Message-ID: <576D7A25.1040000@ti.com>
Date:	Fri, 24 Jun 2016 13:21:25 -0500
From:	Nishanth Menon <nm@...com>
To:	Guenter Roeck <linux@...ck-us.net>
CC:	Jean Delvare <jdelvare@...e.com>, <linux-hwmon@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/5] hwmon: (tmp102) Use devm_add_action to register
 cleanup function

On 06/24/2016 01:18 PM, Guenter Roeck wrote:
> On Fri, Jun 24, 2016 at 01:02:32PM -0500, Nishanth Menon wrote:
>> On 06/24/2016 11:36 AM, Guenter Roeck wrote:
>>> On Fri, Jun 24, 2016 at 10:23:10AM -0500, Nishanth Menon wrote:
>>>> On 06/24/2016 09:54 AM, Guenter Roeck wrote:
>>>>> On 06/24/2016 07:30 AM, Guenter Roeck wrote:
>>>>>> Hi Nishanth,
>>>>>>
>>>>>> On 06/24/2016 07:13 AM, Nishanth Menon wrote:
>>>>>>> On 06/23/2016 07:28 PM, Guenter Roeck wrote:
>>>>>>>> By registering a cleanup function with devm_add_action(), we can
>>>>>>>> simplify the error path in the probe function and drop the remove
>>>>>>>> function entirely.
>>>>>>>>
>>>>>>>> Signed-off-by: Guenter Roeck <linux@...ck-us.net>
>>>>>>>
>>>>>>> I dont seem to have a cover letter to reply to... but anyways..
>>>>>>>
>>>>>>> Before: http://pastebin.ubuntu.com/17801376/
>>>>>>> After all 5 patches: http://pastebin.ubuntu.com/17801824/
>>>>>>>
>>>>>>> Fails on beagleboard-X15 with:
>>>>>>> [   36.781509] tmp102 0-0048: No cache defaults, reading back from HW
>>>>>>> [   36.795940] tmp102 0-0048: unexpected config register value
>>>>>>>
>>>>>>> I have'nt bisected down on the specific patch in the series. Have you had a chance to test the series?
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> Thanks for testing. Yes, I did test it. Maybe different chip revisions, or different
>>>>>> initial config register values and I messed up there. Can you send me the output
>>>>>> of i2cdump (word wide) ?
>>>>>>
>>>>>
>>>>> Before 5 patches:
>>>>>> # i2cdump -f 0 0x48 w
>>>>>>      0,8  1,9  2,a  3,b  4,c  5,d  6,e  7,f
>>>>>> 00: 7912 b062 004b 0050 c018 e006 0000 0000 
>>>
>>> [ ... ]
>>>>>
>>>>> After 5 patches:
>>>>>>  i2cdump -y 0 0x48 w
>>>>>>      0,8  1,9  2,a  3,b  4,c  5,d  6,e  7,f
>>>>>> 00: 5024 a060 004b 0050 c018 e006 0000 0000 
>>>
>>> [ .... ]
>>>
>>>> I can try and debug the series once I get some spare time, might be
>>>> over the weekend or next week.
>>>
>>> The register map, at least the initial one, is pretty much the same as mine
>>> and as expected. The configuration register in the second map is messed up,
>>> possible because of a write with wrong endianness.
>>
>> Got a few mins skipping lunch.. ;)
>>
>> I did a quick bisect, and it is indeed the patch #5 that breaks.
>> added http://pastebin.ubuntu.com/17812044/ and got:
>>
>> tmp102 0-0048: regval = 0x0000ffff
>>
>> That was weird. Does'nt look like endian-ness swap thingy
>>
>> So, did the following hack to see all messages flowing in and out from
>> 0x48 at bus controller driver level: http://pastebin.ubuntu.com/17813093/
>> / # dmesg|grep XXX
>> / #
>>
>> Before patch #5 (and on next-20160624):
>> the same diff gave:
>> http://pastebin.ubuntu.com/17813303/
>>
>>
>>
>>> I bet the regmap_read() of the configuration register returns 0xa060 (or
>>> 0xb062) instead of 0x60a0 / 0x62b0 on your system. If you find the time,
>>> it would be great if you can confirm by printing the register value with
>>> the "unexpected config register value" message (guess I should have left
>>> that in place - I used it during testing ;-).
>>>
>>> If that is the case, I'll probably have to drop the regmap changes, at least
>>> for now. It would mean that regmap is broken for chips like the LM75 (ie
>>> for all chips with 16-bit registers) on controllers supporting I2C_FUNC_I2C.
>>
>> It does look like everything is getting cached out and no actual reads
>> are actually getting through to the bus controller driver even.
>>
> Yes, that is really weird. It also seems to fill the cache with 0xffff,
> which is even more weird.
> 
> Ok, looks like converting drivers to regmap isn't a good idea. I'll need
> to get a system with an adapter supporting I2C_FUNC_I2C and do some more
> testing.
> 
>> I tested on next-20160624 and used omap2plus_defconfig for the test.
>>
> 
> Thanks a lot for the information, and for testing this with your system.


here is more:
http://pastebin.ubuntu.com/17814261/

Looks like return for is_writable etc should probably be true or false

[   32.609935] at24 0-0050: 4096 byte 24c32 EEPROM, writable, 1
bytes/write
[   32.751560] rtc-ds1307 2-006f: SET TIME!
[   32.857593] palmas_pwrbutton
48070000.i2c:tps659038@58:tps659038_pwr_button: h/w controlled
shutdown duration=12 s
econds
[   33.047265] rtc-ds1307 2-006f: rtc core: registered mcp7941x as rtc0
[   33.135774] tmp102 0-0048: No cache defaults, reading back from HW
[   33.538655] rtc-ds1307 2-006f: 64 bytes nvram
[   34.202107] omap_rng 48090000.rng: _od_fail_runtime_resume: FIXME:
missing hwmod/omap_dev info
[   34.211191] omap_rng 48090000.rng: Failed to runtime_get device: -19
[   34.217869] omap_rng 48090000.rng: initialization failed.
[   34.229190] omap_rtc 48838000.rtc: rtc core: registered
48838000.rtc as rtc2
[   34.371375] omap_i2c 48070000.i2c: XXX MSG[0]: add=0x0048, len: 1,
flags: 0x0
[   34.378893] omap_i2c 48070000.i2c: XXX:[0] 0x00
/ # [   34.457000] omap_i2c 48070000.i2c: XXX MSG[1]: add=0x0048, len:
8, flags: 0x1
[   34.464476] omap_i2c 48070000.i2c: XXX:[0] 0x23
[   34.469255] omap_i2c 48070000.i2c: XXX:[1] 0xa0
[   34.473999] omap_i2c 48070000.i2c: XXX:[2] 0xff
[   34.478775] omap_i2c 48070000.i2c: XXX:[3] 0xff
[   34.483518] omap_i2c 48070000.i2c: XXX:[4] 0xff
[   34.488282] omap_i2c 48070000.i2c: XXX:[5] 0xff
[   34.493022] omap_i2c 48070000.i2c: XXX:[6] 0xff
[   34.497788] omap_i2c 48070000.i2c: XXX:[7] 0xff


I probably have to stop now, since I am behind on an internal
deadline. Do let me know if you want me to dig further, I can try at a
later time..
-- 
Regards,
Nishanth Menon

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