Re: ad714x driver help and possible bug
From: Jean-François Dagenais
Date: Tue May 03 2011 - 19:51:05 EST
On May 3, 2011, at 11:16 AM, Michael Hennerich wrote:
> On 05/03/2011 04:33 PM, Michael Hennerich wrote:
>> On 05/03/2011 04:13 PM, Jean-Francois Dagenais wrote:
>>
>>> On Apr 29, 2011, at 5:55, Jonathan Cameron wrote:
>>>
>>>
>>>
>>>> Cc'd input, and analog devices driver list...
>>>>
>>>> On 04/28/11 19:17, Jean-Francois Dagenais wrote:
>>>>
>>>>
>>>>> Hi all,
>>>>>
>>>>> I am having trouble getting the ad714x (i2c) driver to work in my
>>>>> test setup. I am using the VGA i2c bus to talk to the ad7147 I have.
>>>>> I used INTA of a PCI ethernet slot in my PC. I enabled the PCI device
>>>>> without the driver module loaded. I then give the interrupt number
>>>>> to ad714x through the struct i2c_board_info. I actually tried the
>>>>> same setup on two PCs, one intel graphics, the other nvidia to
>>>>> eliminate the i2c master as a possible cause of my problem.
>>>>>
>>>>> The device is successfully loaded and I can see the interrupts going.
>>>>> The eventN device created under /dev/input never spit out anything
>>>>> and so I added printks in the threaded ISR handler to see what is
>>>>> going on.
>>>>>
>>>>> I only have a wheel with 8 stages. In ad714x_wheel_state_machine() I
>>>>> see that upon the first interrupt, the state goes from IDLE to
>>>>> JITTER. After this the JITTER case checks that c_state == mask (with
>>>>> mask being 0xff in our case). This condition is never met and the
>>>>> driver stays indefinitely in this state. After lifting my finger from
>>>>> the wheel, the chip settles down to scanning every so many
>>>>> milliseconds.
>>>>>
>>>>> The STAGE_COMPLETE_INT_STATUS is always 0 when my finger is off, but
>>>>> varies a lot while my finger is on (while interrupt frequency is
>>>>> high). Looking at the value of STAGE_COMPLETE_INT_STATUS in binary
>>>>> reveals that the set bits are always in groups, e.g. 0x0007 or 0x001C
>>>>> or 0x0081(I imagine a roll-over of our start_stage-end_stage (0-7)).
>>>>> There seems to be a timing aspect here. I added a spin counter in the
>>>>> threaded ISR to delay reading the 3 registers and that seemed to make
>>>>> the c_state change a little.
>>>>>
>>>>> I modified the code that reads the 3 registers right after the
>>>>> mutex_lock in ad714x_interrupt_thread so that the
>>>>> STAGE_COMPLETE_INT_STATUS is read before the other two (LOW and HIGH
>>>>> regs). The result was surprising. The COMPLETE reg did read 0xff now
>>>>> and the JITTER case went past the "if(c_state == mask)" but later
>>>>> crashed (divide by 0) in ad714x_wheel_cal_abs_pos() called from the
>>>>> JITTER case.
>>>>>
>>>>>
>>>>> Here's the initial configuration I give the driver:
>>>>>
>>>>> static struct ad714x_wheel_plat wheel_platform_data = {
>>>>> .start_stage = 0, // int start_stage;
>>>>> .end_stage = 7, // int end_stage;
>>>>> .max_coord = 128, // int max_coord;
>>>>> };
>>>>>
>>>>> static struct ad714x_platform_data wheel_dev_platform_data = {
>>>>> .slider_num = 0,
>>>>> .wheel_num = 1,
>>>>> .touchpad_num = 0,
>>>>> .button_num = 0,
>>>>> .slider = 0,
>>>>> .wheel = &wheel_platform_data, // struct ad714x_wheel_plat *wheel;
>>>>> .touchpad = 0, // struct ad714x_touchpad_plat *touchpad;
>>>>> .button = 0, // struct ad714x_button_plat *button;
>>>>> .stage_cfg_reg = { /* unsigned short stage_cfg_reg[STAGE_NUM][STAGE_CFGREG_NUM] */
>>>>> {0xfffe, 0x3fff, 0, 0x2626, 0x3e8, 0x3e8, 0x1388, 0x1388 },
>>>>> {0xfffb, 0x3fff, 0, 0x2626, 0x3e8, 0x3e8, 0x1388, 0x1388 },
>>>>> {0xffef, 0x3fff, 0, 0x2626, 0x3e8, 0x3e8, 0x1388, 0x1388 },
>>>>> {0xffbf, 0x3fff, 0, 0x2626, 0x3e8, 0x3e8, 0x1388, 0x1388 },
>>>>> {0xfeff, 0x3fff, 0, 0x2626, 0x3e8, 0x3e8, 0x1388, 0x1388 },
>>>>> {0xfbff, 0x3fff, 0, 0x2626, 0x3e8, 0x3e8, 0x1388, 0x1388 },
>>>>> {0xefff, 0x3fff, 0, 0x2626, 0x3e8, 0x3e8, 0x1388, 0x1388 },
>>>>> {0xffff, 0x3ffe, 0, 0x2626, 0x3e8, 0x3e8, 0x1388, 0x1388 },
>>>>>
>>>>> {0xffff, 0x3fff, 0, 0x0606, 0x01f4, 0x01f4, 0x0320, 0x0320},
>>>>> {0xffff, 0x3fff, 0, 0x0606, 0x01f4, 0x01f4, 0x0320, 0x0320},
