo_data->getscl(algo_data->data))
>>> break;
>>> }
>>
>> Aren't both of those loops pointless if there's no getscl?
>
> They're reduced to delays - don't know how much critical they are.
I think the code gets somewhat confusing the way you did it.
Maybe instead something like:
if (algo_data->getscl) {
the current loop & delays here;
} else {
msleep(25); // 25 was just a guess...
}
Tomi
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