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Date:   Mon, 18 Feb 2019 00:52:42 +0300
From:   Yauhen Kharuzhy <jekhor@gmail.com>
To:     Hans de Goede <hdegoede@redhat.com>
Cc:     linux-kernel@vger.kernel.org,
        MyungJoo Ham <myungjoo.ham@samsung.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: Re: [PATCH 2/2] extcon intel-cht-wc: Enable external charger
Message-ID: <20190217215242.GA12656@jeknote.loshitsa1.net>
References: <20190210203649.21691-1-jekhor@gmail.com>
 <20190210203649.21691-3-jekhor@gmail.com>
 <1b2f04fc-05a0-4f09-c84e-dc7adc63ec63@redhat.com>
 <20190215063250.GB30250@jeknote.loshitsa1.net>
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On Fri, Feb 15, 2019 at 09:32:50AM +0300, Yauhen Kharuzhy wrote:
> On Thu, Feb 14, 2019 at 05:31:48PM +0100, Hans de Goede wrote:
> > Hi,
> > 
> > On 10-02-19 21:36, Yauhen Kharuzhy wrote:
> > > In some configuration external charge "#charge enable" signal is
> > > connected to PMIC. Enable it at device probing to allow charging.
> > > 
> > > Tested at Lenovo Yoga Book (YB1-X91L).
> > > 
> > > Signed-off-by: Yauhen Kharuzhy <jekhor@gmail.com>
> > > ---
> > >   drivers/extcon/extcon-intel-cht-wc.c | 33 ++++++++++++++++++++++++++++
> > >   1 file changed, 33 insertions(+)
> > > 
> > > diff --git a/drivers/extcon/extcon-intel-cht-wc.c b/drivers/extcon/extcon-intel-cht-wc.c
> > > index 4f6ba249bc30..00cb3084955e 100644
> > > --- a/drivers/extcon/extcon-intel-cht-wc.c
> > > +++ b/drivers/extcon/extcon-intel-cht-wc.c
> > > @@ -57,6 +57,11 @@
> > >   #define CHT_WC_USBSRC_TYPE_OTHER	8
> > >   #define CHT_WC_USBSRC_TYPE_DCP_EXTPHY	9
> > > +#define CHT_WC_CHGDISCTRL		0x5e2f
> > > +#define CHT_WC_CHGDISCTRL_CCSM_DIS	0x11
> > > +#define CHT_WC_CHGDISCTRL_CCSM_EN	0x00
> > 
> > Hmm, the enable mask here does not match the enable mask from:
> > 
> > https://github.com/01org/ProductionKernelQuilts/blob/master/uefi/cht-m1stable/patches/EM-Charger-Disable-battery-charging-in-S3-and-enable.patch
> > 
> > Which has:
> > 
> > #define CHGDISFN_EN_CCSM_VAL           0x50
> > #define CHGDISFN_DIS_CCSM_VAL          0x11
> > #define CHGDISFN_CCSM_MASK             0x51
> > 
> > Where as on my hardware, the PMIC comes up with 0x50
> > in the 0x5e2f register, exactly matching the values
> > from that patch.
> > 
> > Why did you change this value ?
> 
> Good question... I found this values in Lenovo's sources and use them
> 'as is':
> https://github.com/jekhor/yogabook-linux-android-kernel/blob/b7aa015ab794b516da7b6cb76e5e2d427e3b8b0c/drivers/power/intel_pmic_ccsm.h#L255
> 
> I don't remember if charger worked with Intel's value, I need to
> re-check this.

As we know now, value 0x50 meaning is:
- HW mode
- regular output type
- low level at output

0x00 meaning is:
- SW mode
- open-drain output
- low level at output

I don't know what exactly "HW/SW mode" means but I suppose that this pin
can be controlled by PMIC internal charge state algorithm (if it is
enabled) or by software (extcon driver).

So, if we set 0x50 value and disable HW-controlled charging entirely (as
extcon driver does), we don't set 'charger enable' signal to low as
expected. Its exactly state is unknown, but I checked – it is HIGH.
Charger doesn't start charging with this value and starts with 0x00.

