Hi,
On Jul 6 2017 22:59, Daniel Drake wrote:
Thanks for the the info here! Based on the datasheet and newer headers
I have updated it to:
static const SNDRV_CTL_TLVD_DECLARE_DB_RANGE(adc_pga_gain_tlv,
0, 0, TLV_DB_SCALE_ITEM(-3500, 0, 0),
1, 1, TLV_DB_SCALE_ITEM(0, 0, 0),
2, 2, TLV_DB_SCALE_ITEM(250, 0, 0),
3, 3, TLV_DB_SCALE_ITEM(450, 0, 0),
4, 4, TLV_DB_SCALE_ITEM(700, 0, 0),
5, 5, TLV_DB_SCALE_ITEM(1000, 0, 0),
6, 6, TLV_DB_SCALE_ITEM(1300, 0, 0),
7, 7, TLV_DB_SCALE_ITEM(1600, 0, 0),
8, 8, TLV_DB_SCALE_ITEM(1800, 0, 0),
9, 9, TLV_DB_SCALE_ITEM(2100, 0, 0),
10, 10, TLV_DB_SCALE_ITEM(2400, 0, 0),
);
This is valid data as TLV of DB_RANGE type (11 entries).
I believe the final entry means 24dB and does not have the large value
that you have interpreted.
Exactly. I sent my previous message with the mistake. Unit of the first
field of SNDRV_CTL_TLVD_DB_SCALE_ITEM is 0.01 dB, therefore it's 24.0
dB, as you realized.
There are many other drivers using similar values like this from rt5616.c:
/* {0, +20, +24, +30, +35, +40, +44, +50, +52} dB */
static const SNDRV_CTL_TLVD_DECLARE_DB_RANGE(bst_tlv,
0, 0, TLV_DB_SCALE_ITEM(0, 0, 0),
1, 1, TLV_DB_SCALE_ITEM(2000, 0, 0),
2, 2, TLV_DB_SCALE_ITEM(2400, 0, 0),
3, 5, TLV_DB_SCALE_ITEM(3000, 500, 0),
6, 6, TLV_DB_SCALE_ITEM(4400, 0, 0),
7, 7, TLV_DB_SCALE_ITEM(5000, 0, 0),
8, 8, TLV_DB_SCALE_ITEM(5200, 0, 0),
);
I'll test this change and wait for any further review comments before
sending a v4. I've also noticed that hpout_vol_tlv can be corrected
and simplified.
The data is valid. In this case, the table is:
Linear range: dB range: coeff: mute
0 <-> 0: 0 <-> 0: 0: 0
(0 <-> 1: 0 <-> 2000:2000: 0)
1 <-> 1: 2000 <-> 2000: 0: 0
(1 <-> 2: 2000 <-> 2400: 400: 0)
2 <-> 2: 2400 <-> 2400: 0: 0
(2 <-> 3: 2400 <-> 3000: 600: 0)
3 <-> 5: 3000 <-> 4000: 500: 0
(5 <-> 6: 4000 <-> 4400: 400: 0)
6 <-> 6: 4400 <-> 4400: 0: 0
(6 <-> 7: 4400 <-> 5000: 600: 0)
7 <-> 7: 5000 <-> 5000: 0: 0
(7 <-> 8: 5000 <-> 5200: 200: 0)
8 <-> 8: 5200 <-> 5299: 0: 0
We can use an alternate representation of the TLV data with brackets, like:
static const SNDRV_CTL_TLVD_DECLARE_DB_RANGE(bst_tlv,
0, 1, SNDRV_CTL_TLVD_DB_SCALE_ITEM(0, 1000, 0),
1, 2, SNDRV_CTL_TLVD_DB_SCALE_ITEM(2000, 400, 0),
2, 3, SNDRV_CTL_TLVD_DB_SCALE_ITEM(2400, 600, 0),
3, 5, SNDRV_CTL_TLVD_DB_SCALE_ITEM(3000, 500, 0),
5, 6, SNDRV_CTL_TLVD_DB_SCALE_ITEM(4000, 400, 0),
6, 7, SNDRV_CTL_TLVD_DB_SCALE_ITEM(4400, 600, 0),
7, 8, SNDRV_CTL_TLVD_DB_SCALE_ITEM(5000, 200, 0),
);
Well, in your case, the hardware supports between -35 dB and 24 dB with
variable 10 steps and the table can also be:
0 <-> 1: -3500 <-> 0: 3500: 0
1 <-> 2: 0 <-> 250: 250: 0
2 <-> 3: 250 <-> 450: 200: 0
3 <-> 4: 450 <-> 700: 250: 0
4 <-> 7: 700 <-> 1600: 300: 0
7 <-> 8: 1600 <-> 1800: 200: 0
8 <-> 10: 1800 <-> 2400: 300: 0
Therefore, we can also use an alternate representation, below.
static const SNDRV_CTL_TLVD_DECLARE_DB_RANGE(adc_pga_gain_tlv,
0, 1, SNDRV_CTL_TLVD_DB_SCALE_ITEM(-3500, 3500, 0),
1, 2, SNDRV_CTL_TLVD_DB_SCALE_ITEM( 0, 250, 0),
2, 3, SNDRV_CTL_TLVD_DB_SCALE_ITEM( 250, 200, 0),
3, 4, SNDRV_CTL_TLVD_DB_SCALE_ITEM( 450, 250, 0),
4, 7, SNDRV_CTL_TLVD_DB_SCALE_ITEM( 700, 300, 0),
7, 8, SNDRV_CTL_TLVD_DB_SCALE_ITEM( 1600, 200, 0),
8, 10, SNDRV_CTL_TLVD_DB_SCALE_ITEM( 1800, 300, 0),
);
In alsa-lib, there's a sample program for user-defined control element
set[1]. It includes some examples of TLV data.
allocate_int64_elem_set_tlv() adds TLV data similar to your case. This
data can be parsed by alsa-lib, like:
$ amixer contents
...
numid=4566,iface=MIXER,name='userspace-control-element-INTEGER64',index=896
; type=INTEGER64,access=rw---RW-,values=64,min=0,max=10000,step=1
:
values=1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
| dBrange-
rangemin=0,,rangemax=4
| dBscale-min=-59.40dB,step=0.44dB,mute=1
rangemin=4,,rangemax=22
| dBscale-min=-56.36dB,step=0.60dB,mute=0
rangemin=22,,rangemax=33
| dBscale-min=-45.56dB,step=0.76dB,mute=0
rangemin=33,,rangemax=37
| dBscale-min=-40.72dB,step=0.44dB,mute=0
rangemin=37,,rangemax=48
| dBscale-min=-38.32dB,step=0.76dB,mute=0
rangemin=48,,rangemax=66
| dBscale-min=-29.96dB,step=0.60dB,mute=0
rangemin=66,,rangemax=84
| dBscale-min=-22.04dB,step=0.44dB,mute=0
rangemin=84,,rangemax=95
| dBscale-min=-8.36dB,step=0.60dB,mute=0
rangemin=95,,rangemax=99
| dBscale-min=-1.76dB,step=0.76dB,mute=0
rangemin=100,,rangemax=10000
| dBscale-min=0.00dB,step=0.00dB,mute=0
...
Both way of representation is valid. For your information.
[1] user-ctl-element-set.c
http://git.alsa-project.org/?p=alsa-lib.git;a=blob;f=test/user-ctl-element-set.c
Regards
Takashi Sakamoto
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