On Monday 13 June 2016 12:52 PM, Linus Walleij wrote: > On Thu, Jun 9, 2016 at 7:32 AM, Vignesh R <[email protected]> wrote: > >> NBANK() macro assumes that ngpios is a multiple of 8(BANK_SZ) and >> hence results in 0 banks for PCA9536 which has just 4 gpios. This is >> wrong as PCA9356 has 1 bank with 4 gpios. This results in uninitialized >> PCA953X_INVERT register. Fix this by using DIV_ROUND_UP macro in >> NBANK(). >> >> Cc: [email protected] >> Signed-off-by: Vignesh R <[email protected]> > > Patch applied. > > Is this really a regression or affecting systems in development? > > Which machine/device tree makes this problematic? >
I observed this on am335x-icev2 evm which is system in development. Basically, variable with uninitialized value (junk) gets written to PCA953X_INVERT register(in device_pca953x_init()) causing driver to report wrong gpio pin status. So, this bug will affect any platform with PCA9536 chip. Quick grep on arch/*/boot/dts/ folder shows one platform already using pca9536 chip. Hence, I added Cc to stable kernel. -- Regards Vignesh
