[RFC] drivers/gpio/gpio-pca953x.c broken for PCA9505 ?

[Oza Oza <oza.oza@xxxxxxxxxxxx>]

Hi,

Our SOC has PCA9505 IO expander,
Basically I was implementing PCI hotplug, e.g. PCI present lines got
to IO expander.

I had to fix the driver at some places.
but I am not sure, if driver was written considering 9505 chip ?
in fact it declares 9505 as PCA953X_TYPE.

some of the fixes which I have made are

1) #define PCAL953X_INT_MASK       36  (it was 37 before)
pca953x_write_regs_24  has very odd way of calculating register offset.

int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);
i2c write to
reg << bank_shift

which was coming 37 << 3 as 0x128 and which is u8 data type.
will address 0x28 which is invalid locaiton.

36 << 3 as 0x120, which will address 0x20 correctly.
although again thsi is odd way of deriving offset.
I am following datasheet:
http://www.nxp.com/docs/en/data-sheet/PCA9505_9506.pdf

2) #define PCAL953X_IN_LATCH       34
above LATCH is not present.

3) #define PCAL953X_INT_STAT       38
above also points to indirect locaiton.

please suggest if this diver was written with 9505 in mind ?

Regards,
Oza.
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