On 12/03/13 17:12, Ian Abbott wrote:
Advantech has their own Linux (non-Comedi) driver for the PCI-1753 which
detects whether the PCI-1753E expansion card is connected to the
PCI-1753 by fiddling with the control register of an emulated 8255 chip
in the address space of the expansion card. The test doesn't actually
seem to make much sense for a _real_ 8255 chip, but let's assume it
works for whatever hardware is on this board.
I messed up there. Advantech's test uses register offset 53 whereas my
test used register offset PCI1753E_DIO + 3 == 32 + 3 == 35. Offset 53
is not a register of any of the 8255 chips. The braino occurred when I
converted 53 to hex 35, saw that as 0x32 + 3, noticed that PCI1753E_DIO
was 32, but failed to notice the different radix. Oops.
+unsigned long pci_dio_detect_pci1753e(struct pci_dev *pcidev,
+ unsigned long cardtype)
+{
+ if (cardtype != TYPE_PCI1753)
+ return cardtype;
+
+ /*
+ * Change cardtype from TYPE_PCI1753 to TYPE_PCI1753E if expansion
+ * board available. Need to enable PCI device temporarily to perform
+ * the test.
+ */
+ if (comedi_pci_enable(pcidev, "adv_pci_dio") == 0) {
+ /*
+ * This test is based on Advantech's "advdaq" driver source
+ * (which declares its module licence as "GPL" although the
+ * driver source does not include a "COPYING" file). The test
+ * does not make a lot of sense for a real 8255 chip as the
+ * 8255 "single bit set/reset" commands used below shouldn't
+ * affect the values read back from the 8255 command register.
+ * However, the board only claims to emulate 8255 mode 0 and
+ * is not using real 8255 chips. I assume Advantech know what
+ * they are doing in their own driver. -- Ian Abbott
+ */
+ unsigned long cr = pci_resource_start(pcidev, PCIDIO_MAINREG) +
+ PCI1753E_DIO + 3;
I should just use offset 53 (from resource start) there and fix the
remark about it not making sense. It makes perfect sense for a
non-8255, custom register!
+
+ outb(0x05, cr);
+ if ((inb(cr) & 0x07) == 0x02) {
+ outb(0x02, cr);
+ if ((inb(cr) & 0x07) == 0x05)
+ cardtype = TYPE_PCI1753E;
+ }
+ comedi_pci_disable(pcidev);
+ }
+ return cardtype;
+}
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@xxxxxxxxx> )=-
-=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
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