1. Patchew
  2. linux
  3. [PATCH v3 0/8] i2c: riic: driver cleanup and improvements
  4. View patch

[PATCH v3 4/8] i2c: riic: Use GENMASK() macro for bitmask definitions

Prabhakar posted 8 patches 1 year, 1 month ago
There is a newer version of this series
[PATCH v3 4/8] i2c: riic: Use GENMASK() macro for bitmask definitions
Posted by Prabhakar 1 year, 1 month ago 
From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Replace raw bitmask values with the `GENMASK()` macro in the `i2c-riic`
driver to improve readability and maintain consistency.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
---
v2->v3
- Collected RB and tested tags

v1->v2
- Collected RB tag from Geert
---
 drivers/i2c/busses/i2c-riic.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c
index 954e066d61a8..ddae4b74a86b 100644
--- a/drivers/i2c/busses/i2c-riic.c
+++ b/drivers/i2c/busses/i2c-riic.c
@@ -55,7 +55,7 @@
 #define ICCR2_RS	BIT(2)
 #define ICCR2_ST	BIT(1)
 
-#define ICMR1_CKS_MASK	0x70
+#define ICMR1_CKS_MASK	GENMASK(6, 4)
 #define ICMR1_BCWP	BIT(3)
 #define ICMR1_CKS(_x)	((((_x) << 4) & ICMR1_CKS_MASK) | ICMR1_BCWP)
 
@@ -73,7 +73,7 @@
 
 #define ICSR2_NACKF	BIT(4)
 
-#define ICBR_RESERVED	0xe0 /* Should be 1 on writes */
+#define ICBR_RESERVED	GENMASK(7, 5) /* Should be 1 on writes */
 
 #define RIIC_INIT_MSG	-1
 
-- 
2.43.0
Re: [PATCH v3 4/8] i2c: riic: Use GENMASK() macro for bitmask definitions
Posted by David Laight 1 year, 1 month ago 
On Fri, 27 Dec 2024 11:51:50 +0000
Prabhakar <prabhakar.csengg@gmail.com> wrote:

> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Replace raw bitmask values with the `GENMASK()` macro in the `i2c-riic`
> driver to improve readability and maintain consistency.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Tested-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> Reviewed-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> ---
> v2->v3
> - Collected RB and tested tags
> 
> v1->v2
> - Collected RB tag from Geert
> ---
>  drivers/i2c/busses/i2c-riic.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c
> index 954e066d61a8..ddae4b74a86b 100644
> --- a/drivers/i2c/busses/i2c-riic.c
> +++ b/drivers/i2c/busses/i2c-riic.c
> @@ -55,7 +55,7 @@
>  #define ICCR2_RS	BIT(2)
>  #define ICCR2_ST	BIT(1)
>  
> -#define ICMR1_CKS_MASK	0x70
> +#define ICMR1_CKS_MASK	GENMASK(6, 4)
>  #define ICMR1_BCWP	BIT(3)
>  #define ICMR1_CKS(_x)	((((_x) << 4) & ICMR1_CKS_MASK) | ICMR1_BCWP)

I'm really not at all sure how this makes it 'more readable'.
Call me 'old fashioned' but I like hex constants - especially for bytes.
In this case it might be best to be consistent with the hardware datasheet.

Pretty much the only time I've actually used anything like BIT() was
for a spec that numbered the bits from 1 to 32 with bit 1 being the most
significant.

>  
> @@ -73,7 +73,7 @@
>  
>  #define ICSR2_NACKF	BIT(4)
>  
> -#define ICBR_RESERVED	0xe0 /* Should be 1 on writes */
> +#define ICBR_RESERVED	GENMASK(7, 5) /* Should be 1 on writes */

	'Should all be set on writes' ?

