[alsa-devel] [PATCH] ASoC: Allow codecs to override register display
Some codecs have unusual features in their register maps such as very large registers representing arrays of coefficients. Support these codecs in the register cache sysfs file by allowing them to provide a function register_display() overriding the default output for register contents.
Signed-off-by: Mark Brown broonie@opensource.wolfsonmicro.com --- include/sound/soc.h | 1 + sound/soc/soc-core.c | 14 ++++++++++---- 2 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/include/sound/soc.h b/include/sound/soc.h index 1890d87..8b1a3e7 100644 --- a/include/sound/soc.h +++ b/include/sound/soc.h @@ -410,6 +410,7 @@ struct snd_soc_codec { void *control_data; /* codec control (i2c/3wire) data */ unsigned int (*read)(struct snd_soc_codec *, unsigned int); int (*write)(struct snd_soc_codec *, unsigned int, unsigned int); + int (*display_register)(struct snd_soc_codec *, char *, unsigned int); hw_write_t hw_write; hw_read_t hw_read; void *reg_cache; diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index 83f1190..49532d9 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -970,10 +970,16 @@ static ssize_t codec_reg_show(struct device *dev, step = codec->reg_cache_step;
count += sprintf(buf, "%s registers\n", codec->name); - for (i = 0; i < codec->reg_cache_size; i += step) - count += sprintf(buf + count, "%2x: %4x\n", i, - codec->read(codec, i)); - + for (i = 0; i < codec->reg_cache_size; i += step) { + count += sprintf(buf + count, "%2x: ", i); + if (codec->display_register) + count += codec->display_register(codec, + buf + count, i); + else + count += sprintf(buf + count, "%4x", + codec->read(codec, i)); + count += sprintf(buf + count, "\n"); + } return count; } static DEVICE_ATTR(codec_reg, 0444, codec_reg_show, NULL);
On 7/18/08, Mark Brown broonie@opensource.wolfsonmicro.com wrote:
Some codecs have unusual features in their register maps such as very large registers representing arrays of coefficients. Support these codecs in the register cache sysfs file by allowing them to provide a function register_display() overriding the default output for register contents.
My address space is sparse like Grant's. How about display_register() returning -1 to skip the register address. The part printing the address would need to be suppressed too. count += sprintf(buf + count, "%2x: ", i);
Alternatively you could just make the entire codec_reg_show() overridable.
Might want to add another parameter for cached/uncached. Then we could make a debug option to add the non-cached display.
This loop needs to be protected to not write over the sysfs limit of PAGE_SIZE in the result. I think you will corrupt memory if PAGE_SIZE is exceeded.
Signed-off-by: Mark Brown broonie@opensource.wolfsonmicro.com
include/sound/soc.h | 1 + sound/soc/soc-core.c | 14 ++++++++++---- 2 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/include/sound/soc.h b/include/sound/soc.h index 1890d87..8b1a3e7 100644 --- a/include/sound/soc.h +++ b/include/sound/soc.h @@ -410,6 +410,7 @@ struct snd_soc_codec { void *control_data; /* codec control (i2c/3wire) data */ unsigned int (*read)(struct snd_soc_codec *, unsigned int); int (*write)(struct snd_soc_codec *, unsigned int, unsigned int);
int (*display_register)(struct snd_soc_codec *, char *, unsigned int); hw_write_t hw_write; hw_read_t hw_read; void *reg_cache;diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index 83f1190..49532d9 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -970,10 +970,16 @@ static ssize_t codec_reg_show(struct device *dev, step = codec->reg_cache_step;
count += sprintf(buf, "%s registers\n", codec->name);
for (i = 0; i < codec->reg_cache_size; i += step)count += sprintf(buf + count, "%2x: %4x\n", i,codec->read(codec, i));
for (i = 0; i < codec->reg_cache_size; i += step) {count += sprintf(buf + count, "%2x: ", i);if (codec->display_register)count += codec->display_register(codec,buf + count, i);elsecount += sprintf(buf + count, "%4x",codec->read(codec, i));count += sprintf(buf + count, "\n");} return count;} static DEVICE_ATTR(codec_reg, 0444, codec_reg_show, NULL);
-- 1.5.6.3
At Fri, 18 Jul 2008 11:23:09 -0400, Jon Smirl wrote:
On 7/18/08, Mark Brown broonie@opensource.wolfsonmicro.com wrote:
Some codecs have unusual features in their register maps such as very large registers representing arrays of coefficients. Support these codecs in the register cache sysfs file by allowing them to provide a function register_display() overriding the default output for register contents.
