My board file loads, but with a NULL chip_info when I'm in ACPI mode for LPSS & SCC Devices Mode (so IIUC, the NULL chip_info prevents spi-pxa2xx.c from flipping the polarity on the SS line).
My module will explode when in PCI mode (tried in PCI mode because spi-pxa2xx.c has a comment "Slave devices enumerated from ACPI namespace don't usually have chip_info") with: [ 559.236046] divide error: 0000 [#1] PREEMPT SMP [ 559.241217] Modules linked in: low_speed_spidev(O+) [ 559.246686] CPU: 0 PID: 11980 Comm: insmod Tainted: G O 3.17.0-rc4-yocto-standard+ #13 [ 559.256712] Hardware name: Circuitco MinnowBoard MAX B3 PLATFORM/MinnowBoard MAX, BIOS MNW2MAX1.X64.0076.R01.1412081258 12/08/2014 [ 559.269850] task: ffff880073e5dfc0 ti: ffff880078f30000 task.ti: ffff880078f30000 [ 559.278222] RIP: 0010:[<ffffffff8148c57d>] [<ffffffff8148c57d>] ssp_get_clk_div+0x3b/0x4a [ 559.287481] RSP: 0018:ffff880078f33c80 EFLAGS: 00010246 [ 559.293422] RAX: 0000000000000000 RBX: ffff880073f4b660 RCX: 000000000000003f [ 559.301405] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff880073e54428 [ 559.309388] RBP: ffff880078f33c80 R08: 00000000000000df R09: ffffffff82075580 [ 559.317370] R10: 0000000000000000 R11: 0000000000000000 R12: ffff880078578400 [ 559.325353] R13: 0000000000000000 R14: ffff880073e54428 R15: 0000000000002710 [ 559.333338] FS: 00007f8296dcd700(0000) GS:ffff880079200000(0000) knlGS:0000000000000000 [ 559.342392] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 559.348819] CR2: 00007f8296dc9000 CR3: 000000007418b000 CR4: 00000000001007f0 [ 559.356801] Stack: [ 559.359046] ffff880078f33cc0 ffffffff8148caa8 000000e000000040 ffff880078578400 [ 559.367334] 0000000000000000 0000000000000000 ffff880073e54000 0000000000000000 [ 559.375628] ffff880078f33d10 ffffffff814888e6 0000000000000000 ffff880078f33d10 [ 559.383923] Call Trace: [ 559.386660] [<ffffffff8148caa8>] setup+0x1fb/0x4b8 [ 559.392119] [<ffffffff814888e6>] spi_setup+0xfd/0x1ad [ 559.397871] [<ffffffff8143b32f>] ? bus_for_each_dev+0x63/0x85 [ 559.404399] [<ffffffff81488aa4>] spi_add_device+0x10e/0x1a6 [ 559.410732] [<ffffffff81489062>] spi_new_device+0xb5/0xcb [ 559.416874] [<ffffffffa00030bf>] low_speed_spidev_module_init+0xbf/0x133 [low_speed_spidev] [ 559.426318] [<ffffffffa0003000>] ? 0xffffffffa0003000 [ 559.432070] [<ffffffff8100032d>] do_one_initcall+0xff/0x185 [ 559.438404] [<ffffffff8110172a>] ? __vunmap+0xa9/0xaf [ 559.444155] [<ffffffff8108e4fb>] load_module+0x1756/0x1ef0 [ 559.450392] [<ffffffff8108bfd3>] ? free_modinfo_version+0x27/0x27 [ 559.457311] [<ffffffff8108ed57>] SyS_init_module+0xc2/0xcf [ 559.463550] [<ffffffff8175fed2>] system_call_fastpath+0x16/0x1b I notice the below that sounds a little curious when I'm in PCI mode (these are present for other devices, but from looking at /sys/class/spi_master it seems that pci0000:00/0000:00:1e.5 is the pxa2xx). [ 1.282369] pci 0000:00:1e.5: BAR 0: reserving [mem 0x9093c000-0x9093cfff flags 0x40200] (d=0, p=0) [ 1.282377] pci 0000:00:1e.5: can't claim BAR 0 [mem 0x9093c000-0x9093cfff]: no compatible bridge window [ 1.292998] pci 0000:00:1e.5: BAR 1: reserving [mem 0x9093d000-0x9093dfff flags 0x40200] (d=0, p=0) [ 1.293007] pci 0000:00:1e.5: can't claim BAR 1 [mem 0x9093d000-0x9093dfff]: