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Groups > linux.kernel > #1237036 > unrolled thread
| Started by | jon@ringle.org |
|---|---|
| First post | 2015-10-01 08:40 +0200 |
| Last post | 2015-10-02 19:20 +0200 |
| Articles | 4 — 3 participants |
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[PATCH 1/2] regmap: Allow installing custom reg_update_bits function jon@ringle.org - 2015-10-01 08:40 +0200
Re: [PATCH 1/2] regmap: Allow installing custom reg_update_bits function Mark Brown <broonie@kernel.org> - 2015-10-01 11:50 +0200
Re: [PATCH 1/2] regmap: Allow installing custom reg_update_bits function Jon Ringle <jon@ringle.org> - 2015-10-01 14:30 +0200
Re: [PATCH 1/2] regmap: Allow installing custom reg_update_bits function Mark Brown <broonie@kernel.org> - 2015-10-02 19:20 +0200
| From | jon@ringle.org |
|---|---|
| Date | 2015-10-01 08:40 +0200 |
| Subject | [PATCH 1/2] regmap: Allow installing custom reg_update_bits function |
| Message-ID | <qeFH4-4bi-15@gated-at.bofh.it> |
From: Jon Ringle <jringle@gridpoint.com>
This commit allows installing a custom reg_update_bits function for cases where
the hardware provides a mechanism to set or clear register bits without a
read/modify/write cycle. Such is the case with the Microchip ENCX24J600.
Signed-off-by: Jon Ringle <jringle@gridpoint.com>
---
drivers/base/regmap/internal.h | 3 +++
drivers/base/regmap/regmap.c | 5 +++++
include/linux/regmap.h | 4 ++++
3 files changed, 12 insertions(+)
diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index cc55788..4036d7a 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -98,6 +98,9 @@ struct regmap {
int (*reg_read)(void *context, unsigned int reg, unsigned int *val);
int (*reg_write)(void *context, unsigned int reg, unsigned int val);
+ int (*reg_update_bits)(void *context, unsigned int reg,
+ unsigned int mask, unsigned int val,
+ bool *change, bool force_write);
bool defer_caching;
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index afaf562..ba00d62 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -619,6 +619,7 @@ struct regmap *__regmap_init(struct device *dev,
goto skip_format_initialization;
} else {
map->reg_read = _regmap_bus_read;
+ map->reg_update_bits = bus->reg_update_bits;
}
reg_endian = regmap_get_reg_endian(bus, config);
@@ -2509,6 +2510,10 @@ static int _regmap_update_bits(struct regmap *map, unsigned int reg,
int ret;
unsigned int tmp, orig;
+ if (map->reg_update_bits)
+ return map->reg_update_bits(map->bus_context, reg, mask, val,
+ change, force_write);
+
ret = _regmap_read(map, reg, &orig);
if (ret != 0)
return ret;
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 8fc0bfd..4d3a3b1 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -296,6 +296,9 @@ typedef int (*regmap_hw_reg_read)(void *context, unsigned int reg,
unsigned int *val);
typedef int (*regmap_hw_reg_write)(void *context, unsigned int reg,
unsigned int val);
+typedef int (*regmap_hw_reg_update_bits)(void *context, unsigned int reg,
+ unsigned int mask, unsigned int val,
+ bool *change, bool force_write);
typedef struct regmap_async *(*regmap_hw_async_alloc)(void);
typedef void (*regmap_hw_free_context)(void *context);
@@ -335,6 +338,7 @@ struct regmap_bus {
regmap_hw_gather_write gather_write;
regmap_hw_async_write async_write;
regmap_hw_reg_write reg_write;
+ regmap_hw_reg_update_bits reg_update_bits;
regmap_hw_read read;
regmap_hw_reg_read reg_read;
regmap_hw_free_context free_context;
--
2.4.1
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| From | Mark Brown <broonie@kernel.org> |
|---|---|
| Date | 2015-10-01 11:50 +0200 |
| Subject | Re: [PATCH 1/2] regmap: Allow installing custom reg_update_bits function |
| Message-ID | <qeIEW-gR-1@gated-at.bofh.it> |
| In reply to | #1237036 |
[Multipart message — attachments visible in raw view] — view raw
On Thu, Oct 01, 2015 at 02:33:06AM -0400, jon@ringle.org wrote: > @@ -2509,6 +2510,10 @@ static int _regmap_update_bits(struct regmap *map, unsigned int reg, > int ret; > unsigned int tmp, orig; > > + if (map->reg_update_bits) > + return map->reg_update_bits(map->bus_context, reg, mask, val, > + change, force_write); > + > ret = _regmap_read(map, reg, &orig); > if (ret != 0) > return ret; This completely bypasses and therefore breaks the cache infrastructure.
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| From | Jon Ringle <jon@ringle.org> |
|---|---|
| Date | 2015-10-01 14:30 +0200 |
| Subject | Re: [PATCH 1/2] regmap: Allow installing custom reg_update_bits function |
| Message-ID | <qeL9M-3Vj-9@gated-at.bofh.it> |
| In reply to | #1237230 |
On Thu, 1 Oct 2015, Mark Brown wrote:
> On Thu, Oct 01, 2015 at 02:33:06AM -0400, jon@ringle.org wrote:
>
> > @@ -2509,6 +2510,10 @@ static int _regmap_update_bits(struct regmap *map, unsigned int reg,
> > int ret;
> > unsigned int tmp, orig;
> >
> > + if (map->reg_update_bits)
> > + return map->reg_update_bits(map->bus_context, reg, mask, val,
> > + change, force_write);
> > +
> > ret = _regmap_read(map, reg, &orig);
> > if (ret != 0)
> > return ret;
>
> This completely bypasses and therefore breaks the cache infrastructure.
>
Hi Mark,
Right after sending the v2 patch, I realized that calling the
custom reg_update_bits would only be applicable for registers that are
marked as volatile. Would the following solution be acceptable (it would
also simplify the regmap_update_bits in the encx24j600 driver):
if (regmap_volatile(map, reg) && map->reg_update_bits) {
return map->reg_update_bits(map->bus_context, reg, mask,
val, change, force_write);
The cache state should not matter for volatile registers, right?
-Jon
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| From | Mark Brown <broonie@kernel.org> |
|---|---|
| Date | 2015-10-02 19:20 +0200 |
| Subject | Re: [PATCH 1/2] regmap: Allow installing custom reg_update_bits function |
| Message-ID | <qfc9X-1mW-3@gated-at.bofh.it> |
| In reply to | #1237370 |
[Multipart message — attachments visible in raw view] — view raw
On Thu, Oct 01, 2015 at 08:29:19AM -0400, Jon Ringle wrote:
> On Thu, 1 Oct 2015, Mark Brown wrote:
> > This completely bypasses and therefore breaks the cache infrastructure.
> Right after sending the v2 patch, I realized that calling the
> custom reg_update_bits would only be applicable for registers that are
> marked as volatile. Would the following solution be acceptable (it would
Well, it should still *work* with a cache, though it's certainly true
that it's unlikely to have any performance benefit with cached register
since the read part of the read/modify/write cycle is essentially free
with the cache.
> also simplify the regmap_update_bits in the encx24j600 driver):
> if (regmap_volatile(map, reg) && map->reg_update_bits) {
> return map->reg_update_bits(map->bus_context, reg, mask,
> val, change, force_write);
> The cache state should not matter for volatile registers, right?
Right. I see you've sent a new patch already, I'll reply to that after
I've thought about it a little.
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