My address space is sparse like Grant's. How about display_register() returning -1 to skip the register address. The part printing the address would need to be suppressed too. count += sprintf(buf + count, "%2x: ", i);
Alternatively you could just make the entire codec_reg_show() overridable.
Yes, I agree. For non-standard register maps, provide its own codec_reg_show().
Might want to add another parameter for cached/uncached. Then we could make a debug option to add the non-cached display.
That makes sense, too.
This loop needs to be protected to not write over the sysfs limit of PAGE_SIZE in the result. I think you will corrupt memory if PAGE_SIZE is exceeded.
Right. So far, it's been OK since the number of registers is relatively small.
Takashi
Signed-off-by: Mark Brown broonie@opensource.wolfsonmicro.com
include/sound/soc.h | 1 + sound/soc/soc-core.c | 14 ++++++++++---- 2 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/include/sound/soc.h b/include/sound/soc.h index 1890d87..8b1a3e7 100644 --- a/include/sound/soc.h +++ b/include/sound/soc.h @@ -410,6 +410,7 @@ struct snd_soc_codec { void *control_data; /* codec control (i2c/3wire) data */ unsigned int (*read)(struct snd_soc_codec *, unsigned int); int (*write)(struct snd_soc_codec *, unsigned int, unsigned int);
int (*display_register)(struct snd_soc_codec *, char *, unsigned int); hw_write_t hw_write; hw_read_t hw_read; void *reg_cache;diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index 83f1190..49532d9 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -970,10 +970,16 @@ static ssize_t codec_reg_show(struct device *dev, step = codec->reg_cache_step;
count += sprintf(buf, "%s registers\n", codec->name);
for (i = 0; i < codec->reg_cache_size; i += step)count += sprintf(buf + count, "%2x: %4x\n", i,codec->read(codec, i));
for (i = 0; i < codec->reg_cache_size; i += step) {count += sprintf(buf + count, "%2x: ", i);if (codec->display_register)count += codec->display_register(codec,buf + count, i);elsecount += sprintf(buf + count, "%4x",codec->read(codec, i));count += sprintf(buf + count, "\n");} return count;} static DEVICE_ATTR(codec_reg, 0444, codec_reg_show, NULL);
-- 1.5.6.3
-- Jon Smirl jonsmirl@gmail.com
On Fri, Jul 18, 2008 at 05:32:50PM +0200, Takashi Iwai wrote:
Jon Smirl wrote:
My address space is sparse like Grant's. How about display_register() returning -1 to skip the register address. The part printing the
address would need to be suppressed too. count += sprintf(buf + count, "%2x: ", i);
If we want to do sparse register maps I'd really much rather we did it by providing the core with explicit information about it and providing guarantees that only specified registers will be read rather than by adding it separately to each interface. This would make review easier and makes it easier to add new features like...
This loop needs to be protected to not write over the sysfs limit of
Alternatively you could just make the entire codec_reg_show() overridable.
Yes, I agree. For non-standard register maps, provide its own codec_reg_show().
I'd really like a way to just display the value of a register anyway for some other work I've been thinking of.
One of the issues that users run into is that it can be difficult to go from the datasheet to the ALSA controls and back again, especially on more complex chips. The scenario API is one part of dealing with this but that doesn't help the people doing the initial system setup and generatig the scenarios. They could be helped by exporting more information to user space about the mappings and the register values seem like they could be a useful part of that. It's likely that at least some of this will done by user space but even then it still becomes more important to keep the format of the sysfs files regular. Right now I'm not working on this since we've been focused on the v2 merge.
The underlying thing here is that the more code we keep in the core the easier it is to maintain the subsystem and the less redundant code we have in individual drivers.
Might want to add another parameter for cached/uncached. Then we could make a debug option to add the non-cached display.
That makes sense, too.
I've considered doing that myself - I'd say just via a second sysfs file that's always there, there doesn't seem much win from making it a debug only option and it'd be a pain to have to enable it when you do need it. This would need to be optional (conditional on having a hardware read function, I imagine) since a lot of devices don't actually provide any register read capability in hardware so couldn't support it.
PAGE_SIZE in the result. I think you will corrupt memory if PAGE_SIZE is exceeded.
Right. So far, it's been OK since the number of registers is relatively small.
This is a good point, and will likely be an issue for some of the debug interfaces I have been considering. A separate patch, though...
participants (3)
-
Jon Smirl -
Mark Brown -
Takashi Iwai