Messages in this thread | | | Date | Mon, 3 Apr 2023 18:20:56 -0400 | From | William Breathitt Gray <> | Subject | Re: [PATCH v5 3/3] gpio: ws16c48: Migrate to the regmap API |
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On Mon, Apr 03, 2023 at 10:12:44PM +0100, Mark Brown wrote: > On Sun, Apr 02, 2023 at 10:39:02AM -0400, William Breathitt Gray wrote: > > On Mon, Mar 27, 2023 at 02:26:37PM +0300, Andy Shevchenko wrote: > > > On Sun, Mar 26, 2023 at 12:25:59PM -0400, William Breathitt Gray wrote: > > > > > +static const struct regmap_config ws16c48_regmap_config = { > > > > + .reg_bits = 8, > > > > + .reg_stride = 1, > > > > + .val_bits = 8, > > > > + .io_port = true, > > > > + .max_register = 0xA, > > > > + .wr_table = &ws16c48_wr_table, > > > > + .rd_table = &ws16c48_rd_table, > > > > + .volatile_table = &ws16c48_volatile_table, > > > > + .cache_type = REGCACHE_FLAT, > > > > +}; > > > > Do we need regmap lock? > > > We make regmap calls within an interrupt context in this driver so I > > think we need to disable the default regmap mutex locking behavior; I > > believe the current raw_spin_lock locking in this driver is enough to > > protect access. > > The above doesn't configure the regmap locking so you'll have a spinlock > by default (MMIO being a fast bus).
You're right, it'll be a spinlock in this case and not mutex. Unfortunately, we'll still need to change that to avoid deadlocks on -rt kernels [0].
William Breathitt Gray
[0] https://lore.kernel.org/all/1466065537-82027-1-git-send-email-mika.westerberg@linux.intel.com/ [unhandled content-type:application/pgp-signature] | |