0x0b register of 0x6b device on bus 7 – it is the status register of BQ25892
charger, where bits 3,4 describe charging state, 10b means fast charging,
00b means not charging.

root@yogabook:/home/jek# i2cset -y -f 6 0x5e 0x2f 0x00
root@yogabook:/home/jek# i2cget -y -f 7 0x6b 0x0b
0x16
root@yogabook:/home/jek# i2cset -y -f 6 0x5e 0x2f 0x01
root@yogabook:/home/jek# i2cget -y -f 7 0x6b 0x0b
0x06
root@yogabook:/home/jek# i2cset -y -f 6 0x5e 0x2f 0x10
root@yogabook:/home/jek# i2cget -y -f 7 0x6b 0x0b
0x16
root@yogabook:/home/jek# i2cset -y -f 6 0x5e 0x2f 0x11
root@yogabook:/home/jek# i2cget -y -f 7 0x6b 0x0b
0x06
root@yogabook:/home/jek# i2cset -y -f 6 0x5e 0x2f 0x50
root@yogabook:/home/jek# i2cget -y -f 7 0x6b 0x0b
0x06
root@yogabook:/home/jek# i2cset -y -f 6 0x5e 0x2f 0x51
root@yogabook:/home/jek# i2cget -y -f 7 0x6b 0x0b
0x06


After reading of Intel's and Lenovo's sources i understood that Intel's
meaning of CHGDISFN_EN_CCSM_VAL is 'enable HW control of charging' and
Lenovo's is 'enable charging'. Lenovo set this value immediately after
probing and after resume, Intel – only after resume. HW-controlled
charging is disabled entirely at probing, so I don't know how Intel's
driver enables charging.

So, I propose:

1) save initial value of CHGDIS register for restoring it at driver
remove (because the extcon-intel-cht-wc driver restores HW control in
cht_wc_extcon_remove()).
2) at driver start, enable SW control of CHGDIS and set its value to 0.
3) at driver removing, restore the saved state.

Q: In theory, enabling of 'charge enable' output without of properly
configuration of external charger can cause some problems (USB overload,
battery overcurrent etc.). I think that there are no such stupidly
designed devices exist but we cannot be sure. What should we do with this?


> 
> > 
> > It would be interesting to get a dump of the
> > charger's i2c registers using i2cdump before
> > and after writing this new value to register
> > 0x5e2f. Note you can simply leave the patch adding
> > the write out of the kernel, and then do:
> > 
> > i2cdump <charger>
> > i2cget -y -f 6 0x5e 0x2f
> > # check 0x00 is the correct val
> > i2cset -y -f 6 0x5e 0x2f 0x00
> > i2cdump <charger>
> > 
> > To see if any reg values of the charger-ic have changed.
> > 
> > Note bus 6 is the right bus for the PMIC on my systems,
> > but it might be different, to find the right bus do:
> > 
> > ls -l /sys/bus/devices/i2c-INT34D3:00
> > 
> > And look at what the i2c bus-number is in that symlink.
> > 
> > 
> > Also can you please provide i2cdump output for the
> > 0x5e and 0x6e devices of the PMIC, preferably from a
> > clean boot, without your patches, so that we can
> > see what the value of the 0x5e2f register is before
> > your code modifies it.
> > 
> > i2cdump -y -f 6 0x5e
> > i2cdump -y -f 6 0x6e

linux-next (5.0.0-rc5-next-20190208+), extcon module is disabled,
charger is connected before power-on:

root@yogabook:/home/jek# i2cdump -f -y 6 0x5e
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 00 ff 00 XX XX 03 00 00 50 00 XX XX 09 XX 00 XX    ...XX?..P.XX?X.X
10: 00 00 4a 01 0b 0b 10 80 01 29 01 XX 00 74 04 1b    ..J??????)?X.t??
20: 06 ff 00 6b 00 6b 0a 03 73 8a 03 ff 6c 6c 00 10    ?..k.k??s??.ll.?
30: 02 0e 00 fe 00 00 03 ff 00 51 01 3b 01 a7 01 62    ??.?..?..Q?;???b
40: 00 42 00 42 00 9f 00 9f 00 9f 00 d2 00 d2 00 d2    .B.B.?.?.?.?.?.?
50: 01 09 00 4d 00 8e 00 d3 01 11 01 56 02 XX XX XX    ??.M.?.????V?XXX
60: XX 02 0b ff 6a 6c 0e 26 34 44 52 60 XX XX XX XX    X??.jl?&4DR`XXXX
70: 00 00 00 00 00 00 00 00 00 00 00 XX XX XX XX XX    ...........XXXXX
80: XX 00 00 00 XX XX 00 00 00 00 00 00 00 00 00 00    X...XX..........
90: 00 XX XX XX XX XX XX ff ff ff ff ff ff ff ff ff    .XXXXXX.........
a0: ff ff XX XX XX XX XX XX 00 00 XX XX XX XX XX XX    ..XXXXXX..XXXXXX
b0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
c0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
d0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
e0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
f0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX

root@yogabook:/home/jek# i2cdump -f -y 6 0x6e
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 01 02 00 00 00 80 00 18 0d XX 11 00 00 80 af 00    ??...?.??X?..??.
10: 00 00 b0 00 1a ff XX 11 XX 60 03 XX 00 XX 15 00    ..?.?.X?X`?X.X?.
20: 00 00 00 0c ac 0b 5a 11 10 0c 1f 18 2b 00 00 XX    ...???Z?????+..X
30: 4a 4a XX 08 09 00 09 01 09 08 08 00 38 XX XX XX    JJX??.?????.8XXX
40: XX XX XX 09 08 XX XX XX XX XX XX XX XX XX XX XX    XXX??XXXXXXXXXXX
50: XX XX XX 0f XX XX 07 00 07 01 01 9b 63 01 07 01    XXX?XX?.????c???
60: XX XX XX 02 06 06 06 00 06 20 00 00 66 00 XX XX    XXX????.? ..f.XX
70: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
80: XX XX XX XX XX XX XX XX XX XX XX 37 XX XX XX XX    XXXXXXXXXXX7XXXX
90: 01 01 XX XX XX 01 XX XX XX 01 01 01 01 00 01 01    ??XXX?XXX????.??
a0: 01 01 01 01 XX XX XX XX XX XX XX XX XX XX XX XX    ????XXXXXXXXXXXX
b0: XX XX XX XX 12 14 ad XX 00 00 00 18 00 XX XX XX    XXXX???X...?.XXX
c0: 1f 1f 1f 14 14 1f 3d 34 3d 33 33 3d 3d 1f 1f 3d    ??????=4=33==??=
d0: 1f 1f 3d 3d XX XX XX XX XX 00 f0 02 05 00 b0 XX    ??==XXXXX.???.?X
e0: XX XX XX 00 00 00 7d 04 XX XX XX XX XX XX XX XX    XXX...}?XXXXXXXX
f0: 81 08 XX XX XX XX XX XX 0f XX 03 06 06 06 2f XX    ??XXXXXX?X????/X

