staging: comedi: skel: use the pci id_table 'driver_data'

Create an enum to the boardinfo and pass that enum in the pci_driver
id_table as the driver_data.

Change the macro used to fill in the device table from PCI_DEVICE()
to PCI_VDEVICE(). This allows passing the enum as the next field.

This allows removing the 'devid' data from the boardinfo as well the
search function that was used to locate the boardinfo for the PCI
device.

Cleanup some of the comments to describe the usage of the 'context'
in the (*auto_attach).
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/skel.c

@@ -90,25 +90,27 @@ Configuration Options:
  * boards in this way is optional, and completely driver-dependent.
  * Some drivers use arrays such as this, other do not.
  */
+enum skel_boardid {
+	BOARD_SKEL100,
+	BOARD_SKEL200,
+};
+
 struct skel_board {
 	const char *name;
-	unsigned int devid;
 	int ai_chans;
 	int ai_bits;
 	int have_dio;
 };
 
 static const struct skel_board skel_boards[] = {
-	{
+	[BOARD_SKEL100] = {
 	 .name = "skel-100",
-	 .devid = 0x100,
 	 .ai_chans = 16,
 	 .ai_bits = 12,
 	 .have_dio = 1,
 	 },
-	{
+	[BOARD_SKEL200] = {
 	 .name = "skel-200",
-	 .devid = 0x200,
 	 .ai_chans = 8,
 	 .ai_bits = 16,
 	 .have_dio = 0,
@@ -394,22 +396,6 @@ static int skel_dio_insn_config(struct comedi_device *dev,
 	return insn->n;
 }
 
-static const struct skel_board *skel_find_pci_board(struct pci_dev *pcidev)
-{
-	unsigned int i;
-
-/*
- * This example code assumes all the entries in skel_boards[] are PCI boards
- * and all use the same PCI vendor ID.  If skel_boards[] contains a mixture
- * of PCI and non-PCI boards, this loop should skip over the non-PCI boards.
- */
-	for (i = 0; i < ARRAY_SIZE(skel_boards); i++)
-		if (/* skel_boards[i].bustype == pci_bustype && */
-		    pcidev->device == skel_boards[i].devid)
-			return &skel_boards[i];
-	return NULL;
-}
-
 /*
  * Handle common part of skel_attach() and skel_auto_attach().
  */
@@ -541,16 +527,13 @@ static int skel_attach(struct comedi_device *dev, struct comedi_devconfig *it)
  * comedi_usb_auto_config(), etc.) to handle devices that can be attached
  * to the Comedi core automatically without the COMEDI_DEVCONFIG ioctl.
  *
- * The context parameter is usually unused, but if the driver called
- * comedi_auto_config() directly instead of the comedi_pci_auto_config()
- * wrapper function, this will be a copy of the context passed to
- * comedi_auto_config().
+ * The context parameter is driver dependent.
  */
 static int skel_auto_attach(struct comedi_device *dev,
-				      unsigned long context)
+			    unsigned long context)
 {
 	struct pci_dev *pcidev = comedi_to_pci_dev(dev);
-	const struct skel_board *thisboard;
+	const struct skel_board *thisboard = NULL;
 	struct skel_private *devpriv;
 	int ret;
 
@@ -558,12 +541,18 @@ static int skel_auto_attach(struct comedi_device *dev,
 	if (!IS_ENABLED(CONFIG_COMEDI_PCI_DRIVERS))
 		return -EINVAL;
 
-	/* Find a matching board in skel_boards[]. */
-	thisboard = skel_find_pci_board(pcidev);
-	if (!thisboard) {
-		dev_err(dev->class_dev, "BUG! cannot determine board type!\n");
-		return -EINVAL;
-	}
+	/*
+	 * In this example, the _auto_attach is for a PCI device.
+	 *
+	 * The 'context' passed to this function is the id->driver_data
+	 * associated with the PCI device found in the id_table during
+	 * the modprobe. This 'context' is the index of the entry in
+	 * skel_boards[i] that contains the boardinfo for the PCI device.
+	 */
+	if (context < ARRAY_SIZE(skel_boards))
+		thisboard = &skel_boards[context];
+	if (!thisboard)
+		return -ENODEV;
 
 	/*
 	 * Point the struct comedi_device to the matching board info
@@ -706,8 +695,8 @@ static int skel_pci_probe(struct pci_dev *dev,
  * Should only be used for PCI and ISA-PnP devices
  */
 static DEFINE_PCI_DEVICE_TABLE(skel_pci_table) = {
-	{ PCI_DEVICE(PCI_VENDOR_ID_SKEL, 0x0100) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_SKEL, 0x0200) },
+	{ PCI_VDEVICE(SKEL, 0x0100), BOARD_SKEL100 },
+	{ PCI_VDEVICE(SKEL, 0x0200), BOARD_SKEL200 },
 	{ 0 }
 };
 MODULE_DEVICE_TABLE(pci, skel_pci_table);