Messages in this thread | | | From | Andy Shevchenko <> | Date | Tue, 7 Jul 2020 18:07:26 +0300 | Subject | Re: [PATCH v5 1/2] gpio: add GPO driver for PCA9570 |
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On Tue, Jul 7, 2020 at 5:03 PM Sungbo Eo <mans0n@gorani.run> wrote: > On 20. 7. 6. 오후 9:00, Andy Shevchenko wrote:
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> But I don't really understand what mutex does here. The driver does not > need consecutive commands, it only sends/receives only one byte at a > time. And AFAIK each i2c_smbus function is already protected by a mutex. > So what should be exactly inside the lock? Should we protect the output > buffer as well? I'm not an expert on this so please enlighten me.
There are questions, answering them will give you a solution: - Since we have two functions doing i2c communications, can they clash? If so, does the i2c framework guarantee the serialisation? - Since we have a shared resource (buf), can accessors clash? How do we guarantee serialization?
-- With Best Regards, Andy Shevchenko
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