root@yogabook:/home/jek# i2cdump -f -y 6 0x4f
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 06 46 00 00 28 02 00 00 00 00 00 00 00 92 08 04    ?F..(?.......???
10: 00 00 00 00 00 00 00 00 00 00 00 00 00 02 11 52    .............??R
20: 12 00 01 20 b8 10 87 20 b8 10 87 20 b8 10 87 31    ?.? ??? ??? ???1
30: 65 31 65 05 8e 00 20 b8 00 0c 00 38 00 46 00 ff    e1e??. ?.?.8.F..
40: 00 00 00 d8 25 a1 15 12 11 2d 10 fe 10 b8 27 45    ...?%????-????'E
50: 10 87 00 89 06 2f 00 59 00 59 00 59 10 65 10 65    ??.??/.Y.Y.Y?e?e
60: 10 65 05 de 20 b8 20 b8 1f 00 00 00 00 00 00 00    ?e?? ? ??.......
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
80: 00 00 77 07 77 77 77 07 00 00 00 00 00 00 00 00    ..w?www?........
90: 00 00 00 00 00 00 00 00 00 00 00 ff ff ff ff ff    ................
a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff 00 00    ................
b0: 00 00 XX XX XX 00 00 06 00 14 18 3f 3f 2c 3f 3f    ..XXX..?.????,??
c0: 04 1f 1f 04 10 05 00 a8 8e b3 00 1f 04 72 00 83    ??????.???.??r.?
d0: 00 81 17 00 XX 00 00 00 00 00 94 7a b7 XX XX 19    .??.X.....?z?XX?
e0: 06 ff 00 23 3e 3b ff ff 00 02 1f 03 00 08 00 00    ?..#>;...???.?..
f0: 00 00 00 00 00 e9 00 50 00 02 00 01 XX XX 01 00    .....?.P.?.?XX?.


The same, without charger connected:

root@yogabook:/home/jek# i2cdump -f -y 6 0x5e
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 00 ff 00 XX XX 03 00 00 50 00 XX XX 09 XX 00 XX    ...XX?..P.XX?X.X
10: 00 00 4a 01 0b 0b 10 80 01 0b 01 XX 00 74 04 1b    ..J????????X.t??
20: 06 ff 00 6b 00 6b 0a 03 73 43 00 ff 6c 6c 00 10    ?..k.k??sC..ll.?
30: 02 0e 00 fe 00 00 03 ff 00 51 01 3b 01 a7 01 62    ??.?..?..Q?;???b
40: 00 42 00 42 00 9f 00 9f 00 9f 00 d2 00 d2 00 d2    .B.B.?.?.?.?.?.?
50: 01 09 00 4d 00 8e 00 d3 01 11 01 56 02 XX XX XX    ??.M.?.????V?XXX
60: XX 02 0b ff 6a 6c 0e 26 34 44 52 60 XX XX XX XX    X??.jl?&4DR`XXXX
70: 00 00 00 00 00 00 00 00 00 00 00 XX XX XX XX XX    ...........XXXXX
80: XX 00 00 00 XX XX 00 00 00 00 00 00 00 00 00 00    X...XX..........
90: 00 XX XX XX XX XX XX ff ff ff ff ff ff ff ff ff    .XXXXXX.........
a0: ff ff XX XX XX XX XX XX 00 00 XX XX XX XX XX XX    ..XXXXXX..XXXXXX
b0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
c0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
d0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
e0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
f0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