>>>>> {0xffff, 0x3fff, 0, 0x0606, 0x01f4, 0x01f4, 0x0320, 0x0320},
>>>>> {0xffff, 0x3fff, 0, 0x0606, 0x01f4, 0x01f4, 0x0320, 0x0320},
>>>>> },
>>>>> .sys_cfg_reg = {0x027e, 0x00ff, 0x3233, 0x0819, 0x0832, 0x0000, 0x00ff, 0}, /* unsigned short sys_cfg_reg[SYS_CFGREG_NUM] */
>>>>> //.sys_cfg_reg = {0x2b2, 0xfff, 0x3233, 0x819, 0x832, 0xcff, 0xcff, 0x0}, /* unsigned short sys_cfg_reg[SYS_CFGREG_NUM] */
>>>>> };
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>>> I also had to change the request_threaded_irq flags to specify
>>>>> IRQF_ONESHOT so the kernel keeps the interrupt masked while we are
>>>>> running ad714x_interrupt_thread(). Otherwise we were getting storms
>>>>> of interrupts each time only one was requested. I am wondering if
>>>>> this should be pulled back to the mainline kernel?
>>>>>
>>>>> Thanks for pointers and clues!
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>> here's the printk I added to ad714x_wheel_state_machine()
>>>
>>> mask = ((1 << (hw->end_stage + 1)) - 1) - ((1 << hw->start_stage) - 1);
>>>
>>> h_state = ad714x->h_state & mask;
>>> c_state = ad714x->c_state & mask;
>>> dev_dbg(ad714x->dev, "interrupt state:%d mask:0x%x l:0x%x h:0x%x c:0x%x\n",
>>> sw->state,
>>> (u32)mask,
>>> (u32)ad714x->l_state,
>>> (u32)ad714x->h_state,
>>> (u32)ad714x->c_state);
>>>
>>> Here what it looks like upon loading a module which does the i2c_new_device of the AD7147:
>>>
>>> <7>[58302.186886] my-pci-stub 0000:01:04.0: claimed by my platform module PCI stub
>>> <6>[58302.186903] my-pci-stub 0000:01:04.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17
>>> <6>[58302.189815] ad714x_captouch 9-002c: found AD7147(A) captouch, rev:1
>>> <6>[58302.427237] input: Unspecified device as /devices/virtual/input/input8
>>>
>>> [ pause here while my hand goes from my mouse and keyboard to the wheel on the AD7147 ]
>>>
>>> <7>[58311.646183] ad714x_captouch 9-002c: interrupt state:0 mask:0xff l:0x0 h:0x18 c:0x1c
>>> <7>[58311.646192] ad714x_captouch 9-002c: case IDLE in if
>>> <7>[58311.655436] ad714x_captouch 9-002c: wheel 0 touched
>>> <7>[58311.663087] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x18 c:0x7
>>> <7>[58311.674562] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x18 c:0x81
>>> <7>[58311.686803] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x18 c:0x81
>>> <7>[58311.699147] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x18 c:0x81
>>> <7>[58311.711430] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x18 c:0x81
>>> <7>[58311.723585] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x18 c:0x81
>>> <7>[58311.736017] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x38 c:0x81
>>> <7>[58311.748298] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x38 c:0x81
>>> <7>[58311.760581] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x38 c:0x81
>>> <7>[58311.772800] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x38 c:0x81
>>> <7>[58311.785176] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x38 c:0x81
>>> <7>[58311.797473] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x38 c:0x81
>>> <7>[58311.809651] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x10 c:0x81
>>>
>>> [ here I lift my finger ]
>>>
>>> <7>[58311.822059] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x0 c:0x81
>>> <7>[58311.834345] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x0 c:0x81
>>> <7>[58311.846582] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x0 c:0x81
>>> <7>[58311.858800] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x0 c:0x81
>>> <7>[58311.871212] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x0 c:0x81
>>> <7>[58311.883517] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x0 c:0x81
>>> <7>[58311.895802] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x0 c:0x81
>>> <7>[58311.908099] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x0 c:0x81
>>> <7>[58311.920381] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x0 c:0x81
>>> <7>[58311.932585] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x0 c:0x81
>>>
>>> [...]
