[PATCH RFC 0/2] Introduce BITS_MASK macro

[PATCH RFC 0/2] Introduce BITS_MASK macro

[srinivas.kandagatla]

From: Srinivas Kandagatla <srinivas.kandagatla@st.com>

This patch series introduces BITS_MASK macro which creates a mask for a given
lsb and msb bit locations. The usage of masks spread over mutiple bits is
becoming very common for example with regmap_update_bits kind of apis. Having a
common macro for this makes much sense and is clean and readable way to encode
the mask rather than having an hex number for a mask.

Second patch is to show an example usage of this new macro in regmap.

Comments ?

Thanks,
srini

Srinivas Kandagatla (2):
  bitops: introduce BITS_MASK macro
  regmap: move to using BITS_MASK macro

 drivers/base/regmap/regmap.c |    3 +--
 include/linux/bitops.h       |    1 +
 2 files changed, 2 insertions(+), 2 deletions(-)

-- 
1.7.6.5

[PATCH RFC 1/2] bitops: introduce BITS_MASK macro

[srinivas.kandagatla]

From: Srinivas Kandagatla <srinivas.kandagatla@st.com>

This patch introduces BITS_MASK macro which creates a mask for a given
lsb and msb bit locations. The usage of masks spread over mutiple bits
is becoming very common for example with regmap_update_bits kind of
apis. Having a common macro for this makes much sense and is clean and
readable way to encode the mask rather than having an hex number for a
mask.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
---
 include/linux/bitops.h |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index a3b6b82..3ddce97 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -5,6 +5,7 @@
 #ifdef	__KERNEL__
 #define BIT(nr)			(1UL << (nr))
 #define BIT_MASK(nr)		(1UL << ((nr) % BITS_PER_LONG))
+#define BITS_MASK(lsb, msb)	((BIT(msb - lsb + 1) - 1) << lsb)
 #define BIT_WORD(nr)		((nr) / BITS_PER_LONG)
 #define BITS_PER_BYTE		8
 #define BITS_TO_LONGS(nr)	DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
-- 
1.7.6.5

[PATCH RFC 2/2] regmap: move to using BITS_MASK macro

[srinivas.kandagatla]

From: Srinivas Kandagatla <srinivas.kandagatla@st.com>

This patch uses the new BITS_MASK macro for generating mask for multiple
bits.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
---
 drivers/base/regmap/regmap.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 7d689a1..7433939 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -816,11 +816,10 @@ EXPORT_SYMBOL_GPL(devm_regmap_init);
 static void regmap_field_init(struct regmap_field *rm_field,
 	struct regmap *regmap, struct reg_field reg_field)
 {
-	int field_bits = reg_field.msb - reg_field.lsb + 1;
 	rm_field->regmap = regmap;
 	rm_field->reg = reg_field.reg;
 	rm_field->shift = reg_field.lsb;
-	rm_field->mask = ((BIT(field_bits) - 1) << reg_field.lsb);
+	rm_field->mask = BITS_MASK(reg_field.lsb, reg_field.msb);
 }
 
 /**
-- 
1.7.6.5

Re: [PATCH RFC 2/2] regmap: move to using BITS_MASK macro

[Mark Brown]

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On Thu, Oct 31, 2013 at 11:54:01AM +0000, srinivas.kandagatla@st.com wrote:
> From: Srinivas Kandagatla <srinivas.kandagatla@st.com>
> 
> This patch uses the new BITS_MASK macro for generating mask for multiple
> bits.

Acked-by: Mark Brown <broonie@linaro.org>

Or I can apply both.  There's plenty of other places this could be used.

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Re: [PATCH RFC 2/2] regmap: move to using BITS_MASK macro

[srinivas kandagatla]

On 31/10/13 15:38, Mark Brown wrote:
> On Thu, Oct 31, 2013 at 11:54:01AM +0000, srinivas.kandagatla@st.com wrote:
>> From: Srinivas Kandagatla <srinivas.kandagatla@st.com>
>>
>> This patch uses the new BITS_MASK macro for generating mask for multiple
>> bits.
> 
> Acked-by: Mark Brown <broonie@linaro.org>
Thanks Mark,
> 
> Or I can apply both.  There's plenty of other places this could be used.
> 
It makes sense to take it via regmap tree as there is dependency on the
first patch.

Thanks,
srini