	David

>  
>  #define RIIC_INIT_MSG	-1
>
Re: [PATCH v3 4/8] i2c: riic: Use GENMASK() macro for bitmask definitions
Posted by Lad, Prabhakar 1 year, 1 month ago 
Hi Andi,

On Wed, Jan 1, 2025 at 12:11 PM David Laight
<david.laight.linux@gmail.com> wrote:
>
> On Fri, 27 Dec 2024 11:51:50 +0000
> Prabhakar <prabhakar.csengg@gmail.com> wrote:
>
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >
> > Replace raw bitmask values with the `GENMASK()` macro in the `i2c-riic`
> > driver to improve readability and maintain consistency.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> > Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> > Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> > Tested-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> > Reviewed-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> > ---
> > v2->v3
> > - Collected RB and tested tags
> >
> > v1->v2
> > - Collected RB tag from Geert
> > ---
> >  drivers/i2c/busses/i2c-riic.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c
> > index 954e066d61a8..ddae4b74a86b 100644
> > --- a/drivers/i2c/busses/i2c-riic.c
> > +++ b/drivers/i2c/busses/i2c-riic.c
> > @@ -55,7 +55,7 @@
> >  #define ICCR2_RS     BIT(2)
> >  #define ICCR2_ST     BIT(1)
> >
> > -#define ICMR1_CKS_MASK       0x70
> > +#define ICMR1_CKS_MASK       GENMASK(6, 4)
> >  #define ICMR1_BCWP   BIT(3)
> >  #define ICMR1_CKS(_x)        ((((_x) << 4) & ICMR1_CKS_MASK) | ICMR1_BCWP)
>
> I'm really not at all sure how this makes it 'more readable'.
> Call me 'old fashioned' but I like hex constants - especially for bytes.
> In this case it might be best to be consistent with the hardware datasheet.
>
Let me know if you dont accept such patches. I'll drop it from the next version.

> Pretty much the only time I've actually used anything like BIT() was
> for a spec that numbered the bits from 1 to 32 with bit 1 being the most
> significant.
>
> >
> > @@ -73,7 +73,7 @@
> >
> >  #define ICSR2_NACKF  BIT(4)
> >
> > -#define ICBR_RESERVED        0xe0 /* Should be 1 on writes */
> > +#define ICBR_RESERVED        GENMASK(7, 5) /* Should be 1 on writes */
>
>         'Should all be set on writes' ?
>
Yes.

Cheers,
Prabhakar
Re: [PATCH v3 4/8] i2c: riic: Use GENMASK() macro for bitmask definitions
Posted by Andy Shevchenko 1 year, 1 month ago 
Fri, Dec 27, 2024 at 11:51:50AM +0000, Prabhakar kirjoitti:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Replace raw bitmask values with the `GENMASK()` macro in the `i2c-riic`
> driver to improve readability and maintain consistency.

...

> -#define ICBR_RESERVED	0xe0 /* Should be 1 on writes */
> +#define ICBR_RESERVED	GENMASK(7, 5) /* Should be 1 on writes */

I don't understand the comment. Does it mean the value should be 0x20?

-- 
With Best Regards,
Andy Shevchenko
Re: [PATCH v3 4/8] i2c: riic: Use GENMASK() macro for bitmask definitions
Posted by Lad, Prabhakar 1 year, 1 month ago 
Hi Andy,

On Sat, Dec 28, 2024 at 11:36 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> Fri, Dec 27, 2024 at 11:51:50AM +0000, Prabhakar kirjoitti:
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >
> > Replace raw bitmask values with the `GENMASK()` macro in the `i2c-riic`
> > driver to improve readability and maintain consistency.
>
> ...
>
> > -#define ICBR_RESERVED        0xe0 /* Should be 1 on writes */
> > +#define ICBR_RESERVED        GENMASK(7, 5) /* Should be 1 on writes */
>
> I don't understand the comment. Does it mean the value should be 0x20?
>
Bit's 5-7 are marked as reserved and these should always be set to `1`
on write operation.

Cheers,
Prabhakar

Patchew 2.1-devel-b67e4c2

© 2016 - 2026 Red Hat, Inc.