On 1/19/23 05:44, Shyam Sundar S K wrote:
On 1/18/2023 8:04 PM, Andy Shevchenko wrote:
On Wed, Jan 18, 2023 at 07:27:06PM +0530, Shyam Sundar S K wrote:
On 1/17/2023 8:38 PM, Andy Shevchenko wrote:
On Tue, Jan 17, 2023 at 05:58:01PM +0530, Shyam Sundar S K wrote:
In order to use regmap_read() instead of ioread32() in this case, we
have to defer calling i2c_dw_configure()
Comment to change in your previous mail: Moving i2c_dw_configure() after
i2c_dw_probe() will cause regression to high speed mode since
DW_IC_CON_SPEED_HIGH is not set when i2c_dw_set_timings_master() is called.
I think we need to try to be consistent with IO accessors across the driver
which means to try hard to have regmap being initialised beforehand or other
functions being moved accordingly. However, it seems a bit non-trivial
ordering case and I leave this to you, I²C maintainers and this driver
maintainer to decide how to proceed.
Yeah, we don't want to potentially cause a regression on those machines
that use swapped or word accessors by reading and writing a wrong bit in
the DW_IC_CON.
Jarkko, How would you like me to proceed? Would you be OK to pull this
change without regmap_read() or do you like me to submit a patch for
reordering the _configure_* call ?
I think safe place to do this is between i2c_dw_init_regmap() and
dev->init() calls in i2c_dw_probe_master(). Then regmap is initialized
and the DW_IC_CON is not yet written.
Not sure would reading DW_IC_CON require
i2c_dw_acquire_lock()/i2c_dw_release_lock() but I would play safe.