>>>
>>> <7>[58313.432218] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x0 c:0x81
>>> <7>[58314.157343] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x0 c:0x81
>>>
>>> [... after 2 seconds or so, the rhythm slows down to 2 interrupts per second or so ]
>>>
>>> <7>[58314.169629] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x0 c:0x80
>>>
>>> <7>[58314.976518] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x0 c:0x80
>>>
>>> <7>[58315.783342] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x0 c:0x80
>>>
>>>
>>> There is a clue in what I did next. I added a wait time in the isr thread function like so:
>>>
>>> static irqreturn_t ad714x_interrupt_thread(int irq, void *data)
>>> {
>>> struct ad714x_chip *ad714x = data;
>>> volatile int i;
>>>
>>> mutex_lock(&ad714x->mutex);
>>>
>>> i=0xffffff;
>>> while(i)
>>> --i;
>>>
>>> ad714x->read(ad714x->dev, STG_LOW_INT_STA_REG, &ad714x->l_state);
>>> ad714x->read(ad714x->dev, STG_HIGH_INT_STA_REG, &ad714x->h_state);
>>> ad714x->read(ad714x->dev, STG_COM_INT_STA_REG, &ad714x->c_state);
>>> [ ... ]
>>>
>>> this changes the above trace to these values:
>>>
>>> while touching the wheel:
>>> <7>[63085.414268] ad714x_captouch 9-002c: interrupt state:0 mask:0xff l:0x0 h:0x70 c:0x60
>>> <7>[63085.414277] ad714x_captouch 9-002c: case IDLE in if
>>> <7>[63085.423519] ad714x_captouch 9-002c: wheel 0 touched
>>> <7>[63085.578931] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x70 c:0x18
>>> <7>[63085.736079] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x70 c:0x3
>>> <7>[63085.832304] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x70 c:0x60
>>> <7>[63086.938334] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x30 c:0x60
>>> <7>[63087.030835] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x38 c:0x60
>>> <7>[63087.122909] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x38 c:0x60
>>> <7>[63087.215014] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x38 c:0x60
>>> <7>[63087.307071] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x38 c:0x60
>>> <7>[63087.399367] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x38 c:0x60
>>> <7>[63087.739386] ad714x_captouch 9-002c: interrupt state:1 mask:0xff l:0x0 h:0x38 c:0x83
>>>
>>> Again, notice the state going from 0 (IDLE) to 1(JITTER), and never entering the "if" in the JITTER case (needs mask == c_state). The HIGH register varies a lot while I move my finger around, but the COMPLETE looks like its always going and being cleared. I mentioned before that reading the COMPLETE status reg before the LOW and HIGH produces completely different results.
>>>
>>> I am suspecting the register configuration we use is off somehow, I will review them thoroughly. Aside from this we are running out of leads here, anyone has input on this?
>>>
>>> Thanks in advance!
>>> JFD
>>>
>>>
>> Hi Jean-Francois,
>>
>> Barry Song, the driver author left ADI quite some time ago
>> I don't have hardware to test things at the moment.
>>
>> The EVAL-AD7147 only has sliders and buttons, so I don't know how useful
>> it will be here.
>> Need to check if I can find one having a wheel.
>>
>>
> Hi Jean-Francois,
>
> The ADZS-BFLLCD-EZEXT features a AD7147-1 + wheel.
> I'll take a look and get back to you later this week.
>
Hi again Michael,
I forgot to mention something that may be useful. We wired the 8 stages exactly like the wheel example of figure 26, page 15, of the AD7147 datasheet (Rev B, 07/2009). The register configuration I pasted above in the init structures should match this.
Thanks again for your support.
> --
> Greetings,
> Michael
>
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