drivers/ioexpander/iso1i813t.c: fix error startup condition - #19571
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The reference manual (section 3.2.1) states the user has to read GLERR and INTERR registers to clear their bits and release ERR pin after the startup sequence. Error bits are set to 1 after the startup if external power supply is used. Not clearing the bits leads to subsequent read call errors if VBB errors are checked. Signed-off-by: Michal Lenc <michallenc@seznam.cz>
xiaoxiang781216
approved these changes
Jul 28, 2026
linguini1
approved these changes
Jul 28, 2026
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Summary
The reference manual (section 3.2.1) states the user has to read
GLERRandINTERRregisters to clear their bits and release ERR pin after the startup sequence. Error bits are set to 1 after the startup if external power supply is used.Not clearing the bits leads to subsequent read call errors if VBB errors are checked.
Impact
Reading the data after startup doesn't return error for first two calls (one clears
GLERR, otherINTERR) anymore.Testing
With a simple application that reads from the expander. First two reads after the boot failed before the change, the issue is not present anymore.