diff mbox series

[v2,1/3] iio: pressure: bmp280: Use uint8 to store chip ids

Message ID cf08dd2fab1fd91ca7ed0724d1f50435c8c2914b.1692805377.git.ang.iglesiasg@gmail.com (mailing list archive)
State Changes Requested
Headers show
Series iio: pressure: bmp280: Add support for BMP390 | expand

Commit Message

Angel Iglesias Aug. 23, 2023, 3:58 p.m. UTC 
Represent the device id reg values using uint8 to optimize memory use.

Signed-off-by: Angel Iglesias <ang.iglesiasg@gmail.com>

Comments

Andy Shevchenko Aug. 23, 2023, 4:10 p.m. UTC | #1 
On Wed, Aug 23, 2023 at 05:58:05PM +0200, Angel Iglesias wrote:
> Represent the device id reg values using uint8 to optimize memory use.

This doesn't correspond to the code, in the code you used uint8_t.

...

>  struct bmp280_chip_info {
>  	unsigned int id_reg;
> -	const unsigned int chip_id;
> +	uint8_t chip_id;

While this will compile and even work properly in kernel we use uXX types,
here u8.
Andy Shevchenko Aug. 23, 2023, 4:17 p.m. UTC | #2 
On Wed, Aug 23, 2023 at 07:10:33PM +0300, Andy Shevchenko wrote:
> On Wed, Aug 23, 2023 at 05:58:05PM +0200, Angel Iglesias wrote:
> > Represent the device id reg values using uint8 to optimize memory use.
> 
> This doesn't correspond to the code, in the code you used uint8_t.

...

> >  struct bmp280_chip_info {
> >  	unsigned int id_reg;
> > -	const unsigned int chip_id;
> > +	uint8_t chip_id;
> 
> While this will compile and even work properly in kernel we use uXX types,
> here u8.

Actually this patch doesn't optimize memory use. The alignment will create
a gap anyway.

That said, this patch is simply redundant.
Angel Iglesias Aug. 25, 2023, 9:28 a.m. UTC | #3 
On Wed, 2023-08-23 at 19:17 +0300, Andy Shevchenko wrote:
> On Wed, Aug 23, 2023 at 07:10:33PM +0300, Andy Shevchenko wrote:
> > On Wed, Aug 23, 2023 at 05:58:05PM +0200, Angel Iglesias wrote:
> > > Represent the device id reg values using uint8 to optimize memory use.
> > 
> > This doesn't correspond to the code, in the code you used uint8_t.
> 
> ...
> 
> > >  struct bmp280_chip_info {
> > >         unsigned int id_reg;
> > > -       const unsigned int chip_id;
> > > +       uint8_t chip_id;
> > 
> > While this will compile and even work properly in kernel we use uXX types,
> > here u8.
> 
> Actually this patch doesn't optimize memory use. The alignment will create
> a gap anyway.
> 
> That said, this patch is simply redundant.
> 
OK, I'll drop it on v3 then
diff mbox series

Patch

diff --git a/drivers/iio/pressure/bmp280.h b/drivers/iio/pressure/bmp280.h
index 5c0563ce7572..ff72e82f55ad 100644
--- a/drivers/iio/pressure/bmp280.h
+++ b/drivers/iio/pressure/bmp280.h
@@ -418,7 +418,7 @@  struct bmp280_data {
 
 struct bmp280_chip_info {
 	unsigned int id_reg;
-	const unsigned int chip_id;
+	uint8_t chip_id;
 
 	const struct regmap_config *regmap_config;