root@yogabook:/home/jek# i2cdump -f -y 6 0x6e
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 01 02 01 05 00 80 00 18 0d XX 10 00 00 80 af 00    ????.?.??X?..??.
10: 00 00 b0 00 1a ff XX 11 XX 60 03 XX 00 XX 14 00    ..?.?.X?X`?X.X?.
20: 00 00 01 0c ac 0b 5a 11 10 0c 1f 18 2b 00 00 XX    ..????Z?????+..X
30: 4a 4a XX 08 09 00 09 01 09 08 08 00 38 XX XX XX    JJX??.?????.8XXX
40: XX XX XX 09 08 XX XX XX XX XX XX XX XX XX XX XX    XXX??XXXXXXXXXXX
50: XX XX XX 0f XX XX 07 00 07 01 01 9b 63 01 07 01    XXX?XX?.????c???
60: XX XX XX 02 06 06 06 00 06 20 00 00 66 00 XX XX    XXX????.? ..f.XX
70: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
80: XX XX XX XX XX XX XX XX XX XX XX 37 XX XX XX XX    XXXXXXXXXXX7XXXX
90: 01 01 XX XX XX 01 XX XX XX 01 01 01 01 00 01 01    ??XXX?XXX????.??
a0: 01 01 01 01 XX XX XX XX XX XX XX XX XX XX XX XX    ????XXXXXXXXXXXX
b0: XX XX XX XX 12 14 ad XX 00 00 00 18 00 XX XX XX    XXXX???X...?.XXX
c0: 1f 1f 1f 14 14 1f 3d 34 3d 33 33 3d 3d 1f 1f 3d    ??????=4=33==??=
d0: 1f 1f 3d 3d XX XX XX XX XX 00 f0 02 05 00 a0 XX    ??==XXXXX.???.?X
e0: XX XX XX 00 00 00 7d 04 XX XX XX XX XX XX XX XX    XXX...}?XXXXXXXX
f0: 81 08 XX XX XX XX XX XX 0f XX 03 06 06 06 2f XX    ??XXXXXX?X????/X
root@yogabook:/home/jek# i2cdump -f -y 6 0x4f
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 06 46 00 00 a6 02 00 00 00 00 00 00 00 92 08 03    ?F..??.......???
10: 00 00 00 00 00 00 00 00 00 00 00 00 00 02 11 52    .............??R
20: 12 00 01 20 b8 10 87 20 b8 10 87 20 b8 10 87 31    ?.? ??? ??? ???1
30: 65 31 65 05 8e 00 20 b8 00 6f 00 49 00 5f 00 ff    e1e??. ?.o.I._..
40: 00 00 00 d1 25 a1 15 12 11 2d 10 fe 10 b8 27 45    ...?%????-????'E
50: 10 87 00 89 06 2f 00 59 00 59 00 59 10 65 10 65    ??.??/.Y.Y.Y?e?e
60: 10 65 05 de 20 b8 20 b8 08 00 00 00 00 00 00 00    ?e?? ? ??.......
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
80: 00 00 77 07 77 77 77 07 00 00 00 00 00 00 00 00    ..w?www?........
90: 00 00 00 00 00 00 00 00 00 00 00 ff ff ff ff ff    ................
a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff 00 00    ................
b0: 00 00 XX XX XX 00 00 06 00 14 31 3f 3f 2f 3f 3f    ..XXX..?.?1??/??
c0: 04 1f 1f 04 10 05 00 75 8f b3 00 1f 04 72 00 83    ??????.u??.??r.?
d0: 00 81 17 00 XX 00 00 00 00 00 b2 90 7a XX XX 19    .??.X.....??zXX?
e0: 06 ff 00 23 3e 3b ff ff 00 02 1f 03 00 08 00 00    ?..#>;...???.?..
f0: 00 00 00 00 00 9c 00 ac 00 02 00 01 XX XX 01 00    .....?.?.?.?XX?.


