Re: [PATCH v2 2/2] iio: pressure: ms5637: Add variant specific temperature compensation

Louis Adamian <[email protected]>
Newsgroups org.kernel.vger.linux-iio,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-kernel
Message-ID <20260807183301.jojTkoO7qAdG4ooOhaI6oqPjKBj8ters_AwSWjZQZt4@z>
On Fri, 7 Aug 2026 00:27:30 +0300
Andy Shevchenko <[email protected]> wrote:

> On Wed, Aug 05, 2026 at 01:06:51PM -0400, Louis Adamian wrote:
> > On Thu, 11 Jun 2026 22:32:02 +0300
> > Andy Shevchenko <[email protected]> wrote:  
> > > On Thu, Jun 11, 2026 at 03:10:26PM -0400, Louis Adamian wrote:  
> > > > On Wed, 10 Jun 2026 21:37:58 +0300
> > > > Andy Shevchenko <[email protected]> wrote:    
> > > > > On Tue, Jun 09, 2026 at 10:04:58PM -0400, Louis Adamian
> > > > > wrote:    
> 
> ...
> 
> > > > > >  struct ms_tp_dev {
> > > > > >  	struct i2c_client *client;      
> > > > >     
>  [...]  
> > > > > 
> > > > > Please, check with `pahole` if this is the best layout.    
> > > > 
> > > > I will correct the packing on this per pahole's finding.    
>  [...]  
> > > > > 
> > > > > Can this be simply embedded into ms_tp_dev (and copied there
> > > > > if required)?    
> > > > 
> > > > Copying in ms_tp_comp_consts provides no benefit over
> > > > referencing the pointer; the values are per-descriptor, not
> > > > per-instance and never modified. I'll keep the pointer (same as
> > > > ms_tp_hw_data).    
> > > 
> > > Okay, let me ask differently then: Can we use the same data type
> > > in ms_tp_dev instead of adding basically the same fields as in
> > > ms_tp_data?
> > >   
> > Sorry for the very slow reply. Yes, for v3 ms_tp_dev will hold a
> > single const ms_tp_data *data instead of its own hw and
> > comp_consts. This drops the duplicated hw that predates this
> > series. 
> > 
> > One thing worth noting before I do that: ms_tp_data is currently
> > private to ms5637.c and will need to be moved to ms_sensors_i2c.h
> > for ms_tp_dev to point to it. I don't think this is a problem; it
> > matches how ms_tp_hw_data is defined now, but let me know if you
> > would like to avoid it.  
> 
> The pointer may be opaque, in that case it's not needed to be exposed.
> 

ms_sensors_i2c.c dereferences both ->hw->prom_len in
ms_sensors_tp_read_prom and ->comp_consts in
ms_sensors_read_temp_and_pressure, so an opaque ms_tp_data would require
passing both pointers as parameters. I plan on moving ms_tp_data into
ms_sensors_i2c.h, dropping the original duplicate hw, unless you prefer
otherwise.

-- 
Thanks,
Louis
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