Hi Sungbo,
Am 2020-06-23 14:22, schrieb Sungbo Eo:
On 2020-06-23 17:31, Michael Walle wrote:
Am 2020-06-23 08:05, schrieb Sungbo Eo:
This patch adds support for the PCA9570 I2C GPO expander.
Signed-off-by: Sungbo Eo <mans0n@xxxxxxxxxx>
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Tested in kernel 5.4 on an ipq40xx platform.
This is my first time submitting a whole driver patch, and I'm not
really familiar with this PCA expander series.
Please let me know how I can improve this patch further. (Do I also
need to document the DT compatible string?)
Did you have a look at drivers/gpio/gpio-regmap.c ? Your driver seems
to be simple enough to be easily integrated with that. If you need a
blueprint; because at the moment there is no driver in the kernel
using that, you could have a look at:
https://lore.kernel.org/linux-gpio/20200604211039.12689-7-michael@xxxxxxxx/
Thanks for your advice. I didn't really know what regmap is for...
It seems gpio-regmap is for gpio controllers having val/dir registers.
But pca9570 does not use port registers. The master only sends a data
byte without reg address.
Ahh I missed that :(
I'm not sure how to apply gpio-regmap or
regmap-i2c here.
I'll try to investigate if setting reg_size or reg_bits to zero is
possible.
Please correct me if I'm in the wrong direction.
That won't work because the underlying regmap expects the address bits
to be either 8 or 16. In this case I'd guess gpio-regmap, doesn't make
sense, because there is actually no real gain.
-michael
