diff mbox

[1/2] regmap: cache: Fix regcache_sync_block for non-autoincrementing devices

Message ID 1409061793-10495-2-git-send-email-jarkko.nikula@linux.intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Jarkko Nikula Aug. 26, 2014, 2:03 p.m. UTC
Commit 75a5f89f635c ("regmap: cache: Write consecutive registers in a single
block write") expected that autoincrementing writes are supported if
hardware has a register format which can support raw writes.

This is not necessarily true and thus for instance rbtree sync can fail when
there is need to sync multiple consecutive registers but block write to
device fails due not supported autoincrementing writes.

Fix this by spliting raw block sync to series of single register writes for
devices that don't support autoincrementing writes.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
---
I noticed this with Realtek RT5642 audio codec which didn't resume properly
since first block write having more data than for single register failed to
not acknowledged I2C write during regcache_sync(). Chip acknowledges device
address, register address and two data bytes for its word size registers but
next data byte is not which then causes aborted I2C transfer and aborted
register sync.
---
 drivers/base/regmap/regcache.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

Comments

Takashi Iwai Aug. 26, 2014, 2:21 p.m. UTC | #1
At Tue, 26 Aug 2014 17:03:12 +0300,
Jarkko Nikula wrote:
> 
> Commit 75a5f89f635c ("regmap: cache: Write consecutive registers in a single
> block write") expected that autoincrementing writes are supported if
> hardware has a register format which can support raw writes.
> 
> This is not necessarily true and thus for instance rbtree sync can fail when
> there is need to sync multiple consecutive registers but block write to
> device fails due not supported autoincrementing writes.
> 
> Fix this by spliting raw block sync to series of single register writes for
> devices that don't support autoincrementing writes.

Wouldn't it suffice to correct regmap_can_raw_write() to return false
if map->use_single_rw is set?


Takashi

> 
> Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
> ---
> I noticed this with Realtek RT5642 audio codec which didn't resume properly
> since first block write having more data than for single register failed to
> not acknowledged I2C write during regcache_sync(). Chip acknowledges device
> address, register address and two data bytes for its word size registers but
> next data byte is not which then causes aborted I2C transfer and aborted
> register sync.
> ---
>  drivers/base/regmap/regcache.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
> index 29b4128da0b0..54707e586ac8 100644
> --- a/drivers/base/regmap/regcache.c
> +++ b/drivers/base/regmap/regcache.c
> @@ -629,6 +629,7 @@ static int regcache_sync_block_raw_flush(struct regmap *map, const void **data,
>  {
>  	size_t val_bytes = map->format.val_bytes;
>  	int ret, count;
> +	unsigned int i;
>  
>  	if (*data == NULL)
>  		return 0;
> @@ -640,7 +641,18 @@ static int regcache_sync_block_raw_flush(struct regmap *map, const void **data,
>  
>  	map->cache_bypass = 1;
>  
> -	ret = _regmap_raw_write(map, base, *data, count * val_bytes);
> +	if (!map->use_single_rw) {
> +		ret = _regmap_raw_write(map, base, *data, count * val_bytes);
> +	} else {
> +		for (i = 0; i < count; i++) {
> +			ret = _regmap_raw_write(map,
> +						base + (i * map->reg_stride),
> +						*data + (i * val_bytes),
> +						val_bytes);
> +			if (ret != 0)
> +				break;
> +		}
> +	}
>  
>  	map->cache_bypass = 0;
>  
> -- 
> 2.1.0
> 
> _______________________________________________
> Alsa-devel mailing list
> Alsa-devel@alsa-project.org
> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>
Jarkko Nikula Aug. 27, 2014, 5:52 a.m. UTC | #2
On 08/26/2014 05:21 PM, Takashi Iwai wrote:
> At Tue, 26 Aug 2014 17:03:12 +0300,
> Jarkko Nikula wrote:
>> Commit 75a5f89f635c ("regmap: cache: Write consecutive registers in a single
>> block write") expected that autoincrementing writes are supported if
>> hardware has a register format which can support raw writes.
>>
>> This is not necessarily true and thus for instance rbtree sync can fail when
>> there is need to sync multiple consecutive registers but block write to
>> device fails due not supported autoincrementing writes.
>>
>> Fix this by spliting raw block sync to series of single register writes for
>> devices that don't support autoincrementing writes.
> Wouldn't it suffice to correct regmap_can_raw_write() to return false
> if map->use_single_rw is set?
>
I don't know. I was thinking that also but was unsure about it since 
regcache_sync_block_raw() and regcache_sync_block_single() code paths 
use different regmap write functions. regcache_sync_block_raw() ends up 
calling _regmap_raw_write() which takes care of page select operation 
when needed and regcache_sync_block_single() uses _regmap_write() which 
doesn't.

Which makes me thinking should the regcache_sync_block_single() also use 
_regmap_raw_write() in order to take care of page selects?
diff mbox

Patch

diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index 29b4128da0b0..54707e586ac8 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -629,6 +629,7 @@  static int regcache_sync_block_raw_flush(struct regmap *map, const void **data,
 {
 	size_t val_bytes = map->format.val_bytes;
 	int ret, count;
+	unsigned int i;
 
 	if (*data == NULL)
 		return 0;
@@ -640,7 +641,18 @@  static int regcache_sync_block_raw_flush(struct regmap *map, const void **data,
 
 	map->cache_bypass = 1;
 
-	ret = _regmap_raw_write(map, base, *data, count * val_bytes);
+	if (!map->use_single_rw) {
+		ret = _regmap_raw_write(map, base, *data, count * val_bytes);
+	} else {
+		for (i = 0; i < count; i++) {
+			ret = _regmap_raw_write(map,
+						base + (i * map->reg_stride),
+						*data + (i * val_bytes),
+						val_bytes);
+			if (ret != 0)
+				break;
+		}
+	}
 
 	map->cache_bypass = 0;