no compatible bridge window On Wed, Jan 28, 2015 at 4:19 PM, Kevin Shelton <[email protected]> wrote: > through liberal sprinkling of printks I find that when spi_new_device > gets called in my board file, eventually setup_cs gets called in > drivers/spi/spi-pxa2xx.c, but setup_cs returns before it can set > gpio_cs_inverted because chip_info is NULL > > Should board files define a pxa2xx_spi_chip struct (I see this done in > arch/arm/mach-pxa/hx4700.c)? > > Am I correct in calling hx4700.c a board file? > > On Tue, Jan 27, 2015 at 9:21 PM, Darren Hart <[email protected]> wrote: >> This changes the mechanism used to enumerate the hardware device to the >> OS. Recent Linux kernels 3.16+ support for ACPI and PCI enumeration. ACPI >> is supported since 3.14. Either should work for a board-file. >> >> -- >> Darren >> >> >> On 1/27/15, 3:13 PM, "Kevin Shelton" <[email protected]> wrote: >> >>>sorry for the not clear writing: I meant to say ACPI mode for the >>>"LPSS & SCC Devices Mode" setting >>> >>>On Tue, Jan 27, 2015 at 3:11 PM, Kevin Shelton <[email protected]> >>>wrote: >>>> I realized that in my BIOS settings, I was in ACPI mode. Do I need to >>>> be in PCI mode to use a board file? What does that ACPI-PCI switch in >>>> the BIOS do? thanks for all the help >>>> >>>> On Mon, Jan 26, 2015 at 11:35 PM, Darren Hart <[email protected]> >>>>wrote: >>>>> The SPI bus controlled by the pxa2xx driver is on the LPSS, which, yes, >>>>> corresponds to the Low Power IO Controller in that block diagram. >>>>> >>>>> On 1/26/15, 10:38 PM, "Kevin Shelton" <[email protected]> wrote: >>>>> >>>>>>Thanks John and Darren. I will play with spid_devtest and have >>>>>>reached out to [email protected]. >>>>>> >>>>>>A minnowmax-specific question: In the Baytrail block diagram at >>>>>>http://media.bestofmicro.com/Y/3/400395/original/bay-trail-soc.jpg >>>>>>does the Marvell pxa27x correspond to the "Low Power IO Controller"? >>>>>> >>>>>>On Mon, Jan 26, 2015 at 6:33 PM, Darren Hart <[email protected]> >>>>>>wrote: >>>>>>> On 1/26/15, 5:52 PM, "John Hawley" <[email protected]> wrote: >>>>>>> >>>>>>>>On 01/26/2015 05:47 PM, Kevin Shelton wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> On Fri, Jan 23, 2015 at 2:41 PM, John Hawley <[email protected] >>>>>>>>> <mailto:[email protected]>> wrote: >>>>>>>>> >>>>>>>>> > I saw the thread 'Adding an SPI device to the Minnowboard' >>>>>>>>>from >>>>>>>>>late >>>>>>>>> > 2013 and 'SPI support on minnowboard v1' from Aug 2014. >>>>>>>>> > >>>>>>>>> > Darren Hart notes: >>>>>>>>> > Ultimately we want to do things like this without board >>>>>>>>>files by >>>>>>>>>using >>>>>>>>> > the _DSD mechanisms introduced by the ACPI 5.1 specification >>>>>>>>>last >>>>>>>>>week >>>>>>>>> > >>>>>>>>> > I just wanted to confirm the ACPI mechanism is not the >>>>>>>>>recommended way >>>>>>>>> > yet, and that using low-speed-spidev.c as a template is still >>>>>>>>>the >>>>>>>>>way to go. >>>>>>>>> >>>>>>>>> The answer to that will depend on what kernel you are >>>>>>>>>intending to >>>>>>>>> target. Kernel's with ACPI 5.1 _DSD support, I think you'd >>>>>>>>>want >>>>>>>>>to >>>>>>>>>push >>>>>>>>> on that. Older kernels without that, likely spidev or a more >>>>>>>>>targeted >>>>>>>>> driver. >>>>>>>>> >>>>>>>>> >>>>>>>>> Currently, I am targeting 3.17. 