On Sat, Nov 11, 2023 at 11:33 PM Alexander Sverdlin alexander.sverdlin@gmail.com wrote:
On Fri, 2023-07-21 at 17:13 +0300, Andy Shevchenko wrote:
...
spin_lock_irqsave(&ep93xx_swlock, flags);regmap_read(map, EP93XX_SYSCON_DEVCFG, &val);val &= ~clear_bits;val |= set_bits;regmap_write(map, EP93XX_SYSCON_SWLOCK, EP93XX_SWLOCK_MAGICK);regmap_write(map, EP93XX_SYSCON_DEVCFG, val);Is this sequence a must? I.o.w. can you first supply magic and then update devcfg?
spin_unlock_irqrestore(&ep93xx_swlock, flags);
...
+void ep93xx_swlocked_update_bits(struct regmap *map, unsigned int reg,
unsigned int mask, unsigned int val)
Same Q as above.
EP93xx User Manual [1] has most verbose description of SWLock for ADC block: "Writing 0xAA to this register will unlock all locked registers until the next block access. The ARM lock instruction prefix should be used for the two consequtive write cycles when writing to locked chip registers."
One may conclude that RmW (two accesses to the particular block) sequence is not appropriate.
It's not obvious to me. The terms "block access" and "block cycle" occur only once in the very same section that describes ADCSWLock. The meaning of these terms is not fully understandable. So, assuming that you have tried it differently and it indeed doesn't work, let's go with this one.
[1] https://cdn.embeddedts.com/resource-attachments/ts-7000_ep9301-ug.pdf
-- With Best Regards, Andy Shevchenko