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adafruit / Adafruit_CircuitPython_BusDevice

Two helper classes that handle transaction related state for I2C and SPI including locks.
MIT License
105 stars 76 forks source link

added spi write and read to SPIDevice #7

Closed robomike closed 7 years ago

robomike commented 7 years ago

SPI device was missing read and write functionality. So I added it based on the I2CDevice , it works now.

tannewt commented 7 years ago

Hi Mike, I'm really happy to see this pull. I'm glad you are figuring things out on your own.

However, we removed read_into and write intentionally because they don't add any value. Its the documentation that you pointed to that is wrong and it would be awesome if you corrected that instead. Inside the with statement it should be spi.read_into() instead of spi_device.read_into. This works because with calls __enter__ which returns self.spi and its saved by the with as spi.

robomike commented 7 years ago

Scott, working on the code example, SPI has no attribute read_into. Also, I2C devices has those functions, wouldn't be better for users if they worked the same way?

tannewt commented 7 years ago

On SPI its readinto which matches Python's formatting. We should switch I2CDevice to it too.

I2CDevice needs to wrap write and readinto because it stores the device address. Having SPIDevice return the spi object instead of itself means the structure is the same while saving a bit of memory by not having dumb wrapper functions.

tannewt commented 7 years ago

This isn't needed because SPIDevice relies on SPI's methods directly. It does this by returning self.spi from __enter__ unlike I2CDevice which returns self. Thank you anyway for the pull request!