3.17 does not have ACPI 5.1 _DSD >>>>>>>>> support, correct? >>>>>>>> >>>>>>>>Off the top of my head that came in in 3.18, so yes that's correct. >>>>>>> >>>>>>> 3.19 iirc. >>>>>>> >>>>>>> Also, using _DSD required a firmware change, or at least a DSDT >>>>>>>update. >>>>>>> >>>>>>>> >>>>>>>>> > Additional q: >>>>>>>>> > How do you tell the SPI controller that you have an >>>>>>>>>active-high >>>>>>>>>instead >>>>>>>>> > of the usual active-low device? Is it correct to do a >>>>>>>>>bitwise >>>>>>>>>or >>>>>>>>>with >>>>>>>>> > SPI_CS_HIGH (0x4) with your SPI_MODE in your spi_board_info >>>>>>>>>struct, like: >>>>>>>>> > .mode = SPI_MODE_0 | SPI_CS_HIGH >>>>>>>>> >>>>>>>>> That should work, but take my statement with a grain of salt >>>>>>>>>as I >>>>>>>>> haven't tried it with a device. >>>>>>>>> >>>>>>>>> >>>>>>>>> It seems to have no effect that I can discern. Pin 5 idles at 3.3V >>>>>>>>> whether I have >>>>>>>>> .mode = SPI_MODE_3 | SPI_CS_HIGH >>>>>>>>> -or- >>>>>>>>> .mode = SPI_MODE_3 >>>>>>>>> >>>>>>>>> I threw in a >>>>>>>>> pr_info("SPI mode=%i\n", cod_spi_board_info.mode); >>>>>>>>> to sanity check that I am setting the mode to what I think I am (3 >>>>>>>>>or >>>>>>>>>7). >>>>>>>>> >>>>>>>>> Any debugging ideas? >>>>>>>>> What is the best way to learn more about the SPI master? It's >>>>>>>>>built >>>>>>>>> into the CPU, correct? >>>>>>>>> This smells in the ballpark of >>>>>>>>> relatedness: >>>>>>>>>http://lists.infradead.org/pipermail/linux-arm-kernel/2014-June/2634 >>>>>>>>>67. >>>>>>>>>ht >>>>>>>>>ml >>>>>>>>> I don't grok that patch, but I confirmed my version of pxa2xx.c in >>>>>>>>>my >>>>>>>>> 3.17 tree appears to contain that change. >>>>>>>> >>>>>>>>The SPI interface is indeed built into the CPU. It's the pxa2xx >>>>>>>>core, >>>>>>>>which it looks like you've found. I'd have to punt to someone else, >>>>>>>>as >>>>>>>>I'll admit, I don't know the SPI code well enough to say what's going >>>>>>>>on. I've CC'ed Darren Hart, he might know who to check with next. >>>>>>> >>>>>>> Those are some very specific SPI usage questions that I don't know >>>>>>>the >>>>>>> answer to off the top of my head. To find out, I would: >>>>>>> >>>>>>> 1) Search for other drivers in tree and externally that use >>>>>>>active-high >>>>>>> >>>>>>> First hit looks interesting: >>>>>>> https://www.kernel.org/doc/Documentation/spi/spidev_test.c >>>>>>> >>>>>>> >>>>>>> 2) Lookup the right mailing lists for SPI Linux kernel development >>>>>>>and >>>>>>>ask >>>>>>> the same question there >>>>>>> >>>>>>> -- >>>>>>> Darren Hart >>>>>>> Intel Open Source Technology Center >>>>>>> >>>>>>> >>>>>>> >>>>>>> _______________________________________________ >>>>>>> elinux-MinnowBoard mailing list >>>>>>> [email protected] >>>>>>> http://lists.elinux.org/mailman/listinfo/elinux-minnowboard >>>>>> >>>>> >>>>> >>>>> -- >>>>> Darren Hart >>>>> Intel Open Source Technology Center >>>>> >>>>> >>>>> >>> >> >> >> -- >> Darren Hart >> Intel Open Source Technology Center >> >> >> _______________________________________________ elinux-MinnowBoard mailing list [email protected] http://lists.elinux.org/mailman/listinfo/elinux-minnowboard