The same, with USB hub connected (OTG host mode):

root@yogabook:/home/jek# i2cdump -f -y 6 0x5e
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 00 ff 00 XX XX 03 00 01 50 00 XX XX 09 XX 00 XX    ...XX?.?P.XX?X.X
10: 00 00 4a 01 0b 0b 10 c0 01 0f 01 XX 00 74 04 1b    ..J????????X.t??
20: 06 ff 00 6b 00 6b 0a 2a 73 00 00 ff 6c 6c 00 50    ?..k.k?*s...ll.P
30: 02 0e 00 fe 00 00 03 ff 00 51 01 3b 01 a7 01 62    ??.?..?..Q?;???b
40: 00 42 00 42 00 9f 00 9f 00 9f 00 d2 00 d2 00 d2    .B.B.?.?.?.?.?.?
50: 01 09 00 4d 00 8e 00 d3 01 11 01 56 02 XX XX XX    ??.M.?.????V?XXX
60: XX 02 0b ff 6a 6c 0e 26 34 44 52 60 XX XX XX XX    X??.jl?&4DR`XXXX
70: 00 00 00 00 00 00 00 00 00 00 00 XX XX XX XX XX    ...........XXXXX
80: XX 00 00 00 XX XX 00 00 00 00 00 00 00 00 00 00    X...XX..........
90: 00 XX XX XX XX XX XX ff ff ff ff ff ff ff ff ff    .XXXXXX.........
a0: ff ff XX XX XX XX XX XX 00 00 XX XX XX XX XX XX    ..XXXXXX..XXXXXX
b0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
c0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
d0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
e0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
f0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
root@yogabook:/home/jek# i2cdump -f -y 6 0x6e
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 01 02 01 15 00 00 00 18 0d XX 00 00 00 80 af 00    ????...??X...??.
10: 00 00 b0 00 1a ff XX 11 XX 60 03 XX 00 XX 0d 00    ..?.?.X?X`?X.X?.
20: 00 00 01 0c ac 0b 5a 11 10 0c 1f 18 2b 00 00 XX    ..????Z?????+..X
30: 4a 4a XX 08 09 00 09 01 09 08 08 00 38 XX XX XX    JJX??.?????.8XXX
40: XX XX XX 09 08 XX XX XX XX XX XX XX XX XX XX XX    XXX??XXXXXXXXXXX
50: XX XX XX 0f XX XX 07 00 07 01 01 9b 63 01 07 01    XXX?XX?.????c???
60: XX XX XX 02 06 06 06 00 06 20 00 00 66 00 XX XX    XXX????.? ..f.XX
70: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
80: XX XX XX XX XX XX XX XX XX XX XX 37 XX XX XX XX    XXXXXXXXXXX7XXXX
90: 01 01 XX XX XX 01 XX XX XX 01 01 01 01 00 01 01    ??XXX?XXX????.??
a0: 01 01 01 01 XX XX XX XX XX XX XX XX XX XX XX XX    ????XXXXXXXXXXXX
b0: XX XX XX XX 12 14 ad XX 00 00 00 18 00 XX XX XX    XXXX???X...?.XXX
c0: 1f 1f 1f 14 14 1f 3d 34 3d 33 33 3d 3d 1f 1f 3d    ??????=4=33==??=
d0: 1f 1f 3d 3d XX XX XX XX XX 00 f0 02 05 00 c0 XX    ??==XXXXX.???.?X
e0: XX XX XX 00 00 00 7d 04 XX XX XX XX XX XX XX XX    XXX...}?XXXXXXXX
f0: 81 08 XX XX XX XX XX XX 0f XX 03 06 06 06 2f XX    ??XXXXXX?X????/X
root@yogabook:/home/jek# i2cdump -f -y 6 0x4f
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 06 46 00 00 99 02 00 00 00 00 00 00 00 92 08 04    ?F..??.......???
10: 00 00 00 00 00 00 00 00 00 00 00 00 00 02 11 52    .............??R
20: 12 00 07 20 b8 10 87 20 b8 10 87 20 b8 10 87 31    ?.? ??? ??? ???1
30: 65 31 65 05 8e 00 20 b8 00 d9 00 a2 00 c6 00 ff    e1e??. ?.?.?.?..
40: 00 00 00 cc 25 a1 15 12 11 2d 10 fe 10 b8 27 45    ...?%????-????'E
50: 10 87 00 89 06 2f 00 59 00 59 00 59 10 65 10 65    ??.??/.Y.Y.Y?e?e
60: 10 65 05 de 20 b8 20 b8 08 00 00 00 00 00 00 00    ?e?? ? ??.......
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
80: 00 00 77 07 77 77 77 07 00 00 00 00 00 00 00 00    ..w?www?........
90: 00 00 00 00 00 00 00 00 00 00 00 ff ff ff ff ff    ................
a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff 00 00    ................
b0: 00 00 XX XX XX 00 00 06 00 14 39 3f 3f 36 3f 3f    ..XXX..?.?9??6??
c0: 04 1f 1f 04 10 05 00 21 91 b3 00 1f 04 72 00 83    ??????.!??.??r.?
d0: 00 81 17 00 XX 00 00 00 00 00 b2 92 67 XX XX 19    .??.X.....??gXX?
e0: 06 ff 00 23 3e 3b ff ff 00 02 1f 03 00 08 00 00    ?..#>;...???.?..
f0: 00 00 00 00 00 94 00 99 00 03 00 03 XX XX 01 00    .....?.?.?.?XX?.

-- 
Yauhen Kharuzhy